Fixed bug where ImageBitmaps did not get upscaled.

src/renderers/webgl/WebGLTextures.js

@@ -45,7 +45,7 @@ function WebGLTextures( _gl, extensions, state, properties, capabilities, utils,
 
 	function makePowerOfTwo( image ) {
 
-		if ( image instanceof HTMLImageElement || image instanceof HTMLCanvasElement ) {
+		if ( image instanceof HTMLImageElement || image instanceof HTMLCanvasElement || image instanceof ImageBitmap ) {
 
 			var canvas = document.createElementNS( 'http://www.w3.org/1999/xhtml', 'canvas' );
 			canvas.width = _Math.nearestPowerOfTwo( image.width );