Do not destroy non-existent uniforms

engine/RenderWorld.cpp

@@ -115,8 +115,6 @@ RenderWorld::~RenderWorld()
 	r->destroy_gpu_program(default_program);
 	r->destroy_gpu_program(texture_program);
 	r->destroy_uniform(u_albedo_0);
-	r->destroy_uniform(u_lightmap_0);
-	r->destroy_uniform(u_brightness);
 }
 
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