Creating Caustic Effects in Three.js

Creating caustic light effects on 3D models can be achieved more efficiently than duplicating your entire model. Here are some approaches that would be more memory-efficient:

1. Custom Shader Material

Instead of using two separate models, you can create a single custom shader material that combines both your base material and the caustic effect. This way, you're only loading the geometry once.

JAVASCRIPTCopied
// Example of a custom shader material with caustics
const causticMaterial = new THREE.ShaderMaterial({
  uniforms: {
    baseTexture: { value: yourBaseTexture },
    causticTexture: { value: causticTexture },
    time: { value: 0 }
  },
  vertexShader: /* your vertex shader */,
  fragmentShader: /* your fragment shader that combines base color and caustics */
});

// Update the time uniform in your animation loop
function animate() {
  causticMaterial.uniforms.time.value += 0.01;
  renderer.render(scene, camera);
  requestAnimationFrame(animate);
}

2. Post-Processing

You could render the caustic effect as a post-processing step using Three.js's EffectComposer. This would allow you to render your model normally and then apply the caustic effect afterward.

JAVASCRIPTCopied
// Set up EffectComposer
const composer = new EffectComposer(renderer);
const renderPass = new RenderPass(scene, camera);
composer.addPass(renderPass);

// Create a custom shader pass for caustics
const causticShader = {
  uniforms: {
    tDiffuse: { value: null },
    causticTexture: { value: causticTexture },
    time: { value: 0 }
  },
  vertexShader: /* your vertex shader */,
  fragmentShader: /* your fragment shader */
};

const causticPass = new ShaderPass(causticShader);
composer.addPass(causticPass);

// Update in animation loop
function animate() {
  causticPass.uniforms.time.value += 0.01;
  composer.render();
  requestAnimationFrame(animate);
}

3. Using MeshDepthMaterial for Optimization

If you still prefer the two-model approach, you could optimize by using a simplified version of your geometry with the caustic material:

JAVASCRIPTCopied
// Create your main model with full detail
const mainModel = new THREE.Mesh(detailedGeometry, baseMaterial);

// Create a simplified version for the caustic effect
const simplifiedGeometry = detailedGeometry.clone().mergeVertices();
// Further simplification could be done here
const causticModel = new THREE.Mesh(simplifiedGeometry, causticMaterial);

scene.add(mainModel);
scene.add(causticModel);

Additional Resources

For implementing these effects, you might want to explore some of the Three.js addons:

• EffectComposer for post-processing
• BufferGeometryUtils for geometry optimization

The caustic effect itself is typically achieved by animating a texture or pattern that simulates the light refraction. You can create this texture procedurally in a shader or use pre-rendered caustic textures that you animate over time.

Remember that shader-based approaches will generally be more performance-efficient than geometry-based ones for these kinds of effects.