Customizing Scene Rendering in Three.js

Based on your issue with scene.overrideMaterial, there are better approaches than modifying the Three.js source code directly, which as you've discovered gets reset with every package update.

Alternative Approaches

Instead of modifying the source code, consider these options:

1. Use Multiple Scenes

   The most straightforward approach is to use multiple scenes. Objects that should be affected by overrideMaterial go in one scene, while objects that should render normally go in another.

   JAVASCRIPTCopied
   // Create two scenes
   const mainScene = new THREE.Scene();
   const overrideScene = new THREE.Scene();
   
   // Add objects to appropriate scenes
   mainScene.add(normalObject1, normalObject2);
   overrideScene.add(overrideObject1, overrideObject2);
   
   // Set override material only on the override scene
   overrideScene.overrideMaterial = myMaterial;
   
   // In your render loop
   function render() {
     // Render both scenes
     renderer.render(mainScene, camera);
     renderer.render(overrideScene, camera);
   }

2. Use Layers

   Three.js has a layers system that can be used to control which objects are rendered:

   JAVASCRIPTCopied
   // Set up camera to see both layers
   camera.layers.enable(0); // default layer
   camera.layers.enable(1); // custom layer
   
   // Objects to be affected by override material
   overrideObject1.layers.set(1);
   overrideObject2.layers.set(1);
   
   // Normal objects stay on default layer 0
   
   // In your render function
   function render() {
     // First render without override
     camera.layers.set(0);
     renderer.render(scene, camera);
     
     // Then render with override
     scene.overrideMaterial = myMaterial;
     camera.layers.set(1);
     renderer.render(scene, camera);
     scene.overrideMaterial = null;
   }

3. Create a Custom Renderer Wrapper

   Instead of modifying the Three.js source, create a wrapper around the renderer:

   JAVASCRIPTCopied
   class CustomRenderer {
     constructor(renderer) {
       this.renderer = renderer;
     }
     
     render(scene, camera) {
       // Your custom rendering logic here
       // For example, render objects in groups based on whether they should
       // be affected by the override material
       
       // First render objects that should use override material
       const originalOverrideMaterial = scene.overrideMaterial;
       this.renderer.render(scene, camera);
       
       // Then render objects that shouldn't use override material
       scene.overrideMaterial = null;
       // Set up to only render specific objects
       this.renderer.render(scene, camera);
       
       // Restore original state
       scene.overrideMaterial = originalOverrideMaterial;
     }
   }
   
   // Usage
   const renderer = new THREE.WebGLRenderer();
   const customRenderer = new CustomRenderer(renderer);
   customRenderer.render(scene, camera);

These approaches allow you to achieve the desired effect without modifying the Three.js source code, ensuring your code remains compatible with future updates.