Friction, velocity, rendering

src/display/camera.c

@@ -63,6 +63,7 @@ void cameraPushMatrix(camera_t *camera) {
       );
       break;
 
+    case CAMERA_PROJECTION_TYPE_PERSPECTIVE_FLIPPED:
     case CAMERA_PROJECTION_TYPE_PERSPECTIVE:
       const float_t aspect = (
         (float_t)frameBufferGetWidth(FRAMEBUFFER_BOUND) /
@@ -75,6 +76,12 @@ void cameraPushMatrix(camera_t *camera) {
         camera->farClip,
         projection
       );
+
+      if(camera->projType == CAMERA_PROJECTION_TYPE_PERSPECTIVE_FLIPPED) {
+        // Flip Y axis
+        projection[1][1] *= -1;
+      }
+      break;
   }
 
   switch(camera->viewType) {

src/display/camera.h

@@ -13,6 +13,7 @@
 
 typedef enum {
   CAMERA_PROJECTION_TYPE_PERSPECTIVE,
+  CAMERA_PROJECTION_TYPE_PERSPECTIVE_FLIPPED,
   CAMERA_PROJECTION_TYPE_ORTHOGRAPHIC
 } cameraprojectiontype_t;