Three.js detect webgl support and fallback to regu

问题:

Can anyone who has used three.js tell me if its possible to detect webgl support, and, if not present, fallback to a standard Canvas render?

回答1:

Yes, it's possible. You can use CanvasRenderer instead of WebGLRenderer.

About WebGL detection:

1) Read this WebGL wiki article: http://www.khronos.org/webgl/wiki/FAQ

 if (!window.WebGLRenderingContext) {
    // the browser doesn't even know what WebGL is
    window.location = "http://get.webgl.org";
  } else {
    var canvas = document.getElementById("myCanvas");
    var context = canvas.getContext("webgl");
    if (!context) {
      // browser supports WebGL but initialization failed.
      window.location = "http://get.webgl.org/troubleshooting";
    }
  }

2) Three.js already has a WebGL detector: https://github.com/mrdoob/three.js/blob/master/examples/js/Detector.js

renderer = Detector.webgl? new THREE.WebGLRenderer(): new THREE.CanvasRenderer();

3) Check also the Modernizr detector: https://github.com/Modernizr/Modernizr/blob/master/feature-detects/webgl.js

回答2:

Juan Mellado's pointer to the Three.js detector was super useful, but I prefer not to bring the whole file into my project. So here is the extracted Detector.webgl() function.

function webglAvailable() {
    try {
        var canvas = document.createElement("canvas");
        return !!
            window.WebGLRenderingContext && 
            (canvas.getContext("webgl") || 
                canvas.getContext("experimental-webgl"));
    } catch(e) { 
        return false;
    } 
}

And it is used similar to his example:

renderer = webglAvailable() ? new THREE.WebGLRenderer() : new THREE.CanvasRenderer();