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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
found in the LICENSE.txt file.
-->
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<title>WebGL Rendering and Sampling Feedback Loop Tests</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="8" height="8"></canvas>
<div id="description"></div>
<div id="console"></div>
<script id="vs100" type="x-shader/x-vertex">
attribute vec4 aPosition;
attribute vec2 aTexCoord;
varying vec2 texCoord;
void main() {
gl_Position = aPosition;
texCoord = aTexCoord;
}
</script>
<script id="fs100" type="x-shader/x-fragment">
#extension GL_EXT_draw_buffers : require
precision mediump float;
uniform sampler2D tex;
varying vec2 texCoord;
void main() {
gl_FragData[0] = texture2D(tex, texCoord);
gl_FragData[1] = texture2D(tex, texCoord);
}
</script>
<script id="fs100-no-ext-draw-buffers" type="x-shader/x-fragment">
precision mediump float;
uniform sampler2D tex;
varying vec2 texCoord;
void main() {
gl_FragData[0] = texture2D(tex, texCoord);
}
</script>
<script id="vs300" type="x-shader/x-vertex">#version 300 es
in highp vec4 aPosition;
in vec2 aTexCoord;
out vec2 texCoord;
void main() {
gl_Position = aPosition;
texCoord = aTexCoord;
}
</script>
<script id="fs300" type="x-shader/x-fragment">#version 300 es
precision mediump float;
uniform sampler2D tex;
in vec2 texCoord;
out vec4 oColor;
void main() {
oColor = texture(tex, texCoord);
}
</script>
<script>
"use strict";
const wtu = WebGLTestUtils;
description("This test verifies the functionality of rendering to the same texture where it samples from.");
const gl = wtu.create3DContext("example");
const width = 8;
const height = 8;
let tex;
let fbo;
let drawBuffers = null;
if (!gl) {
testFailed("WebGL context does not exist");
} else {
testPassed("WebGL context exists");
if (gl.drawBuffers) {
debug("Using webgl2.drawBuffers.");
drawBuffers = (x) => gl.drawBuffers(x);
} else {
const ext = gl.getExtension("WEBGL_draw_buffers");
if (ext) {
debug("Using WEBGL_draw_buffers.drawBuffersWEBGL.");
drawBuffers = (x) => ext.drawBuffersWEBGL(x);
}
}
init();
// The sampling texture is bound to COLOR_ATTACHMENT1 during resource allocation
allocate_resource();
rendering_sampling_feedback_loop(null);
if (drawBuffers) {
rendering_sampling_feedback_loop([gl.NONE]);
rendering_sampling_feedback_loop([gl.COLOR_ATTACHMENT0,
gl.COLOR_ATTACHMENT0+1]);
rendering_sampling_feedback_loop([gl.NONE,
gl.COLOR_ATTACHMENT0+1]);
}
}
function init() {
let shaders = ["vs100", "fs100"];
if (gl.texStorage2D) {
shaders = ["vs300", "fs300"];
} else if (!drawBuffers) {
shaders = ["vs100", "fs100-no-ext-draw-buffers"];
}
const program = wtu.setupProgram(gl, shaders, ["aPosition", "aTexCoord"], [0, 1]);
const positionLoc = gl.getAttribLocation(program, "aPosition");
const texCoordLoc = gl.getAttribLocation(program, "aTexCoord");
if (!program || positionLoc < 0 || texCoordLoc < 0) {
testFailed("Set up program failed");
return;
}
const texLoc = gl.getUniformLocation(program, "tex");
gl.uniform1i(texLoc, 0);
testPassed("Set up program succeeded");
wtu.setupUnitQuad(gl, 0, 1);
gl.viewport(0, 0, width, height);
}
function allocate_resource() {
tex = gl.createTexture();
gl.bindTexture(gl.TEXTURE_2D, tex);
gl.texImage2D(gl.TEXTURE_2D, 0, gl.RGBA, 2, 2, 0, gl.RGBA, gl.UNSIGNED_BYTE, null);
fbo = gl.createFramebuffer();
gl.bindFramebuffer(gl.FRAMEBUFFER, fbo);
gl.framebufferTexture2D(gl.FRAMEBUFFER, gl.COLOR_ATTACHMENT0, gl.TEXTURE_2D, tex, 0);
}
function rendering_sampling_feedback_loop(draw_buffers) {
debug("draw_buffers: " + JSON.stringify(draw_buffers));
if (draw_buffers) {
drawBuffers(draw_buffers);
}
// Make sure framebuffer is complete before feedback loop detection
if (gl.checkFramebufferStatus(gl.FRAMEBUFFER) != gl.FRAMEBUFFER_COMPLETE) {
testFailed("Framebuffer incomplete.");
return;
}
gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_MIN_FILTER, gl.NEAREST);
wtu.clearAndDrawUnitQuad(gl);
wtu.glErrorShouldBe(gl, gl.INVALID_OPERATION, "Feedback loop detection should ignore drawBuffers settings.");
gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_MIN_FILTER, gl.NEAREST_MIPMAP_NEAREST);
// The texture will be mipmap incomplete, so feedback cannot occur nor be consistently evaluated.
wtu.clearAndDrawUnitQuad(gl);
wtu.glErrorShouldBe(gl, gl.NO_ERROR, "Feedback loop detection should ignore sampled incomplete textures.");
if (draw_buffers) {
drawBuffers([gl.COLOR_ATTACHMENT0]);
}
}
gl.deleteTexture(tex);
gl.deleteFramebuffer(fbo);
var successfullyParsed = true;
</script>
<script src="../../js/js-test-post.js"></script>
</body>
</html>