Documentation

Unity Engine

User Manual

Script Reference

Unity Engine

Web graphics

How to use the Web Graphics API.
Read time 3 minutesLast updated 14 days ago
WebGL is an API for rendering graphics in web browsers, which is based on the functionality of the OpenGL ES graphics library. WebGL 2.0 roughly matches with the OpenGL ES 3.0 functionality.

Camera clear

By default, Unity Web clears the drawing buffer after each frame, which means the content of the frame buffer clears regardless of the Camera.clearFlags setting. However, you can change this behavior at instantiation time. To do this, set 
webglContextAttributes.preserveDrawingBuffer
to 
true
in the 
index.html
file of your Web template.
Note
If you set any WebGL context attributes, you must also add a line to preserve the Power Preference Player setting.
script.onload = () => {  config['webglContextAttributes'] = {    preserveDrawingBuffer: true, //Add this line to preserve the Camera.clearFlags setting    powerPreference: {{{ WEBGL_POWER_PREFERENCE }}} //Add this line to preserve the Power Preference Player setting  };  createUnityInstance(canvas, config, (progress) => {

Global illumination

Unity Web only supports baked GI. Realtime Global Illumination isn't currently supported in Web. In addition, Unity Web supports Non-Directional lightmaps only.

Linear rendering

Some web browsers don't support sRGB DXT texture compression. This can decrease the quality of rendering performance when using linear rendering, due to runtime decompression of all the DXT textures.

Video clip importer

You can't use 
VideoClipImporter
to import video clips to your Unity project, because it might increase the initial asset data download size and prevent network streaming. For video playback, use the URL option in the VideoPlayer component and place the asset in the StreamingAssets/ directory to use the built-in network streaming of your browser.

Web shader code restrictions

The WebGL 2.0 specification imposes some limitations on GLSLS shader code. This is mainly relevant when you write your own shaders. Here are some of the restrictions:
  • Precision qualifiers: WebGL 2.0 requires you to specify the precision of all variables in the shader. You can use 
    highp
    , 
    mediump
    , or 
    lowp
    to specify the precision of the variable. If you don't specify the precision, the shader will use the default precision, which is 
    mediump
    . You can also use 
    precision
    to specify the precision of a block of variables.
Note
Due to limited available memory in Web, avoid including unwanted shader variants which can lead to unnecessary memory usage. Therefore, it's recommended to familiarize yourself with shader variants and shader stripping, and take extra care to ensure that you don’t add shaders with too many variants (for example, Unity's Standard Shader) to the Always-included Shaders section in Graphics Settings.

Font rendering

Unity Web supports dynamic font rendering similar to other Unity platforms. However, as it doesn't have access to the fonts installed on the user's machine, if you want to use any fonts, make sure to include them in the project folder (including any fallback fonts for international characters, or bold/italic versions of fonts), and set as fallback font names.

Anti-aliasing

WebGL supports anti-aliasing on most (but not on all) combinations of browsers and GPUs. To use it, anti-aliasing must be enabled in the default Quality setting for the Web platform.

Reflection probes

Unity Web supports all reflection probes.

WebGL 2.0 support

Unity includes support for the WebGL 2.0 API, which brings OpenGL ES 3.0-level rendering capabilities to the web. By default, Unity Web builds support the WebGL 2.0 API.
Browsers with WebGL 2.0 support have the following advantages:
  • The content in the Standard Shader is of high quality.
  • Support for GPU Instancing and directional lightmap.
  • There's no restrictions on indexing and loops in shader code.
  • Improved performance.

Additional resources: