How To

Put Shader Code in BJS


Putting Shader Code in BabylonJS

Here are four ways of putting shader code into your scene:

  1. Use BabylonJS Create Your Own Shader (CYOS) and download a zip file;
  2. Write the Vertex and Fragment Shader Code into &ltscript&gt tags
  3. Write, save and import a Vertex and Fragment Shader file of type .fx into your code;
  4. Use the shaderBuilder extension of BabylonJS.

Methods 1, 2 and 3 use BABYLON.ShaderMaterial to pass data to the shaders.

BabylonJS CYOS Download

This site allows you to write code for a Vertex Shader and a Fragment Shader and see the results on a variety of meshes. Downloading a zip file produces a folder containing and index.html file and some image files for texture.

CYOS Screen;

The index.html file contains the shader code in the correct format to apply as a material.

Within the HTML page the shader code becomes (in Javascript)

BABYLON.Effect.ShadersStore["customVertexShader"]= "\r\n"+
    "precision highp float;\r\n"+

   "// Attributes\r\n"+
   "attribute vec3 position;\r\n"+
   "attribute vec2 uv;\r\n"+

   "// Uniforms\r\n"+
   "uniform mat4 worldViewProjection;\r\n"+

   "// Varying\r\n"+
   "varying vec2 vUV;\r\n"+

   "void main(void) {\r\n"+
   "    gl_Position = worldViewProjection * vec4(position, 1.0);\r\n"+

   "    vUV = uv;\r\n"+
   "}\r\n";

BABYLON.Effect.ShadersStore["customFragmentShader"]= "\r\n"+
   "precision highp float;\r\n"+

   "varying vec2 vUV;\r\n"+

   "uniform sampler2D textureSampler;\r\n"+

   "void main(void) {\r\n"+
   "    gl_FragColor = texture2D(textureSampler, vUV);\r\n"+
   "}\r\n";

the Javascript code to use the shader as a material is

var shaderMaterial = new BABYLON.ShaderMaterial("shader", scene, {
        vertex: "custom",
        fragment: "custom",
    },
    {
        attributes: ["position", "normal", "uv"],
        uniforms: ["world", "worldView", "worldViewProjection", "view", "projection"]
});

and the Javascript code to set a texture to the material is

var mainTexture = new BABYLON.Texture("amiga.jpg", scene);
shaderMaterial.setTexture("textureSampler", mainTexture);

and to use the material on a mesh is

mesh.material = shaderMaterial;

Extracting the appropriate sections of Javascript code allows you to transfer them to your own scenes.

Guide Example From CYOS Zip

This method can easily be used in the Playground.

Playgound Example From CYOS -


;

Shader Code in <script> Tags

In the index.html file the Javascript code for the shaders is

<script type="application/vertexShader" id="vertexShaderCode">
    #ifdef GL_ES
        precision highp float;
    #endif

    // Attributes
    attribute vec3 position;
    attribute vec2 uv;

    // Uniforms
    uniform mat4 worldViewProjection;

    // Normal
    varying vec2 vUV;

    void main(void) {
    gl_Position = worldViewProjection * vec4(position, 1.0);

    vUV = uv;
    }
</script>

<script type="application/fragmentShader" id="fragmentShaderCode">
    #ifdef GL_ES
        precision mediump float;
    #endif

    varying vec2 vUV;

    uniform sampler2D textureSampler;

    void main(void) {
        gl_FragColor = texture2D(textureSampler, vUV);
    }
</script>

the Javascript code to use the shader as a material becomes

var shaderMaterial = new BABYLON.ShaderMaterial("shader", scene, {
        vertexElement: "vertexShaderCode",
        fragmentElement: "fragmentShaderCode",
    },
    {
        attributes: ["position", "normal", "uv"],
        uniforms: ["world", "worldView", "worldViewProjection", "view", "projection"]
});

Guide Example From Script

Shader Code in fx Files

Save your code in two files, one for the Vertex Shader and one for the Fragment Shader.

These files must be in the same folder as your index.html page and the names of the files must follow this format

COMMON_NAME.vertex.fx

COMMON_NAME.fragment.fx

The Javascript code to use the shader as material becomes

var shaderMaterial = new BABYLON.ShaderMaterial("shader", scene, "./COMMON_NAME",
    {
        attributes: ["position", "normal", "uv"],
        uniforms: ["world", "worldView", "worldViewProjection", "view", "projection"]
});

Note ./ is neccesary before the COMMON_NAME

It is also possible to access the fx files from an URL by giving the full address of the URL, provide CORS is enabled for them.

Guide Example From Import

Shader Builder

This is an extension to BabylonJS. Copy and save the source code for the extension and add as

<script>Babylonx.ShaderBuilder.js</script>

The Shader Builder engine needs to be initialised

BABYLONX.ShaderBuilder.InitializeEngine();

The format for writing a ShaderBuilder is fluent coding and it deals with attributes and BABYLONJS uniforms automatically.
An example for the shader code used in 1 to 3 above would be

mesh.material = new BABYLONX.ShaderBuilder()
    .Map({ path: 'textures/amiga.jpg' })
    .BuildMaterial(scene);

Guide Example using ShaderBuilder

This method can be used in the Playground. However it does require the loading of the ShaderBuilder Javascript file and an onLoad function before it can be called.

Playground Example using ShaderBuilder -


Further Reading

Introduction To Shaders in BabylonJS
ShaderMaterial Object