Add ray-triangle intersection check

include/cglm/call.h

@@ -31,6 +31,7 @@ extern "C" {
 #include "call/ease.h"
 #include "call/curve.h"
 #include "call/bezier.h"
+#include "call/ray.h"
 
 #ifdef __cplusplus
 }

include/cglm/call/ray.h

@@ -0,0 +1,22 @@
+/*
+ * Copyright (c), Recep Aslantas.
+ *
+ * MIT License (MIT), http://opensource.org/licenses/MIT
+ * Full license can be found in the LICENSE file
+ */
+
+#ifndef cglmc_ray_h
+#define cglmc_ray_h
+#ifdef __cplusplus
+extern "C" {
+#endif
+#include "../cglm.h"
+
+CGLM_EXPORT
+bool
+glmc_ray_triangle(vec3 origin, vec3 direction, vec3 v0, vec3 v1, vec3 v2, float *d);
+    
+#ifdef __cplusplus
+}
+#endif
+#endif /* cglmc_ray_h */

include/cglm/cglm.h

@@ -30,5 +30,6 @@
 #include "ease.h"
 #include "curve.h"
 #include "bezier.h"
+#include "ray.h"
 
 #endif /* cglm_h */

include/cglm/ray.h

@@ -0,0 +1,66 @@
+/*
+ * 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 Möller–Trumbore 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
+ * @param[out] intersection  whether there is intersection
+ */
+
+CGLM_INLINE
+bool
+glm_ray_triangle(vec3 origin, vec3 direction, vec3 v0, vec3 v1, vec3 v2, float *d) {
+    const float epsilon = 0.000001;
+    vec3 edge1, edge2, p, t, q;
+    float det, inv_det, u, v;
+
+    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 0;
+    inv_det = 1.0 / det;
+
+    glm_vec3_sub(origin, v0, t);
+
+    u = inv_det * glm_vec3_dot(t, p);
+
+    if (u < 0.0 || u > 1.0)
+        return 0;
+
+    glm_vec3_cross(t, edge1, q);
+
+    v = inv_det * glm_vec3_dot(direction, q);
+
+    if (v < 0.0 || u + v > 1.0)
+        return 0;
+
+    *d = inv_det * glm_vec3_dot(edge2, q);
+    return *d > epsilon;
+}
+
+#endif