NodeMaterial: unlit property (#26429)

* NodeMaterial: unlit property

* cleanup

examples/jsm/nodes/materials/NodeMaterial.js

@@ -1,4 +1,4 @@
-import { Material, ShaderMaterial, NoColorSpace } from 'three';
+import { Material, ShaderMaterial, NoColorSpace, LinearSRGBColorSpace } from 'three';
 import { getNodeChildren, getCacheKey } from '../core/NodeUtils.js';
 import { attribute } from '../core/AttributeNode.js';
 import { output, diffuseColor } from '../core/PropertyNode.js';
@@ -34,6 +34,7 @@ class NodeMaterial extends ShaderMaterial {
 
 		this.lights = true;
 		this.normals = true;
+		this.unlit = this.constructor === NodeMaterial.prototype.constructor; // Extended materials are not unlit by default
 
 		this.lightsNode = null;
 		this.envNode = null;
@@ -78,7 +79,7 @@ class NodeMaterial extends ShaderMaterial {
 
 		let outputNode;
 
-		if ( this.isUnlit === false ) {
+		if ( this.unlit === false ) {
 
 			if ( this.normals === true ) this.constructNormal( builder );
 
@@ -89,6 +90,12 @@ class NodeMaterial extends ShaderMaterial {
 
 			outputNode = this.constructOutput( builder, vec4( outgoingLightNode, diffuseColor.a ) );
 
+			// OUTPUT NODE
+
+			builder.stack.assign( output, outputNode );
+
+			//
+
 			if ( this.outputNode !== null ) outputNode = this.outputNode;
 
 		} else {
@@ -328,7 +335,11 @@ class NodeMaterial extends ShaderMaterial {
 
 		}
 
-		if ( outputColorSpace !== NoColorSpace ) outputNode = outputNode.linearToColorSpace( outputColorSpace );
+		if ( outputColorSpace !== LinearSRGBColorSpace && outputColorSpace !== NoColorSpace ) {
+
+			outputNode = outputNode.linearToColorSpace( outputColorSpace );
+
+		}
 
 		// FOG
 
@@ -336,10 +347,6 @@ class NodeMaterial extends ShaderMaterial {
 
 		if ( fogNode ) outputNode = vec4( fogNode.mixAssign( outputNode.rgb ), outputNode.a );
 
-		// OUTPUT NODE
-
-		builder.stack.assign( output, outputNode );
-
 		return outputNode;
 
 	}
@@ -439,12 +446,6 @@ class NodeMaterial extends ShaderMaterial {
 
 	}
 
-	get isUnlit() {
-
-		return this.constructor === NodeMaterial.prototype.constructor;
-
-	}
-
 	copy( source ) {
 
 		this.lightsNode = source.lightsNode;