---
title: "Random Noise Shader Additions"
description: "Demonstrates how to use the shaderAdditions property to inject custom GLSL code into the default fragment shader, creating dynamic noise effects with time-based uniforms."
phaser: "4.1.0"
size: "1280x720"
files: 1
url: https://phaser.io/oss/examples/v4.1.0/game%20objects/shader/view/custom-shader-random-noise
site: Phaser - https://phaser.io
---

> This page is about the open-source Phaser framework, for writing a game's code by hand. To make a game with AI, use Phaser AE (https://phaser.io/): the desk's tools work with Web MCP, and the CLI works with your own coding agent. See "For AI agents: Phaser AE" at the end of this page.

# Random Noise Shader Additions

Demonstrates how to use the shaderAdditions property to inject custom GLSL code into the default fragment shader, creating dynamic noise effects with time-based uniforms.

A Phaser 4.1.0 example in [Game Objects / Shader](https://phaser.io/oss/examples/v4.1.0/game%20objects/shader.md). It runs at 1280 × 720, and loads its assets from https://cdn.phaserfiles.com/v410. See it running, with its code, at https://phaser.io/oss/examples/v4.1.0/game%20objects/shader/view/custom-shader-random-noise.

To run it, load Phaser 4.1.0 (`https://cdn.jsdelivr.net/npm/phaser@4.1.0/dist/phaser.min.js`), then the file, on a page with a `<div id="game-container">`.

## Code

### custom shader random noise.js

```js
const randomNoiseFunction = `
uniform vec2 uSeed;
float randomNoise (vec2 uv, vec2 extraSeed) {
    return fract(sin(dot(uv, uSeed + extraSeed)) * 43758.5453123);
}
`;

const randomBWProcess = `fragColor = vec4(vec3(step(0.5, randomNoise(outTexCoord, vec2(0.0)))), 1.0);`;

const randomGrayProcess = `fragColor = vec4(vec3(mix(0.25, 1.0, randomNoise(outTexCoord, vec2(0.0)))), 1.0);`;

const randomColorProcess = `fragColor = vec4(randomNoise(outTexCoord, vec2(0.0)), randomNoise(outTexCoord, vec2(1.0)), randomNoise(outTexCoord, vec2(2.0)), 1.0);`;

class Example extends Phaser.Scene
{
    constructor()
    {
        super();
    }

    preload()
    {
        this.load.setBaseURL('https://cdn.phaserfiles.com/v410');
        this.load.atlas('megaset', 'assets/atlas/megaset-1.png', 'assets/atlas/megaset-1.json');
    }

    create()
    {
        this.cameras.main.setBackgroundColor(0x222233);

        this.add.image(240, 440, 'megaset', 'atari800').setTint(0x808080);
        this.add.image(640, 440, 'megaset', 'atari1200xl').setTint(0x808080);
        this.add.image(1040, 440, 'megaset', 'atari130xe').setTint(0x808080);

        // Define a list of shader additions to insert.
        // We could combine additions in a single entry in the list,
        // but this way we can easily swap out individual parts.
        const shaderAdditions = [
            {
                name: 'RandomNoise',
                additions: { fragmentHeader: randomNoiseFunction }
            },
            {
                name: 'BWProcess',
                additions: { fragmentProcess: randomBWProcess }
            }
        ];

        const shaderConfig = {
            name: 'Noise',
            // By omitting `fragmentSource`, the default fragment shader is used.
            // It has template points for accepting additions.
            shaderAdditions,
            setupUniforms: (setUniform, drawingContext) => {
                // Prevent the seed from becoming too large and losing precision.
                const time = this.game.loop.time % 100000;
                setUniform('uSeed', [time * 12.3456789 + 98.7654321, time * 98.7654321 + 12.3456789]);
            }
        };

        const shader1 = this.add.shader(shaderConfig, 240, 300, 200, 100);

        shaderAdditions.pop();
        shaderAdditions.push({
            name: 'GrayProcess',
            additions: { fragmentProcess: randomGrayProcess }
        });

        const shader2 = this.add.shader(shaderConfig, 640, 300, 200, 100);

        shaderAdditions.pop();
        shaderAdditions.push({
            name: 'ColorProcess',
            additions: { fragmentProcess: randomColorProcess }
        });

        const shader3 = this.add.shader(shaderConfig, 1040, 300, 200, 100);

        // Add a bloom filter to the screen.
        const parallel = this.cameras.main.filters.internal.addParallelFilters();
        parallel.top.addThreshold(0.5, 1.0);
        parallel.top.addBlur(1, 4, 4, 1, 0xddddff);
        parallel.blend.blendMode = Phaser.BlendModes.ADD;

    }
}

const config = {
    scale: { mode: Phaser.Scale.FIT },
    type: Phaser.WEBGL,
    parent: 'game-container',
    width: 1280,
    height: 720,
    scene: Example
};

const game = new Phaser.Game(config);
```

## More in Shader

- [Custom Shader Texture Coordinates](https://phaser.io/oss/examples/v4.1.0/game%20objects/shader/view/custom-shader-texture-coordinates.md): Demonstrates how to apply a custom shader to a specific frame from a texture atlas using setTextureCoordinatesFromFrame and building shaders using modular additions.
- [Gradient Circle Wipe Mask](https://phaser.io/oss/examples/v4.1.0/game%20objects/shader/view/gradient-circle-wipe.md): Demonstrates creating a radial transition between two images by using a dynamic shader as a mask, with the circle's radius controlled by the distance of the pointer from the center.
- [Gradient Linear Wipe Mask](https://phaser.io/oss/examples/v4.1.0/game%20objects/shader/view/gradient-linear-wipe.md): Demonstrates how to use a shader-generated linear gradient as a dynamic mask to create a smooth transition between two images controlled by the pointer.
- [Gradient Ripple Reflection](https://phaser.io/oss/examples/v4.1.0/game%20objects/shader/view/gradient-ripples.md): Demonstrates how to use a procedurally generated gradient shader as a displacement map to create a dynamic water ripple effect on a reflected scene.
- [Gradient Shine](https://phaser.io/oss/examples/v4.1.0/game%20objects/shader/view/gradient-shine.md): Create an animated gradient shine effect by combining modular shader additions with normal map displacement and additive blending.
- [Linear Gradient Shader](https://phaser.io/oss/examples/v4.1.0/game%20objects/shader/view/gradient-linear.md): Demonstrates creating a linear gradient using the Shader Game Object by composing multiple GLSL fragments and configuring uniforms for positions, colors, and step counts.
- [Perlin Noise Custom Shader Displacement](https://phaser.io/oss/examples/v4.1.0/game%20objects/shader/view/custom-shader-perlin-noise.md): Demonstrates how to inject custom GLSL code into a shader using shader additions to generate Perlin noise. The resulting shader is rendered to a texture and applied as a real-time displacement filter to an image.
- [Shader Bilinear Gradient Displacement](https://phaser.io/oss/examples/v4.1.0/game%20objects/shader/view/gradient-bilinear.md): Create complex background effects by combining modular shader additions, render-to-texture, and displacement filters using bilinear and linear gradients.

---

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