Install

Ndoe

npm install three-multipass-shader-helper
# or
yarn add three-multipass-shader-helper

Browser

Download the IIFE style module from build/MultipassShaderHelper.browser.js.

Import

Node

import { MultipassShaderHelper } from "three-multipass-shader-helper";

Browser

<script src="three.js"></script>
<script src="MultipassShaderHelper.browser.js"></script>

<!-- Your script -->
<script src="main.js" defer></script>

Use

It's quite straightforward.

Create passes

const passes = {
  BufferA: {
    vertexShader: `...`,
    fragmentShader: `...`,
    uniforms: {
      // Takes in regular uniforms
      uDelta: { value: 0 },

      // And other passes
      BufferB: { value: new MultipassShaderHelper.Dependency() },
      //                    Must have this type
    },
    onLoadTexture: (texture) => {
      /*...Fill texture maybe?*/
    },
  },
  BufferB: {
    vertexShader: pVert,
    fragmentShader: pFrag,
    // Uniforms and `onLoadTexture` are optional
  },
};

Apply passes

const gpuCompute = new MultipassShaderHelper(renderer, passes);
const material = new THREE.ShaderMaterial({
  vertexShader: `...`,
  fragmentShader: `...`,
  uniforms: {
    BufferA: { value: gpu.textures.BufferA() },
    BufferB: { value: gpu.textures.BufferB() },
  },
});

// ...

const clock = new THREE.Clock();
function render() {
  const delta = clock.getDelta();

  // Get a buffer's variable
  const { BufferA } = gpuCompute.allVariables;
  // Update its uniforms
  BufferA.material.uniforms.uDelta = delta;

  // Use it
  material.uniforms.BufferA.value = gpu.textures.BufferA();
  material.uniforms.BufferB.value = gpu.textures.BufferB();

  // Compute the shaders
  gpuCompute.compute();
}