WebGL はウェブブラウザーでグラフィックスをレンダリングするための API で、OpenGL ES グラフィックスライブラリの機能にもとづいています。WebGL 1.0 は OpenGL ES 2.0 の機能とほぼ一致し、WebGL 2.0 は OpenGL ES 3.0 の機能とほぼ一致します。
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 your Web template:
script.onload = () => {
config['webglContextAttributes'] = {"preserveDrawingBuffer": true}; // Add this line to the index.html file in a Web Template
createUnityInstance(canvas, config, (progress) => }
Unity Web only supports Deferred Rendering Path if WebGL2.0 is available. On WebGL 1.0, Unity Web runtime falls back to Forward Rendering.
Unity Web only supports baked GI. Realtime Global Illumination isn’t currently supported in Web. In addition, Unity Web supports Non-Directional lightmaps only.
Unity Web only supports linear color space rendering with WebGL 2.0. Linear color space rendering doesn’t have fallback support for WebGL 1.0. To build a Web player using linear color space rendering, you need to remove WebGL 1.0 API in the Player settings, open the Other Settings panel, disable the Automatic Graphics API setting.
一部のウェブブラウザーは sRGB DXT テクスチャ圧縮 をサポートしていません。これにより、すべての DXT テクスチャをランタイムに解凍するため、リニアレンダリングを使用するときにレンダリングパフォーマンスの品質が低下します。
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.
The WebGL 1.0 specification imposes some limitations on GLSLS shader code, which are more restrictive than most OpenGL ES 2.0 implementations. This is mostly relevant when you write your own shaders.
WebGL has specific restrictions on which values to use to index arrays or matrices. For example, WebGL only allows dynamic indexing with constant expressions, loop indices or a combination, except for uniform access in vertex shaders, which you can index using any expression.
Note for WebGL 1.0: Additional restrictions apply on control structures in WebGL 1.0, where it doesn’t allow while loops and most type of for loops. However, it allows counting for loops, where the field initializer sets a variable to a constant, the update adds a constant to or subtracts a constant from the variable, and the continuation test compares the variable to a constant.
Note: Due to limited available memory in Web, you should avoid including unneeded shader variants which can lead to unnecessary memory usage. Therefore, Unity recommends familiarizing 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(class-GraphicsSettings#Always) in Graphics Settings.
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.
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.
Unity Web supports all reflection probes. Note: WebGL 1.0 doesn’t support Smooth realtime reflection probes.
Unity には WebGL 2.0 API のサポートが含まれており、ウェブに対する OpenGL ES 3.0 レベルのレンダリング機能を提供します。
By default, Unity Web builds support the WebGL 2.0 API. You can configure this in the Web Player settings > Other Settings panel by disabling the Automatic Graphics API property and adding the WebGL 1.0 API to your project.
Browsers with WebGL 2.0 support have the following advantages:
ランタイムに SystemInfo.graphicsDeviceType を使用すると、Unity インスタンスが OpenGLES3 (WebGL2.0) と OpenGLES2 (WebGL1.0)、どちらでレンダリングしているかを判断できます。