add renderer prop in onBeforeCompile

src/renderers/WebGLRenderer.js

@@ -1522,7 +1522,8 @@ function WebGLRenderer( parameters ) {
 					name: material.type,
 					uniforms: UniformsUtils.clone( shader.uniforms ),
 					vertexShader: shader.vertexShader,
-					fragmentShader: shader.fragmentShader
+					fragmentShader: shader.fragmentShader,
+					renderer: _this
 				};
 
 			} else {
@@ -1531,7 +1532,8 @@ function WebGLRenderer( parameters ) {
 					name: material.type,
 					uniforms: material.uniforms,
 					vertexShader: material.vertexShader,
-					fragmentShader: material.fragmentShader
+					fragmentShader: material.fragmentShader,
+					renderer: _this
 				};
 
 			}