pixijs-custom-rendering

Custom shaders bind GLSL and WGSL programs to scene objects via

Shader.from({ gl, gpu, resources })

. Uniforms live in typed

UniformGroup

s, textures are passed as separate resources, and the same shader can target both WebGL and WebGPU.

Quick Start

const uniforms = new UniformGroup({
  uTime: { value: 0, type: "f32" },
});

const shader = Shader.from({
  gl: { vertex: vertexSrc, fragment: fragmentSrc },
  resources: { uniforms },
});

const geometry = new MeshGeometry({
  positions: new Float32Array([0, 0, 100, 0, 100, 100, 0, 100]),
  uvs: new Float32Array([0, 0, 1, 0, 1, 1, 0, 1]),
  indices: new Uint32Array([0, 1, 2, 0, 2, 3]),
});

const mesh = new Mesh({ geometry, shader });
app.stage.addChild(mesh);

app.ticker.add(() => {
  shader.resources.uniforms.uniforms.uTime = performance.now() / 1000;
});

Related skills:

pixijs-filters

(built-in filters),

pixijs-scene-mesh

(custom geometry),

pixijs-performance

(batch optimization),

pixijs-migration-v8

(shader API migration from v7).

Core Patterns

Dual-renderer shader (WebGL + WebGPU)

import { Shader, GlProgram, GpuProgram, UniformGroup } from "pixi.js";

const glVertex = `...`; // GLSL vertex (write `#version 300 es` yourself if you want WebGL2/GLSL ES 3.0)
const glFragment = `...`; // GLSL fragment
const wgslSource = `...`; // WGSL combined

const shader = Shader.from({
  gl: { vertex: glVertex, fragment: glFragment },
  gpu: {
    // entryPoint names are arbitrary; they must match the @vertex / @fragment
    // function names in your WGSL source. PixiJS ships examples using
    // 'mainVert' / 'mainFrag' but `main` is equally valid.
    vertex: { entryPoint: "mainVert", source: wgslSource },
    fragment: { entryPoint: "mainFrag", source: wgslSource },
  },
  resources: {
    myUniforms: new UniformGroup({
      uColor: { value: new Float32Array([1, 0, 0, 1]), type: "vec4<f32>" },
      uMatrix: { value: new Float32Array(16), type: "mat4x4<f32>" },
    }),
  },
});

If only

gl

is provided, the shader works with WebGL only. If only

gpu

is provided, it works with WebGPU only. The

compatibleRenderers

bitmask is set automatically.

GlProgram

does not auto-inject

#version 300 es

. If you write

#version 300 es

yourself, PixiJS preserves it and treats the shader as GLSL ES 3.0; otherwise it injects WebGL1 compat macros (

#define in varying

#define texture texture2D

) and runs the shader as WebGL1-style GLSL.

GlProgram

always injects a default precision (

highp

vertex,

mediump

fragment) and the program name. For GLSL ES 3.0, use

in

out

instead of

attribute

varying

texture()

instead of

texture2D()

, and an

out vec4

instead of

gl_FragColor

Textures as resources

Textures are resources, not uniforms. Pass the texture's

source

and

style

separately:

import { Shader, UniformGroup, Texture, Assets } from "pixi.js";

const texture = await Assets.load("myImage.png");

const shader = Shader.from({
  gl: { vertex: vertSrc, fragment: fragSrc },
  resources: {
    uTexture: texture.source,
    uSampler: texture.source.style,
    myUniforms: new UniformGroup({
      uAlpha: { value: 1.0, type: "f32" },
    }),
  },
});

// Swap texture at runtime
shader.resources.uTexture = otherTexture.source;

Resources are a flat key-value map. The key must match the uniform/binding name in the shader source.

Resources can also be plain objects (auto-wrapped into

UniformGroup

const shader = Shader.from({
  gl: { vertex: vertSrc, fragment: fragSrc },
  resources: {
    myUniforms: {
      uTime: { value: 0, type: "f32" },
    },
  },
});

UBO mode (Uniform Buffer Objects)

UBO mode packs uniforms into a single GPU buffer. Required for WebGPU; optional (WebGL2+) for WebGL.

import { UniformGroup } from "pixi.js";

const ubo = new UniformGroup(
  {
    uProjection: { value: new Float32Array(16), type: "mat4x4<f32>" },
    uAlpha: { value: 1.0, type: "f32" },
  },
  { ubo: true, isStatic: true },
);

// Must call update() manually when isStatic is true
ubo.uniforms.uAlpha = 0.5;
ubo.update();

UBO rules:

Only
```
f32
```
and
```
i32
```
based types are supported (no
```
u32
```
). Matrices are float-only.
Samplers/textures cannot go in a UBO.
The UniformGroup name in resources must exactly match the UBO block name in the shader.
Structure and order must exactly match the shader layout.
UBO sync uses
```
new Function
```
under the hood. In strict-CSP environments (no
```
unsafe-eval
```
), import
```
pixi.js/unsafe-eval
```
once at startup to swap in the fallback sync path; without it, UBO-backed shaders (and therefore WebGPU) will throw on first use.

Custom filter

Filter.from({ gl, resources })

is the shorthand. Pass only a fragment shader; PixiJS supplies a default vertex shader that handles output frame positioning.

import { Filter } from "pixi.js";

const filter = Filter.from({
  gl: {
    fragment: `
            in vec2 vTextureCoord;
            out vec4 finalColor;
            uniform sampler2D uTexture;
            uniform float uStrength;

            void main(void) {
                vec4 color = texture(uTexture, vTextureCoord);
                finalColor = mix(color, vec4(1.0 - color.rgb, color.a), uStrength);
            }
        `,
  },
  resources: {
    filterUniforms: {
      uStrength: { value: 0.5, type: "f32" },
    },
  },
});

filter.resources.filterUniforms.uniforms.uStrength = 1.0;

For a custom vertex shader, use

new Filter({ glProgram: new GlProgram({ vertex, fragment }), resources })

Filter shader conventions (GLSL ES 3.0)

in vec2 vTextureCoord;

instead of

varying vec2 vTextureCoord;

```
out vec4 finalColor;
```
instead of
```
gl_FragColor
```

texture(uTexture, uv)

instead of

texture2D(uTexture, uv)

The default vertex shader exposes

uInputSize

uOutputFrame

uOutputTexture

and helpers

filterVertexPosition()

filterTextureCoord()

Sampling the render target behind the filter

Set

blendRequired: true

and sample

uBackTexture

in the fragment shader. PixiJS copies the destination pixels into that uniform before running the filter:

const blendFilter = Filter.from({
  gl: { fragment: blendFragSrc },
  resources: { uniforms: { uAmount: { value: 0.5, type: "f32" } } },
  blendRequired: true,
});

Only enable

blendRequired

when you need it; it forces an extra GPU copy every frame.

Updating uniforms at runtime

// Access the UniformGroup via resources
shader.resources.myUniforms.uniforms.uTime = performance.now() / 1000;

// For isStatic UBOs, call update() after changing values
shader.resources.myUniforms.update();

Uniform type reference

See references/uniform-types.md for the complete table of supported types, their WGSL/GLSL equivalents, and value formats.

Custom Batcher (extension-based)

The

Batcher

abstract class enables custom batching for specialized rendering. Subclass it and register via extensions:

import { Batcher, extensions, ExtensionType } from "pixi.js";
import type {
  BatcherOptions,
  BatchableMeshElement,
  BatchableQuadElement,
  Geometry,
  Shader,
} from "pixi.js";

class MyBatcher extends Batcher {
  public static extension = {
    type: [ExtensionType.Batcher],
    name: "my-batcher",
  };

  public name = "my-batcher";
  protected vertexSize = 6; // floats per vertex
  public geometry: Geometry;
  public shader: Shader;

  constructor(options: BatcherOptions) {
    super(options);
    // Initialize geometry and shader
  }

  public packAttributes(
    element: BatchableMeshElement,
    float32View: Float32Array,
    uint32View: Uint32Array,
    index: number,
    textureId: number,
  ): void {
    // Pack mesh vertex attributes into the batch buffer
  }

  public packQuadAttributes(
    element: BatchableQuadElement,
    float32View: Float32Array,
    uint32View: Uint32Array,
    index: number,
    textureId: number,
  ): void {
    // Pack quad vertex attributes into the batch buffer
  }
}

extensions.add(MyBatcher);

Elements reference the batcher by

batcherName

. The

BatchableElement

interface requires:

batcherName

texture

blendMode

indexSize

attributeSize

topology

, and

packAsQuad

Common Mistakes

[CRITICAL] Old Shader.from(vertex, fragment, uniforms) constructor

Wrong:

const shader = Shader.from(vertex, fragment, { uTime: 1 });

Correct:

const shader = Shader.from({
  gl: { vertex, fragment },
  resources: {
    uniforms: new UniformGroup({
      uTime: { value: 1, type: "f32" },
    }),
  },
});

v8 requires an options object with

gl

gpu

programs and

resources

. The positional API was removed.

[CRITICAL] UniformGroup without type annotation

Wrong:

new UniformGroup({ uTime: 1 });

Correct:

new UniformGroup({ uTime: { value: 1, type: "f32" } });

Every uniform requires an explicit

{ value, type }

pair. Omitting the type causes a runtime error: "Uniform type undefined is not supported."

[HIGH] UBO with unsupported types or wrong structure

UBO mode supports

f32

and

i32

based types (scalars and vectors).

u32

is not in the supported

UniformGroup

type list and will throw. Matrices are float-only (

mat*<f32>

). Samplers cannot be placed in UBOs.

The struct name and field order must exactly match the shader's UBO declaration. Mismatches produce garbled rendering with no error.

[HIGH] Putting textures in UniformGroup

Wrong:

new UniformGroup({
  uTexture: { value: texture, type: "f32" },
});

Correct:

const shader = Shader.from({
  gl: { vertex, fragment },
  resources: {
    uTexture: texture.source,
    uSampler: texture.source.style,
    myUniforms: new UniformGroup({
      uAlpha: { value: 1.0, type: "f32" },
    }),
  },
});

Textures are resources, not uniforms. Pass

texture.source

(TextureSource) and

texture.source.style

(TextureStyle) as top-level resource entries.

pixijs-custom-rendering

NPX Install

Tags

SKILL.md Content

Quick Start

Core Patterns

Dual-renderer shader (WebGL + WebGPU)

Textures as resources

UBO mode (Uniform Buffer Objects)

Custom filter

Filter shader conventions (GLSL ES 3.0)

Sampling the render target behind the filter

Updating uniforms at runtime

Uniform type reference

Custom Batcher (extension-based)

Common Mistakes

[CRITICAL] Old Shader.from(vertex, fragment, uniforms) constructor

[CRITICAL] UniformGroup without type annotation

[HIGH] UBO with unsupported types or wrong structure

[HIGH] Putting textures in UniformGroup

API Reference