WebGLDeferredRenderer: flipped light proxies faces orientation and depth test.

It makes lights work when the camera is inside the light volume and somehow it's also 10% faster.

You just need to make sure camera far plane is far enough to encompass the whole light proxy, otherwise there are not lit slices of proxy sphere.

(I don't really understand why flipping the depth test works, originally depth test was supposed to be just disabled)

See #2624

examples/js/renderers/WebGLDeferredRenderer.js

@@ -253,7 +253,9 @@ THREE.WebGLDeferredRenderer = function ( parameters ) {
 
 			blending:		THREE.AdditiveBlending,
 			depthWrite:		false,
-			transparent:	true
+			transparent:	true,
+
+			side: THREE.BackSide
 
 		} );
 
@@ -294,9 +296,7 @@ THREE.WebGLDeferredRenderer = function ( parameters ) {
 
 			blending:		THREE.AdditiveBlending,
 			depthWrite:		false,
-			transparent:	true,
-
-			//side: THREE.BackSide
+			transparent:	true
 
 		} );
 
@@ -535,7 +535,7 @@ THREE.WebGLDeferredRenderer = function ( parameters ) {
 		// still no touching shared depth buffer
 		// (write light proxy color pixel if in front of scene pixel)
 
-		gl.depthFunc( gl.LEQUAL );
+		gl.depthFunc( gl.GEQUAL );
 
 		compLight.render();