/** Helper to transform a normal when non-uniform scale is present. */
static PxVec3 TransformNormalToShapeSpace(const PxMeshScale& meshScale, const PxVec3& nIn)
{
// Uniform scale makes this unnecessary
if (meshScale.scale.x == meshScale.scale.y &&
meshScale.scale.x == meshScale.scale.z)
{
return nIn;
}
if (PxQuatIsIdentity(meshScale.rotation))
{
// Inverse transpose: inverse is 1/scale, transpose = original when rotation is identity.
const PxVec3 tmp = PxVec3(nIn.x / meshScale.scale.x, nIn.y / meshScale.scale.y, nIn.z / meshScale.scale.z);
const PxReal denom = 1.0f / tmp.magnitude();
return tmp * denom;
}
else
{
const PxMat33 rot(meshScale.rotation);
const PxMat33 diagonal = PxMat33::createDiagonal(meshScale.scale);
const PxMat33 vertex2Shape = (rot.getTranspose() * diagonal) * rot;
const PxMat33 shape2Vertex = vertex2Shape.getInverse();
const PxVec3 tmp = shape2Vertex.transformTranspose(nIn);
const PxReal denom = 1.0f / tmp.magnitude();
return tmp * denom;
}
}
void scalePlanes(PxPlane* scaledPlaneBuf, const Gu::ConvexHullData* convexHullData, const PxMat33& invScaling)
{
PxU32 numPlanes = convexHullData->mNbPolygons;
PxPlane* planeIt = scaledPlaneBuf;
const Gu::HullPolygonData* polygonIt = convexHullData->mPolygons;
for(; numPlanes>0; --numPlanes, ++planeIt, ++polygonIt)
{
PxVec3 normal=polygonIt->mPlane.n;
PxF32 d=polygonIt->mPlane.d;
normal = invScaling.transformTranspose(normal);
PxReal magnitude = normal.normalize();
*planeIt = PxPlane(normal, d / magnitude);
}
}