PxU32 physx::PxFindFaceIndex(const PxConvexMeshGeometry& convexGeom, const PxTransform& pose, const PxVec3& impactPos, const PxVec3& unitDir) { PX_ASSERT(unitDir.isFinite()); PX_ASSERT(unitDir.isNormalized()); PX_ASSERT(impactPos.isFinite()); PX_ASSERT(pose.isFinite()); const PxVec3 impact = impactPos - unitDir * gEpsilon; const PxVec3 localPoint = pose.transformInv(impact); const PxVec3 localDir = pose.rotateInv(unitDir); // Create shape to vertex scale transformation matrix const PxMeshScale& meshScale = convexGeom.scale; const PxMat33 rot(meshScale.rotation); PxMat33 shape2VertexSkew = rot.getTranspose(); const PxMat33 diagonal = PxMat33::createDiagonal(PxVec3(1.0f / meshScale.scale.x, 1.0f / meshScale.scale.y, 1.0f / meshScale.scale.z)); shape2VertexSkew = shape2VertexSkew * diagonal; shape2VertexSkew = shape2VertexSkew * rot; const PxU32 nbPolys = convexGeom.convexMesh->getNbPolygons(); PxU32 minIndex = 0; PxReal minD = PX_MAX_REAL; for (PxU32 j = 0; j < nbPolys; j++) { PxHullPolygon hullPolygon; convexGeom.convexMesh->getPolygonData(j, hullPolygon); // transform hull plane into shape space PxPlane plane; const PxVec3 tmp = shape2VertexSkew.transformTranspose(PxVec3(hullPolygon.mPlane[0],hullPolygon.mPlane[1],hullPolygon.mPlane[2])); const PxReal denom = 1.0f / tmp.magnitude(); plane.n = tmp * denom; plane.d = hullPolygon.mPlane[3] * denom; PxReal d = plane.distance(localPoint); if (d < 0.0f) continue; const PxReal tweak = plane.n.dot(localDir) * gEpsilon; d += tweak; if (d < minD) { minIndex = j; minD = d; } } return minIndex; }