Method InitQuery

Engine/lib/opcode/OPC_SphereCollider.cpp:165–272

////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////// * Initializes a collision query : * - reset stats & contact status * - setup matrices * - check temporal coherence * * \param cache [in/out] a sphere cache * \param sphere [in] sphere in local sp

 */
///////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
BOOL SphereCollider::InitQuery(SphereCache& cache, const Sphere& sphere, const Matrix4x4* worlds, const Matrix4x4* worldm)
{
	// 1) Call the base method
	VolumeCollider::InitQuery();

	// 2) Compute sphere in model space:
	// - Precompute R^2
	mRadius2 = sphere.mRadius * sphere.mRadius;
	// - Compute center position
	mCenter = sphere.mCenter;
	// -> to world space
	if(worlds)	mCenter *= *worlds;
	// -> to model space
	if(worldm)
	{
		// Invert model matrix
		Matrix4x4 InvWorldM;
		InvertPRMatrix(InvWorldM, *worldm);

		mCenter *= InvWorldM;
	}

	// 3) Setup destination pointer
	mTouchedPrimitives = &cache.TouchedPrimitives;

	// 4) Special case: 1-triangle meshes [Opcode 1.3]
	if(mCurrentModel && mCurrentModel->HasSingleNode())
	{
		if(!SkipPrimitiveTests())
		{
			// We simply perform the BV-Prim overlap test each time. We assume single triangle has index 0.
			mTouchedPrimitives->Reset();

			// Perform overlap test between the unique triangle and the sphere (and set contact status if needed)
			SPHERE_PRIM(udword(0), OPC_CONTACT)

			// Return immediately regardless of status
			return TRUE;
		}
	}

	// 5) Check temporal coherence :
	if(TemporalCoherenceEnabled())
	{
		// Here we use temporal coherence
		// => check results from previous frame before performing the collision query
		if(FirstContactEnabled())
		{
			// We're only interested in the first contact found => test the unique previously touched face
			if(mTouchedPrimitives->GetNbEntries())
			{
				// Get index of previously touched face = the first entry in the array
				udword PreviouslyTouchedFace = mTouchedPrimitives->GetEntry(0);

				// Then reset the array:
				// - if the overlap test below is successful, the index we'll get added back anyway
				// - if it isn't, then the array should be reset anyway for the normal query
				mTouchedPrimitives->Reset();