Fix thinWall and passes

leenkx/Sources/iron/RenderPath.hx

@@ -908,7 +908,9 @@ class RenderPath {
 		#end
 
 		Data.getShader(shaderPath[0], shaderPath[1], function(res: ShaderData) {
-			cc.context = res.getContext(shaderPath[2]);
+			if (res != null) {
+				cc.context = res.getContext(shaderPath[2]);
+			}
 			loading--;
 		});
 	}

leenkx/Sources/iron/data/ShaderData.hx

@@ -55,6 +55,7 @@ class ShaderData {
 			if (raw == null) {
 				trace('Shader data "$name" not found!');
 				done(null);
+				return;
 			}
 			new ShaderData(raw, done, overrideContext);
 		});