overlaps_box_triangle.h

// Description: Overlap tests between a box and a triangle

#ifndef PASTELGEOMETRY_OVERLAPS_BOX_TRIANGLE_H
#define PASTELGEOMETRY_OVERLAPS_BOX_TRIANGLE_H

#include "pastel/geometry/shape/box.h"
#include "pastel/geometry/shape/triangle.h"
#include "pastel/geometry/overlap/overlaps_alignedbox_triangle.h"

#include "pastel/sys/mytypes.h"
#include "pastel/sys/vector.h"

#include "pastel/math/matrix/matrix.h"

namespace Pastel
{

    //! Tests if an box and a triangle overlap.
    template <typename Real, int N>
    bool overlaps(
        const Box<Real, N>& box,
        const PASTEL_TRIANGLE(Real, N)& triangle)
    {
        // The coordinates are transformed such that
        // the box becomes an origin centered aligned box.
        // Then the test for aligned box-triangle overlap
        // is used.

        Matrix<Real, N, N> boxRotationInverse(
            transpose(box.rotation()));

        PASTEL_TRIANGLE(Real, N) transformedTriangle(
            (triangle[0] - box.position()) *
            boxRotationInverse,
            (triangle[1] - box.position()) *
            boxRotationInverse,
            (triangle[2] - box.position()) *
            boxRotationInverse);

        AlignedBox<Real, N> transformedBox(
            Vector<Real, N>(-box.width()),
            Vector<Real, N>(box.width()));

        return Pastel::overlaps(transformedBox,
            transformedTriangle);
    }

}

#endif