implement glm_aabb_sphere as GraphicsGems Solid Box - Solid Sphere test

CREDITS

@@ -1,7 +1,7 @@
 This library [initially] used some [piece of] implementations
 (may include codes) from these open source projects/resources:
 
-1. Affine Transforms
+1. Initial Affine Transforms
 The original glm repo (g-truc), url: https://github.com/g-truc/glm
 
 LICENSE[S]:
@@ -11,7 +11,7 @@ LICENSE[S]:
 
 FULL LICENSE: https://github.com/g-truc/glm/blob/master/copying.txt
 
-2. Quaternions
+2. Initial Quaternions
 Anton's OpenGL 4 Tutorials book source code:
 
 LICENSE:
@@ -47,6 +47,8 @@ http://old.cescg.org/CESCG-2002/DSykoraJJelinek/
 7. Quaternions
 Initial mat4_quat is borrowed from Apple's simd library
 
-
 8. Vector Rotation using Quaternion
 https://gamedev.stackexchange.com/questions/28395/rotating-vector3-by-a-quaternion
+
+9. Sphere AABB intersect
+https://github.com/erich666/GraphicsGems/blob/master/gems/BoxSphere.c

include/cglm/box.h

@@ -229,24 +229,27 @@ glm_aabb_aabb(vec3 box[2], vec3 other[2]) {
 /*!
  * @brief check if AABB intersects with sphere
  *
- * @param[in]   box    bounding box
- * @param[in]   other  other bounding box
+ * https://github.com/erich666/GraphicsGems/blob/master/gems/BoxSphere.c
+ * Solid Box - Solid Sphere test.
+ *
+ * @param[in]   box    solid bounding box
+ * @param[in]   s      solid sphere
  */
 CGLM_INLINE
 bool
-glm_aabb_sphere(vec3 box[2], vec4 sph) {
-  vec3  v;
-  float dist;
+glm_aabb_sphere(vec3 box[2], vec4 s) {
+  float dmin;
+  int   a, b, c;
 
-  /* get box closest point to sphere center by clamping */
-  v[0] = glm_max(box[0][0], glm_min(sph[0], box[1][0]));
-  v[1] = glm_max(box[0][1], glm_min(sph[1], box[1][1]));
-  v[2] = glm_max(box[0][2], glm_min(sph[2], box[1][2]));
+  a = s[0] >= box[0][0];
+  b = s[1] >= box[0][1];
+  c = s[2] >= box[0][2];
 
-  /* this is the same as glm_sphere_point */
-  dist = glm_vec_distance(v, sph);
+  dmin  = glm_pow2(s[0] - box[a][0])
+        + glm_pow2(s[1] - box[b][1])
+        + glm_pow2(s[2] - box[c][2]);
 
-  return dist < sph[3];
+  return dmin <= glm_pow2(s[3]);
 }
 
 /*!

include/cglm/call/box.h

@@ -70,7 +70,7 @@ glmc_aabb_contains(vec3 box[2], vec3 other[2]);
 
 CGLM_EXPORT
 bool
-glmc_aabb_sphere(vec3 box[2], vec4 sph);
+glmc_aabb_sphere(vec3 box[2], vec4 s);
 
 #ifdef __cplusplus
 }

include/cglm/util.h

@@ -98,7 +98,6 @@ glm_make_deg(float *rad) {
 CGLM_INLINE
 float
 glm_pow2(float x) {
-
   return x * x;
 }
 

src/box.c

@@ -91,6 +91,6 @@ glmc_aabb_contains(vec3 box[2], vec3 other[2]) {
 
 CGLM_EXPORT
 bool
-glmc_aabb_sphere(vec3 box[2], vec4 sph) {
-  return glm_aabb_sphere(box, sph);
+glmc_aabb_sphere(vec3 box[2], vec4 s) {
+  return glm_aabb_sphere(box, s);
 }