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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">
<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>
<script id="vshader" type="x-shader/x-vertex">
attribute vec2 pos;
void main()
{
gl_Position = vec4(pos, 0, 1);
}
</script>
<script id="fshader" type="x-shader/x-fragment">
precision mediump float;
uniform vec4 col;
void main()
{
gl_FragColor = col;
}
</script>
<script>
"use strict";
var wtu = WebGLTestUtils;
function draw(gl, arr, colLoc, col) {
var vertices = new Float32Array(arr);
var vertBuf = gl.createBuffer();
gl.bindBuffer(gl.ARRAY_BUFFER, vertBuf);
gl.bufferData(gl.ARRAY_BUFFER, vertices, gl.STATIC_DRAW);
gl.vertexAttribPointer(0, 2, gl.FLOAT, false, 0, 0);
gl.uniform4fv(colLoc, col);
gl.drawArrays(gl.TRIANGLE_STRIP, 0, vertices.length / 2);
}
function clear(gl, col) {
gl.clearColor(col[0], col[1], col[2], col[3]);
gl.clear(gl.COLOR_BUFFER_BIT | gl.DEPTH_BUFFER_BIT);
}
function check(gl, winding, shoulddraw) {
var msg = winding + ' face was ' + (shoulddraw ? '' : 'not ') + 'drawn.';
wtu.checkCanvasRect(gl, 0, 0, 1, 1, [0, 255, 0, 255], msg);
}
function runTest() {
var cwVertices = [-1, -1, -1, 1, 1, -1, 1, 1];
var ccwVertices = [-1, 1, -1, -1, 1, 1, 1, -1];
var red = [1, 0, 0, 1];
var green = [0, 1, 0, 1];
var ok;
var gl = wtu.create3DContext('testbed', { antialias: false });
if (!gl) {
testFailed('could not create context');
return;
}
var program = wtu.setupProgram(gl, ['vshader', 'fshader'], ['pos']);
var colLoc = gl.getUniformLocation(program, 'col');
gl.enableVertexAttribArray(0);
debug('CULL_FACE should be off by default');
clear(gl, red);
draw(gl, ccwVertices, colLoc, green);
check(gl, 'CCW', true);
clear(gl, red);
draw(gl, cwVertices, colLoc, green);
check(gl, 'CW', true);
debug('Enabling CULL_FACE');
gl.enable(gl.CULL_FACE);
debug('BACK and CCW should be set by default');
clear(gl, red);
draw(gl, ccwVertices, colLoc, green);
check(gl, 'CCW', true);
clear(gl, green);
draw(gl, cwVertices, colLoc, red);
check(gl, 'CW', false);
var tests = [{ cullFace : 'BACK', frontFace : 'CCW', drawCCW : true, drawCW : false},
{ cullFace : 'BACK', frontFace : 'CW', drawCCW : false, drawCW : true},
{ cullFace : 'FRONT', frontFace : 'CCW', drawCCW : false, drawCW : true },
{ cullFace : 'FRONT', frontFace : 'CW', drawCCW : true, drawCW : false},
{ cullFace : 'FRONT_AND_BACK', frontFace : 'CCW', drawCCW : false, drawCW : false},
{ cullFace : 'FRONT_AND_BACK', frontFace : 'CW', drawCCW : false, drawCW : false}];
for (var i = 0; i < tests.length; ++i) {
var t = tests[i];
debug('Setting ' + t.cullFace + ' and ' + t.frontFace);
gl.cullFace(gl[t.cullFace]);
gl.frontFace(gl[t.frontFace]);
clear(gl, t.drawCCW ? red : green);
draw(gl, ccwVertices, colLoc, t.drawCCW ? green : red);
check(gl, 'CCW', t.drawCCW);
clear(gl, t.drawCW ? red : green);
draw(gl, cwVertices, colLoc, t.drawCW ? green : red);
check(gl, 'CW', t.drawCW);
}
}
</script>
</head>
<body>
<canvas id="testbed" width="16" height="16" style="width:50px; height:50px"></canvas>
<div id="description"></div>
<div id="console"></div>
<script>
"use strict";
description('Verify that culling works');
runTest();
var successfullyParsed = true;
</script>
<script src="../../js/js-test-post.js"></script>
</body>
</html>
|
