| <!-- |
| 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> |
