In the following Github example, init webgl, the clearing, size in html, pixels in canvas.
Init Webgl:
canvas.getContext("webgl2");
Clear:
gl.clearColor(1.0,0.0,0.0,1.0);
this.clear(this.COLOR_BUFFER_BIT | this.DEPTH_BUFFER_BIT);
Size in html:
this.canvas.style.width = width;
this.canvas.style.height = height;
Pixels in Canvas:
this.viewport(0, 0, width, height);
The result is:
