polycode-engine/include/Bullet3Collision/NarrowPhaseCollision/shared/b3FindSeparatingAxis.h

#ifndef B3_FIND_SEPARATING_AXIS_H
#define B3_FIND_SEPARATING_AXIS_H


inline void b3ProjectAxis(const b3ConvexPolyhedronData& hull,  const b3Float4& pos, const b3Quaternion& orn, const b3Float4& dir, const b3AlignedObjectArray<b3Vector3>& vertices, b3Scalar& min, b3Scalar& max)
{
	min = FLT_MAX;
	max = -FLT_MAX;
	int numVerts = hull.m_numVertices;

	const b3Float4 localDir = b3QuatRotate(orn.inverse(),dir);

	b3Scalar offset = b3Dot3F4(pos,dir);

	for(int i=0;i<numVerts;i++)
	{
		//b3Vector3 pt = trans * vertices[m_vertexOffset+i];
		//b3Scalar dp = pt.dot(dir);
		b3Vector3 vertex = vertices[hull.m_vertexOffset+i];
		b3Scalar dp = b3Dot3F4((b3Float4&)vertices[hull.m_vertexOffset+i],localDir);
		//b3Assert(dp==dpL);
		if(dp < min)	min = dp;
		if(dp > max)	max = dp;
	}
	if(min>max)
	{
		b3Scalar tmp = min;
		min = max;
		max = tmp;
	}
	min += offset;
	max += offset;
}


inline bool b3TestSepAxis(const b3ConvexPolyhedronData& hullA, const b3ConvexPolyhedronData& hullB, 
	const b3Float4& posA,const b3Quaternion& ornA,
	const b3Float4& posB,const b3Quaternion& ornB,
	const b3Float4& sep_axis, const b3AlignedObjectArray<b3Vector3>& verticesA,const b3AlignedObjectArray<b3Vector3>& verticesB,b3Scalar& depth)
{
	b3Scalar Min0,Max0;
	b3Scalar Min1,Max1;
	b3ProjectAxis(hullA,posA,ornA,sep_axis,verticesA, Min0, Max0);
	b3ProjectAxis(hullB,posB,ornB, sep_axis,verticesB, Min1, Max1);

	if(Max0<Min1 || Max1<Min0)
		return false;

	b3Scalar d0 = Max0 - Min1;
	b3Assert(d0>=0.0f);
	b3Scalar d1 = Max1 - Min0;
	b3Assert(d1>=0.0f);
	depth = d0<d1 ? d0:d1;
	return true;
}


inline bool b3FindSeparatingAxis(	const b3ConvexPolyhedronData& hullA, const b3ConvexPolyhedronData& hullB, 
	const b3Float4& posA1,
	const b3Quaternion& ornA,
	const b3Float4& posB1,
	const b3Quaternion& ornB,
	const b3AlignedObjectArray<b3Vector3>& verticesA,
	const b3AlignedObjectArray<b3Vector3>& uniqueEdgesA, 
	const b3AlignedObjectArray<b3GpuFace>& facesA,
	const b3AlignedObjectArray<int>& indicesA,
	const b3AlignedObjectArray<b3Vector3>& verticesB, 
	const b3AlignedObjectArray<b3Vector3>& uniqueEdgesB, 
	const b3AlignedObjectArray<b3GpuFace>& facesB,
	const b3AlignedObjectArray<int>& indicesB,

	b3Vector3& sep)
{
	B3_PROFILE("findSeparatingAxis");

	b3Float4 posA = posA1;
	posA.w = 0.f;
	b3Float4 posB = posB1;
	posB.w = 0.f;
//#ifdef TEST_INTERNAL_OBJECTS
	b3Float4 c0local = (b3Float4&)hullA.m_localCenter;

	b3Float4 c0 = b3TransformPoint(c0local, posA, ornA);
	b3Float4 c1local = (b3Float4&)hullB.m_localCenter;
	b3Float4 c1 = b3TransformPoint(c1local,posB,ornB);
	const b3Float4 deltaC2 = c0 - c1;
//#endif

	b3Scalar dmin = FLT_MAX;
	int curPlaneTests=0;

	int numFacesA = hullA.m_numFaces;
	// Test normals from hullA
	for(int i=0;i<numFacesA;i++)
	{
		const b3Float4& normal = (b3Float4&)facesA[hullA.m_faceOffset+i].m_plane;
		b3Float4 faceANormalWS = b3QuatRotate(ornA,normal);

		if (b3Dot3F4(deltaC2,faceANormalWS)<0)
			faceANormalWS*=-1.f;

		curPlaneTests++;
#ifdef TEST_INTERNAL_OBJECTS
		gExpectedNbTests++;
		if(gUseInternalObject && !TestInternalObjects(transA,transB, DeltaC2, faceANormalWS, hullA, hullB, dmin))
			continue;
		gActualNbTests++;
#endif

		
		b3Scalar d;
		if(!b3TestSepAxis( hullA, hullB, posA,ornA,posB,ornB,faceANormalWS, verticesA, verticesB,d))
			return false;

		if(d<dmin)
		{
			dmin = d;
			sep = (b3Vector3&)faceANormalWS;
		}
	}

	int numFacesB = hullB.m_numFaces;
	// Test normals from hullB
	for(int i=0;i<numFacesB;i++)
	{
		b3Float4 normal = (b3Float4&)facesB[hullB.m_faceOffset+i].m_plane;
		b3Float4 WorldNormal = b3QuatRotate(ornB, normal);

		if (b3Dot3F4(deltaC2,WorldNormal)<0)
		{
			WorldNormal*=-1.f;
		}
		curPlaneTests++;
#ifdef TEST_INTERNAL_OBJECTS
		gExpectedNbTests++;
		if(gUseInternalObject && !TestInternalObjects(transA,transB,DeltaC2, WorldNormal, hullA, hullB, dmin))
			continue;
		gActualNbTests++;
#endif

		b3Scalar d;
		if(!b3TestSepAxis(hullA, hullB,posA,ornA,posB,ornB,WorldNormal,verticesA,verticesB,d))
			return false;

		if(d<dmin)
		{
			dmin = d;
			sep = (b3Vector3&)WorldNormal;
		}
	}

//	b3Vector3 edgeAstart,edgeAend,edgeBstart,edgeBend;

	int curEdgeEdge = 0;
	// Test edges
	for(int e0=0;e0<hullA.m_numUniqueEdges;e0++)
	{
		const b3Float4& edge0 = (b3Float4&) uniqueEdgesA[hullA.m_uniqueEdgesOffset+e0];
		b3Float4 edge0World = b3QuatRotate(ornA,(b3Float4&)edge0);

		for(int e1=0;e1<hullB.m_numUniqueEdges;e1++)
		{
			const b3Vector3 edge1 = uniqueEdgesB[hullB.m_uniqueEdgesOffset+e1];
			b3Float4 edge1World = b3QuatRotate(ornB,(b3Float4&)edge1);


			b3Float4 crossje = b3Cross3(edge0World,edge1World);

			curEdgeEdge++;
			if(!b3IsAlmostZero((b3Vector3&)crossje))
			{
				crossje = b3FastNormalized3(crossje);
				if (b3Dot3F4(deltaC2,crossje)<0)
					crossje*=-1.f;


#ifdef TEST_INTERNAL_OBJECTS
				gExpectedNbTests++;
				if(gUseInternalObject && !TestInternalObjects(transA,transB,DeltaC2, Cross, hullA, hullB, dmin))
					continue;
				gActualNbTests++;
#endif

				b3Scalar dist;
				if(!b3TestSepAxis( hullA, hullB, posA,ornA,posB,ornB,crossje, verticesA,verticesB,dist))
					return false;

				if(dist<dmin)
				{
					dmin = dist;
					sep = (b3Vector3&)crossje;
				}
			}
		}

	}

	
	if((b3Dot3F4(-deltaC2,(b3Float4&)sep))>0.0f)
		sep = -sep;

	return true;
}

#endif //B3_FIND_SEPARATING_AXIS_H