moller-trumbore.cpp

void rayTriangle(RayResult& result, const btVector3& raySource, const btVector3& rayDir, const btVector3& v0, const btVector3& v1, const btVector3& v2, unsigned int tri) const
    {
        btVector3 edge1 = v1 - v0;
        btVector3 edge2 = v2 - v0;
        btVector3 P = rayDir.cross(edge2);

        float det = edge1.dot(P);
        if (det <= 0)
            return;

        btVector3 T = raySource - v0;

        float u = T.dot(P);
        if (u < 0 || u > det)
            return;

        btVector3 Q = T.cross(edge1);

        float v = rayDir.dot(Q);
        if (v < 0 || u + v > det)
            return;

        float t = edge2.dot(Q) / det;

        if (t < 0 || t >= result.fraction)
            return;

        result = RayResult(t, this, tri);
    }