Fix note #2 of https://github.com/mrdoob/three.js/pull/5805#issuecomment-75610227

src/renderers/shaders/ShaderChunk/linear_to_gamma_fragment.glsl

@@ -1 +1,2 @@
-	outgoingLight.xyz = linearToOutput( outgoingLight.xyz );
+
+	outgoingLight = linearToOutput( outgoingLight );