Start implementing clipping triangles

include/rasteriser/rasteriser.h

@@ -41,7 +41,8 @@ typedef struct {
   list_scene_triangle_t *triangles;
 } model_t;
 #define NULL_MODEL ((model_t){0})
-#define IS_NULL_MODEL(MODEL) (MODEL.vertices == NULL && MODEL.triangles == NULL)
+#define IS_NULL_MODEL(MODEL_PTR)                                               \
+  (MODEL_PTR->vertices == NULL && MODEL_PTR->triangles == NULL)
 
 typedef struct {
   f32 scale;