WebGLRenderer vs WebGPURenderer Performance Issues

Based on the information you've provided, there are a few considerations regarding the performance difference between WebGLRenderer and WebGPURenderer when dealing with thousands of non-instanced meshes.

Potential Issues

1. WebGPU Implementation Status: WebGPU is still relatively new compared to WebGL, and the Three.js implementation might not be fully optimized yet. This could explain some of the performance differences you're experiencing.

2. Non-instanced Meshes: Having thousands of non-instanced meshes is generally not optimal for either renderer, but WebGPU might handle this scenario differently than WebGL.

3. Node Materials: You're using MeshBasicNodeMaterial which is part of the newer node-based materials system. This system might have different performance characteristics between the two renderers.

Recommendations

1. Consider Instancing: If possible, use instanced meshes instead of individual meshes. This would significantly improve performance in both renderers.

JAVASCRIPTCopied
import { InstancedMesh } from 'three';

const count = 1000; // Number of instances
const instancedMesh = new InstancedMesh(geometry, material, count);
// Set positions and other properties for each instance

2. Try Standard Materials: If you don't specifically need node materials, try using the standard Three.js materials to see if performance improves:

JAVASCRIPTCopied
import { MeshBasicMaterial } from 'three';

const material = new MeshBasicMaterial({ color: 0x00ff00 });

3. Renderer Configuration: Make sure your WebGPURenderer is properly configured. You might need to adjust some parameters:

JAVASCRIPTCopied
const renderer = new WebGPURenderer({
  antialias: false, // Try disabling antialiasing
  powerPreference: "high-performance"
});

4. Compile Shaders Asynchronously: Use the compileAsync method to prevent shader compilation from blocking the rendering process:

JAVASCRIPTCopied
await renderer.compileAsync(scene, camera);
// Then start your animation loop

The error you're seeing with WebGLRenderer (Cannot read properties of undefined (reading 'replace')) suggests there might be an incompatibility with the node materials system in WebGL. This could be why WebGPURenderer doesn't show the error but still has performance issues.

Without more specific information about your scene setup and rendering loop, it's difficult to pinpoint the exact cause of the performance difference, but these suggestions should help you troubleshoot the issue.