orthographic projection for fov=0, rework of order and defaults for 3d camera api

src/twn_camera.c

@@ -52,3 +52,24 @@ Matrix4 camera_perspective(const Camera *const camera) {
 
     return result;
 }
+
+Matrix4 camera_orthographic(const Camera *const camera) {
+    /* from cglm */
+    (void)camera;
+
+    Matrix4 result = {0};
+
+    const float rl =  1.0f / (float)1;
+    const float tb =  1.0f / (float)1;
+    const float fn = -1.0f / (CAMERA_FAR_Z - CAMERA_NEAR_Z);
+
+    result.row[0].x =  2.0f * rl;
+    result.row[1].y =  2.0f * tb;
+    result.row[2].z =  2.0f * fn;
+    result.row[3].x = -(float)1   * rl;
+    result.row[3].y = -(float)1  * tb;
+    result.row[3].z =  (CAMERA_FAR_Z + CAMERA_NEAR_Z) * fn;
+    result.row[3].w =  1.0f;
+
+    return result;
+}