frillrun/include/cglm/ray.h
2024-08-24 00:47:58 -04:00

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/*
* Copyright (c), Recep Aslantas.
*
* MIT License (MIT), http://opensource.org/licenses/MIT
* Full license can be found in the LICENSE file
*/
/*
Functions:
CGLM_INLINE bool glm_line_triangle_intersect(vec3 origin,
vec3 direction,
vec3 v0,
vec3 v1,
vec3 v2,
float *d);
*/
#ifndef cglm_ray_h
#define cglm_ray_h
#include "vec3.h"
/*!
* @brief MöllerTrumbore ray-triangle intersection algorithm
*
* @param[in] origin origin of ray
* @param[in] direction direction of ray
* @param[in] v0 first vertex of triangle
* @param[in] v1 second vertex of triangle
* @param[in] v2 third vertex of triangle
* @param[in, out] d distance to intersection
* @return whether there is intersection
*/
CGLM_INLINE
bool
glm_ray_triangle(vec3 origin,
vec3 direction,
vec3 v0,
vec3 v1,
vec3 v2,
float *d) {
vec3 edge1, edge2, p, t, q;
float det, inv_det, u, v, dist;
const float epsilon = 0.000001f;
glm_vec3_sub(v1, v0, edge1);
glm_vec3_sub(v2, v0, edge2);
glm_vec3_cross(direction, edge2, p);
det = glm_vec3_dot(edge1, p);
if (det > -epsilon && det < epsilon)
return false;
inv_det = 1.0f / det;
glm_vec3_sub(origin, v0, t);
u = inv_det * glm_vec3_dot(t, p);
if (u < 0.0f || u > 1.0f)
return false;
glm_vec3_cross(t, edge1, q);
v = inv_det * glm_vec3_dot(direction, q);
if (v < 0.0f || u + v > 1.0f)
return false;
dist = inv_det * glm_vec3_dot(edge2, q);
if (d)
*d = dist;
return dist > epsilon;
}
#endif