WebGL - texSubImage2D - only square data?
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I am trying to update texture in GPU using WebGL. I use

    gl.texSubImage2D(gl.TEXTURE_2D, 0, 0, 0, width, height, 
                     gl.RGBA, gl.UNSIGNED_BYTE, buff);

where `buff` is `Uint8Array` of size (width*height*4). It updates only the sub-square with size `min(width, height)`.

Is it normal? I didn't find anything about it in specification, but it works this way in Chrome, Firefox and Opera for Android. If it should work this way, why are there two parameters width and height? Do you know anything about it?
