virtualx-engine/thirdparty/bullet/BulletCollision/CollisionDispatch/btConvexConcaveCollisionAlgorithm.cpp

/*
Bullet Continuous Collision Detection and Physics Library
Copyright (c) 2003-2006 Erwin Coumans  https://bulletphysics.org

This software is provided 'as-is', without any express or implied warranty.
In no event will the authors be held liable for any damages arising from the use of this software.
Permission is granted to anyone to use this software for any purpose, 
including commercial applications, and to alter it and redistribute it freely, 
subject to the following restrictions:

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.
2. Altered source versions must be plainly marked as such, and must not be misrepresented as being the original software.
3. This notice may not be removed or altered from any source distribution.
*/

#include "btConvexConcaveCollisionAlgorithm.h"
#include "LinearMath/btQuickprof.h"
#include "BulletCollision/CollisionDispatch/btCollisionObject.h"
#include "BulletCollision/CollisionShapes/btMultiSphereShape.h"
#include "BulletCollision/BroadphaseCollision/btBroadphaseProxy.h"
#include "BulletCollision/CollisionShapes/btConcaveShape.h"
#include "BulletCollision/CollisionDispatch/btManifoldResult.h"
#include "BulletCollision/NarrowPhaseCollision/btRaycastCallback.h"
#include "BulletCollision/CollisionShapes/btTriangleShape.h"
#include "BulletCollision/CollisionShapes/btSphereShape.h"
#include "LinearMath/btIDebugDraw.h"
#include "BulletCollision/NarrowPhaseCollision/btSubSimplexConvexCast.h"
#include "BulletCollision/CollisionDispatch/btCollisionObjectWrapper.h"
#include "BulletCollision/CollisionShapes/btSdfCollisionShape.h"

btConvexConcaveCollisionAlgorithm::btConvexConcaveCollisionAlgorithm(const btCollisionAlgorithmConstructionInfo& ci, const btCollisionObjectWrapper* body0Wrap, const btCollisionObjectWrapper* body1Wrap, bool isSwapped)
	: btActivatingCollisionAlgorithm(ci, body0Wrap, body1Wrap),
	  m_btConvexTriangleCallback(ci.m_dispatcher1, body0Wrap, body1Wrap, isSwapped),
	  m_isSwapped(isSwapped)
{
}

btConvexConcaveCollisionAlgorithm::~btConvexConcaveCollisionAlgorithm()
{
}

void btConvexConcaveCollisionAlgorithm::getAllContactManifolds(btManifoldArray& manifoldArray)
{
	if (m_btConvexTriangleCallback.m_manifoldPtr)
	{
		manifoldArray.push_back(m_btConvexTriangleCallback.m_manifoldPtr);
	}
}

btConvexTriangleCallback::btConvexTriangleCallback(btDispatcher* dispatcher, const btCollisionObjectWrapper* body0Wrap, const btCollisionObjectWrapper* body1Wrap, bool isSwapped) : m_dispatcher(dispatcher),
																																													 m_dispatchInfoPtr(0)
{
	m_convexBodyWrap = isSwapped ? body1Wrap : body0Wrap;
	m_triBodyWrap = isSwapped ? body0Wrap : body1Wrap;

	//
	// create the manifold from the dispatcher 'manifold pool'
	//
	m_manifoldPtr = m_dispatcher->getNewManifold(m_convexBodyWrap->getCollisionObject(), m_triBodyWrap->getCollisionObject());

	clearCache();
}

btConvexTriangleCallback::~btConvexTriangleCallback()
{
	clearCache();
	m_dispatcher->releaseManifold(m_manifoldPtr);
}

void btConvexTriangleCallback::clearCache()
{
	m_dispatcher->clearManifold(m_manifoldPtr);
}

void btConvexTriangleCallback::processTriangle(btVector3* triangle, int partId, int triangleIndex)
{
	BT_PROFILE("btConvexTriangleCallback::processTriangle");

	if (!TestTriangleAgainstAabb2(triangle, m_aabbMin, m_aabbMax))
	{
		return;
	}

	//just for debugging purposes
	//printf("triangle %d",m_triangleCount++);

	btCollisionAlgorithmConstructionInfo ci;
	ci.m_dispatcher1 = m_dispatcher;

#if 0	
	
	///debug drawing of the overlapping triangles
	if (m_dispatchInfoPtr && m_dispatchInfoPtr->m_debugDraw && (m_dispatchInfoPtr->m_debugDraw->getDebugMode() &btIDebugDraw::DBG_DrawWireframe ))
	{
		const btCollisionObject* ob = const_cast<btCollisionObject*>(m_triBodyWrap->getCollisionObject());
		btVector3 color(1,1,0);
		btTransform& tr = ob->getWorldTransform();
		m_dispatchInfoPtr->m_debugDraw->drawLine(tr(triangle[0]),tr(triangle[1]),color);
		m_dispatchInfoPtr->m_debugDraw->drawLine(tr(triangle[1]),tr(triangle[2]),color);
		m_dispatchInfoPtr->m_debugDraw->drawLine(tr(triangle[2]),tr(triangle[0]),color);
	}
#endif

	if (m_convexBodyWrap->getCollisionShape()->isConvex())
	{
#ifdef BT_ENABLE_CONVEX_CONCAVE_EARLY_OUT
    //todo: check this issue https://github.com/bulletphysics/bullet3/issues/4263
		//an early out optimisation if the object is separated from the triangle
		//projected on the triangle normal)
		{
			const btVector3 v0 = m_triBodyWrap->getWorldTransform()*triangle[0];
			const btVector3 v1 = m_triBodyWrap->getWorldTransform()*triangle[1];
			const btVector3 v2 = m_triBodyWrap->getWorldTransform()*triangle[2];

			btVector3 triangle_normal_world = ( v1 - v0).cross(v2 - v0);
			triangle_normal_world.normalize();

		    btConvexShape* convex = (btConvexShape*)m_convexBodyWrap->getCollisionShape();
			
			btVector3 localPt = convex->localGetSupportingVertex(m_convexBodyWrap->getWorldTransform().getBasis().inverse()*triangle_normal_world);
			btVector3 worldPt = m_convexBodyWrap->getWorldTransform()*localPt;
			//now check if this is fully on one side of the triangle
			btScalar proj_distPt = triangle_normal_world.dot(worldPt);
			btScalar proj_distTr = triangle_normal_world.dot(v0);
			btScalar contact_threshold = m_manifoldPtr->getContactBreakingThreshold()+ m_resultOut->m_closestPointDistanceThreshold;
			btScalar dist = proj_distTr - proj_distPt;
			if (dist > contact_threshold)
				return;

			//also check the other side of the triangle
			triangle_normal_world*=-1;

			localPt = convex->localGetSupportingVertex(m_convexBodyWrap->getWorldTransform().getBasis().inverse()*triangle_normal_world);
			worldPt = m_convexBodyWrap->getWorldTransform()*localPt;
			//now check if this is fully on one side of the triangle
			proj_distPt = triangle_normal_world.dot(worldPt);
			proj_distTr = triangle_normal_world.dot(v0);
			
			dist = proj_distTr - proj_distPt;
			if (dist > contact_threshold)
				return;
        }
#endif //BT_ENABLE_CONVEX_CONCAVE_EARLY_OUT

		btTriangleShape tm(triangle[0], triangle[1], triangle[2]);
		tm.setMargin(m_collisionMarginTriangle);

		btCollisionObjectWrapper triObWrap(m_triBodyWrap, &tm, m_triBodyWrap->getCollisionObject(), m_triBodyWrap->getWorldTransform(), partId, triangleIndex);  //correct transform?
		btCollisionAlgorithm* colAlgo = 0;

		if (m_resultOut->m_closestPointDistanceThreshold > 0)
		{
			colAlgo = ci.m_dispatcher1->findAlgorithm(m_convexBodyWrap, &triObWrap, 0, BT_CLOSEST_POINT_ALGORITHMS);
		}
		else
		{
			colAlgo = ci.m_dispatcher1->findAlgorithm(m_convexBodyWrap, &triObWrap, m_manifoldPtr, BT_CONTACT_POINT_ALGORITHMS);
		}
		const btCollisionObjectWrapper* tmpWrap = 0;

		if (m_resultOut->getBody0Internal() == m_triBodyWrap->getCollisionObject())
		{
			tmpWrap = m_resultOut->getBody0Wrap();
			m_resultOut->setBody0Wrap(&triObWrap);
			m_resultOut->setShapeIdentifiersA(partId, triangleIndex);
		}
		else
		{
			tmpWrap = m_resultOut->getBody1Wrap();
			m_resultOut->setBody1Wrap(&triObWrap);
			m_resultOut->setShapeIdentifiersB(partId, triangleIndex);
		}

		{
			BT_PROFILE("processCollision (GJK?)");
			colAlgo->processCollision(m_convexBodyWrap, &triObWrap, *m_dispatchInfoPtr, m_resultOut);
		}

		if (m_resultOut->getBody0Internal() == m_triBodyWrap->getCollisionObject())
		{
			m_resultOut->setBody0Wrap(tmpWrap);
		}
		else
		{
			m_resultOut->setBody1Wrap(tmpWrap);
		}

		colAlgo->~btCollisionAlgorithm();
		ci.m_dispatcher1->freeCollisionAlgorithm(colAlgo);
	}
}

void btConvexTriangleCallback::setTimeStepAndCounters(btScalar collisionMarginTriangle, const btDispatcherInfo& dispatchInfo, const btCollisionObjectWrapper* convexBodyWrap, const btCollisionObjectWrapper* triBodyWrap, btManifoldResult* resultOut)
{
	m_convexBodyWrap = convexBodyWrap;
	m_triBodyWrap = triBodyWrap;

	m_dispatchInfoPtr = &dispatchInfo;
	m_collisionMarginTriangle = collisionMarginTriangle;
	m_resultOut = resultOut;

	//recalc aabbs
	btTransform convexInTriangleSpace;
	convexInTriangleSpace = m_triBodyWrap->getWorldTransform().inverse() * m_convexBodyWrap->getWorldTransform();
	const btCollisionShape* convexShape = static_cast<const btCollisionShape*>(m_convexBodyWrap->getCollisionShape());
	//CollisionShape* triangleShape = static_cast<btCollisionShape*>(triBody->m_collisionShape);
	convexShape->getAabb(convexInTriangleSpace, m_aabbMin, m_aabbMax);
	btScalar extraMargin = collisionMarginTriangle + resultOut->m_closestPointDistanceThreshold;

	btVector3 extra(extraMargin, extraMargin, extraMargin);

	m_aabbMax += extra;
	m_aabbMin -= extra;
}

void btConvexConcaveCollisionAlgorithm::clearCache()
{
	m_btConvexTriangleCallback.clearCache();
}

void btConvexConcaveCollisionAlgorithm::processCollision(const btCollisionObjectWrapper* body0Wrap, const btCollisionObjectWrapper* body1Wrap, const btDispatcherInfo& dispatchInfo, btManifoldResult* resultOut)
{
	BT_PROFILE("btConvexConcaveCollisionAlgorithm::processCollision");

	const btCollisionObjectWrapper* convexBodyWrap = m_isSwapped ? body1Wrap : body0Wrap;
	const btCollisionObjectWrapper* triBodyWrap = m_isSwapped ? body0Wrap : body1Wrap;

	if (triBodyWrap->getCollisionShape()->isConcave())
	{
		if (triBodyWrap->getCollisionShape()->getShapeType() == SDF_SHAPE_PROXYTYPE)
		{
			btSdfCollisionShape* sdfShape = (btSdfCollisionShape*)triBodyWrap->getCollisionShape();
			if (convexBodyWrap->getCollisionShape()->isConvex())
			{
				btConvexShape* convex = (btConvexShape*)convexBodyWrap->getCollisionShape();
				btAlignedObjectArray<btVector3> queryVertices;

				if (convex->isPolyhedral())
				{
					btPolyhedralConvexShape* poly = (btPolyhedralConvexShape*)convex;
					for (int v = 0; v < poly->getNumVertices(); v++)
					{
						btVector3 vtx;
						poly->getVertex(v, vtx);
						queryVertices.push_back(vtx);
					}
				}
				btScalar maxDist = SIMD_EPSILON;

				if (convex->getShapeType() == SPHERE_SHAPE_PROXYTYPE)
				{
					queryVertices.push_back(btVector3(0, 0, 0));
					btSphereShape* sphere = (btSphereShape*)convex;
					maxDist = sphere->getRadius() + SIMD_EPSILON;
				}
				if (queryVertices.size())
				{
					resultOut->setPersistentManifold(m_btConvexTriangleCallback.m_manifoldPtr);
					//m_btConvexTriangleCallback.m_manifoldPtr->clearManifold();

					btPolyhedralConvexShape* poly = (btPolyhedralConvexShape*)convex;
					for (int v = 0; v < queryVertices.size(); v++)
					{
						const btVector3& vtx = queryVertices[v];
						btVector3 vtxWorldSpace = convexBodyWrap->getWorldTransform() * vtx;
						btVector3 vtxInSdf = triBodyWrap->getWorldTransform().invXform(vtxWorldSpace);

						btVector3 normalLocal;
						btScalar dist;
						if (sdfShape->queryPoint(vtxInSdf, dist, normalLocal))
						{
							if (dist <= maxDist)
							{
								normalLocal.safeNormalize();
								btVector3 normal = triBodyWrap->getWorldTransform().getBasis() * normalLocal;

								if (convex->getShapeType() == SPHERE_SHAPE_PROXYTYPE)
								{
									btSphereShape* sphere = (btSphereShape*)convex;
									dist -= sphere->getRadius();
									vtxWorldSpace -= sphere->getRadius() * normal;
								}
								resultOut->addContactPoint(normal, vtxWorldSpace - normal * dist, dist);
							}
						}
					}
					resultOut->refreshContactPoints();
				}
			}
		}
		else
		{
			const btConcaveShape* concaveShape = static_cast<const btConcaveShape*>(triBodyWrap->getCollisionShape());

			if (convexBodyWrap->getCollisionShape()->isConvex())
			{
				btScalar collisionMarginTriangle = concaveShape->getMargin();

				resultOut->setPersistentManifold(m_btConvexTriangleCallback.m_manifoldPtr);
				m_btConvexTriangleCallback.setTimeStepAndCounters(collisionMarginTriangle, dispatchInfo, convexBodyWrap, triBodyWrap, resultOut);

				m_btConvexTriangleCallback.m_manifoldPtr->setBodies(convexBodyWrap->getCollisionObject(), triBodyWrap->getCollisionObject());

				concaveShape->processAllTriangles(&m_btConvexTriangleCallback, m_btConvexTriangleCallback.getAabbMin(), m_btConvexTriangleCallback.getAabbMax());

				resultOut->refreshContactPoints();

				m_btConvexTriangleCallback.clearWrapperData();
			}
		}
	}
}

btScalar btConvexConcaveCollisionAlgorithm::calculateTimeOfImpact(btCollisionObject* body0, btCollisionObject* body1, const btDispatcherInfo& dispatchInfo, btManifoldResult* resultOut)
{
	(void)resultOut;
	(void)dispatchInfo;
	btCollisionObject* convexbody = m_isSwapped ? body1 : body0;
	btCollisionObject* triBody = m_isSwapped ? body0 : body1;

	//quick approximation using raycast, todo: hook up to the continuous collision detection (one of the btConvexCast)

	//only perform CCD above a certain threshold, this prevents blocking on the long run
	//because object in a blocked ccd state (hitfraction<1) get their linear velocity halved each frame...
	btScalar squareMot0 = (convexbody->getInterpolationWorldTransform().getOrigin() - convexbody->getWorldTransform().getOrigin()).length2();
	if (squareMot0 < convexbody->getCcdSquareMotionThreshold())
	{
		return btScalar(1.);
	}

	//const btVector3& from = convexbody->m_worldTransform.getOrigin();
	//btVector3 to = convexbody->m_interpolationWorldTransform.getOrigin();
	//todo: only do if the motion exceeds the 'radius'

	btTransform triInv = triBody->getWorldTransform().inverse();
	btTransform convexFromLocal = triInv * convexbody->getWorldTransform();
	btTransform convexToLocal = triInv * convexbody->getInterpolationWorldTransform();

	struct LocalTriangleSphereCastCallback : public btTriangleCallback
	{
		btTransform m_ccdSphereFromTrans;
		btTransform m_ccdSphereToTrans;
		btTransform m_meshTransform;

		btScalar m_ccdSphereRadius;
		btScalar m_hitFraction;

		LocalTriangleSphereCastCallback(const btTransform& from, const btTransform& to, btScalar ccdSphereRadius, btScalar hitFraction)
			: m_ccdSphereFromTrans(from),
			  m_ccdSphereToTrans(to),
			  m_ccdSphereRadius(ccdSphereRadius),
			  m_hitFraction(hitFraction)
		{
		}

		virtual void processTriangle(btVector3* triangle, int partId, int triangleIndex)
		{
			BT_PROFILE("processTriangle");
			(void)partId;
			(void)triangleIndex;
			//do a swept sphere for now
			btTransform ident;
			ident.setIdentity();
			btConvexCast::CastResult castResult;
			castResult.m_fraction = m_hitFraction;
			btSphereShape pointShape(m_ccdSphereRadius);
			btTriangleShape triShape(triangle[0], triangle[1], triangle[2]);
			btVoronoiSimplexSolver simplexSolver;
			btSubsimplexConvexCast convexCaster(&pointShape, &triShape, &simplexSolver);
			//GjkConvexCast	convexCaster(&pointShape,convexShape,&simplexSolver);
			//ContinuousConvexCollision convexCaster(&pointShape,convexShape,&simplexSolver,0);
			//local space?

			if (convexCaster.calcTimeOfImpact(m_ccdSphereFromTrans, m_ccdSphereToTrans,
											  ident, ident, castResult))
			{
				if (m_hitFraction > castResult.m_fraction)
					m_hitFraction = castResult.m_fraction;
			}
		}
	};

	if (triBody->getCollisionShape()->isConcave())
	{
		btVector3 rayAabbMin = convexFromLocal.getOrigin();
		rayAabbMin.setMin(convexToLocal.getOrigin());
		btVector3 rayAabbMax = convexFromLocal.getOrigin();
		rayAabbMax.setMax(convexToLocal.getOrigin());
		btScalar ccdRadius0 = convexbody->getCcdSweptSphereRadius();
		rayAabbMin -= btVector3(ccdRadius0, ccdRadius0, ccdRadius0);
		rayAabbMax += btVector3(ccdRadius0, ccdRadius0, ccdRadius0);

		btScalar curHitFraction = btScalar(1.);  //is this available?
		LocalTriangleSphereCastCallback raycastCallback(convexFromLocal, convexToLocal,
														convexbody->getCcdSweptSphereRadius(), curHitFraction);

		raycastCallback.m_hitFraction = convexbody->getHitFraction();

		btCollisionObject* concavebody = triBody;

		btConcaveShape* triangleMesh = (btConcaveShape*)concavebody->getCollisionShape();

		if (triangleMesh)
		{
			triangleMesh->processAllTriangles(&raycastCallback, rayAabbMin, rayAabbMax);
		}

		if (raycastCallback.m_hitFraction < convexbody->getHitFraction())
		{
			convexbody->setHitFraction(raycastCallback.m_hitFraction);
			return raycastCallback.m_hitFraction;
		}
	}

	return btScalar(1.);
}