Add ray-triangle intersection check

Makefile.am

@@ -63,7 +63,8 @@ cglm_HEADERS = include/cglm/version.h \
                include/cglm/ease.h \
                include/cglm/curve.h \
                include/cglm/bezier.h \
-               include/cglm/applesimd.h
+               include/cglm/applesimd.h \
+               include/cglm/ray.h
 
 cglm_calldir=$(includedir)/cglm/call
 cglm_call_HEADERS = include/cglm/call/mat4.h \
@@ -84,7 +85,8 @@ cglm_call_HEADERS = include/cglm/call/mat4.h \
                     include/cglm/call/sphere.h \
                     include/cglm/call/ease.h \
                     include/cglm/call/curve.h \
-                    include/cglm/call/bezier.h
+                    include/cglm/call/bezier.h \
+                    include/cglm/call/ray.h
 
 cglm_simddir=$(includedir)/cglm/simd
 cglm_simd_HEADERS = include/cglm/simd/intrin.h \
@@ -147,7 +149,8 @@ libcglm_la_SOURCES=\
     src/sphere.c \
     src/ease.c \
     src/curve.c \
-    src/bezier.c
+    src/bezier.c \
+    src/ray.c
 
 test_tests_SOURCES=\
     test/runner.c \

docs/source/api.rst

@@ -52,3 +52,4 @@ Follow the :doc:`build` documentation for this
    curve
    bezier
    version
+   ray

docs/source/ray.rst

@@ -0,0 +1,31 @@
+.. default-domain:: C
+
+ray
+====
+
+Header: cglm/ray.h
+
+This is for collision-checks used by ray-tracers and the like.
+
+Table of contents (click to go):
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+Functions:
+
+1. :c:func:`glm_ray_triangle`
+
+Functions documentation
+~~~~~~~~~~~~~~~~~~~~~~~
+
+.. c:function:: bool  glm_ray_triangle(vec3 origin, vec3 direction, vec3 v0, vec3 v1, vec3 v2, float *d)
+
+    Möller–Trumbore ray-triangle intersection algorithm
+
+    Parameters:
+      | *[in]*       **origin**        origin of ray
+      | *[in]*       **direction**     direction of ray
+      | *[in]*       **v0**            first vertex of triangle
+      | *[in]*       **v1**            second vertex of triangle
+      | *[in]*       **v2**            third vertex of triangle
+      | *[in, out]*  **d**             float pointer to save distance to intersection
+      | *[out]*      **intersection**  whether there is intersection

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

src/ray.c

@@ -0,0 +1,8 @@
+#include "../include/cglm/cglm.h"
+#include "../include/cglm/call.h"
+
+CGLM_EXPORT
+bool
+glmc_ray_triangle(vec3 origin, vec3 direction, vec3 v0, vec3 v1, vec3 v2, float *d) {
+    return glm_ray_triangle(origin, direction, v0, v1, v2, d);
+}

win/cglm.vcxproj

@@ -34,6 +34,7 @@
     <ClCompile Include="..\src\plane.c" />
     <ClCompile Include="..\src\project.c" />
     <ClCompile Include="..\src\quat.c" />
+    <ClCompile Include="..\src\ray.c" />
     <ClCompile Include="..\src\sphere.c" />
     <ClCompile Include="..\src\vec2.c" />
     <ClCompile Include="..\src\vec3.c" />
@@ -61,6 +62,7 @@
     <ClInclude Include="..\include\cglm\call\plane.h" />
     <ClInclude Include="..\include\cglm\call\project.h" />
     <ClInclude Include="..\include\cglm\call\quat.h" />
+    <ClInclude Include="..\include\cglm\call\ray.h" />
     <ClInclude Include="..\include\cglm\call\sphere.h" />
     <ClInclude Include="..\include\cglm\call\vec2.h" />
     <ClInclude Include="..\include\cglm\call\vec3.h" />
@@ -80,6 +82,7 @@
     <ClInclude Include="..\include\cglm\plane.h" />
     <ClInclude Include="..\include\cglm\project.h" />
     <ClInclude Include="..\include\cglm\quat.h" />
+    <ClInclude Include="..\include\cglm\ray.h" />
     <ClInclude Include="..\include\cglm\simd\arm.h" />
     <ClInclude Include="..\include\cglm\simd\avx\affine.h" />
     <ClInclude Include="..\include\cglm\simd\avx\mat4.h" />

win/cglm.vcxproj.filters

@@ -92,6 +92,9 @@
     <ClCompile Include="..\src\vec2.c">
       <Filter>src</Filter>
     </ClCompile>
+    <ClCompile Include="..\src\ray.c">
+      <Filter>src</Filter>
+    </ClCompile>
   </ItemGroup>
   <ItemGroup>
     <ClInclude Include="..\src\config.h">
@@ -124,6 +127,9 @@
     <ClInclude Include="..\include\cglm\call\vec4.h">
       <Filter>include\cglm\call</Filter>
     </ClInclude>
+    <ClInclude Include="..\include\cglm\call\ray.h">
+      <Filter>include\cglm\call</Filter>
+    </ClInclude>
     <ClInclude Include="..\include\cglm\simd\avx\affine.h">
       <Filter>include\cglm\simd\avx</Filter>
     </ClInclude>
@@ -241,6 +247,9 @@
     <ClInclude Include="..\include\cglm\ease.h">
       <Filter>include\cglm</Filter>
     </ClInclude>
+    <ClInclude Include="..\include\cglm\ray.h">
+      <Filter>include\cglm</Filter>
+    </ClInclude>
     <ClInclude Include="..\include\cglm\simd\arm.h">
       <Filter>include\cglm\simd</Filter>
     </ClInclude>