1 /* 2 * Copyright (C) 2013 The Android Open Source Project 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); 5 * you may not use this file except in compliance with the License. 6 * You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 * See the License for the specific language governing permissions and 14 * limitations under the License. 15 */ 16 17 #include <math.h> 18 #include <utils/Log.h> 19 #include <utils/MathUtils.h> 20 #include <utils/Trace.h> 21 22 #include "AmbientShadow.h" 23 #include "Properties.h" 24 #include "ShadowTessellator.h" 25 #include "SpotShadow.h" 26 #include "Vector.h" 27 28 namespace android { 29 namespace uirenderer { 30 31 void ShadowTessellator::tessellateAmbientShadow(bool isCasterOpaque, const Vector3* casterPolygon, 32 int casterVertexCount, const Vector3& centroid3d, 33 const Rect& casterBounds, const Rect& localClip, 34 float maxZ, VertexBuffer& shadowVertexBuffer) { 35 ATRACE_CALL(); 36 37 // A bunch of parameters to tweak the shadow. 38 // TODO: Allow some of these changable by debug settings or APIs. 39 float heightFactor = 1.0f / 128; 40 const float geomFactor = 64; 41 42 if (CC_UNLIKELY(Properties::overrideAmbientRatio > 0.0f)) { 43 heightFactor *= Properties::overrideAmbientRatio; 44 } 45 46 Rect ambientShadowBounds(casterBounds); 47 ambientShadowBounds.outset(maxZ * geomFactor * heightFactor); 48 49 if (!localClip.intersects(ambientShadowBounds)) { 50 #if DEBUG_SHADOW 51 ALOGD("Ambient shadow is out of clip rect!"); 52 #endif 53 return; 54 } 55 56 AmbientShadow::createAmbientShadow(isCasterOpaque, casterPolygon, casterVertexCount, centroid3d, 57 heightFactor, geomFactor, shadowVertexBuffer); 58 } 59 60 void ShadowTessellator::tessellateSpotShadow(bool isCasterOpaque, const Vector3* casterPolygon, 61 int casterVertexCount, const Vector3& casterCentroid, 62 const mat4& receiverTransform, 63 const Vector3& lightCenter, int lightRadius, 64 const Rect& casterBounds, const Rect& localClip, 65 VertexBuffer& shadowVertexBuffer) { 66 ATRACE_CALL(); 67 68 Vector3 adjustedLightCenter(lightCenter); 69 if (CC_UNLIKELY(Properties::overrideLightPosY > 0)) { 70 adjustedLightCenter.y = -Properties::overrideLightPosY; // negated since this shifts up 71 } 72 if (CC_UNLIKELY(Properties::overrideLightPosZ > 0)) { 73 adjustedLightCenter.z = Properties::overrideLightPosZ; 74 } 75 76 #if DEBUG_SHADOW 77 ALOGD("light center %f %f %f %d", adjustedLightCenter.x, adjustedLightCenter.y, 78 adjustedLightCenter.z, lightRadius); 79 #endif 80 if (isnan(adjustedLightCenter.x) || isnan(adjustedLightCenter.y) || 81 isnan(adjustedLightCenter.z)) { 82 return; 83 } 84 85 // light position (because it's in local space) needs to compensate for receiver transform 86 // TODO: should apply to light orientation, not just position 87 Matrix4 reverseReceiverTransform; 88 reverseReceiverTransform.loadInverse(receiverTransform); 89 reverseReceiverTransform.mapPoint3d(adjustedLightCenter); 90 91 if (CC_UNLIKELY(Properties::overrideLightRadius > 0)) { 92 lightRadius = Properties::overrideLightRadius; 93 } 94 95 // Now light and caster are both in local space, we will check whether 96 // the shadow is within the clip area. 97 Rect lightRect = Rect(adjustedLightCenter.x - lightRadius, adjustedLightCenter.y - lightRadius, 98 adjustedLightCenter.x + lightRadius, adjustedLightCenter.y + lightRadius); 99 lightRect.unionWith(localClip); 100 if (!lightRect.intersects(casterBounds)) { 101 #if DEBUG_SHADOW 102 ALOGD("Spot shadow is out of clip rect!"); 103 #endif 104 return; 105 } 106 107 SpotShadow::createSpotShadow(isCasterOpaque, adjustedLightCenter, lightRadius, casterPolygon, 108 casterVertexCount, casterCentroid, shadowVertexBuffer); 109 110 #if DEBUG_SHADOW 111 if (shadowVertexBuffer.getVertexCount() <= 0) { 112 ALOGD("Spot shadow generation failed %d", shadowVertexBuffer.getVertexCount()); 113 } 114 #endif 115 } 116 117 /** 118 * Calculate the centroid of a 2d polygon. 119 * 120 * @param poly The polygon, which is represented in a Vector2 array. 121 * @param polyLength The length of the polygon in terms of number of vertices. 122 * @return the centroid of the polygon. 123 */ 124 Vector2 ShadowTessellator::centroid2d(const Vector2* poly, int polyLength) { 125 double sumx = 0; 126 double sumy = 0; 127 int p1 = polyLength - 1; 128 double area = 0; 129 for (int p2 = 0; p2 < polyLength; p2++) { 130 double x1 = poly[p1].x; 131 double y1 = poly[p1].y; 132 double x2 = poly[p2].x; 133 double y2 = poly[p2].y; 134 double a = (x1 * y2 - x2 * y1); 135 sumx += (x1 + x2) * a; 136 sumy += (y1 + y2) * a; 137 area += a; 138 p1 = p2; 139 } 140 141 Vector2 centroid = poly[0]; 142 if (area != 0) { 143 centroid = (Vector2){static_cast<float>(sumx / (3 * area)), 144 static_cast<float>(sumy / (3 * area))}; 145 } else { 146 ALOGW("Area is 0 while computing centroid!"); 147 } 148 return centroid; 149 } 150 151 // Make sure p1 -> p2 is going CW around the poly. 152 Vector2 ShadowTessellator::calculateNormal(const Vector2& p1, const Vector2& p2) { 153 Vector2 result = p2 - p1; 154 if (result.x != 0 || result.y != 0) { 155 result.normalize(); 156 // Calculate the normal , which is CCW 90 rotate to the delta. 157 float tempy = result.y; 158 result.y = result.x; 159 result.x = -tempy; 160 } 161 return result; 162 } 163 164 int ShadowTessellator::getExtraVertexNumber(const Vector2& vector1, const Vector2& vector2, 165 float divisor) { 166 // When there is no distance difference, there is no need for extra vertices. 167 if (vector1.lengthSquared() == 0 || vector2.lengthSquared() == 0) { 168 return 0; 169 } 170 // The formula is : 171 // extraNumber = floor(acos(dot(n1, n2)) / (M_PI / EXTRA_VERTEX_PER_PI)) 172 // The value ranges for each step are: 173 // dot( ) --- [-1, 1] 174 // acos( ) --- [0, M_PI] 175 // floor(...) --- [0, EXTRA_VERTEX_PER_PI] 176 float dotProduct = vector1.dot(vector2); 177 // make sure that dotProduct value is in acsof input range [-1, 1] 178 dotProduct = MathUtils::clamp(dotProduct, -1.0f, 1.0f); 179 // TODO: Use look up table for the dotProduct to extraVerticesNumber 180 // computation, if needed. 181 float angle = acosf(dotProduct); 182 return (int)floor(angle / divisor); 183 } 184 185 void ShadowTessellator::checkOverflow(int used, int total, const char* bufferName) { 186 LOG_ALWAYS_FATAL_IF(used > total, "Error: %s overflow!!! used %d, total %d", bufferName, used, 187 total); 188 } 189 190 }; // namespace uirenderer 191 }; // namespace android 192
