[Determinated738]

This PR fixes a segfault that happens when using PBOs, as well as implementing getBufferSubData as it was missing.

Minimal code for recreating the segfault:

import createGL from "gl";

const width = 512;
const height = 512;
const size = width * height * 4;

const gl = createGL(width, height, { createWebGL2Context: true });

try {
    const pbo = gl.createBuffer();
    gl.bindBuffer(gl.PIXEL_PACK_BUFFER, pbo);
    gl.bufferData(gl.PIXEL_PACK_BUFFER, size, gl.STREAM_READ);
    gl.bindBuffer(gl.PIXEL_PACK_BUFFER, null);

    gl.clearColor(1, 0, 0, 1);
    gl.clear(gl.COLOR_BUFFER_BIT);

    gl.bindBuffer(gl.PIXEL_PACK_BUFFER, pbo);
    gl.readPixels(0, 0, width, height, gl.RGBA, gl.UNSIGNED_BYTE, 0);

    const pixels = new Uint8Array(size);
    gl.getBufferSubData(gl.PIXEL_PACK_BUFFER, 0, pixels);
    console.log(pixels);
} catch (e) {
    console.error("Caught JS Error:", e);
}

[Determinated738]

Hey @dhritzkiv, I went through the failed tests, they seem to be unrelated to my PR, if you need any help going through each one and fixing them, i'm more than happy to do a separate PR for this.

[dhritzkiv]

Hey! No worries about the failed tests. Your latest fixes will be integrated into other fixes that will be in an upcoming release