tex-image-10bpc.html

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<html>

<head>

<meta charset="utf-8" />

<title>Ensure 10bpc image is not crushed to 8bpc in texImage2D</title>

<link rel="stylesheet" href="../../../resources/js-test-style.css" />

<script src="../../../js/js-test-pre.js"></script>

<script src="../../../js/webgl-test-utils.js"></script>

</head>

<body>

<canvas id="example" width="24" height="24"></canvas>

<div id="description"></div>

<div id="console"></div>

<script>

"use strict";

description(document.title);

var wtu = WebGLTestUtils;

var gl = wtu.create3DContext("example", undefined, 2);

var uniquePixels;

// This is an 8x1, 10-bit-per-channel PNG (encoded as 16bpc).

// The first pixel is black, and each next pixel is one brighter; approximately:

// (0/1023,0,0), (1/1023,0,0), (2/1023,0,0), ..., (7/1023,0,0)

const imgW = 8, imgH = 1;

const imgURL = "../../../resources/red-gradient-8x1-10bit-untagged.png";

const img = document.createElement("img");

img.onload = () => {

  const tex = gl.createTexture();

  gl.bindTexture(gl.TEXTURE_2D, tex);

  const level = 0;

  const internalformat = gl.RGB10_A2;

  const border = 0;

  const format = gl.RGBA;

  const type = gl.UNSIGNED_INT_2_10_10_10_REV;

  gl.texImage2D(gl.TEXTURE_2D, level, internalformat, imgW, imgH, border, format, type, img);

  const fbo = gl.createFramebuffer();

  gl.bindFramebuffer(gl.FRAMEBUFFER, fbo);

  gl.framebufferTexture2D(gl.FRAMEBUFFER, gl.COLOR_ATTACHMENT0, gl.TEXTURE_2D, tex, 0);

  shouldBe("gl.checkFramebufferStatus(gl.FRAMEBUFFER)", "gl.FRAMEBUFFER_COMPLETE");

  const pixels = new Uint32Array(imgW * imgH);

  gl.readPixels(0, 0, imgW, imgH, format, type, pixels);

  uniquePixels = new Set(pixels);

  // If the image was crushed to 8bpc, there will be 2-3 distinct values:

  // (0/255,0,0), (1/255,0,0), and maybe (2/255,0,0) (depending on truncation vs rounding).

  // If it wasn't, there should be 7-8.

  // At time of writing, on Mac M1, Chrome gets 2 if it's crushed, and 7 if it's not.

  shouldBeGreaterThanOrEqual("uniquePixels.size", "7", "there should be at least 7 distinct color values");

  finishTest();

};

img.src = imgURL;

var successfullyParsed = true;

</script>

</body>

</html>