GuSweepConvexTri.h

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#ifndef GU_SWEEP_CONVEX_TRI
#define GU_SWEEP_CONVEX_TRI
 
#include "geometry/PxConvexMeshGeometry.h"
#include "GuVecTriangle.h"
#include "GuVecConvexHull.h"
#include "GuConvexMesh.h"
#include "GuGJKRaycast.h"
 
// return true if hit, false if no hit
static PX_FORCE_INLINE bool sweepConvexVsTriangle(
    const PxVec3& v0, const PxVec3& v1, const PxVec3& v2,
    ConvexHullV& convexHull, const aos::PxMatTransformV& meshToConvex, const aos::PxTransformV& convexTransfV,
    const aos::Vec3VArg convexSpaceDir, const PxVec3& unitDir, const PxVec3& meshSpaceUnitDir,
    const aos::FloatVArg fullDistance, PxReal shrunkDistance,
    PxGeomSweepHit& hit, bool isDoubleSided, const PxReal inflation, bool& initialOverlap, PxU32 faceIndex)
{
    using namespace aos;
    if(!isDoubleSided)
    {
        // Create triangle normal
        const PxVec3 denormalizedNormal = (v1 - v0).cross(v2 - v1);
 
        // Backface culling
        // PT: WARNING, the test is reversed compared to usual because we pass -unitDir to this function
        const bool culled = denormalizedNormal.dot(meshSpaceUnitDir) <= 0.0f;
        if(culled)
            return false;
    }
 
    const Vec3V zeroV = V3Zero();
    const FloatV zero = FZero();
 
    const Vec3V p0 = V3LoadU(v0); // in mesh local space
    const Vec3V p1 = V3LoadU(v1);
    const Vec3V p2 = V3LoadU(v2);
 
    // transform triangle verts from mesh local to convex local space
    TriangleV triangleV(meshToConvex.transform(p0), meshToConvex.transform(p1), meshToConvex.transform(p2));
 
    FloatV toi;
    Vec3V closestA,normal;
 
    const LocalConvex<TriangleV> convexA(triangleV);
    const LocalConvex<ConvexHullV> convexB(convexHull);
    const Vec3V initialSearchDir = V3Sub(triangleV.getCenter(), convexHull.getCenter());
    // run GJK raycast
    // sweep triangle in convex local space vs convex, closestA will be the impact point in convex local space
    const bool gjkHit = gjkRaycastPenetration<LocalConvex<TriangleV>, LocalConvex<ConvexHullV> >(
        convexA, convexB, initialSearchDir, zero, zeroV, convexSpaceDir, toi, normal, closestA, inflation, false);
    if(!gjkHit)
        return false;
 
    if(FAllGrtrOrEq(zero, toi))
    {
        initialOverlap  = true; // PT: TODO: redundant with hit distance, consider removing
        return setInitialOverlapResults(hit, unitDir, faceIndex);
    }
 
    const FloatV minDist = FLoad(shrunkDistance);
    const FloatV dist = FMul(toi, fullDistance); // scale the toi to original full sweep distance
    if(FAllGrtr(minDist, dist)) // is current dist < minDist?
    {
        hit.faceIndex   = faceIndex;
        hit.flags       = PxHitFlag::ePOSITION | PxHitFlag::eNORMAL | PxHitFlag::eFACE_INDEX;
        const Vec3V destWorldPointA = convexTransfV.transform(closestA);
        const Vec3V destNormal = V3Normalize(convexTransfV.rotate(normal));
        V3StoreU(destWorldPointA, hit.position);
        V3StoreU(destNormal, hit.normal);
        FStore(dist, &hit.distance);
        return true; // report a hit
    }
    return false; // report no hit
}
 
#endif