Added WORLDSPACE_LIGHTING define (#461)

Co-authored-by: Gregory Heskett <gheskett@gmail.com>

include/config/config_graphics.h

@@ -9,6 +9,14 @@
  */
 #define GFX_POOL_SIZE 10000
 
+/**
+ * Causes the global light direction to be in world space,
+ * this allows you to have a singular light source that doesn't change with the camera's rotation.
+ * By modifying `globalLightDirection`, you can choose the direction that points TOWARDS the light,
+ * but keep in mind that this direction should be normalized to roughly ~127 if changed.
+ */
+// #define WORLDSPACE_LIGHTING
+
 /**
  * Show a watermark on the title screen that reads "Made with HackerSM64", instead of the copyright message.
  */

src/game/rendering_graph_node.c

@@ -573,13 +573,18 @@ void setup_global_light() {
     Lights1* curLight = (Lights1*)alloc_display_list(sizeof(Lights1));
     bcopy(&defaultLight, curLight, sizeof(Lights1));
 
+#ifdef WORLDSPACE_LIGHTING
+    curLight->l->l.dir[0] = (s8)(globalLightDirection[0]);
+    curLight->l->l.dir[1] = (s8)(globalLightDirection[1]);
+    curLight->l->l.dir[2] = (s8)(globalLightDirection[2]);
+#else
     Vec3f transformedLightDirection;
-
     linear_mtxf_transpose_mul_vec3f(gCameraTransform, transformedLightDirection, globalLightDirection);
-
     curLight->l->l.dir[0] = (s8)(transformedLightDirection[0]);
     curLight->l->l.dir[1] = (s8)(transformedLightDirection[1]);
     curLight->l->l.dir[2] = (s8)(transformedLightDirection[2]);
+#endif
+
     gSPSetLights1(gDisplayListHead++, (*curLight));
 }
 

src/game/rendering_graph_node.h

@@ -13,6 +13,7 @@ extern struct GraphNodeObject      *gCurGraphNodeObject;
 extern struct GraphNodeHeldObject  *gCurGraphNodeHeldObject;
 #define gCurGraphNodeObjectNode ((struct Object *)gCurGraphNodeObject)
 extern u16 gAreaUpdateCounter;
+extern Vec3f globalLightDirection;
 
 enum AnimType {
     // after processing an object, the type is reset to this