WebGL - reading pixel data from render buffer

Question

Is there a way to get the raw pixel data from a WebGL render buffer or frame buffer that is off screen?

I\'m using WebGL to do some image processing, e.g. blurring a

Answer 1

Yes, you can read raw pixel data. Set preserveDrawingBuffer as true while getting webgl context and afterwards make use of readPixels by WebGL.

var context = canvasElement.getContext("webgl", {preserveDrawingBuffer: true}
var pixels = new Uint8Array(4 * width * height);
context.readPixels(x, y, width, height, context.RGBA, context.UNSIGNED_BYTE, pixels)