preact

frontend/node_modules/three/examples/jsm/nodes/display/FrontFacingNode.js

@@ -0,0 +1,40 @@
+import Node, { addNodeClass } from '../core/Node.js';
+import { nodeImmutable, float } from '../shadernode/ShaderNode.js';
+import { BackSide, WebGLCoordinateSystem } from 'three';
+
+class FrontFacingNode extends Node {
+
+	constructor() {
+
+		super( 'bool' );
+
+		this.isFrontFacingNode = true;
+
+	}
+
+	generate( builder ) {
+
+		const { renderer, material } = builder;
+
+		if ( renderer.coordinateSystem === WebGLCoordinateSystem ) {
+
+			if ( material.side === BackSide ) {
+
+				return 'false';
+
+			}
+
+		}
+
+		return builder.getFrontFacing();
+
+	}
+
+}
+
+export default FrontFacingNode;
+
+export const frontFacing = nodeImmutable( FrontFacingNode );
+export const faceDirection = float( frontFacing ).mul( 2.0 ).sub( 1.0 );
+
+addNodeClass( 'FrontFacingNode', FrontFacingNode );