Update webgl_furnace_test.html

examples/webgl_furnace_test.html

@@ -111,6 +111,7 @@
 
 					const envScene = new THREE.Scene();
 					envScene.background = new THREE.Color( COLOR );
+					if ( renderer.outputEncoding === THREE.sRGBEncoding ) envScene.background.convertSRGBToLinear();
 
 					const pmremGenerator = new THREE.PMREMGenerator( renderer );
 					radianceMap = pmremGenerator.fromScene( envScene ).texture;