---
title: "Gradient Ripple Reflection"
description: "Demonstrates how to use a procedurally generated gradient shader as a displacement map to create a dynamic water ripple effect on a reflected scene."
phaser: "4.1.0"
size: "1280x720"
files: 1
url: https://phaser.io/oss/examples/v4.1.0/game%20objects/shader/view/gradient-ripples
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.

# Gradient Ripple Reflection

Demonstrates how to use a procedurally generated gradient shader as a displacement map to create a dynamic water ripple effect on a reflected scene.

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/gradient-ripples.

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

### gradient ripples.js

```js
class Example extends Phaser.Scene
{
    preload ()
    {
        this.load.setBaseURL('https://cdn.phaserfiles.com/v410');
        this.load.image('spooky', 'assets/skies/spooky.png');
        this.load.image('wizball', 'assets/sprites/wizball.png');

        this.load.glsl('gradient-color', 'assets/shaders/gradients/gradient-color.glsl');
        this.load.glsl('gradient-process', 'assets/shaders/gradients/gradient-process.glsl');
        this.load.glsl('srgb', 'assets/shaders/gradients/srgb-color.glsl');
        this.load.glsl('value-bicircle', 'assets/shaders/gradients/value-bicircle.glsl');
    }

    create ()
    {
        const w = this.scale.gameSize.width;
        const h = this.scale.gameSize.height;

        // Define a space a bit larger than the screen, to absorb displacement.
        const wPlus = w + 100;
        const hPlus = h + 100;

        const getSource = (key) => this.cache.shader.get(key).glsl;
        const gradientShader = this.add.shader({
            name: 'Gradient',
            shaderAdditions: [
                // This addition controls a bi-circle gradient.
                // It must be defined in the shader before the gradient function is called.
                {
                    name: 'BICIRCLE',
                    additions: { fragmentHeader: getSource('value-bicircle') }
                },
                // This addition defines standard gradient functionality.
                {
                    name: 'STANDARD',
                    additions: {
                        fragmentHeader: [
                            getSource('srgb'),
                            getSource('gradient-color')
                        ].join('\n'),
                        fragmentProcess: getSource('gradient-process')
                    }
                }
            ],
            setupUniforms: (setUniform) => {
                setUniform('center', [0.5, 0.33]);
                setUniform('radius', 1.4);
                setUniform('feather', 1.4);
                setUniform('scale', [1, 0.5]);
                setUniform('color1', [1, 1, 1, 1]); // Interior color.
                setUniform('color2', [0, 0, 0, 0]); // Exterior color.
                setUniform('steps', 0); // Smooth gradient.
                setUniform('repeat', 32);
                setUniform('offset', (-this.game.loop.time / 30000) % (1.4 / 32) + (1.4 / 32)); // Animation.
                // 1.4 / 32 is the width of a single gradient step.
            }
        }, 0, 0, wPlus, hPlus)
        .setRenderToTexture('gradient');

        // Create a dynamic texture for inverting the gradient.
        // Using `redraw` mode, we automatically update the texture every frame.
        // Note that this is the size of `gradientShader`, not the screen.
        const gradientInverse = this.add.renderTexture(
            0, 0,
            wPlus, hPlus
        );
        gradientInverse
            .clear()
            .stamp('gradient', null, wPlus / 2, hPlus / 2, { scaleY: -1 })
            .preserve(true)
            .setRenderMode('redraw')
            .saveTexture('gradient-inverse');

        // Add a scaled-up background to be reflected.
        const spookyTextureFrame = this.textures.get('spooky').get();
        const bg = this.add.image(wPlus / 2, hPlus / 2, 'spooky').setScale(
            wPlus / spookyTextureFrame.width,
            hPlus / spookyTextureFrame.height
        );

        // Add a reflection ball.
        const reflection = this.add.image(wPlus / 2, hPlus * 1 / 8, 'wizball');
        this.reflection = reflection;

        // Create a container for the reflected world.
        const reflectionContainer = this.add.container(0, 0)
            .add([ bg, reflection ])
            .setVisible(false);

        // Render the container to a texture.
        const reflectionTexture = this.add.renderTexture(w / 2, h / 2, wPlus, hPlus)
            .setFlipY(true);

        reflectionTexture.enableFilters();
        reflectionTexture.filters.internal.addBlur(1, 2, 2);
        reflectionTexture.filters.internal.addDisplacement('gradient-inverse');
        
        reflectionTexture
            .clear()
            .draw(reflectionContainer)
            .preserve(true)
            .setRenderMode('all');


        const rippleBase = this.add.image(w / 2, h / 2, 'gradient')
        .setAlpha(0.125)
        .setTint(0x1800cc)
        .setBlendMode(Phaser.BlendModes.ADD);
        const rippleTop = this.add.image(w / 2, h / 2 - 8, 'gradient')
        .setAlpha(0.125)
        .setTint(0x66aaff)
        .setBlendMode(Phaser.BlendModes.ADD);

        const ball = this.add.image(w / 2, h / 2, 'wizball');
        this.ball = ball;

        // this.cameras.main.filters.internal.addTiltShift();

        this.tweens.add({
            targets: ball,
            y: h / 2 + 32,
            duration: 1000,
            yoyo: true,
            repeat: -1,
            ease: 'Sine.easeInOut',
            delay: 0
        });
    }

    update ()
    {
        // Sync the reflection with the ball.
        const height = this.scale.gameSize.height;
        const ball = this.ball;
        const reflection = this.reflection;
        const surface = height * 0.66;
        const distance = ball.y - surface;
        reflection.y = (height - surface) + distance;
    }
}

const config = {
    scale: { mode: Phaser.Scale.FIT },
    type: Phaser.AUTO,
    width: 1280,
    height: 720,
    backgroundColor: '#0a0033',
    parent: 'game-container',
    scene: Example
};

let 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 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.
- [Random Noise Shader Additions](https://phaser.io/oss/examples/v4.1.0/game%20objects/shader/view/custom-shader-random-noise.md): 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.
- [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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