| <!-- |
| |
| /* |
| ** Copyright (c) 2014 The Khronos Group Inc. |
| ** |
| ** Permission is hereby granted, free of charge, to any person obtaining a |
| ** copy of this software and/or associated documentation files (the |
| ** "Materials"), to deal in the Materials without restriction, including |
| ** without limitation the rights to use, copy, modify, merge, publish, |
| ** distribute, sublicense, and/or sell copies of the Materials, and to |
| ** permit persons to whom the Materials are furnished to do so, subject to |
| ** the following conditions: |
| ** |
| ** The above copyright notice and this permission notice shall be included |
| ** in all copies or substantial portions of the Materials. |
| ** |
| ** THE MATERIALS ARE PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, |
| ** EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF |
| ** MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. |
| ** IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY |
| ** CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, |
| ** TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE |
| ** MATERIALS OR THE USE OR OTHER DEALINGS IN THE MATERIALS. |
| */ |
| |
| --> |
| |
| <!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 vec3 pos; |
| |
| void main() |
| { |
| gl_Position = vec4(pos, 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, 3, gl.FLOAT, false, 0, 0); |
| gl.uniform4fv(colLoc, col); |
| gl.drawArrays(gl.TRIANGLE_STRIP, 0, vertices.length / 3); |
| } |
| |
| function clear(gl, col, z) |
| { |
| gl.clearColor(col[0], col[1], col[2], col[3]); |
| gl.clearDepth(z); |
| gl.clear(gl.COLOR_BUFFER_BIT | gl.DEPTH_BUFFER_BIT); |
| } |
| |
| function check(gl) |
| { |
| wtu.checkCanvasRect(gl, 0, 0, 16, 16, [0, 255, 0, 255], 'result should be green'); |
| } |
| |
| function runTest() |
| { |
| var flatSquare = [-1, -1, 0, |
| -1, 1, 0, |
| 1, -1, 0, |
| 1, 1, 0]; |
| var slantedSquare = [-1, -1, -0.5, |
| -1, 1, -0.5, |
| 1, -1, 0.5, |
| 1, 1, 0.5]; |
| var red = [1, 0, 0, 1]; |
| var green = [0, 1, 0, 1]; |
| var blue = [0, 0, 1, 1]; |
| |
| 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); |
| |
| gl.enable(gl.DEPTH_TEST); |
| gl.depthFunc(gl.LEQUAL); |
| |
| debug('Polygon offset fill should be off by default'); |
| clear(gl, red, 1.0); |
| draw(gl, slantedSquare, colLoc, blue); |
| draw(gl, slantedSquare, colLoc, green); |
| check(gl); |
| |
| debug('Polygon offset units should have no effect when fill is off'); |
| clear(gl, red, 1.0); |
| draw(gl, slantedSquare, colLoc, blue); |
| gl.polygonOffset(0, 10); |
| draw(gl, slantedSquare, colLoc, green); |
| check(gl); |
| |
| debug('Polygon offset factor should have no effect when fill is off'); |
| clear(gl, red, 1.0); |
| gl.polygonOffset(0, 0); |
| draw(gl, slantedSquare, colLoc, blue); |
| gl.polygonOffset(1.0, 0); |
| draw(gl, slantedSquare, colLoc, green); |
| check(gl); |
| |
| debug('Zero polygon offset units and factor should have no effect'); |
| clear(gl, red, 1.0); |
| gl.enable(gl.POLYGON_OFFSET_FILL); |
| gl.polygonOffset(0, 0); |
| draw(gl, slantedSquare, colLoc, blue); |
| draw(gl, slantedSquare, colLoc, green); |
| check(gl); |
| |
| // It appears to be VERY common for drivers to implement the units offset in |
| // floating-point arithmetic, which results in rount-to-nearest-even to cause |
| // an offset of 1 to sometimes not alter the order between these polygons. |
| debug('Polygon offset units of 2 should alter order of flat polygons'); |
| clear(gl, red, 1.0); |
| draw(gl, flatSquare, colLoc, green); |
| gl.polygonOffset(0, 2); |
| draw(gl, flatSquare, colLoc, blue); |
| check(gl); |
| |
| debug('Polygon offset factor of 0.1 should alter order of slanted polygons'); |
| clear(gl, red, 1.0); |
| draw(gl, slantedSquare, colLoc, green); |
| gl.polygonOffset(0.1, 0); |
| draw(gl, slantedSquare, colLoc, blue); |
| check(gl); |
| |
| debug('Polygon offset factor of 0.1 should not alter order of flat polygons'); |
| clear(gl, red, 1.0); |
| draw(gl, flatSquare, colLoc, blue); |
| gl.polygonOffset(0.1, 0); |
| draw(gl, flatSquare, colLoc, green); |
| check(gl); |
| |
| debug('Disabling polygon offset fill should leave order unaffected'); |
| clear(gl, red, 1.0); |
| gl.polygonOffset(0.1, 1); |
| gl.disable(gl.POLYGON_OFFSET_FILL); |
| draw(gl, slantedSquare, colLoc, blue); |
| draw(gl, slantedSquare, colLoc, green); |
| check(gl); |
| |
| debug('Enabling polygon offset fill should affect order again'); |
| clear(gl, red, 1.0); |
| draw(gl, slantedSquare, colLoc, green); |
| gl.enable(gl.POLYGON_OFFSET_FILL); |
| draw(gl, slantedSquare, colLoc, blue); |
| check(gl); |
| } |
| </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 polygon offset works'); |
| runTest(); |
| var successfullyParsed = true; |
| </script> |
| <script src="../../js/js-test-post.js"></script> |
| |
| </body> |
| </html> |
