Source code
Revision control
Copy as Markdown
Other Tools
<!--
Copyright (c) 2019 The Khronos Group Inc.
Use of this source code is governed by an MIT-style license that can be
found in the LICENSE.txt file.
-->
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<title>WebGL Rendering Feedback Loop</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="1" height="1" style="width: 40px; height: 40px;"></canvas>
<div id="description"></div>
<div id="console"></div>
<script id="vs" type="text/something-not-javascript">
attribute vec4 a_position;
attribute vec2 a_texCoord;
varying vec2 v_texCoord;
void main() {
gl_Position = a_position;
v_texCoord = a_texCoord;
}
</script>
<script id="fs" type="text/something-not-javascript">
precision mediump float;
varying vec2 v_texCoord;
uniform sampler2D u_texture;
void main() {
// Shader swizzles color channels so we can tell if the draw succeeded.
gl_FragColor = texture2D(u_texture, v_texCoord).gbra;
}
</script>
<script>
"use strict";
description("Checks that rendering feedback loops fail correctly.");
var wtu = WebGLTestUtils;
var gl = wtu.create3DContext("example");
var texture = gl.createTexture();
gl.bindTexture(gl.TEXTURE_2D, texture);
gl.texImage2D(gl.TEXTURE_2D, 0, gl.RGBA, 1, 1, 0, gl.RGBA, gl.UNSIGNED_BYTE,
new Uint8Array([255, 0, 0, 255]));
gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_MIN_FILTER, gl.NEAREST);
gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_MAG_FILTER, gl.NEAREST);
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);
wtu.glErrorShouldBe(gl, gl.NO_ERROR, "after creating texture");
var framebuffer = gl.createFramebuffer();
gl.bindFramebuffer(gl.FRAMEBUFFER, framebuffer);
gl.framebufferTexture2D(gl.FRAMEBUFFER, gl.COLOR_ATTACHMENT0, gl.TEXTURE_2D, texture, 0);
assertMsg(gl.checkFramebufferStatus(gl.FRAMEBUFFER) == gl.FRAMEBUFFER_COMPLETE,
"framebuffer should be FRAMEBUFFER_COMPLETE.");
var program = wtu.setupProgram(gl, ["vs", "fs"], ["a_position", "a_texCoord"]);
gl.uniform1i(gl.getUniformLocation(program, "u_texture"), 0);
gl.disable(gl.BLEND);
gl.disable(gl.DEPTH_TEST);
wtu.glErrorShouldBe(gl, gl.NO_ERROR, "after initWebGL");
// Drawing with a texture that is also bound to the current framebuffer should fail
var bufferObjects = wtu.setupUnitQuad(gl, 0, 1);
gl.bindTexture(gl.TEXTURE_2D, texture);
wtu.drawUnitQuad(gl);
wtu.glErrorShouldBe(gl, gl.INVALID_OPERATION, "after draw with invalid feedback loop");
// Ensure that the texture contents did not change after the previous render
gl.bindFramebuffer(gl.FRAMEBUFFER, null);
wtu.clearAndDrawUnitQuad(gl);
wtu.glErrorShouldBe(gl, gl.NO_ERROR, "after drawing");
wtu.checkCanvas(gl, [0, 0, 255, 255], "Should be blue.");
// Drawing when texture is bound to an inactive uniform should succeed
var texture2 = gl.createTexture();
gl.bindTexture(gl.TEXTURE_2D, texture2);
gl.texImage2D(gl.TEXTURE_2D, 0, gl.RGBA, 1, 1, 0, gl.RGBA, gl.UNSIGNED_BYTE,
new Uint8Array([0, 255, 0, 255]));
gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_MIN_FILTER, gl.NEAREST);
gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_MAG_FILTER, gl.NEAREST);
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.bindFramebuffer(gl.FRAMEBUFFER, framebuffer);
gl.activeTexture(gl.TEXTURE1);
gl.bindTexture(gl.TEXTURE_2D, texture);
wtu.drawUnitQuad(gl);
wtu.glErrorShouldBe(gl, gl.NO_ERROR, "after draw where framebuffer texture is bound to inactive texture unit");
wtu.checkCanvas(gl, [255, 0, 0, 255], "Should be red.");
var successfullyParsed = true;
</script>
<script src="../../js/js-test-post.js"></script>
</body>
</html>