xref: /external/deqp/modules/glshared/glsRasterizationTestUtil.cpp

/*-------------------------------------------------------------------------
 * drawElements Quality Program OpenGL (ES) Module
 * -----------------------------------------------
 *
 * Copyright 2014 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 *
 *//*!
 * \file
 * \brief rasterization test utils.
 *//*--------------------------------------------------------------------*/

#include "glsRasterizationTestUtil.hpp"
#include "tcuVector.hpp"
#include "tcuSurface.hpp"
#include "tcuTestLog.hpp"
#include "tcuTextureUtil.hpp"
#include "tcuVectorUtil.hpp"
#include "tcuFloat.hpp"
#include "deMath.h"

#include "rrRasterizer.hpp"

#include <limits>

namespace deqp
{
namespace gls
{
namespace RasterizationTestUtil
{
namespace
{

bool lineLineIntersect (const tcu::Vector<deInt64, 2>& line0Beg, const tcu::Vector<deInt64, 2>& line0End, const tcu::Vector<deInt64, 2>& line1Beg, const tcu::Vector<deInt64, 2>& line1End)
{
	typedef tcu::Vector<deInt64, 2> I64Vec2;

	// Lines do not intersect if the other line's endpoints are on the same side
	// otherwise, the do intersect

	// Test line 0
	{
		const I64Vec2 line			= line0End - line0Beg;
		const I64Vec2 v0			= line1Beg - line0Beg;
		const I64Vec2 v1			= line1End - line0Beg;
		const deInt64 crossProduct0	= (line.x() * v0.y() - line.y() * v0.x());
		const deInt64 crossProduct1	= (line.x() * v1.y() - line.y() * v1.x());

		// check signs
		if ((crossProduct0 < 0 && crossProduct1 < 0) ||
			(crossProduct0 > 0 && crossProduct1 > 0))
			return false;
	}

	// Test line 1
	{
		const I64Vec2 line			= line1End - line1Beg;
		const I64Vec2 v0			= line0Beg - line1Beg;
		const I64Vec2 v1			= line0End - line1Beg;
		const deInt64 crossProduct0	= (line.x() * v0.y() - line.y() * v0.x());
		const deInt64 crossProduct1	= (line.x() * v1.y() - line.y() * v1.x());

		// check signs
		if ((crossProduct0 < 0 && crossProduct1 < 0) ||
			(crossProduct0 > 0 && crossProduct1 > 0))
			return false;
	}

	return true;
}

bool isTriangleClockwise (const tcu::Vec4& p0, const tcu::Vec4& p1, const tcu::Vec4& p2)
{
	const tcu::Vec2	u				(p1.x() / p1.w() - p0.x() / p0.w(), p1.y() / p1.w() - p0.y() / p0.w());
	const tcu::Vec2	v				(p2.x() / p2.w() - p0.x() / p0.w(), p2.y() / p2.w() - p0.y() / p0.w());
	const float		crossProduct	= (u.x() * v.y() - u.y() * v.x());

	return crossProduct > 0.0f;
}

bool compareColors (const tcu::RGBA& colorA, const tcu::RGBA& colorB, int redBits, int greenBits, int blueBits)
{
	const int thresholdRed		= 1 << (8 - redBits);
	const int thresholdGreen	= 1 << (8 - greenBits);
	const int thresholdBlue		= 1 << (8 - blueBits);

	return	deAbs32(colorA.getRed()   - colorB.getRed())   <= thresholdRed   &&
			deAbs32(colorA.getGreen() - colorB.getGreen()) <= thresholdGreen &&
			deAbs32(colorA.getBlue()  - colorB.getBlue())  <= thresholdBlue;
}

bool pixelNearLineSegment (const tcu::IVec2& pixel, const tcu::Vec2& p0, const tcu::Vec2& p1)
{
	const tcu::Vec2 pixelCenterPosition = tcu::Vec2(pixel.x() + 0.5f, pixel.y() + 0.5f);

	// "Near" = Distance from the line to the pixel is less than 2 * pixel_max_radius. (pixel_max_radius = sqrt(2) / 2)
	const float maxPixelDistance		= 1.414f;
	const float maxPixelDistanceSquared	= 2.0f;

	// Near the line
	{
		const tcu::Vec2	line			= p1                  - p0;
		const tcu::Vec2	v				= pixelCenterPosition - p0;
		const float		crossProduct	= (line.x() * v.y() - line.y() * v.x());

		// distance to line: (line x v) / |line|
		//     |(line x v) / |line|| > maxPixelDistance
		// ==> (line x v)^2 / |line|^2 > maxPixelDistance^2
		// ==> (line x v)^2 > maxPixelDistance^2 * |line|^2

		if (crossProduct * crossProduct > maxPixelDistanceSquared * tcu::lengthSquared(line))
			return false;
	}

	// Between the endpoints
	{
		// distance from line endpoint 1 to pixel is less than line length + maxPixelDistance
		const float maxDistance = tcu::length(p1 - p0) + maxPixelDistance;

		if (tcu::length(pixelCenterPosition - p0) > maxDistance)
			return false;
		if (tcu::length(pixelCenterPosition - p1) > maxDistance)
			return false;
	}

	return true;
}

bool pixelOnlyOnASharedEdge (const tcu::IVec2& pixel, const TriangleSceneSpec::SceneTriangle& triangle, const tcu::IVec2& viewportSize)
{
	if (triangle.sharedEdge[0] || triangle.sharedEdge[1] || triangle.sharedEdge[2])
	{
		const tcu::Vec2 triangleNormalizedDeviceSpace[3] =
		{
			tcu::Vec2(triangle.positions[0].x() / triangle.positions[0].w(), triangle.positions[0].y() / triangle.positions[0].w()),
			tcu::Vec2(triangle.positions[1].x() / triangle.positions[1].w(), triangle.positions[1].y() / triangle.positions[1].w()),
			tcu::Vec2(triangle.positions[2].x() / triangle.positions[2].w(), triangle.positions[2].y() / triangle.positions[2].w()),
		};
		const tcu::Vec2 triangleScreenSpace[3] =
		{
			(triangleNormalizedDeviceSpace[0] + tcu::Vec2(1.0f, 1.0f)) * 0.5f * tcu::Vec2((float)viewportSize.x(), (float)viewportSize.y()),
			(triangleNormalizedDeviceSpace[1] + tcu::Vec2(1.0f, 1.0f)) * 0.5f * tcu::Vec2((float)viewportSize.x(), (float)viewportSize.y()),
			(triangleNormalizedDeviceSpace[2] + tcu::Vec2(1.0f, 1.0f)) * 0.5f * tcu::Vec2((float)viewportSize.x(), (float)viewportSize.y()),
		};

		const bool pixelOnEdge0 = pixelNearLineSegment(pixel, triangleScreenSpace[0], triangleScreenSpace[1]);
		const bool pixelOnEdge1 = pixelNearLineSegment(pixel, triangleScreenSpace[1], triangleScreenSpace[2]);
		const bool pixelOnEdge2 = pixelNearLineSegment(pixel, triangleScreenSpace[2], triangleScreenSpace[0]);

		// If the pixel is on a multiple edges return false

		if (pixelOnEdge0 && !pixelOnEdge1 && !pixelOnEdge2)
			return triangle.sharedEdge[0];
		if (!pixelOnEdge0 && pixelOnEdge1 && !pixelOnEdge2)
			return triangle.sharedEdge[1];
		if (!pixelOnEdge0 && !pixelOnEdge1 && pixelOnEdge2)
			return triangle.sharedEdge[2];
	}

	return false;
}

float triangleArea (const tcu::Vec2& s0, const tcu::Vec2& s1, const tcu::Vec2& s2)
{
	const tcu::Vec2	u				(s1.x() - s0.x(), s1.y() - s0.y());
	const tcu::Vec2	v				(s2.x() - s0.x(), s2.y() - s0.y());
	const float		crossProduct	= (u.x() * v.y() - u.y() * v.x());

	return crossProduct / 2.0f;
}

tcu::IVec4 getTriangleAABB (const TriangleSceneSpec::SceneTriangle& triangle, const tcu::IVec2& viewportSize)
{
	const tcu::Vec2 normalizedDeviceSpace[3] =
	{
		tcu::Vec2(triangle.positions[0].x() / triangle.positions[0].w(), triangle.positions[0].y() / triangle.positions[0].w()),
		tcu::Vec2(triangle.positions[1].x() / triangle.positions[1].w(), triangle.positions[1].y() / triangle.positions[1].w()),
		tcu::Vec2(triangle.positions[2].x() / triangle.positions[2].w(), triangle.positions[2].y() / triangle.positions[2].w()),
	};
	const tcu::Vec2 screenSpace[3] =
	{
		(normalizedDeviceSpace[0] + tcu::Vec2(1.0f, 1.0f)) * 0.5f * tcu::Vec2((float)viewportSize.x(), (float)viewportSize.y()),
		(normalizedDeviceSpace[1] + tcu::Vec2(1.0f, 1.0f)) * 0.5f * tcu::Vec2((float)viewportSize.x(), (float)viewportSize.y()),
		(normalizedDeviceSpace[2] + tcu::Vec2(1.0f, 1.0f)) * 0.5f * tcu::Vec2((float)viewportSize.x(), (float)viewportSize.y()),
	};

	tcu::IVec4 aabb;

	aabb.x() = (int)deFloatFloor(de::min(de::min(screenSpace[0].x(), screenSpace[1].x()), screenSpace[2].x()));
	aabb.y() = (int)deFloatFloor(de::min(de::min(screenSpace[0].y(), screenSpace[1].y()), screenSpace[2].y()));
	aabb.z() = (int)deFloatCeil (de::max(de::max(screenSpace[0].x(), screenSpace[1].x()), screenSpace[2].x()));
	aabb.w() = (int)deFloatCeil (de::max(de::max(screenSpace[0].y(), screenSpace[1].y()), screenSpace[2].y()));

	return aabb;
}

float getExponentEpsilonFromULP (int valueExponent, deUint32 ulp)
{
	DE_ASSERT(ulp < (1u<<10));

	// assume mediump precision, using ulp as ulps in a 10 bit mantissa
	return tcu::Float32::construct(+1, valueExponent, (1u<<23) + (ulp << (23 - 10))).asFloat() - tcu::Float32::construct(+1, valueExponent, (1u<<23)).asFloat();
}

float getValueEpsilonFromULP (float value, deUint32 ulp)
{
	DE_ASSERT(value != std::numeric_limits<float>::infinity() && value != -std::numeric_limits<float>::infinity());

	const int exponent = tcu::Float32(value).exponent();
	return getExponentEpsilonFromULP(exponent, ulp);
}

float getMaxValueWithinError (float value, deUint32 ulp)
{
	if (value == std::numeric_limits<float>::infinity() || value == -std::numeric_limits<float>::infinity())
		return value;

	return value + getValueEpsilonFromULP(value, ulp);
}

float getMinValueWithinError (float value, deUint32 ulp)
{
	if (value == std::numeric_limits<float>::infinity() || value == -std::numeric_limits<float>::infinity())
		return value;

	return value - getValueEpsilonFromULP(value, ulp);
}

float getMinFlushToZero (float value)
{
	// flush to zero if that decreases the value
	// assume mediump precision
	if (value > 0.0f && value < tcu::Float32::construct(+1, -14, 1u<<23).asFloat())
		return 0.0f;
	return value;
}

float getMaxFlushToZero (float value)
{
	// flush to zero if that increases the value
	// assume mediump precision
	if (value < 0.0f && value > tcu::Float32::construct(-1, -14, 1u<<23).asFloat())
		return 0.0f;
	return value;
}

tcu::IVec3 convertRGB8ToNativeFormat (const tcu::RGBA& color, const RasterizationArguments& args)
{
	tcu::IVec3 pixelNativeColor;

	for (int channelNdx = 0; channelNdx < 3; ++channelNdx)
	{
		const int channelBitCount	= (channelNdx == 0) ? (args.redBits) : (channelNdx == 1) ? (args.greenBits) : (args.blueBits);
		const int channelPixelValue	= (channelNdx == 0) ? (color.getRed()) : (channelNdx == 1) ? (color.getGreen()) : (color.getBlue());

		if (channelBitCount <= 8)
			pixelNativeColor[channelNdx] = channelPixelValue >> (8 - channelBitCount);
		else if (channelBitCount == 8)
			pixelNativeColor[channelNdx] = channelPixelValue;
		else
		{
			// just in case someone comes up with 8+ bits framebuffers pixel formats. But as
			// we can only read in rgba8, we have to guess the trailing bits. Guessing 0.
			pixelNativeColor[channelNdx] = channelPixelValue << (channelBitCount - 8);
		}
	}

	return pixelNativeColor;
}

/*--------------------------------------------------------------------*//*!
 * Returns the maximum value of x / y, where x c [minDividend, maxDividend]
 * and y c [minDivisor, maxDivisor]
 *//*--------------------------------------------------------------------*/
float maximalRangeDivision (float minDividend, float maxDividend, float minDivisor, float maxDivisor)
{
	DE_ASSERT(minDividend <= maxDividend);
	DE_ASSERT(minDivisor <= maxDivisor);

	// special cases
	if (minDividend == 0.0f && maxDividend == 0.0f)
		return 0.0f;
	if (minDivisor <= 0.0f && maxDivisor >= 0.0f)
		return std::numeric_limits<float>::infinity();

	return de::max(de::max(minDividend / minDivisor, minDividend / maxDivisor), de::max(maxDividend / minDivisor, maxDividend / maxDivisor));
}

/*--------------------------------------------------------------------*//*!
 * Returns the minimum value of x / y, where x c [minDividend, maxDividend]
 * and y c [minDivisor, maxDivisor]
 *//*--------------------------------------------------------------------*/
float minimalRangeDivision (float minDividend, float maxDividend, float minDivisor, float maxDivisor)
{
	DE_ASSERT(minDividend <= maxDividend);
	DE_ASSERT(minDivisor <= maxDivisor);

	// special cases
	if (minDividend == 0.0f && maxDividend == 0.0f)
		return 0.0f;
	if (minDivisor <= 0.0f && maxDivisor >= 0.0f)
		return -std::numeric_limits<float>::infinity();

	return de::min(de::min(minDividend / minDivisor, minDividend / maxDivisor), de::min(maxDividend / minDivisor, maxDividend / maxDivisor));
}

struct InterpolationRange
{
	tcu::Vec3 max;
	tcu::Vec3 min;
};

struct LineInterpolationRange
{
	tcu::Vec2 max;
	tcu::Vec2 min;
};

InterpolationRange calcTriangleInterpolationWeights (const tcu::Vec4& p0, const tcu::Vec4& p1, const tcu::Vec4& p2, const tcu::Vec2& ndpixel)
{
	const int roundError		= 1;
	const int barycentricError	= 3;
	const int divError			= 8;

	const tcu::Vec2 nd0 = p0.swizzle(0, 1) / p0.w();
	const tcu::Vec2 nd1 = p1.swizzle(0, 1) / p1.w();
	const tcu::Vec2 nd2 = p2.swizzle(0, 1) / p2.w();

	const float ka = triangleArea(ndpixel, nd1, nd2);
	const float kb = triangleArea(ndpixel, nd2, nd0);
	const float kc = triangleArea(ndpixel, nd0, nd1);

	const float kaMax = getMaxFlushToZero(getMaxValueWithinError(ka, barycentricError));
	const float kbMax = getMaxFlushToZero(getMaxValueWithinError(kb, barycentricError));
	const float kcMax = getMaxFlushToZero(getMaxValueWithinError(kc, barycentricError));
	const float kaMin = getMinFlushToZero(getMinValueWithinError(ka, barycentricError));
	const float kbMin = getMinFlushToZero(getMinValueWithinError(kb, barycentricError));
	const float kcMin = getMinFlushToZero(getMinValueWithinError(kc, barycentricError));
	DE_ASSERT(kaMin <= kaMax);
	DE_ASSERT(kbMin <= kbMax);
	DE_ASSERT(kcMin <= kcMax);

	// calculate weights: vec3(ka / p0.w, kb / p1.w, kc / p2.w) / (ka / p0.w + kb / p1.w + kc / p2.w)
	const float maxPreDivisionValues[3] =
	{
		getMaxFlushToZero(getMaxValueWithinError(getMaxFlushToZero(kaMax / p0.w()), divError)),
		getMaxFlushToZero(getMaxValueWithinError(getMaxFlushToZero(kbMax / p1.w()), divError)),
		getMaxFlushToZero(getMaxValueWithinError(getMaxFlushToZero(kcMax / p2.w()), divError)),
	};
	const float minPreDivisionValues[3] =
	{
		getMinFlushToZero(getMinValueWithinError(getMinFlushToZero(kaMin / p0.w()), divError)),
		getMinFlushToZero(getMinValueWithinError(getMinFlushToZero(kbMin / p1.w()), divError)),
		getMinFlushToZero(getMinValueWithinError(getMinFlushToZero(kcMin / p2.w()), divError)),
	};
	DE_ASSERT(minPreDivisionValues[0] <= maxPreDivisionValues[0]);
	DE_ASSERT(minPreDivisionValues[1] <= maxPreDivisionValues[1]);
	DE_ASSERT(minPreDivisionValues[2] <= maxPreDivisionValues[2]);

	const float maxDivisor = getMaxFlushToZero(getMaxValueWithinError(maxPreDivisionValues[0] + maxPreDivisionValues[1] + maxPreDivisionValues[2], 2*roundError));
	const float minDivisor = getMinFlushToZero(getMinValueWithinError(minPreDivisionValues[0] + minPreDivisionValues[1] + minPreDivisionValues[2], 2*roundError));
	DE_ASSERT(minDivisor <= maxDivisor);

	InterpolationRange returnValue;

	returnValue.max.x() = getMaxFlushToZero(getMaxValueWithinError(getMaxFlushToZero(maximalRangeDivision(minPreDivisionValues[0], maxPreDivisionValues[0], minDivisor, maxDivisor)), divError));
	returnValue.max.y() = getMaxFlushToZero(getMaxValueWithinError(getMaxFlushToZero(maximalRangeDivision(minPreDivisionValues[1], maxPreDivisionValues[1], minDivisor, maxDivisor)), divError));
	returnValue.max.z() = getMaxFlushToZero(getMaxValueWithinError(getMaxFlushToZero(maximalRangeDivision(minPreDivisionValues[2], maxPreDivisionValues[2], minDivisor, maxDivisor)), divError));
	returnValue.min.x() = getMinFlushToZero(getMinValueWithinError(getMinFlushToZero(minimalRangeDivision(minPreDivisionValues[0], maxPreDivisionValues[0], minDivisor, maxDivisor)), divError));
	returnValue.min.y() = getMinFlushToZero(getMinValueWithinError(getMinFlushToZero(minimalRangeDivision(minPreDivisionValues[1], maxPreDivisionValues[1], minDivisor, maxDivisor)), divError));
	returnValue.min.z() = getMinFlushToZero(getMinValueWithinError(getMinFlushToZero(minimalRangeDivision(minPreDivisionValues[2], maxPreDivisionValues[2], minDivisor, maxDivisor)), divError));

	DE_ASSERT(returnValue.min.x() <= returnValue.max.x());
	DE_ASSERT(returnValue.min.y() <= returnValue.max.y());
	DE_ASSERT(returnValue.min.z() <= returnValue.max.z());

	return returnValue;
}

LineInterpolationRange calcSingleSampleLineInterpolationWeights (const tcu::Vec4& p0, const tcu::Vec4& p1, const tcu::Vec2& ndpoint)
{
	const int divError = 3;

	const tcu::Vec2 nd0 = p0.swizzle(0, 1) / p0.w();
	const tcu::Vec2 nd1 = p1.swizzle(0, 1) / p1.w();

	// project p to the line along the minor direction

	const bool		xMajor		= (de::abs(nd0.x() - nd1.x()) >= de::abs(nd0.y() - nd1.y()));
	const tcu::Vec2	minorDir	= (xMajor) ? (tcu::Vec2(0.0f, 1.0f)) : (tcu::Vec2(1.0f, 0.0f));
	const tcu::Vec2	lineDir		(nd1 - nd0);
	const tcu::Vec2	d			(ndpoint - nd0);

	// calculate factors: vec2((1-t) / p0.w, t / p1.w) / ((1-t) / p0.w + t / p1.w)

	const float		tFactorMax				= getMaxValueWithinError(-(1.0f / (minorDir.x()*lineDir.y() - lineDir.x()*minorDir.y())), divError);
	const float		tFactorMin				= getMinValueWithinError(-(1.0f / (minorDir.x()*lineDir.y() - lineDir.x()*minorDir.y())), divError);
	DE_ASSERT(tFactorMin <= tFactorMax);

	const float		tResult1				= tFactorMax * (minorDir.y()*d.x() - minorDir.x()*d.y());
	const float		tResult2				= tFactorMin * (minorDir.y()*d.x() - minorDir.x()*d.y());
	const float		tMax					= de::max(tResult1, tResult2);
	const float		tMin					= de::min(tResult1, tResult2);
	DE_ASSERT(tMin <= tMax);

	const float		perspectiveTMax			= getMaxValueWithinError(maximalRangeDivision(tMin, tMax, p1.w(), p1.w()), divError);
	const float		perspectiveTMin			= getMinValueWithinError(minimalRangeDivision(tMin, tMax, p1.w(), p1.w()), divError);
	DE_ASSERT(perspectiveTMin <= perspectiveTMax);

	const float		perspectiveInvTMax		= getMaxValueWithinError(maximalRangeDivision((1.0f - tMax), (1.0f - tMin), p0.w(), p0.w()), divError);
	const float		perspectiveInvTMin		= getMinValueWithinError(minimalRangeDivision((1.0f - tMax), (1.0f - tMin), p0.w(), p0.w()), divError);
	DE_ASSERT(perspectiveInvTMin <= perspectiveInvTMax);

	const float		perspectiveDivisorMax	= perspectiveTMax + perspectiveInvTMax;
	const float		perspectiveDivisorMin	= perspectiveTMin + perspectiveInvTMin;
	DE_ASSERT(perspectiveDivisorMin <= perspectiveDivisorMax);

	LineInterpolationRange returnValue;
	returnValue.max.x() = getMaxValueWithinError(maximalRangeDivision(perspectiveInvTMin,	perspectiveInvTMax,	perspectiveDivisorMin, perspectiveDivisorMax), divError);
	returnValue.max.y() = getMaxValueWithinError(maximalRangeDivision(perspectiveTMin,		perspectiveTMax,	perspectiveDivisorMin, perspectiveDivisorMax), divError);
	returnValue.min.x() = getMinValueWithinError(minimalRangeDivision(perspectiveInvTMin,	perspectiveInvTMax,	perspectiveDivisorMin, perspectiveDivisorMax), divError);
	returnValue.min.y() = getMinValueWithinError(minimalRangeDivision(perspectiveTMin,		perspectiveTMax,	perspectiveDivisorMin, perspectiveDivisorMax), divError);

	DE_ASSERT(returnValue.min.x() <= returnValue.max.x());
	DE_ASSERT(returnValue.min.y() <= returnValue.max.y());

	return returnValue;
}

LineInterpolationRange calcMultiSampleLineInterpolationWeights (const tcu::Vec4& p0, const tcu::Vec4& p1, const tcu::Vec2& ndpoint)
{
	const int divError = 3;

	// calc weights: vec2((1-t) / p0.w, t / p1.w) / ((1-t) / p0.w + t / p1.w)

	// highp vertex shader
	const tcu::Vec2 nd0 = p0.swizzle(0, 1) / p0.w();
	const tcu::Vec2 nd1 = p1.swizzle(0, 1) / p1.w();

	// Allow 1 ULP
	const float		dividend	= tcu::dot(ndpoint - nd0, nd1 - nd0);
	const float		dividendMax	= getMaxValueWithinError(dividend, 1);
	const float		dividendMin	= getMaxValueWithinError(dividend, 1);
	DE_ASSERT(dividendMin <= dividendMax);

	// Assuming lengthSquared will not be implemented as sqrt(x)^2, allow 1 ULP
	const float		divisor		= tcu::lengthSquared(nd1 - nd0);
	const float		divisorMax	= getMaxValueWithinError(divisor, 1);
	const float		divisorMin	= getMaxValueWithinError(divisor, 1);
	DE_ASSERT(divisorMin <= divisorMax);

	// Allow 3 ULP precision for division
	const float		tMax		= getMaxValueWithinError(maximalRangeDivision(dividendMin, dividendMax, divisorMin, divisorMax), divError);
	const float		tMin		= getMinValueWithinError(minimalRangeDivision(dividendMin, dividendMax, divisorMin, divisorMax), divError);
	DE_ASSERT(tMin <= tMax);

	const float		perspectiveTMax			= getMaxValueWithinError(maximalRangeDivision(tMin, tMax, p1.w(), p1.w()), divError);
	const float		perspectiveTMin			= getMinValueWithinError(minimalRangeDivision(tMin, tMax, p1.w(), p1.w()), divError);
	DE_ASSERT(perspectiveTMin <= perspectiveTMax);

	const float		perspectiveInvTMax		= getMaxValueWithinError(maximalRangeDivision((1.0f - tMax), (1.0f - tMin), p0.w(), p0.w()), divError);
	const float		perspectiveInvTMin		= getMinValueWithinError(minimalRangeDivision((1.0f - tMax), (1.0f - tMin), p0.w(), p0.w()), divError);
	DE_ASSERT(perspectiveInvTMin <= perspectiveInvTMax);

	const float		perspectiveDivisorMax	= perspectiveTMax + perspectiveInvTMax;
	const float		perspectiveDivisorMin	= perspectiveTMin + perspectiveInvTMin;
	DE_ASSERT(perspectiveDivisorMin <= perspectiveDivisorMax);

	LineInterpolationRange returnValue;
	returnValue.max.x() = getMaxValueWithinError(maximalRangeDivision(perspectiveInvTMin,	perspectiveInvTMax,	perspectiveDivisorMin, perspectiveDivisorMax), divError);
	returnValue.max.y() = getMaxValueWithinError(maximalRangeDivision(perspectiveTMin,		perspectiveTMax,	perspectiveDivisorMin, perspectiveDivisorMax), divError);
	returnValue.min.x() = getMinValueWithinError(minimalRangeDivision(perspectiveInvTMin,	perspectiveInvTMax,	perspectiveDivisorMin, perspectiveDivisorMax), divError);
	returnValue.min.y() = getMinValueWithinError(minimalRangeDivision(perspectiveTMin,		perspectiveTMax,	perspectiveDivisorMin, perspectiveDivisorMax), divError);

	DE_ASSERT(returnValue.min.x() <= returnValue.max.x());
	DE_ASSERT(returnValue.min.y() <= returnValue.max.y());

	return returnValue;
}

LineInterpolationRange calcSingleSampleLineInterpolationRange (const tcu::Vec4& p0, const tcu::Vec4& p1, const tcu::IVec2& pixel, const tcu::IVec2& viewportSize, int subpixelBits)
{
	// allow interpolation weights anywhere in the central subpixels
	const float testSquareSize = (2.0f / (1UL << subpixelBits));
	const float testSquarePos  = (0.5f - testSquareSize / 2);
	const tcu::Vec2 corners[4] =
	{
		tcu::Vec2((pixel.x() + testSquarePos + 0.0f)           / viewportSize.x() * 2.0f - 1.0f, (pixel.y() + testSquarePos + 0.0f          ) / viewportSize.y() * 2.0f - 1.0f),
		tcu::Vec2((pixel.x() + testSquarePos + 0.0f)           / viewportSize.x() * 2.0f - 1.0f, (pixel.y() + testSquarePos + testSquareSize) / viewportSize.y() * 2.0f - 1.0f),
		tcu::Vec2((pixel.x() + testSquarePos + testSquareSize) / viewportSize.x() * 2.0f - 1.0f, (pixel.y() + testSquarePos + testSquareSize) / viewportSize.y() * 2.0f - 1.0f),
		tcu::Vec2((pixel.x() + testSquarePos + testSquareSize) / viewportSize.x() * 2.0f - 1.0f, (pixel.y() + testSquarePos + 0.0f          ) / viewportSize.y() * 2.0f - 1.0f),
	};

	// calculate interpolation as a line
	const LineInterpolationRange weights[4] =
	{
		calcSingleSampleLineInterpolationWeights(p0, p1, corners[0]),
		calcSingleSampleLineInterpolationWeights(p0, p1, corners[1]),
		calcSingleSampleLineInterpolationWeights(p0, p1, corners[2]),
		calcSingleSampleLineInterpolationWeights(p0, p1, corners[3]),
	};

	const tcu::Vec2 minWeights = tcu::min(tcu::min(weights[0].min, weights[1].min), tcu::min(weights[2].min, weights[3].min));
	const tcu::Vec2 maxWeights = tcu::max(tcu::max(weights[0].max, weights[1].max), tcu::max(weights[2].max, weights[3].max));

	// convert to three-component form. For all triangles, the vertex 0 is always emitted by the line starting point, and vertex 2 by the ending point
	LineInterpolationRange result;
	result.min = minWeights;
	result.max = maxWeights;
	return result;
}

struct TriangleInterpolator
{
	const TriangleSceneSpec& scene;

	TriangleInterpolator (const TriangleSceneSpec& scene_)
		: scene(scene_)
	{
	}

	InterpolationRange interpolate (int primitiveNdx, const tcu::IVec2 pixel, const tcu::IVec2 viewportSize, bool multisample, int subpixelBits) const
	{
		// allow anywhere in the pixel area in multisample
		// allow only in the center subpixels (4 subpixels) in singlesample
		const float testSquareSize = (multisample) ? (1.0f) : (2.0f / (1UL << subpixelBits));
		const float testSquarePos  = (multisample) ? (0.0f) : (0.5f - testSquareSize / 2);
		const tcu::Vec2 corners[4] =
		{
			tcu::Vec2((pixel.x() + testSquarePos + 0.0f)           / viewportSize.x() * 2.0f - 1.0f, (pixel.y() + testSquarePos + 0.0f          ) / viewportSize.y() * 2.0f - 1.0f),
			tcu::Vec2((pixel.x() + testSquarePos + 0.0f)           / viewportSize.x() * 2.0f - 1.0f, (pixel.y() + testSquarePos + testSquareSize) / viewportSize.y() * 2.0f - 1.0f),
			tcu::Vec2((pixel.x() + testSquarePos + testSquareSize) / viewportSize.x() * 2.0f - 1.0f, (pixel.y() + testSquarePos + testSquareSize) / viewportSize.y() * 2.0f - 1.0f),
			tcu::Vec2((pixel.x() + testSquarePos + testSquareSize) / viewportSize.x() * 2.0f - 1.0f, (pixel.y() + testSquarePos + 0.0f          ) / viewportSize.y() * 2.0f - 1.0f),
		};
		const InterpolationRange weights[4] =
		{
			calcTriangleInterpolationWeights(scene.triangles[primitiveNdx].positions[0], scene.triangles[primitiveNdx].positions[1], scene.triangles[primitiveNdx].positions[2], corners[0]),
			calcTriangleInterpolationWeights(scene.triangles[primitiveNdx].positions[0], scene.triangles[primitiveNdx].positions[1], scene.triangles[primitiveNdx].positions[2], corners[1]),
			calcTriangleInterpolationWeights(scene.triangles[primitiveNdx].positions[0], scene.triangles[primitiveNdx].positions[1], scene.triangles[primitiveNdx].positions[2], corners[2]),
			calcTriangleInterpolationWeights(scene.triangles[primitiveNdx].positions[0], scene.triangles[primitiveNdx].positions[1], scene.triangles[primitiveNdx].positions[2], corners[3]),
		};

		InterpolationRange result;
		result.min = tcu::min(tcu::min(weights[0].min, weights[1].min), tcu::min(weights[2].min, weights[3].min));
		result.max = tcu::max(tcu::max(weights[0].max, weights[1].max), tcu::max(weights[2].max, weights[3].max));
		return result;
	}
};

/*--------------------------------------------------------------------*//*!
 * Used only by verifyMultisampleLineGroupInterpolation to calculate
 * correct line interpolations for the triangulated lines.
 *//*--------------------------------------------------------------------*/
struct MultisampleLineInterpolator
{
	const LineSceneSpec& scene;

	MultisampleLineInterpolator (const LineSceneSpec& scene_)
		: scene(scene_)
	{
	}

	InterpolationRange interpolate (int primitiveNdx, const tcu::IVec2 pixel, const tcu::IVec2 viewportSize, bool multisample, int subpixelBits) const
	{
		DE_ASSERT(multisample);
		DE_UNREF(multisample);
		DE_UNREF(subpixelBits);

		// in triangulation, one line emits two triangles
		const int		lineNdx		= primitiveNdx / 2;

		// allow interpolation weights anywhere in the pixel
		const tcu::Vec2 corners[4] =
		{
			tcu::Vec2((pixel.x() + 0.0f) / viewportSize.x() * 2.0f - 1.0f, (pixel.y() + 0.0f) / viewportSize.y() * 2.0f - 1.0f),
			tcu::Vec2((pixel.x() + 0.0f) / viewportSize.x() * 2.0f - 1.0f, (pixel.y() + 1.0f) / viewportSize.y() * 2.0f - 1.0f),
			tcu::Vec2((pixel.x() + 1.0f) / viewportSize.x() * 2.0f - 1.0f, (pixel.y() + 1.0f) / viewportSize.y() * 2.0f - 1.0f),
			tcu::Vec2((pixel.x() + 1.0f) / viewportSize.x() * 2.0f - 1.0f, (pixel.y() + 0.0f) / viewportSize.y() * 2.0f - 1.0f),
		};

		// calculate interpolation as a line
		const LineInterpolationRange weights[4] =
		{
			calcMultiSampleLineInterpolationWeights(scene.lines[lineNdx].positions[0], scene.lines[lineNdx].positions[1], corners[0]),
			calcMultiSampleLineInterpolationWeights(scene.lines[lineNdx].positions[0], scene.lines[lineNdx].positions[1], corners[1]),
			calcMultiSampleLineInterpolationWeights(scene.lines[lineNdx].positions[0], scene.lines[lineNdx].positions[1], corners[2]),
			calcMultiSampleLineInterpolationWeights(scene.lines[lineNdx].positions[0], scene.lines[lineNdx].positions[1], corners[3]),
		};

		const tcu::Vec2 minWeights = tcu::min(tcu::min(weights[0].min, weights[1].min), tcu::min(weights[2].min, weights[3].min));
		const tcu::Vec2 maxWeights = tcu::max(tcu::max(weights[0].max, weights[1].max), tcu::max(weights[2].max, weights[3].max));

		// convert to three-component form. For all triangles, the vertex 0 is always emitted by the line starting point, and vertex 2 by the ending point
		InterpolationRange result;
		result.min = tcu::Vec3(minWeights.x(), 0.0f, minWeights.y());
		result.max = tcu::Vec3(maxWeights.x(), 0.0f, maxWeights.y());
		return result;
	}
};

template <typename Interpolator>
bool verifyTriangleGroupInterpolationWithInterpolator (const tcu::Surface& surface, const TriangleSceneSpec& scene, const RasterizationArguments& args, tcu::TestLog& log, const Interpolator& interpolator)
{
	const tcu::RGBA		invalidPixelColor	= tcu::RGBA(255, 0, 0, 255);
	const bool			multisampled		= (args.numSamples != 0);
	const tcu::IVec2	viewportSize		= tcu::IVec2(surface.getWidth(), surface.getHeight());
	const int			errorFloodThreshold	= 4;
	int					errorCount			= 0;
	int					invalidPixels		= 0;
	int					subPixelBits		= args.subpixelBits;
	tcu::Surface		errorMask			(surface.getWidth(), surface.getHeight());

	tcu::clear(errorMask.getAccess(), tcu::Vec4(0.0f, 0.0f, 0.0f, 1.0f));

	// log format

	log << tcu::TestLog::Message << "Verifying rasterization result. Native format is RGB" << args.redBits << args.greenBits << args.blueBits << tcu::TestLog::EndMessage;
	if (args.redBits > 8 || args.greenBits > 8 || args.blueBits > 8)
		log << tcu::TestLog::Message << "Warning! More than 8 bits in a color channel, this may produce false negatives." << tcu::TestLog::EndMessage;

	// subpixel bits in in a valid range?

	if (subPixelBits < 0)
	{
		log << tcu::TestLog::Message << "Invalid subpixel count (" << subPixelBits << "), assuming 0" << tcu::TestLog::EndMessage;
		subPixelBits = 0;
	}
	else if (subPixelBits > 16)
	{
		// At high subpixel bit counts we might overflow. Checking at lower bit count is ok, but is less strict
		log << tcu::TestLog::Message << "Subpixel count is greater than 16 (" << subPixelBits << "). Checking results using less strict 16 bit requirements. This may produce false positives." << tcu::TestLog::EndMessage;
		subPixelBits = 16;
	}

	// check pixels

	for (int y = 0; y < surface.getHeight(); ++y)
	for (int x = 0; x < surface.getWidth();  ++x)
	{
		const tcu::RGBA		color				= surface.getPixel(x, y);
		bool				stackBottomFound	= false;
		int					stackSize			= 0;
		tcu::Vec4			colorStackMin;
		tcu::Vec4			colorStackMax;

		// Iterate triangle coverage front to back, find the stack of pontentially contributing fragments
		for (int triNdx = (int)scene.triangles.size() - 1; triNdx >= 0; --triNdx)
		{
			const CoverageType coverage = calculateTriangleCoverage(scene.triangles[triNdx].positions[0],
																	scene.triangles[triNdx].positions[1],
																	scene.triangles[triNdx].positions[2],
																	tcu::IVec2(x, y),
																	viewportSize,
																	subPixelBits,
																	multisampled);

			if (coverage == COVERAGE_FULL || coverage == COVERAGE_PARTIAL)
			{
				// potentially contributes to the result fragment's value
				const InterpolationRange weights = interpolator.interpolate(triNdx, tcu::IVec2(x, y), viewportSize, multisampled, subPixelBits);

				const tcu::Vec4 fragmentColorMax =	de::clamp(weights.max.x(), 0.0f, 1.0f) * scene.triangles[triNdx].colors[0] +
													de::clamp(weights.max.y(), 0.0f, 1.0f) * scene.triangles[triNdx].colors[1] +
													de::clamp(weights.max.z(), 0.0f, 1.0f) * scene.triangles[triNdx].colors[2];
				const tcu::Vec4 fragmentColorMin =	de::clamp(weights.min.x(), 0.0f, 1.0f) * scene.triangles[triNdx].colors[0] +
													de::clamp(weights.min.y(), 0.0f, 1.0f) * scene.triangles[triNdx].colors[1] +
													de::clamp(weights.min.z(), 0.0f, 1.0f) * scene.triangles[triNdx].colors[2];

				if (stackSize++ == 0)
				{
					// first triangle, set the values properly
					colorStackMin = fragmentColorMin;
					colorStackMax = fragmentColorMax;
				}
				else
				{
					// contributing triangle
					colorStackMin = tcu::min(colorStackMin, fragmentColorMin);
					colorStackMax = tcu::max(colorStackMax, fragmentColorMax);
				}

				if (coverage == COVERAGE_FULL)
				{
					// loop terminates, this is the bottommost fragment
					stackBottomFound = true;
					break;
				}
			}
		}

		// Partial coverage == background may be visible
		if (stackSize != 0 && !stackBottomFound)
		{
			stackSize++;
			colorStackMin = tcu::Vec4(0.0f, 0.0f, 0.0f, 1.0f);
		}

		// Is the result image color in the valid range.
		if (stackSize == 0)
		{
			// No coverage, allow only background (black, value=0)
			const tcu::IVec3	pixelNativeColor	= convertRGB8ToNativeFormat(color, args);
			const int			threshold			= 1;

			if (pixelNativeColor.x() > threshold ||
				pixelNativeColor.y() > threshold ||
				pixelNativeColor.z() > threshold)
			{
				++errorCount;

				// don't fill the logs with too much data
				if (errorCount < errorFloodThreshold)
				{
					log << tcu::TestLog::Message
						<< "Found an invalid pixel at (" << x << "," << y << ")\n"
						<< "\tPixel color:\t\t" << color << "\n"
						<< "\tExpected background color.\n"
						<< tcu::TestLog::EndMessage;
				}

				++invalidPixels;
				errorMask.setPixel(x, y, invalidPixelColor);
			}
		}
		else
		{
			DE_ASSERT(stackSize);

			// Each additional step in the stack may cause conversion error of 1 bit due to undefined rounding direction
			const int			thresholdRed	= stackSize - 1;
			const int			thresholdGreen	= stackSize - 1;
			const int			thresholdBlue	= stackSize - 1;

			const tcu::Vec3		valueRangeMin	= tcu::Vec3(colorStackMin.xyz());
			const tcu::Vec3		valueRangeMax	= tcu::Vec3(colorStackMax.xyz());

			const tcu::IVec3	formatLimit		((1 << args.redBits) - 1, (1 << args.greenBits) - 1, (1 << args.blueBits) - 1);
			const tcu::Vec3		colorMinF		(de::clamp(valueRangeMin.x() * formatLimit.x(), 0.0f, (float)formatLimit.x()),
												 de::clamp(valueRangeMin.y() * formatLimit.y(), 0.0f, (float)formatLimit.y()),
												 de::clamp(valueRangeMin.z() * formatLimit.z(), 0.0f, (float)formatLimit.z()));
			const tcu::Vec3		colorMaxF		(de::clamp(valueRangeMax.x() * formatLimit.x(), 0.0f, (float)formatLimit.x()),
												 de::clamp(valueRangeMax.y() * formatLimit.y(), 0.0f, (float)formatLimit.y()),
												 de::clamp(valueRangeMax.z() * formatLimit.z(), 0.0f, (float)formatLimit.z()));
			const tcu::IVec3	colorMin		((int)deFloatFloor(colorMinF.x()),
												 (int)deFloatFloor(colorMinF.y()),
												 (int)deFloatFloor(colorMinF.z()));
			const tcu::IVec3	colorMax		((int)deFloatCeil (colorMaxF.x()),
												 (int)deFloatCeil (colorMaxF.y()),
												 (int)deFloatCeil (colorMaxF.z()));

			// Convert pixel color from rgba8 to the real pixel format. Usually rgba8 or 565
			const tcu::IVec3 pixelNativeColor = convertRGB8ToNativeFormat(color, args);

			// Validity check
			if (pixelNativeColor.x() < colorMin.x() - thresholdRed   ||
				pixelNativeColor.y() < colorMin.y() - thresholdGreen ||
				pixelNativeColor.z() < colorMin.z() - thresholdBlue  ||
				pixelNativeColor.x() > colorMax.x() + thresholdRed   ||
				pixelNativeColor.y() > colorMax.y() + thresholdGreen ||
				pixelNativeColor.z() > colorMax.z() + thresholdBlue)
			{
				++errorCount;

				// don't fill the logs with too much data
				if (errorCount <= errorFloodThreshold)
				{
					log << tcu::TestLog::Message
						<< "Found an invalid pixel at (" << x << "," << y << ")\n"
						<< "\tPixel color:\t\t" << color << "\n"
						<< "\tNative color:\t\t" << pixelNativeColor << "\n"
						<< "\tAllowed error:\t\t" << tcu::IVec3(thresholdRed, thresholdGreen, thresholdBlue) << "\n"
						<< "\tReference native color min: " << tcu::clamp(colorMin - tcu::IVec3(thresholdRed, thresholdGreen, thresholdBlue), tcu::IVec3(0,0,0), formatLimit) << "\n"
						<< "\tReference native color max: " << tcu::clamp(colorMax + tcu::IVec3(thresholdRed, thresholdGreen, thresholdBlue), tcu::IVec3(0,0,0), formatLimit) << "\n"
						<< "\tReference native float min: " << tcu::clamp(colorMinF - tcu::IVec3(thresholdRed, thresholdGreen, thresholdBlue).cast<float>(), tcu::Vec3(0.0f, 0.0f, 0.0f), formatLimit.cast<float>()) << "\n"
						<< "\tReference native float max: " << tcu::clamp(colorMaxF + tcu::IVec3(thresholdRed, thresholdGreen, thresholdBlue).cast<float>(), tcu::Vec3(0.0f, 0.0f, 0.0f), formatLimit.cast<float>()) << "\n"
						<< "\tFmin:\t" << tcu::clamp(valueRangeMin, tcu::Vec3(0.0f, 0.0f, 0.0f), tcu::Vec3(1.0f, 1.0f, 1.0f)) << "\n"
						<< "\tFmax:\t" << tcu::clamp(valueRangeMax, tcu::Vec3(0.0f, 0.0f, 0.0f), tcu::Vec3(1.0f, 1.0f, 1.0f)) << "\n"
						<< tcu::TestLog::EndMessage;
				}

				++invalidPixels;
				errorMask.setPixel(x, y, invalidPixelColor);
			}
		}
	}

	// don't just hide failures
	if (errorCount > errorFloodThreshold)
		log << tcu::TestLog::Message << "Omitted " << (errorCount-errorFloodThreshold) << " pixel error description(s)." << tcu::TestLog::EndMessage;

	// report result
	if (invalidPixels)
	{
		log << tcu::TestLog::Message << invalidPixels << " invalid pixel(s) found." << tcu::TestLog::EndMessage;
		log << tcu::TestLog::ImageSet("Verification result", "Result of rendering")
			<< tcu::TestLog::Image("Result", "Result",			surface)
			<< tcu::TestLog::Image("ErrorMask", "ErrorMask",	errorMask)
			<< tcu::TestLog::EndImageSet;

		return false;
	}
	else
	{
		log << tcu::TestLog::Message << "No invalid pixels found." << tcu::TestLog::EndMessage;
		log << tcu::TestLog::ImageSet("Verification result", "Result of rendering")
			<< tcu::TestLog::Image("Result", "Result", surface)
			<< tcu::TestLog::EndImageSet;

		return true;
	}
}

bool verifyMultisampleLineGroupRasterization (const tcu::Surface& surface, const LineSceneSpec& scene, const RasterizationArguments& args, tcu::TestLog& log)
{
	// Multisampled line == 2 triangles

	const tcu::Vec2		viewportSize	= tcu::Vec2((float)surface.getWidth(), (float)surface.getHeight());
	const float			halfLineWidth	= scene.lineWidth * 0.5f;
	TriangleSceneSpec	triangleScene;

	triangleScene.triangles.resize(2 * scene.lines.size());
	for (int lineNdx = 0; lineNdx < (int)scene.lines.size(); ++lineNdx)
	{
		// Transform to screen space, add pixel offsets, convert back to normalized device space, and test as triangles
		const tcu::Vec2 lineNormalizedDeviceSpace[2] =
		{
			tcu::Vec2(scene.lines[lineNdx].positions[0].x() / scene.lines[lineNdx].positions[0].w(), scene.lines[lineNdx].positions[0].y() / scene.lines[lineNdx].positions[0].w()),
			tcu::Vec2(scene.lines[lineNdx].positions[1].x() / scene.lines[lineNdx].positions[1].w(), scene.lines[lineNdx].positions[1].y() / scene.lines[lineNdx].positions[1].w()),
		};
		const tcu::Vec2 lineScreenSpace[2] =
		{
			(lineNormalizedDeviceSpace[0] + tcu::Vec2(1.0f, 1.0f)) * 0.5f * viewportSize,
			(lineNormalizedDeviceSpace[1] + tcu::Vec2(1.0f, 1.0f)) * 0.5f * viewportSize,
		};

		const tcu::Vec2 lineDir			= tcu::normalize(lineScreenSpace[1] - lineScreenSpace[0]);
		const tcu::Vec2 lineNormalDir	= tcu::Vec2(lineDir.y(), -lineDir.x());

		const tcu::Vec2 lineQuadScreenSpace[4] =
		{
			lineScreenSpace[0] + lineNormalDir * halfLineWidth,
			lineScreenSpace[0] - lineNormalDir * halfLineWidth,
			lineScreenSpace[1] - lineNormalDir * halfLineWidth,
			lineScreenSpace[1] + lineNormalDir * halfLineWidth,
		};
		const tcu::Vec2 lineQuadNormalizedDeviceSpace[4] =
		{
			lineQuadScreenSpace[0] / viewportSize * 2.0f - tcu::Vec2(1.0f, 1.0f),
			lineQuadScreenSpace[1] / viewportSize * 2.0f - tcu::Vec2(1.0f, 1.0f),
			lineQuadScreenSpace[2] / viewportSize * 2.0f - tcu::Vec2(1.0f, 1.0f),
			lineQuadScreenSpace[3] / viewportSize * 2.0f - tcu::Vec2(1.0f, 1.0f),
		};

		triangleScene.triangles[lineNdx*2 + 0].positions[0] = tcu::Vec4(lineQuadNormalizedDeviceSpace[0].x(), lineQuadNormalizedDeviceSpace[0].y(), 0.0f, 1.0f);	triangleScene.triangles[lineNdx*2 + 0].sharedEdge[0] = false;
		triangleScene.triangles[lineNdx*2 + 0].positions[1] = tcu::Vec4(lineQuadNormalizedDeviceSpace[1].x(), lineQuadNormalizedDeviceSpace[1].y(), 0.0f, 1.0f);	triangleScene.triangles[lineNdx*2 + 0].sharedEdge[1] = false;
		triangleScene.triangles[lineNdx*2 + 0].positions[2] = tcu::Vec4(lineQuadNormalizedDeviceSpace[2].x(), lineQuadNormalizedDeviceSpace[2].y(), 0.0f, 1.0f);	triangleScene.triangles[lineNdx*2 + 0].sharedEdge[2] = true;

		triangleScene.triangles[lineNdx*2 + 1].positions[0] = tcu::Vec4(lineQuadNormalizedDeviceSpace[0].x(), lineQuadNormalizedDeviceSpace[0].y(), 0.0f, 1.0f);	triangleScene.triangles[lineNdx*2 + 1].sharedEdge[0] = true;
		triangleScene.triangles[lineNdx*2 + 1].positions[1] = tcu::Vec4(lineQuadNormalizedDeviceSpace[2].x(), lineQuadNormalizedDeviceSpace[2].y(), 0.0f, 1.0f);	triangleScene.triangles[lineNdx*2 + 1].sharedEdge[1] = false;
		triangleScene.triangles[lineNdx*2 + 1].positions[2] = tcu::Vec4(lineQuadNormalizedDeviceSpace[3].x(), lineQuadNormalizedDeviceSpace[3].y(), 0.0f, 1.0f);	triangleScene.triangles[lineNdx*2 + 1].sharedEdge[2] = false;
	}

	return verifyTriangleGroupRasterization(surface, triangleScene, args, log);
}

bool verifyMultisampleLineGroupInterpolation (const tcu::Surface& surface, const LineSceneSpec& scene, const RasterizationArguments& args, tcu::TestLog& log)
{
	// Multisampled line == 2 triangles

	const tcu::Vec2		viewportSize	= tcu::Vec2((float)surface.getWidth(), (float)surface.getHeight());
	const float			halfLineWidth	= scene.lineWidth * 0.5f;
	TriangleSceneSpec	triangleScene;

	triangleScene.triangles.resize(2 * scene.lines.size());
	for (int lineNdx = 0; lineNdx < (int)scene.lines.size(); ++lineNdx)
	{
		// Transform to screen space, add pixel offsets, convert back to normalized device space, and test as triangles
		const tcu::Vec2 lineNormalizedDeviceSpace[2] =
		{
			tcu::Vec2(scene.lines[lineNdx].positions[0].x() / scene.lines[lineNdx].positions[0].w(), scene.lines[lineNdx].positions[0].y() / scene.lines[lineNdx].positions[0].w()),
			tcu::Vec2(scene.lines[lineNdx].positions[1].x() / scene.lines[lineNdx].positions[1].w(), scene.lines[lineNdx].positions[1].y() / scene.lines[lineNdx].positions[1].w()),
		};
		const tcu::Vec2 lineScreenSpace[2] =
		{
			(lineNormalizedDeviceSpace[0] + tcu::Vec2(1.0f, 1.0f)) * 0.5f * viewportSize,
			(lineNormalizedDeviceSpace[1] + tcu::Vec2(1.0f, 1.0f)) * 0.5f * viewportSize,
		};

		const tcu::Vec2 lineDir			= tcu::normalize(lineScreenSpace[1] - lineScreenSpace[0]);
		const tcu::Vec2 lineNormalDir	= tcu::Vec2(lineDir.y(), -lineDir.x());

		const tcu::Vec2 lineQuadScreenSpace[4] =
		{
			lineScreenSpace[0] + lineNormalDir * halfLineWidth,
			lineScreenSpace[0] - lineNormalDir * halfLineWidth,
			lineScreenSpace[1] - lineNormalDir * halfLineWidth,
			lineScreenSpace[1] + lineNormalDir * halfLineWidth,
		};
		const tcu::Vec2 lineQuadNormalizedDeviceSpace[4] =
		{
			lineQuadScreenSpace[0] / viewportSize * 2.0f - tcu::Vec2(1.0f, 1.0f),
			lineQuadScreenSpace[1] / viewportSize * 2.0f - tcu::Vec2(1.0f, 1.0f),
			lineQuadScreenSpace[2] / viewportSize * 2.0f - tcu::Vec2(1.0f, 1.0f),
			lineQuadScreenSpace[3] / viewportSize * 2.0f - tcu::Vec2(1.0f, 1.0f),
		};

		triangleScene.triangles[lineNdx*2 + 0].positions[0] = tcu::Vec4(lineQuadNormalizedDeviceSpace[0].x(), lineQuadNormalizedDeviceSpace[0].y(), 0.0f, 1.0f);
		triangleScene.triangles[lineNdx*2 + 0].positions[1] = tcu::Vec4(lineQuadNormalizedDeviceSpace[1].x(), lineQuadNormalizedDeviceSpace[1].y(), 0.0f, 1.0f);
		triangleScene.triangles[lineNdx*2 + 0].positions[2] = tcu::Vec4(lineQuadNormalizedDeviceSpace[2].x(), lineQuadNormalizedDeviceSpace[2].y(), 0.0f, 1.0f);

		triangleScene.triangles[lineNdx*2 + 0].sharedEdge[0] = false;
		triangleScene.triangles[lineNdx*2 + 0].sharedEdge[1] = false;
		triangleScene.triangles[lineNdx*2 + 0].sharedEdge[2] = true;

		triangleScene.triangles[lineNdx*2 + 0].colors[0] = scene.lines[lineNdx].colors[0];
		triangleScene.triangles[lineNdx*2 + 0].colors[1] = scene.lines[lineNdx].colors[0];
		triangleScene.triangles[lineNdx*2 + 0].colors[2] = scene.lines[lineNdx].colors[1];

		triangleScene.triangles[lineNdx*2 + 1].positions[0] = tcu::Vec4(lineQuadNormalizedDeviceSpace[0].x(), lineQuadNormalizedDeviceSpace[0].y(), 0.0f, 1.0f);
		triangleScene.triangles[lineNdx*2 + 1].positions[1] = tcu::Vec4(lineQuadNormalizedDeviceSpace[2].x(), lineQuadNormalizedDeviceSpace[2].y(), 0.0f, 1.0f);
		triangleScene.triangles[lineNdx*2 + 1].positions[2] = tcu::Vec4(lineQuadNormalizedDeviceSpace[3].x(), lineQuadNormalizedDeviceSpace[3].y(), 0.0f, 1.0f);

		triangleScene.triangles[lineNdx*2 + 1].sharedEdge[0] = true;
		triangleScene.triangles[lineNdx*2 + 1].sharedEdge[1] = false;
		triangleScene.triangles[lineNdx*2 + 1].sharedEdge[2] = false;

		triangleScene.triangles[lineNdx*2 + 1].colors[0] = scene.lines[lineNdx].colors[0];
		triangleScene.triangles[lineNdx*2 + 1].colors[1] = scene.lines[lineNdx].colors[1];
		triangleScene.triangles[lineNdx*2 + 1].colors[2] = scene.lines[lineNdx].colors[1];
	}

	return verifyTriangleGroupInterpolationWithInterpolator(surface, triangleScene, args, log, MultisampleLineInterpolator(scene));
}

bool verifyMultisamplePointGroupRasterization (const tcu::Surface& surface, const PointSceneSpec& scene, const RasterizationArguments& args, tcu::TestLog& log)
{
	// Multisampled point == 2 triangles

	const tcu::Vec2		viewportSize	= tcu::Vec2((float)surface.getWidth(), (float)surface.getHeight());
	TriangleSceneSpec	triangleScene;

	triangleScene.triangles.resize(2 * scene.points.size());
	for (int pointNdx = 0; pointNdx < (int)scene.points.size(); ++pointNdx)
	{
		// Transform to screen space, add pixel offsets, convert back to normalized device space, and test as triangles
		const tcu::Vec2	pointNormalizedDeviceSpace			= tcu::Vec2(scene.points[pointNdx].position.x() / scene.points[pointNdx].position.w(), scene.points[pointNdx].position.y() / scene.points[pointNdx].position.w());
		const tcu::Vec2	pointScreenSpace					= (pointNormalizedDeviceSpace + tcu::Vec2(1.0f, 1.0f)) * 0.5f * viewportSize;
		const float		offset								= scene.points[pointNdx].pointSize * 0.5f;
		const tcu::Vec2	lineQuadNormalizedDeviceSpace[4]	=
		{
			(pointScreenSpace + tcu::Vec2(-offset, -offset))/ viewportSize * 2.0f - tcu::Vec2(1.0f, 1.0f),
			(pointScreenSpace + tcu::Vec2(-offset,  offset))/ viewportSize * 2.0f - tcu::Vec2(1.0f, 1.0f),
			(pointScreenSpace + tcu::Vec2( offset,  offset))/ viewportSize * 2.0f - tcu::Vec2(1.0f, 1.0f),
			(pointScreenSpace + tcu::Vec2( offset, -offset))/ viewportSize * 2.0f - tcu::Vec2(1.0f, 1.0f),
		};

		triangleScene.triangles[pointNdx*2 + 0].positions[0] = tcu::Vec4(lineQuadNormalizedDeviceSpace[0].x(), lineQuadNormalizedDeviceSpace[0].y(), 0.0f, 1.0f);	triangleScene.triangles[pointNdx*2 + 0].sharedEdge[0] = false;
		triangleScene.triangles[pointNdx*2 + 0].positions[1] = tcu::Vec4(lineQuadNormalizedDeviceSpace[1].x(), lineQuadNormalizedDeviceSpace[1].y(), 0.0f, 1.0f);	triangleScene.triangles[pointNdx*2 + 0].sharedEdge[1] = false;
		triangleScene.triangles[pointNdx*2 + 0].positions[2] = tcu::Vec4(lineQuadNormalizedDeviceSpace[2].x(), lineQuadNormalizedDeviceSpace[2].y(), 0.0f, 1.0f);	triangleScene.triangles[pointNdx*2 + 0].sharedEdge[2] = true;

		triangleScene.triangles[pointNdx*2 + 1].positions[0] = tcu::Vec4(lineQuadNormalizedDeviceSpace[0].x(), lineQuadNormalizedDeviceSpace[0].y(), 0.0f, 1.0f);	triangleScene.triangles[pointNdx*2 + 1].sharedEdge[0] = true;
		triangleScene.triangles[pointNdx*2 + 1].positions[1] = tcu::Vec4(lineQuadNormalizedDeviceSpace[2].x(), lineQuadNormalizedDeviceSpace[2].y(), 0.0f, 1.0f);	triangleScene.triangles[pointNdx*2 + 1].sharedEdge[1] = false;
		triangleScene.triangles[pointNdx*2 + 1].positions[2] = tcu::Vec4(lineQuadNormalizedDeviceSpace[3].x(), lineQuadNormalizedDeviceSpace[3].y(), 0.0f, 1.0f);	triangleScene.triangles[pointNdx*2 + 1].sharedEdge[2] = false;
	}

	return verifyTriangleGroupRasterization(surface, triangleScene, args, log);
}

bool verifySinglesampleLineGroupRasterization (const tcu::Surface& surface, const LineSceneSpec& scene, const RasterizationArguments& args, tcu::TestLog& log)
{
	DE_ASSERT(deFloatFrac(scene.lineWidth) != 0.5f); // rounding direction is not defined, disallow undefined cases
	DE_ASSERT(scene.lines.size() < 255); // indices are stored as unsigned 8-bit ints

	bool				allOK				= true;
	bool				overdrawInReference	= false;
	int					referenceFragments	= 0;
	int					resultFragments		= 0;
	int					lineWidth			= deFloorFloatToInt32(scene.lineWidth + 0.5f);
	bool				imageShown			= false;
	std::vector<bool>	lineIsXMajor		(scene.lines.size());

	// Reference renderer produces correct fragments using the diamond-rule. Make 2D int array, each cell contains the highest index (first index = 1) of the overlapping lines or 0 if no line intersects the pixel
	tcu::TextureLevel referenceLineMap(tcu::TextureFormat(tcu::TextureFormat::R, tcu::TextureFormat::UNSIGNED_INT8), surface.getWidth(), surface.getHeight());
	tcu::clear(referenceLineMap.getAccess(), tcu::IVec4(0, 0, 0, 0));

	for (int lineNdx = 0; lineNdx < (int)scene.lines.size(); ++lineNdx)
	{
		rr::SingleSampleLineRasterizer rasterizer(tcu::IVec4(0, 0, surface.getWidth(), surface.getHeight()));

		const tcu::Vec2 lineNormalizedDeviceSpace[2] =
		{
			tcu::Vec2(scene.lines[lineNdx].positions[0].x() / scene.lines[lineNdx].positions[0].w(), scene.lines[lineNdx].positions[0].y() / scene.lines[lineNdx].positions[0].w()),
			tcu::Vec2(scene.lines[lineNdx].positions[1].x() / scene.lines[lineNdx].positions[1].w(), scene.lines[lineNdx].positions[1].y() / scene.lines[lineNdx].positions[1].w()),
		};
		const tcu::Vec4 lineScreenSpace[2] =
		{
			tcu::Vec4((lineNormalizedDeviceSpace[0].x() + 1.0f) * 0.5f * (float)surface.getWidth(), (lineNormalizedDeviceSpace[0].y() + 1.0f) * 0.5f * (float)surface.getHeight(), 0.0f, 1.0f),
			tcu::Vec4((lineNormalizedDeviceSpace[1].x() + 1.0f) * 0.5f * (float)surface.getWidth(), (lineNormalizedDeviceSpace[1].y() + 1.0f) * 0.5f * (float)surface.getHeight(), 0.0f, 1.0f),
		};

		rasterizer.init(lineScreenSpace[0], lineScreenSpace[1], scene.lineWidth);

		// calculate majority of later use
		lineIsXMajor[lineNdx] = de::abs(lineScreenSpace[1].x() - lineScreenSpace[0].x()) >= de::abs(lineScreenSpace[1].y() - lineScreenSpace[0].y());

		for (;;)
		{
			const int			maxPackets			= 32;
			int					numRasterized		= 0;
			rr::FragmentPacket	packets[maxPackets];

			rasterizer.rasterize(packets, DE_NULL, maxPackets, numRasterized);

			for (int packetNdx = 0; packetNdx < numRasterized; ++packetNdx)
			{
				for (int fragNdx = 0; fragNdx < 4; ++fragNdx)
				{
					if ((deUint32)packets[packetNdx].coverage & (1 << fragNdx))
					{
						const tcu::IVec2 fragPos = packets[packetNdx].position + tcu::IVec2(fragNdx%2, fragNdx/2);

						// Check for overdraw
						if (!overdrawInReference)
							overdrawInReference = referenceLineMap.getAccess().getPixelInt(fragPos.x(), fragPos.y()).x() != 0;

						// Output pixel
						referenceLineMap.getAccess().setPixel(tcu::IVec4(lineNdx + 1, 0, 0, 0), fragPos.x(), fragPos.y());
					}
				}
			}

			if (numRasterized != maxPackets)
				break;
		}
	}

	// Requirement 1: The coordinates of a fragment produced by the algorithm may not deviate by more than one unit
	{
		tcu::Surface	errorMask			(surface.getWidth(), surface.getHeight());
		bool			missingFragments	= false;

		tcu::clear(errorMask.getAccess(), tcu::IVec4(0, 255, 0, 255));

		log << tcu::TestLog::Message << "Searching for deviating fragments." << tcu::TestLog::EndMessage;

		for (int y = 0; y < referenceLineMap.getHeight(); ++y)
		for (int x = 0; x < referenceLineMap.getWidth(); ++x)
		{
			const bool reference	= referenceLineMap.getAccess().getPixelInt(x, y).x() != 0;
			const bool result		= compareColors(surface.getPixel(x, y), tcu::RGBA::white, args.redBits, args.greenBits, args.blueBits);

			if (reference)
				++referenceFragments;
			if (result)
				++resultFragments;

			if (reference == result)
				continue;

			// Reference fragment here, matching result fragment must be nearby
			if (reference && !result)
			{
				bool foundFragment = false;

				if (x == 0 || y == 0 || x == referenceLineMap.getWidth() - 1 || y == referenceLineMap.getHeight() -1)
				{
					// image boundary, missing fragment could be over the image edge
					foundFragment = true;
				}

				// find nearby fragment
				for (int dy = -1; dy < 2 && !foundFragment; ++dy)
				for (int dx = -1; dx < 2 && !foundFragment; ++dx)
				{
					if (compareColors(surface.getPixel(x+dx, y+dy), tcu::RGBA::white, args.redBits, args.greenBits, args.blueBits))
						foundFragment = true;
				}

				if (!foundFragment)
				{
					missingFragments = true;
					errorMask.setPixel(x, y, tcu::RGBA::red);
				}
			}
		}

		if (missingFragments)
		{
			log << tcu::TestLog::Message << "Invalid deviation(s) found." << tcu::TestLog::EndMessage;
			log << tcu::TestLog::ImageSet("Verification result", "Result of rendering")
				<< tcu::TestLog::Image("Result", "Result",			surface)
				<< tcu::TestLog::Image("ErrorMask", "ErrorMask",	errorMask)
				<< tcu::TestLog::EndImageSet;

			imageShown = true;
			allOK = false;
		}
		else
		{
			log << tcu::TestLog::Message << "No invalid deviations found." << tcu::TestLog::EndMessage;
		}
	}

	// Requirement 2: The total number of fragments produced by the algorithm may differ from
	//                that produced by the diamond-exit rule by no more than one.
	{
		// Check is not valid if the primitives intersect or otherwise share same fragments
		if (!overdrawInReference)
		{
			int allowedDeviation = (int)scene.lines.size() * lineWidth; // one pixel per primitive in the major direction

			log << tcu::TestLog::Message << "Verifying fragment counts:\n"
				<< "\tDiamond-exit rule: " << referenceFragments << " fragments.\n"
				<< "\tResult image: " << resultFragments << " fragments.\n"
				<< "\tAllowing deviation of " << allowedDeviation << " fragments.\n"
				<< tcu::TestLog::EndMessage;

			if (deAbs32(referenceFragments - resultFragments) > allowedDeviation)
			{
				tcu::Surface reference(surface.getWidth(), surface.getHeight());

				// show a helpful reference image
				tcu::clear(reference.getAccess(), tcu::IVec4(0, 0, 0, 255));
				for (int y = 0; y < surface.getHeight(); ++y)
				for (int x = 0; x < surface.getWidth(); ++x)
					if (referenceLineMap.getAccess().getPixelInt(x, y).x())
						reference.setPixel(x, y, tcu::RGBA::white);

				log << tcu::TestLog::Message << "Invalid fragment count in result image." << tcu::TestLog::EndMessage;
				log << tcu::TestLog::ImageSet("Verification result", "Result of rendering")
					<< tcu::TestLog::Image("Reference", "Reference",	reference)
					<< tcu::TestLog::Image("Result", "Result",			surface)
					<< tcu::TestLog::EndImageSet;

				allOK = false;
				imageShown = true;
			}
			else
			{
				log << tcu::TestLog::Message << "Fragment count is valid." << tcu::TestLog::EndMessage;
			}
		}
		else
		{
			log << tcu::TestLog::Message << "Overdraw in scene. Fragment count cannot be verified. Skipping fragment count checks." << tcu::TestLog::EndMessage;
		}
	}

	// Requirement 3: Line width must be constant
	{
		bool invalidWidthFound = false;

		log << tcu::TestLog::Message << "Verifying line widths of the x-major lines." << tcu::TestLog::EndMessage;
		for (int y = 1; y < referenceLineMap.getHeight() - 1; ++y)
		{
			bool	fullyVisibleLine		= false;
			bool	previousPixelUndefined	= false;
			int		currentLine				= 0;
			int		currentWidth			= 1;

			for (int x = 1; x < referenceLineMap.getWidth() - 1; ++x)
			{
				const bool	result	= compareColors(surface.getPixel(x, y), tcu::RGBA::white, args.redBits, args.greenBits, args.blueBits);
				int			lineID	= 0;

				// Which line does this fragment belong to?

				if (result)
				{
					bool multipleNearbyLines = false;

					for (int dy = -1; dy < 2; ++dy)
					for (int dx = -1; dx < 2; ++dx)
					{
						const int nearbyID = referenceLineMap.getAccess().getPixelInt(x+dx, y+dy).x();
						if (nearbyID)
						{
							if (lineID && lineID != nearbyID)
								multipleNearbyLines = true;
							lineID = nearbyID;
						}
					}

					if (multipleNearbyLines)
					{
						// Another line is too close, don't try to calculate width here
						previousPixelUndefined = true;
						continue;
					}
				}

				// Only line with id of lineID is nearby

				if (previousPixelUndefined)
				{
					// The line might have been overdrawn or not
					currentLine = lineID;
					currentWidth = 1;
					fullyVisibleLine = false;
					previousPixelUndefined = false;
				}
				else if (lineID == currentLine)
				{
					// Current line continues
					++currentWidth;
				}
				else if (lineID > currentLine)
				{
					// Another line was drawn over or the line ends
					currentLine = lineID;
					currentWidth = 1;
					fullyVisibleLine = true;
				}
				else
				{
					// The line ends
					if (fullyVisibleLine && !lineIsXMajor[currentLine-1])
					{
						// check width
						if (currentWidth != lineWidth)
						{
							log << tcu::TestLog::Message << "\tInvalid line width at (" << x - currentWidth << ", " << y << ") - (" << x - 1 << ", " << y << "). Detected width of " << currentWidth << ", expected " << lineWidth << tcu::TestLog::EndMessage;
							invalidWidthFound = true;
						}
					}

					currentLine = lineID;
					currentWidth = 1;
					fullyVisibleLine = false;
				}
			}
		}

		log << tcu::TestLog::Message << "Verifying line widths of the y-major lines." << tcu::TestLog::EndMessage;
		for (int x = 1; x < referenceLineMap.getWidth() - 1; ++x)
		{
			bool	fullyVisibleLine		= false;
			bool	previousPixelUndefined	= false;
			int		currentLine				= 0;
			int		currentWidth			= 1;

			for (int y = 1; y < referenceLineMap.getHeight() - 1; ++y)
			{
				const bool	result	= compareColors(surface.getPixel(x, y), tcu::RGBA::white, args.redBits, args.greenBits, args.blueBits);
				int			lineID	= 0;

				// Which line does this fragment belong to?

				if (result)
				{
					bool multipleNearbyLines = false;

					for (int dy = -1; dy < 2; ++dy)
					for (int dx = -1; dx < 2; ++dx)
					{
						const int nearbyID = referenceLineMap.getAccess().getPixelInt(x+dx, y+dy).x();
						if (nearbyID)
						{
							if (lineID && lineID != nearbyID)
								multipleNearbyLines = true;
							lineID = nearbyID;
						}
					}

					if (multipleNearbyLines)
					{
						// Another line is too close, don't try to calculate width here
						previousPixelUndefined = true;
						continue;
					}
				}

				// Only line with id of lineID is nearby

				if (previousPixelUndefined)
				{
					// The line might have been overdrawn or not
					currentLine = lineID;
					currentWidth = 1;
					fullyVisibleLine = false;
					previousPixelUndefined = false;
				}
				else if (lineID == currentLine)
				{
					// Current line continues
					++currentWidth;
				}
				else if (lineID > currentLine)
				{
					// Another line was drawn over or the line ends
					currentLine = lineID;
					currentWidth = 1;
					fullyVisibleLine = true;
				}
				else
				{
					// The line ends
					if (fullyVisibleLine && lineIsXMajor[currentLine-1])
					{
						// check width
						if (currentWidth != lineWidth)
						{
							log << tcu::TestLog::Message << "\tInvalid line width at (" << x << ", " << y - currentWidth << ") - (" << x  << ", " << y - 1 << "). Detected width of " << currentWidth << ", expected " << lineWidth << tcu::TestLog::EndMessage;
							invalidWidthFound = true;
						}
					}

					currentLine = lineID;
					currentWidth = 1;
					fullyVisibleLine = false;
				}
			}
		}

		if (invalidWidthFound)
		{
			log << tcu::TestLog::Message << "Invalid line width found, image is not valid." << tcu::TestLog::EndMessage;
			allOK = false;
		}
		else
		{
			log << tcu::TestLog::Message << "Line widths are valid." << tcu::TestLog::EndMessage;
		}
	}

	//\todo [2013-10-24 jarkko].
	//Requirement 4. If two line segments share a common endpoint, and both segments are either
	//x-major (both left-to-right or both right-to-left) or y-major (both bottom-totop
	//or both top-to-bottom), then rasterizing both segments may not produce
	//duplicate fragments, nor may any fragments be omitted so as to interrupt
	//continuity of the connected segments.

	if (!imageShown)
	{
		log << tcu::TestLog::ImageSet("Verification result", "Result of rendering")
			<< tcu::TestLog::Image("Result", "Result", surface)
			<< tcu::TestLog::EndImageSet;
	}

	return allOK;
}

struct SingleSampleLineCoverageCandidate
{
	int			lineNdx;
	tcu::IVec3	colorMin;
	tcu::IVec3	colorMax;
	tcu::Vec3	colorMinF;
	tcu::Vec3	colorMaxF;
	tcu::Vec3	valueRangeMin;
	tcu::Vec3	valueRangeMax;
};

bool verifySinglesampleLineGroupInterpolation (const tcu::Surface& surface, const LineSceneSpec& scene, const RasterizationArguments& args, tcu::TestLog& log)
{
	DE_ASSERT(deFloatFrac(scene.lineWidth) != 0.5f); // rounding direction is not defined, disallow undefined cases
	DE_ASSERT(scene.lines.size() < 8); // coverage indices are stored as bitmask in a unsigned 8-bit ints

	const tcu::RGBA		invalidPixelColor	= tcu::RGBA(255, 0, 0, 255);
	const tcu::IVec2	viewportSize		= tcu::IVec2(surface.getWidth(), surface.getHeight());
	const int			errorFloodThreshold	= 4;
	int					errorCount			= 0;
	tcu::Surface		errorMask			(surface.getWidth(), surface.getHeight());
	int					invalidPixels		= 0;

	// log format

	log << tcu::TestLog::Message << "Verifying rasterization result. Native format is RGB" << args.redBits << args.greenBits << args.blueBits << tcu::TestLog::EndMessage;
	if (args.redBits > 8 || args.greenBits > 8 || args.blueBits > 8)
		log << tcu::TestLog::Message << "Warning! More than 8 bits in a color channel, this may produce false negatives." << tcu::TestLog::EndMessage;

	// Reference renderer produces correct fragments using the diamond-exit-rule. Make 2D int array, store line coverage as a 8-bit bitfield
	// The map is used to find lines with potential coverage to a given pixel
	tcu::TextureLevel referenceLineMap(tcu::TextureFormat(tcu::TextureFormat::R, tcu::TextureFormat::UNSIGNED_INT8), surface.getWidth(), surface.getHeight());
	tcu::clear(referenceLineMap.getAccess(), tcu::IVec4(0, 0, 0, 0));

	tcu::clear(errorMask.getAccess(), tcu::Vec4(0.0f, 0.0f, 0.0f, 1.0f));

	for (int lineNdx = 0; lineNdx < (int)scene.lines.size(); ++lineNdx)
	{
		rr::SingleSampleLineRasterizer rasterizer(tcu::IVec4(0, 0, surface.getWidth(), surface.getHeight()));

		const tcu::Vec2 lineNormalizedDeviceSpace[2] =
		{
			tcu::Vec2(scene.lines[lineNdx].positions[0].x() / scene.lines[lineNdx].positions[0].w(), scene.lines[lineNdx].positions[0].y() / scene.lines[lineNdx].positions[0].w()),
			tcu::Vec2(scene.lines[lineNdx].positions[1].x() / scene.lines[lineNdx].positions[1].w(), scene.lines[lineNdx].positions[1].y() / scene.lines[lineNdx].positions[1].w()),
		};
		const tcu::Vec4 lineScreenSpace[2] =
		{
			tcu::Vec4((lineNormalizedDeviceSpace[0].x() + 1.0f) * 0.5f * (float)surface.getWidth(), (lineNormalizedDeviceSpace[0].y() + 1.0f) * 0.5f * (float)surface.getHeight(), 0.0f, 1.0f),
			tcu::Vec4((lineNormalizedDeviceSpace[1].x() + 1.0f) * 0.5f * (float)surface.getWidth(), (lineNormalizedDeviceSpace[1].y() + 1.0f) * 0.5f * (float)surface.getHeight(), 0.0f, 1.0f),
		};

		rasterizer.init(lineScreenSpace[0], lineScreenSpace[1], scene.lineWidth);

		// Calculate correct line coverage
		for (;;)
		{
			const int			maxPackets			= 32;
			int					numRasterized		= 0;
			rr::FragmentPacket	packets[maxPackets];

			rasterizer.rasterize(packets, DE_NULL, maxPackets, numRasterized);

			for (int packetNdx = 0; packetNdx < numRasterized; ++packetNdx)
			{
				for (int fragNdx = 0; fragNdx < 4; ++fragNdx)
				{
					if ((deUint32)packets[packetNdx].coverage & (1 << fragNdx))
					{
						const tcu::IVec2	fragPos			= packets[packetNdx].position + tcu::IVec2(fragNdx%2, fragNdx/2);
						const int			previousMask	= referenceLineMap.getAccess().getPixelInt(fragPos.x(), fragPos.y()).x();
						const int			newMask			= (previousMask) | (1UL << lineNdx);

						referenceLineMap.getAccess().setPixel(tcu::IVec4(newMask, 0, 0, 0), fragPos.x(), fragPos.y());
					}
				}
			}

			if (numRasterized != maxPackets)
				break;
		}
	}

	// Find all possible lines with coverage, check pixel color matches one of them

	for (int y = 1; y < surface.getHeight() - 1; ++y)
	for (int x = 1; x < surface.getWidth()  - 1; ++x)
	{
		const tcu::RGBA		color					= surface.getPixel(x, y);
		const tcu::IVec3	pixelNativeColor		= convertRGB8ToNativeFormat(color, args);	// Convert pixel color from rgba8 to the real pixel format. Usually rgba8 or 565
		int					lineCoverageSet			= 0;										// !< lines that may cover this fragment
		int					lineSurroundingCoverage = 0xFFFF;									// !< lines that will cover this fragment
		bool				matchFound				= false;
		const tcu::IVec3	formatLimit				((1 << args.redBits) - 1, (1 << args.greenBits) - 1, (1 << args.blueBits) - 1);

		std::vector<SingleSampleLineCoverageCandidate> candidates;

		// Find lines with possible coverage

		for (int dy = -1; dy < 2; ++dy)
		for (int dx = -1; dx < 2; ++dx)
		{
			const int coverage = referenceLineMap.getAccess().getPixelInt(x+dx, y+dy).x();

			lineCoverageSet			|= coverage;
			lineSurroundingCoverage	&= coverage;
		}

		// background color is possible?
		if (lineSurroundingCoverage == 0 && compareColors(color, tcu::RGBA::black, args.redBits, args.greenBits, args.blueBits))
			continue;

		// Check those lines

		for (int lineNdx = 0; lineNdx < (int)scene.lines.size(); ++lineNdx)
		{
			if (((lineCoverageSet >> lineNdx) & 0x01) != 0)
			{
				const LineInterpolationRange range = calcSingleSampleLineInterpolationRange(scene.lines[lineNdx].positions[0],
																							scene.lines[lineNdx].positions[1],
																							tcu::IVec2(x, y),
																							viewportSize,
																							args.subpixelBits);

				const tcu::Vec4		valueMin		= de::clamp(range.min.x(), 0.0f, 1.0f) * scene.lines[lineNdx].colors[0] + de::clamp(range.min.y(), 0.0f, 1.0f) * scene.lines[lineNdx].colors[1];
				const tcu::Vec4		valueMax		= de::clamp(range.max.x(), 0.0f, 1.0f) * scene.lines[lineNdx].colors[0] + de::clamp(range.max.y(), 0.0f, 1.0f) * scene.lines[lineNdx].colors[1];

				const tcu::Vec3		colorMinF		(de::clamp(valueMin.x() * formatLimit.x(), 0.0f, (float)formatLimit.x()),
													 de::clamp(valueMin.y() * formatLimit.y(), 0.0f, (float)formatLimit.y()),
													 de::clamp(valueMin.z() * formatLimit.z(), 0.0f, (float)formatLimit.z()));
				const tcu::Vec3		colorMaxF		(de::clamp(valueMax.x() * formatLimit.x(), 0.0f, (float)formatLimit.x()),
													 de::clamp(valueMax.y() * formatLimit.y(), 0.0f, (float)formatLimit.y()),
													 de::clamp(valueMax.z() * formatLimit.z(), 0.0f, (float)formatLimit.z()));
				const tcu::IVec3	colorMin		((int)deFloatFloor(colorMinF.x()),
													 (int)deFloatFloor(colorMinF.y()),
													 (int)deFloatFloor(colorMinF.z()));
				const tcu::IVec3	colorMax		((int)deFloatCeil (colorMaxF.x()),
													 (int)deFloatCeil (colorMaxF.y()),
													 (int)deFloatCeil (colorMaxF.z()));

				// Verify validity
				if (pixelNativeColor.x() < colorMin.x() ||
					pixelNativeColor.y() < colorMin.y() ||
					pixelNativeColor.z() < colorMin.z() ||
					pixelNativeColor.x() > colorMax.x() ||
					pixelNativeColor.y() > colorMax.y() ||
					pixelNativeColor.z() > colorMax.z())
				{
					if (errorCount < errorFloodThreshold)
					{
						// Store candidate information for logging
						SingleSampleLineCoverageCandidate candidate;

						candidate.lineNdx		= lineNdx;
						candidate.colorMin		= colorMin;
						candidate.colorMax		= colorMax;
						candidate.colorMinF		= colorMinF;
						candidate.colorMaxF		= colorMaxF;
						candidate.valueRangeMin	= valueMin.swizzle(0, 1, 2);
						candidate.valueRangeMax	= valueMax.swizzle(0, 1, 2);

						candidates.push_back(candidate);
					}
				}
				else
				{
					matchFound = true;
					break;
				}
			}
		}

		if (matchFound)
			continue;

		// invalid fragment
		++invalidPixels;
		errorMask.setPixel(x, y, invalidPixelColor);

		++errorCount;

		// don't fill the logs with too much data
		if (errorCount < errorFloodThreshold)
		{
			log << tcu::TestLog::Message
				<< "Found an invalid pixel at (" << x << "," << y << "), " << (int)candidates.size() << " candidate reference value(s) found:\n"
				<< "\tPixel color:\t\t" << color << "\n"
				<< "\tNative color:\t\t" << pixelNativeColor << "\n"
				<< tcu::TestLog::EndMessage;

			for (int candidateNdx = 0; candidateNdx < (int)candidates.size(); ++candidateNdx)
			{
				const SingleSampleLineCoverageCandidate& candidate = candidates[candidateNdx];

				log << tcu::TestLog::Message << "\tCandidate (line " << candidate.lineNdx << "):\n"
					<< "\t\tReference native color min: " << tcu::clamp(candidate.colorMin, tcu::IVec3(0,0,0), formatLimit) << "\n"
					<< "\t\tReference native color max: " << tcu::clamp(candidate.colorMax, tcu::IVec3(0,0,0), formatLimit) << "\n"
					<< "\t\tReference native float min: " << tcu::clamp(candidate.colorMinF, tcu::Vec3(0.0f, 0.0f, 0.0f), formatLimit.cast<float>()) << "\n"
					<< "\t\tReference native float max: " << tcu::clamp(candidate.colorMaxF, tcu::Vec3(0.0f, 0.0f, 0.0f), formatLimit.cast<float>()) << "\n"
					<< "\t\tFmin:\t" << tcu::clamp(candidate.valueRangeMin, tcu::Vec3(0.0f, 0.0f, 0.0f), tcu::Vec3(1.0f, 1.0f, 1.0f)) << "\n"
					<< "\t\tFmax:\t" << tcu::clamp(candidate.valueRangeMax, tcu::Vec3(0.0f, 0.0f, 0.0f), tcu::Vec3(1.0f, 1.0f, 1.0f)) << "\n"
					<< tcu::TestLog::EndMessage;
			}
		}
	}

	// don't just hide failures
	if (errorCount > errorFloodThreshold)
		log << tcu::TestLog::Message << "Omitted " << (errorCount-errorFloodThreshold) << " pixel error description(s)." << tcu::TestLog::EndMessage;

	// report result
	if (invalidPixels)
	{
		log << tcu::TestLog::Message << invalidPixels << " invalid pixel(s) found." << tcu::TestLog::EndMessage;
		log << tcu::TestLog::ImageSet("Verification result", "Result of rendering")
			<< tcu::TestLog::Image("Result", "Result",			surface)
			<< tcu::TestLog::Image("ErrorMask", "ErrorMask",	errorMask)
			<< tcu::TestLog::EndImageSet;

		return false;
	}
	else
	{
		log << tcu::TestLog::Message << "No invalid pixels found." << tcu::TestLog::EndMessage;
		log << tcu::TestLog::ImageSet("Verification result", "Result of rendering")
			<< tcu::TestLog::Image("Result", "Result", surface)
			<< tcu::TestLog::EndImageSet;

		return true;
	}
}

} // anonymous

CoverageType calculateTriangleCoverage (const tcu::Vec4& p0, const tcu::Vec4& p1, const tcu::Vec4& p2, const tcu::IVec2& pixel, const tcu::IVec2& viewportSize, int subpixelBits, bool multisample)
{
	typedef tcu::Vector<deInt64, 2> I64Vec2;

	const deUint64		numSubPixels						= ((deUint64)1) << subpixelBits;
	const deUint64		pixelHitBoxSize						= (multisample) ? (numSubPixels) : (2+2);	//!< allow 4 central (2x2) for non-multisample pixels. Rounding may move edges 1 subpixel to any direction.
	const bool			order								= isTriangleClockwise(p0, p1, p2);			//!< clockwise / counter-clockwise
	const tcu::Vec4&	orderedP0							= p0;										//!< vertices of a clockwise triangle
	const tcu::Vec4&	orderedP1							= (order) ? (p1) : (p2);
	const tcu::Vec4&	orderedP2							= (order) ? (p2) : (p1);
	const tcu::Vec2		triangleNormalizedDeviceSpace[3]	=
	{
		tcu::Vec2(orderedP0.x() / orderedP0.w(), orderedP0.y() / orderedP0.w()),
		tcu::Vec2(orderedP1.x() / orderedP1.w(), orderedP1.y() / orderedP1.w()),
		tcu::Vec2(orderedP2.x() / orderedP2.w(), orderedP2.y() / orderedP2.w()),
	};
	const tcu::Vec2		triangleScreenSpace[3]				=
	{
		(triangleNormalizedDeviceSpace[0] + tcu::Vec2(1.0f, 1.0f)) * 0.5f * tcu::Vec2((float)viewportSize.x(), (float)viewportSize.y()),
		(triangleNormalizedDeviceSpace[1] + tcu::Vec2(1.0f, 1.0f)) * 0.5f * tcu::Vec2((float)viewportSize.x(), (float)viewportSize.y()),
		(triangleNormalizedDeviceSpace[2] + tcu::Vec2(1.0f, 1.0f)) * 0.5f * tcu::Vec2((float)viewportSize.x(), (float)viewportSize.y()),
	};

	// Broad bounding box - pixel check
	{
		const float minX = de::min(de::min(triangleScreenSpace[0].x(), triangleScreenSpace[1].x()), triangleScreenSpace[2].x());
		const float minY = de::min(de::min(triangleScreenSpace[0].y(), triangleScreenSpace[1].y()), triangleScreenSpace[2].y());
		const float maxX = de::max(de::max(triangleScreenSpace[0].x(), triangleScreenSpace[1].x()), triangleScreenSpace[2].x());
		const float maxY = de::max(de::max(triangleScreenSpace[0].y(), triangleScreenSpace[1].y()), triangleScreenSpace[2].y());

		if ((float)pixel.x() > maxX + 1 ||
			(float)pixel.y() > maxY + 1 ||
			(float)pixel.x() < minX - 1 ||
			(float)pixel.y() < minY - 1)
			return COVERAGE_NONE;
	}

	// Broad triangle - pixel area intersection
	{
		const I64Vec2 pixelCenterPosition = I64Vec2(pixel.x(), pixel.y()) * I64Vec2(numSubPixels, numSubPixels) + I64Vec2(numSubPixels / 2, numSubPixels / 2);
		const I64Vec2 triangleSubPixelSpaceRound[3] =
		{
			I64Vec2(deRoundFloatToInt32(triangleScreenSpace[0].x()*numSubPixels), deRoundFloatToInt32(triangleScreenSpace[0].y()*numSubPixels)),
			I64Vec2(deRoundFloatToInt32(triangleScreenSpace[1].x()*numSubPixels), deRoundFloatToInt32(triangleScreenSpace[1].y()*numSubPixels)),
			I64Vec2(deRoundFloatToInt32(triangleScreenSpace[2].x()*numSubPixels), deRoundFloatToInt32(triangleScreenSpace[2].y()*numSubPixels)),
		};

		// Check (using cross product) if pixel center is
		// a) too far from any edge
		// b) fully inside all edges
		bool insideAllEdges = true;
		for (int vtxNdx = 0; vtxNdx < 3; ++vtxNdx)
		{
			const int		otherVtxNdx				= (vtxNdx + 1) % 3;
			const deInt64	maxPixelDistanceSquared	= pixelHitBoxSize*pixelHitBoxSize; // Max distance from the pixel center from within the pixel is (sqrt(2) * boxWidth/2). Use 2x value for rounding tolerance
			const I64Vec2	edge					= triangleSubPixelSpaceRound[otherVtxNdx]	- triangleSubPixelSpaceRound[vtxNdx];
			const I64Vec2	v						= pixelCenterPosition						- triangleSubPixelSpaceRound[vtxNdx];
			const deInt64	crossProduct			= (edge.x() * v.y() - edge.y() * v.x());

			// distance from edge: (edge x v) / |edge|
			//     (edge x v) / |edge| > maxPixelDistance
			// ==> (edge x v)^2 / edge^2 > maxPixelDistance^2    | edge x v > 0
			// ==> (edge x v)^2 > maxPixelDistance^2 * edge^2
			if (crossProduct < 0 && crossProduct*crossProduct > maxPixelDistanceSquared * tcu::lengthSquared(edge))
				return COVERAGE_NONE;
			if (crossProduct < 0 || crossProduct*crossProduct < maxPixelDistanceSquared * tcu::lengthSquared(edge))
				insideAllEdges = false;
		}

		if (insideAllEdges)
			return COVERAGE_FULL;
	}

	// Accurate intersection for edge pixels
	{
		//  In multisampling, the sample points can be anywhere in the pixel, and in single sampling only in the center.
		const I64Vec2 pixelCorners[4] =
		{
			I64Vec2((pixel.x()+0) * numSubPixels, (pixel.y()+0) * numSubPixels),
			I64Vec2((pixel.x()+1) * numSubPixels, (pixel.y()+0) * numSubPixels),
			I64Vec2((pixel.x()+1) * numSubPixels, (pixel.y()+1) * numSubPixels),
			I64Vec2((pixel.x()+0) * numSubPixels, (pixel.y()+1) * numSubPixels),
		};
		const I64Vec2 pixelCenterCorners[4] =
		{
			I64Vec2(pixel.x() * numSubPixels + numSubPixels/2 + 0, pixel.y() * numSubPixels + numSubPixels/2 + 0),
			I64Vec2(pixel.x() * numSubPixels + numSubPixels/2 + 1, pixel.y() * numSubPixels + numSubPixels/2 + 0),
			I64Vec2(pixel.x() * numSubPixels + numSubPixels/2 + 1, pixel.y() * numSubPixels + numSubPixels/2 + 1),
			I64Vec2(pixel.x() * numSubPixels + numSubPixels/2 + 0, pixel.y() * numSubPixels + numSubPixels/2 + 1),
		};

		// both rounding directions
		const I64Vec2 triangleSubPixelSpaceFloor[3] =
		{
			I64Vec2(deFloorFloatToInt32(triangleScreenSpace[0].x()*numSubPixels), deFloorFloatToInt32(triangleScreenSpace[0].y()*numSubPixels)),
			I64Vec2(deFloorFloatToInt32(triangleScreenSpace[1].x()*numSubPixels), deFloorFloatToInt32(triangleScreenSpace[1].y()*numSubPixels)),
			I64Vec2(deFloorFloatToInt32(triangleScreenSpace[2].x()*numSubPixels), deFloorFloatToInt32(triangleScreenSpace[2].y()*numSubPixels)),
		};
		const I64Vec2 triangleSubPixelSpaceCeil[3] =
		{
			I64Vec2(deCeilFloatToInt32(triangleScreenSpace[0].x()*numSubPixels), deCeilFloatToInt32(triangleScreenSpace[0].y()*numSubPixels)),
			I64Vec2(deCeilFloatToInt32(triangleScreenSpace[1].x()*numSubPixels), deCeilFloatToInt32(triangleScreenSpace[1].y()*numSubPixels)),
			I64Vec2(deCeilFloatToInt32(triangleScreenSpace[2].x()*numSubPixels), deCeilFloatToInt32(triangleScreenSpace[2].y()*numSubPixels)),
		};
		const I64Vec2* const corners = (multisample) ? (pixelCorners) : (pixelCenterCorners);

		// Test if any edge (with any rounding) intersects the pixel (boundary). If it does => Partial. If not => fully inside or outside

		for (int edgeNdx = 0; edgeNdx < 3; ++edgeNdx)
		for (int startRounding = 0; startRounding < 4; ++startRounding)
		for (int endRounding = 0; endRounding < 4; ++endRounding)
		{
			const int		nextEdgeNdx	= (edgeNdx+1) % 3;
			const I64Vec2	startPos	((startRounding&0x01)	? (triangleSubPixelSpaceFloor[edgeNdx].x())		: (triangleSubPixelSpaceCeil[edgeNdx].x()),		(startRounding&0x02)	? (triangleSubPixelSpaceFloor[edgeNdx].y())		: (triangleSubPixelSpaceCeil[edgeNdx].y()));
			const I64Vec2	endPos		((endRounding&0x01)		? (triangleSubPixelSpaceFloor[nextEdgeNdx].x())	: (triangleSubPixelSpaceCeil[nextEdgeNdx].x()),	(endRounding&0x02)		? (triangleSubPixelSpaceFloor[nextEdgeNdx].y())	: (triangleSubPixelSpaceCeil[nextEdgeNdx].y()));
			const I64Vec2	edge		= endPos - startPos;

			for (int pixelEdgeNdx = 0; pixelEdgeNdx < 4; ++pixelEdgeNdx)
			{
				const int pixelEdgeEnd = (pixelEdgeNdx + 1) % 4;

				if (lineLineIntersect(startPos, endPos, corners[pixelEdgeNdx], corners[pixelEdgeEnd]))
					return COVERAGE_PARTIAL;
			}
		}

		// fully inside or outside
		for (int edgeNdx = 0; edgeNdx < 3; ++edgeNdx)
		{
			const int		nextEdgeNdx		= (edgeNdx+1) % 3;
			const I64Vec2&	startPos		= triangleSubPixelSpaceFloor[edgeNdx];
			const I64Vec2&	endPos			= triangleSubPixelSpaceFloor[nextEdgeNdx];
			const I64Vec2	edge			= endPos - startPos;
			const I64Vec2	v				= corners[0] - endPos;
			const deInt64	crossProduct	= (edge.x() * v.y() - edge.y() * v.x());

			// a corner of the pixel is outside => "fully inside" option is impossible
			if (crossProduct < 0)
				return COVERAGE_NONE;
		}

		return COVERAGE_FULL;
	}
}

bool verifyTriangleGroupRasterization (const tcu::Surface& surface, const TriangleSceneSpec& scene, const RasterizationArguments& args, tcu::TestLog& log, VerificationMode mode)
{
	DE_ASSERT(mode < VERIFICATIONMODE_LAST);

	const tcu::RGBA		backGroundColor				= tcu::RGBA(0, 0, 0, 255);
	const tcu::RGBA		triangleColor				= tcu::RGBA(255, 255, 255, 255);
	const tcu::RGBA		missingPixelColor			= tcu::RGBA(255, 0, 255, 255);
	const tcu::RGBA		unexpectedPixelColor		= tcu::RGBA(255, 0, 0, 255);
	const tcu::RGBA		partialPixelColor			= tcu::RGBA(255, 255, 0, 255);
	const tcu::RGBA		primitivePixelColor			= tcu::RGBA(30, 30, 30, 255);
	const int			weakVerificationThreshold	= 10;
	const bool			multisampled				= (args.numSamples != 0);
	const tcu::IVec2	viewportSize				= tcu::IVec2(surface.getWidth(), surface.getHeight());
	int					missingPixels				= 0;
	int					unexpectedPixels			= 0;
	int					subPixelBits				= args.subpixelBits;
	tcu::TextureLevel	coverageMap					(tcu::TextureFormat(tcu::TextureFormat::R, tcu::TextureFormat::UNSIGNED_INT8), surface.getWidth(), surface.getHeight());
	tcu::Surface		errorMask					(surface.getWidth(), surface.getHeight());

	// subpixel bits in in a valid range?

	if (subPixelBits < 0)
	{
		log << tcu::TestLog::Message << "Invalid subpixel count (" << subPixelBits << "), assuming 0" << tcu::TestLog::EndMessage;
		subPixelBits = 0;
	}
	else if (subPixelBits > 16)
	{
		// At high subpixel bit counts we might overflow. Checking at lower bit count is ok, but is less strict
		log << tcu::TestLog::Message << "Subpixel count is greater than 16 (" << subPixelBits << "). Checking results using less strict 16 bit requirements. This may produce false positives." << tcu::TestLog::EndMessage;
		subPixelBits = 16;
	}

	// generate coverage map

	tcu::clear(coverageMap.getAccess(), tcu::IVec4(COVERAGE_NONE, 0, 0, 0));

	for (int triNdx = 0; triNdx < (int)scene.triangles.size(); ++triNdx)
	{
		const tcu::IVec4 aabb = getTriangleAABB(scene.triangles[triNdx], viewportSize);

		for (int y = de::max(0, aabb.y()); y <= de::min(aabb.w(), coverageMap.getHeight() - 1); ++y)
		for (int x = de::max(0, aabb.x()); x <= de::min(aabb.z(), coverageMap.getWidth() - 1); ++x)
		{
			if (coverageMap.getAccess().getPixelUint(x, y).x() == COVERAGE_FULL)
				continue;

			const CoverageType coverage = calculateTriangleCoverage(scene.triangles[triNdx].positions[0],
																	scene.triangles[triNdx].positions[1],
																	scene.triangles[triNdx].positions[2],
																	tcu::IVec2(x, y),
																	viewportSize,
																	subPixelBits,
																	multisampled);

			if (coverage == COVERAGE_FULL)
			{
				coverageMap.getAccess().setPixel(tcu::IVec4(COVERAGE_FULL, 0, 0, 0), x, y);
			}
			else if (coverage == COVERAGE_PARTIAL)
			{
				CoverageType resultCoverage = COVERAGE_PARTIAL;

				// Sharing an edge with another triangle?
				// There should always be such a triangle, but the pixel in the other triangle might be
				// on multiple edges, some of which are not shared. In these cases the coverage cannot be determined.
				// Assume full coverage if the pixel is only on a shared edge in shared triangle too.
				if (pixelOnlyOnASharedEdge(tcu::IVec2(x, y), scene.triangles[triNdx], viewportSize))
				{
					bool friendFound = false;
					for (int friendTriNdx = 0; friendTriNdx < (int)scene.triangles.size(); ++friendTriNdx)
					{
						if (friendTriNdx != triNdx && pixelOnlyOnASharedEdge(tcu::IVec2(x, y), scene.triangles[friendTriNdx], viewportSize))
						{
							friendFound = true;
							break;
						}
					}

					if (friendFound)
						resultCoverage = COVERAGE_FULL;
				}

				coverageMap.getAccess().setPixel(tcu::IVec4(resultCoverage, 0, 0, 0), x, y);
			}
		}
	}

	// check pixels

	tcu::clear(errorMask.getAccess(), tcu::Vec4(0.0f, 0.0f, 0.0f, 1.0f));

	for (int y = 0; y < surface.getHeight(); ++y)
	for (int x = 0; x < surface.getWidth(); ++x)
	{
		const tcu::RGBA		color				= surface.getPixel(x, y);
		const bool			imageNoCoverage		= compareColors(color, backGroundColor, args.redBits, args.greenBits, args.blueBits);
		const bool			imageFullCoverage	= compareColors(color, triangleColor, args.redBits, args.greenBits, args.blueBits);
		CoverageType		referenceCoverage	= (CoverageType)coverageMap.getAccess().getPixelUint(x, y).x();

		switch (referenceCoverage)
		{
			case COVERAGE_NONE:
				if (!imageNoCoverage)
				{
					// coverage where there should not be
					++unexpectedPixels;
					errorMask.setPixel(x, y, unexpectedPixelColor);
				}
				break;

			case COVERAGE_PARTIAL:
				// anything goes
				errorMask.setPixel(x, y, partialPixelColor);
				break;

			case COVERAGE_FULL:
				if (!imageFullCoverage)
				{
					// no coverage where there should be
					++missingPixels;
					errorMask.setPixel(x, y, missingPixelColor);
				}
				else
				{
					errorMask.setPixel(x, y, primitivePixelColor);
				}
				break;

			default:
				DE_ASSERT(false);
		};
	}

	// Output results
	log << tcu::TestLog::Message << "Verifying rasterization result." << tcu::TestLog::EndMessage;

	if (((mode == VERIFICATIONMODE_STRICT) && (missingPixels + unexpectedPixels > 0)) ||
		((mode == VERIFICATIONMODE_WEAK)   && (missingPixels + unexpectedPixels > weakVerificationThreshold)))
	{
		log << tcu::TestLog::Message << "Invalid pixels found:\n\t"
			<< missingPixels << " missing pixels. (Marked with purple)\n\t"
			<< unexpectedPixels << " incorrectly filled pixels. (Marked with red)\n\t"
			<< "Unknown (subpixel on edge) pixels are marked with yellow."
			<< tcu::TestLog::EndMessage;
		log << tcu::TestLog::ImageSet("Verification result", "Result of rendering")
			<< tcu::TestLog::Image("Result",	"Result",		surface)
			<< tcu::TestLog::Image("ErrorMask", "ErrorMask",	errorMask)
			<< tcu::TestLog::EndImageSet;

		return false;
	}
	else
	{
		log << tcu::TestLog::Message << "No invalid pixels found." << tcu::TestLog::EndMessage;
		log << tcu::TestLog::ImageSet("Verification result", "Result of rendering")
			<< tcu::TestLog::Image("Result", "Result", surface)
			<< tcu::TestLog::EndImageSet;

		return true;
	}
}

bool verifyLineGroupRasterization (const tcu::Surface& surface, const LineSceneSpec& scene, const RasterizationArguments& args, tcu::TestLog& log)
{
	const bool multisampled = args.numSamples != 0;

	if (multisampled)
		return verifyMultisampleLineGroupRasterization(surface, scene, args, log);
	else
		return verifySinglesampleLineGroupRasterization(surface, scene, args, log);
}

bool verifyPointGroupRasterization (const tcu::Surface& surface, const PointSceneSpec& scene, const RasterizationArguments& args, tcu::TestLog& log)
{
	// Splitting to triangles is a valid solution in multisampled cases and even in non-multisample cases too.
	return verifyMultisamplePointGroupRasterization(surface, scene, args, log);
}

bool verifyTriangleGroupInterpolation (const tcu::Surface& surface, const TriangleSceneSpec& scene, const RasterizationArguments& args, tcu::TestLog& log)
{
	return verifyTriangleGroupInterpolationWithInterpolator(surface, scene, args, log, TriangleInterpolator(scene));
}

bool verifyLineGroupInterpolation (const tcu::Surface& surface, const LineSceneSpec& scene, const RasterizationArguments& args, tcu::TestLog& log)
{
	const bool multisampled = args.numSamples != 0;

	if (multisampled)
		return verifyMultisampleLineGroupInterpolation(surface, scene, args, log);
	else
		return verifySinglesampleLineGroupInterpolation(surface, scene, args, log);
}

} // StateQueryUtil
} // gls
} // deqp