Fixed gimbal lock by fixing the quaternion multiplication order when getting absolute rotation for camera entity

src/game/player.c

@@ -77,10 +77,10 @@ void player_update(struct Player* player, struct Scene* scene, float dt)
 	vec3  rot_axis_pitch     = { 1, 0, 0 };
 	vec3  rot_axis_yaw       = { 0, 1, 0 };
 
-    if(input_map_state_get("Turn_Up",    KS_PRESSED)) pitch    += player->turn_speed;
+    if(input_map_state_get("Turn_Up",    KS_PRESSED)) pitch += player->turn_speed;
-    if(input_map_state_get("Turn_Down",  KS_PRESSED)) pitch    -= player->turn_speed;
+    if(input_map_state_get("Turn_Down",  KS_PRESSED)) pitch -= player->turn_speed;
-    if(input_map_state_get("Turn_Right", KS_PRESSED)) yaw += player->turn_speed;
+    if(input_map_state_get("Turn_Right", KS_PRESSED)) yaw   += player->turn_speed;
-    if(input_map_state_get("Turn_Left",  KS_PRESSED)) yaw -= player->turn_speed;
+    if(input_map_state_get("Turn_Left",  KS_PRESSED)) yaw   -= player->turn_speed;
 
 	int cursor_yaw, cursor_pitch;
 	input_mouse_delta_get(&cursor_yaw, &cursor_pitch);
@@ -106,14 +106,10 @@ void player_update(struct Player* player, struct Scene* scene, float dt)
     }
 
     if(yaw != 0.f)
-    {
+		transform_rotate(player, &rot_axis_yaw, -yaw, TS_WORLD);
-		transform_rotate(player->camera_node, &rot_axis_yaw, -yaw, TS_WORLD);
-    }
 
     if(pitch != 0.f)
-    {
 		transform_rotate(player->camera_node, &rot_axis_pitch, pitch, TS_LOCAL);
-    }
 
     /* Movement */
     float move_speed = player->move_speed;

src/game/transform.c

@@ -319,7 +319,8 @@ void transform_get_absolute_rot(struct Entity* entity, quat* res)
 			done = true;
 			break;
 		}
-		quat_mul(res, res, &parent->transform.rotation);
+		//quat_mul(res, res, &parent->transform.rotation);
+		quat_mul(res, &parent->transform.rotation, res);
 		parent = parent->transform.parent;
 	}
 }

todo.txt

@@ -1,10 +1,11 @@
 Todo:
-	- Fix gimbal lock in fps camera
+	- Fix hierarchical transforms not working in editor mode
 	- Fix weird rotational bug when rotation resets or inverts after 180 degrees
 	- Better, more accurate picking
 	- Add editor undo for transformation operations
 	- Add material export for blender exporter?
 	- Remove flickering from selection in editor
+	- Fix crash when exiting from fullscreen mode
 	- Allow renaming scene objects in editor
 	- Check if we still need to rotate by 90 degrees when exporting from blender
 	- Fire an event when the game mode is changed so that editor camera state and other game related systems know when to update
@@ -355,3 +356,4 @@ Done:
 	* Added parameter to entity_load command that renames the newly loaded object to whatever the second specified parameter is
 	* Implment/Test reading/writing scene that has a mixture of default entites and entity archetypes
 	* Add simple player fps controls 
+	* Fixed gimbal lock in fps camera by fixing the order of quaternion multiplication when getting absolute rotation