add support for spheres

include/cglm/cglm.h

@@ -24,5 +24,6 @@
 #include "util.h"
 #include "io.h"
 #include "project.h"
+#include "sphere.h"
 
 #endif /* cglm_h */

include/cglm/sphere.h

@@ -0,0 +1,40 @@
+/*
+ * Copyright (c), Recep Aslantas.
+ *
+ * MIT License (MIT), http://opensource.org/licenses/MIT
+ * Full license can be found in the LICENSE file
+ */
+
+#ifndef cglm_sphere_h
+#define cglm_sphere_h
+
+#include "common.h"
+#include "mat4.h"
+
+/*
+  Sphere Representation in cglm: [center.x, center.y, center.z, radii]
+
+  You could use this representation or you can convert it to vec4 before call
+  any function
+ */
+
+CGLM_INLINE
+void
+glm_sphere_transform(vec4 s, mat4 m, vec4 dest) {
+  glm_mat4_mulv3(m, s, 1.0f, dest);
+  dest[3] = s[3];
+}
+
+CGLM_INLINE
+void
+glm_sphere_merge(vec4 s1, vec4 s2, vec4 dest) {
+  float dist, radii;
+
+  dist  = glm_vec_distance(s1, s2);
+  radii = dist + s1[3] + s2[3];
+
+  glm_vec_center(s1, s2, dest);
+  dest[3] = radii;
+}
+
+#endif /* cglm_sphere_h */