Material: Fix .needsUpdate + .alphaHash (#26900)

docs/scenes/material-browser.html

@@ -352,6 +352,7 @@
 				// folder.add( material, 'polygonOffsetFactor' );
 				// folder.add( material, 'polygonOffsetUnits' );
 				folder.add( material, 'alphaTest', 0, 1 ).step( 0.01 ).onChange( needsUpdate( material, geometry ) );
+				folder.add( material, 'alphaHash' ).onChange( needsUpdate( material, geometry ) );
 				folder.add( material, 'visible' );
 				folder.add( material, 'side', constants.side ).onChange( needsUpdate( material, geometry ) );
 

src/renderers/webgl/WebGLPrograms.js

@@ -500,6 +500,8 @@ function WebGLPrograms( renderer, cubemaps, cubeuvmaps, extensions, capabilities
 			_programLayers.enable( 16 );
 		if ( parameters.anisotropy )
 			_programLayers.enable( 17 );
+		if ( parameters.alphaHash )
+			_programLayers.enable( 18 );
 
 		array.push( _programLayers.mask );
 		_programLayers.disableAll();