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150 lines
3.5 KiB
C++
150 lines
3.5 KiB
C++
// This code is in the public domain -- Ignacio Castaño <castanyo@yahoo.es>
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#ifndef NV_MATH_TRIANGLE_H
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#define NV_MATH_TRIANGLE_H
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#include <nvmath/nvmath.h>
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#include <nvmath/Vector.h>
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#include <nvmath/Box.h>
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//#include <nvmath/Plane.h>
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namespace nv
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{
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// Tomas Akenine-Möller box-triangle test.
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NVMATH_API bool triBoxOverlap(Vector3::Arg boxcenter, Vector3::Arg boxhalfsize, const Vector3 * restrict triverts);
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NVMATH_API bool triBoxOverlapNoBounds(Vector3::Arg boxcenter, Vector3::Arg boxhalfsize, const Vector3 * restrict triverts);
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/// Triangle class with three vertices.
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class Triangle
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{
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public:
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Triangle() {};
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Triangle(const Vector3 & v0, const Vector3 & v1, const Vector3 & v2)
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{
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v[0] = v0;
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v[1] = v1;
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v[2] = v2;
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}
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/// Get the bounds of the triangle.
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Box bounds() const {
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Box bounds;
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bounds.clearBounds();
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bounds.addPointToBounds(v[0]);
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bounds.addPointToBounds(v[1]);
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bounds.addPointToBounds(v[2]);
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return bounds;
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}
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/*
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/// Get barycentric coordinates of the given point in this triangle.
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Vector3 barycentricCoordinates(Vector3::Arg p)
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{
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Vector3 bar;
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// p must lie in the triangle plane.
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Plane plane;
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plane.set(v[0], v[1], v[2]);
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nvCheck( equalf(plane.Distance(p), 0.0f) );
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Vector3 n;
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// Compute signed area of triangle <v0, v1, p>
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n = cross(v[1] - v[0], p - v[0]);
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bar.x = length(n);
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if (dot(n, plane.vector) < 0) {
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bar->x = -bar->x;
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}
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// Compute signed area of triangle <v1, v2, p>
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n = cross(v[2] - v[1], p - v[1]);
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bar->y = length(cross(e, d));
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if (dot(n, plane.vector) < 0) {
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bar->y = -bar->y;
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}
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// Compute signed area of triangle <v2, v0, p>
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n = cross(v[0] - v[2], p - v[2]);
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bar->z = length(n);
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if (dot(n, plane.vector) < 0) {
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bar->z = -bar->z;
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}
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// We cannot just do this because we need the signed areas.
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// bar->x = Vector3Area(e0, d0);
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// bar->y = Vector3Area(e1, d1);
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// bar->z = Vector3Area(e2, d2);
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// bar->x = Vector3TripleProduct(v[1], v[2], p);
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// bar->y = Vector3TripleProduct(v[2], v[0], p);
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// bar->z = Vector3TripleProduct(v[0], v[1], p);
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}
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*/
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// Moller ray triangle test.
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bool TestRay_Moller(const Vector3 & orig, const Vector3 & dir, float * out_t, float * out_u, float * out_v);
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Vector3 v[3];
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};
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#if 0
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/** A planar triangle. */
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class Triangle2 {
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public:
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Triangle2() {};
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Triangle2(const Vec2 & v0, const Vec2 & v1, const Vec2 & v2) {
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v[0] = v0;
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v[1] = v1;
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v[2] = v2;
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}
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/** Get the barycentric coordinates of the given point for this triangle.
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* http://stevehollasch.com/cgindex/math/barycentric.html
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*/
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void GetBarycentricCoordinates(const Vec2 & p, Vector3 * bar) const {
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float denom = 1.0f / (v[1].x - v[0].x) * (v[2].y - v[0].y) - (v[2].x - v[0].x) * (v[1].y - v[0].y);
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bar->x = ((v[1].x - p.x) * (v[2].y - p.y) - (v[2].x - p.x) * (v[1].y - p.y)) * denom;
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bar->y = ((v[2].x - p.x) * (v[0].y - p.y) - (v[0].x - p.x) * (v[2].y - p.y)) * denom;
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//bar->z = ((v[0].x - p.x) * (v[1].y - p.y) - (v[1].x - p.x) * (v[0].y - p.y)) * denom;
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bar->z = 1 - bar->x - bar->y;
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}
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Vec2 v[3];
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};
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#endif // 0
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inline bool overlap(const Triangle & t, const Box & b)
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{
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Vector3 center = b.center();
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Vector3 extents = b.extents();
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return triBoxOverlap(center, extents, t.v);
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}
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inline bool Overlap(const Box & b, const Triangle & t)
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{
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return overlap(t, b);
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}
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inline bool overlapNoBounds(const Triangle & t, const Box & b)
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{
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Vector3 center = b.center();
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Vector3 extents = b.extents();
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return triBoxOverlapNoBounds(center, extents, t.v);
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}
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} // nv namespace
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#endif // NV_MATH_TRIANGLE_H
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