Method raycast

src/collision/shapes/TriangleShape.cpp:143–214

Raycast method with feedback information This method use the line vs triangle raycasting technique described in Real-time Collision Detection by Christer Ericson.

/// This method use the line vs triangle raycasting technique described in
/// Real-time Collision Detection by Christer Ericson.
bool TriangleShape::raycast(const Ray& ray, RaycastInfo& raycastInfo, Collider* collider, MemoryAllocator& /*allocator*/) const {

    RP3D_PROFILE("TriangleShape::raycast()", mProfiler);

    const Vector3 pq = ray.point2 - ray.point1;
    const Vector3 pa = mPoints[0] - ray.point1;
    const Vector3 pb = mPoints[1] - ray.point1;
    const Vector3 pc = mPoints[2] - ray.point1;

    // Test if the line PQ is inside the eges BC, CA and AB. We use the triple
    // product for this test.
    const Vector3 m = pq.cross(pc);
    decimal u = pb.dot(m);
    if (mRaycastTestType == TriangleRaycastSide::FRONT) {
        if (u < decimal(0.0)) return false;
    }
    else if (mRaycastTestType == TriangleRaycastSide::BACK) {
        if (u > decimal(0.0)) return false;
    }

    decimal v = -pa.dot(m);
    if (mRaycastTestType == TriangleRaycastSide::FRONT) {
        if (v < decimal(0.0)) return false;
    }
    else if (mRaycastTestType == TriangleRaycastSide::BACK) {
        if (v > decimal(0.0)) return false;
    }
    else if (mRaycastTestType == TriangleRaycastSide::FRONT_AND_BACK) {
        if (!sameSign(u, v)) return false;
    }

    decimal w = pa.dot(pq.cross(pb));
    if (mRaycastTestType == TriangleRaycastSide::FRONT) {
        if (w < decimal(0.0)) return false;
    }
    else if (mRaycastTestType == TriangleRaycastSide::BACK) {
        if (w > decimal(0.0)) return false;
    }
    else if (mRaycastTestType == TriangleRaycastSide::FRONT_AND_BACK) {
        if (!sameSign(u, w)) return false;
    }

    // If the line PQ is in the triangle plane (case where u=v=w=0)
    if (approxEqual(u, 0) && approxEqual(v, 0) && approxEqual(w, 0)) return false;

    // Compute the barycentric coordinates (u, v, w) to determine the
    // intersection point R, R = u * a + v * b + w * c
    const decimal denom = decimal(1.0) / (u + v + w);
    u *= denom;
    v *= denom;
    w *= denom;

    // Compute the local hit point using the barycentric coordinates
    const Vector3 localHitPoint = u * mPoints[0] + v * mPoints[1] + w * mPoints[2];
    const Vector3 point1ToHitPoint = localHitPoint - ray.point1;
    const decimal hitFraction = point1ToHitPoint.dot(pq) / pq.lengthSquare();

    if (hitFraction < decimal(0.0) || hitFraction > ray.maxFraction) return false;