texel-fetch-undefined.html

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Copyright (c) 2019 The Khronos Group Inc.

Use of this source code is governed by an MIT-style license that can be

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<!DOCTYPE html>

<html>

<head>

<meta charset="utf-8">

<title>WebGL texel fetch test.</title>

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

<link rel="stylesheet" href="../../../resources/glsl-feature-tests.css"/>

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

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

</head>

<body>

<canvas id="c" width="256" height="256"></canvas>

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

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

<script id="vertex-shader" type="x-shader/x-vertex">#version 300 es

  precision highp float;

  in vec4 aPosition;

  void main() {

    gl_Position = aPosition;

</script>

<script id="fragment-shader" type="x-shader/x-fragment">#version 300 es

  precision mediump float;

  uniform sampler2D uSampler;

  uniform ivec2 uTestPos;

  out vec4 my_FragColor;

  void main() {

    my_FragColor = texelFetch(uSampler, uTestPos, 0);

</script>

<script>

"use strict";

description("This test makes sure that texelFetch works to the WebGL 2.0 spec when retrieving a texel outside of the texture's size.");

var wtu = WebGLTestUtils;

var textureSize = 24;

var gl = wtu.create3DContext('c', undefined, 2);

function testFetchAt(x, y, expectedColor) {

  debug("");

  debug("Test fetching a texel of the texture at x = " + x +", y = " + y);

  gl.uniform2i(uTestPos, x, y);

  wtu.clearAndDrawUnitQuad(gl);

  wtu.checkCanvas(gl, expectedColor);

var program = wtu.setupProgram(gl, ["vertex-shader", "fragment-shader"]);

var aPosition = gl.getAttribLocation(program, "aPosition");

var uTestPos = gl.getUniformLocation(program, "uTestPos");

debug('Creating a texture with size ' + textureSize + '*' + textureSize);

var tex = gl.createTexture();

gl.bindTexture(gl.TEXTURE_2D, tex);

gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_WRAP_S, gl.CLAMP_TO_EDGE);

gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_WRAP_T, gl.CLAMP_TO_EDGE);

gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_MIN_FILTER, gl.NEAREST);

gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_MAG_FILTER, gl.NEAREST);

wtu.fillTexture(gl, tex, textureSize, textureSize, [0, 255, 0, 255]);

wtu.setupUnitQuad(gl, aPosition);

testFetchAt(0, 0, [0, 255, 0, 255]);

testFetchAt(textureSize - 1, textureSize - 1, [0, 255, 0, 255]);

testFetchAt(textureSize, 0, [0, 0, 0, 0]);

testFetchAt(0, textureSize, [0, 0, 0, 0]);

testFetchAt(-1, 0, [0, 0, 0, 0]);

testFetchAt(0, -1, [0, 0, 0, 0]);

testFetchAt(-1, 1, [0, 0, 0, 0]);

finishTest();

</script>

</body>

</html>