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      1 /*
      2 Bullet Continuous Collision Detection and Physics Library
      3 Copyright (c) 2003-2006 Erwin Coumans  http://continuousphysics.com/Bullet/
      4 
      5 This software is provided 'as-is', without any express or implied warranty.
      6 In no event will the authors be held liable for any damages arising from the use of this software.
      7 Permission is granted to anyone to use this software for any purpose,
      8 including commercial applications, and to alter it and redistribute it freely,
      9 subject to the following restrictions:
     10 
     11 1. The origin of this software must not be misrepresented; you must not claim that you wrote the original software. If you use this software in a product, an acknowledgment in the product documentation would be appreciated but is not required.
     12 2. Altered source versions must be plainly marked as such, and must not be misrepresented as being the original software.
     13 3. This notice may not be removed or altered from any source distribution.
     14 */
     15 
     16 //#include <stdio.h>
     17 
     18 #include "BulletCollision/CollisionShapes/btConvexShape.h"
     19 #include "BulletCollision/CollisionShapes/btTriangleShape.h"
     20 #include "BulletCollision/NarrowPhaseCollision/btSubSimplexConvexCast.h"
     21 #include "BulletCollision/NarrowPhaseCollision/btGjkConvexCast.h"
     22 #include "BulletCollision/NarrowPhaseCollision/btContinuousConvexCollision.h"
     23 #include "BulletCollision/NarrowPhaseCollision/btGjkEpaPenetrationDepthSolver.h"
     24 #include "btRaycastCallback.h"
     25 
     26 btTriangleRaycastCallback::btTriangleRaycastCallback(const btVector3& from,const btVector3& to, unsigned int flags)
     27 	:
     28 	m_from(from),
     29 	m_to(to),
     30    //@BP Mod
     31    m_flags(flags),
     32 	m_hitFraction(btScalar(1.))
     33 {
     34 
     35 }
     36 
     37 
     38 
     39 void btTriangleRaycastCallback::processTriangle(btVector3* triangle,int partId, int triangleIndex)
     40 {
     41 	const btVector3 &vert0=triangle[0];
     42 	const btVector3 &vert1=triangle[1];
     43 	const btVector3 &vert2=triangle[2];
     44 
     45 	btVector3 v10; v10 = vert1 - vert0 ;
     46 	btVector3 v20; v20 = vert2 - vert0 ;
     47 
     48 	btVector3 triangleNormal; triangleNormal = v10.cross( v20 );
     49 
     50 	const btScalar dist = vert0.dot(triangleNormal);
     51 	btScalar dist_a = triangleNormal.dot(m_from) ;
     52 	dist_a-= dist;
     53 	btScalar dist_b = triangleNormal.dot(m_to);
     54 	dist_b -= dist;
     55 
     56 	if ( dist_a * dist_b >= btScalar(0.0) )
     57 	{
     58 		return ; // same sign
     59 	}
     60 
     61 	if (((m_flags & kF_FilterBackfaces) != 0) && (dist_a <= btScalar(0.0)))
     62 	{
     63 		// Backface, skip check
     64 		return;
     65 	}
     66 
     67 
     68 	const btScalar proj_length=dist_a-dist_b;
     69 	const btScalar distance = (dist_a)/(proj_length);
     70 	// Now we have the intersection point on the plane, we'll see if it's inside the triangle
     71 	// Add an epsilon as a tolerance for the raycast,
     72 	// in case the ray hits exacly on the edge of the triangle.
     73 	// It must be scaled for the triangle size.
     74 
     75 	if(distance < m_hitFraction)
     76 	{
     77 
     78 
     79 		btScalar edge_tolerance =triangleNormal.length2();
     80 		edge_tolerance *= btScalar(-0.0001);
     81 		btVector3 point; point.setInterpolate3( m_from, m_to, distance);
     82 		{
     83 			btVector3 v0p; v0p = vert0 - point;
     84 			btVector3 v1p; v1p = vert1 - point;
     85 			btVector3 cp0; cp0 = v0p.cross( v1p );
     86 
     87 			if ( (btScalar)(cp0.dot(triangleNormal)) >=edge_tolerance)
     88 			{
     89 
     90 
     91 				btVector3 v2p; v2p = vert2 -  point;
     92 				btVector3 cp1;
     93 				cp1 = v1p.cross( v2p);
     94 				if ( (btScalar)(cp1.dot(triangleNormal)) >=edge_tolerance)
     95 				{
     96 					btVector3 cp2;
     97 					cp2 = v2p.cross(v0p);
     98 
     99 					if ( (btScalar)(cp2.dot(triangleNormal)) >=edge_tolerance)
    100 					{
    101 					  //@BP Mod
    102 					  // Triangle normal isn't normalized
    103 				      triangleNormal.normalize();
    104 
    105 					 //@BP Mod - Allow for unflipped normal when raycasting against backfaces
    106 						if (((m_flags & kF_KeepUnflippedNormal) == 0) && (dist_a <= btScalar(0.0)))
    107 						{
    108 							m_hitFraction = reportHit(-triangleNormal,distance,partId,triangleIndex);
    109 						}
    110 						else
    111 						{
    112 							m_hitFraction = reportHit(triangleNormal,distance,partId,triangleIndex);
    113 						}
    114 					}
    115 				}
    116 			}
    117 		}
    118 	}
    119 }
    120 
    121 
    122 btTriangleConvexcastCallback::btTriangleConvexcastCallback (const btConvexShape* convexShape, const btTransform& convexShapeFrom, const btTransform& convexShapeTo, const btTransform& triangleToWorld, const btScalar triangleCollisionMargin)
    123 {
    124 	m_convexShape = convexShape;
    125 	m_convexShapeFrom = convexShapeFrom;
    126 	m_convexShapeTo = convexShapeTo;
    127 	m_triangleToWorld = triangleToWorld;
    128 	m_hitFraction = 1.0f;
    129 	m_triangleCollisionMargin = triangleCollisionMargin;
    130 	m_allowedPenetration = 0.f;
    131 }
    132 
    133 void
    134 btTriangleConvexcastCallback::processTriangle (btVector3* triangle, int partId, int triangleIndex)
    135 {
    136 	btTriangleShape triangleShape (triangle[0], triangle[1], triangle[2]);
    137     triangleShape.setMargin(m_triangleCollisionMargin);
    138 
    139 	btVoronoiSimplexSolver	simplexSolver;
    140 	btGjkEpaPenetrationDepthSolver	gjkEpaPenetrationSolver;
    141 
    142 //#define  USE_SUBSIMPLEX_CONVEX_CAST 1
    143 //if you reenable USE_SUBSIMPLEX_CONVEX_CAST see commented out code below
    144 #ifdef USE_SUBSIMPLEX_CONVEX_CAST
    145 	btSubsimplexConvexCast convexCaster(m_convexShape, &triangleShape, &simplexSolver);
    146 #else
    147 	//btGjkConvexCast	convexCaster(m_convexShape,&triangleShape,&simplexSolver);
    148 	btContinuousConvexCollision convexCaster(m_convexShape,&triangleShape,&simplexSolver,&gjkEpaPenetrationSolver);
    149 #endif //#USE_SUBSIMPLEX_CONVEX_CAST
    150 
    151 	btConvexCast::CastResult castResult;
    152 	castResult.m_fraction = btScalar(1.);
    153 	castResult.m_allowedPenetration = m_allowedPenetration;
    154 	if (convexCaster.calcTimeOfImpact(m_convexShapeFrom,m_convexShapeTo,m_triangleToWorld, m_triangleToWorld, castResult))
    155 	{
    156 		//add hit
    157 		if (castResult.m_normal.length2() > btScalar(0.0001))
    158 		{
    159 			if (castResult.m_fraction < m_hitFraction)
    160 			{
    161 /* btContinuousConvexCast's normal is already in world space */
    162 /*
    163 #ifdef USE_SUBSIMPLEX_CONVEX_CAST
    164 				//rotate normal into worldspace
    165 				castResult.m_normal = m_convexShapeFrom.getBasis() * castResult.m_normal;
    166 #endif //USE_SUBSIMPLEX_CONVEX_CAST
    167 */
    168 				castResult.m_normal.normalize();
    169 
    170 				reportHit (castResult.m_normal,
    171 							castResult.m_hitPoint,
    172 							castResult.m_fraction,
    173 							partId,
    174 							triangleIndex);
    175 			}
    176 		}
    177 	}
    178 }
    179