| <!-- |
| 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>Alpha blending bug on WebGL canvas</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> |
| <div id="description"></div> |
| <div id="console"></div> |
| <canvas id="canvas" width="128" height="128"> </canvas> |
| |
| <script id="vshader" type="x-shader/x-vertex"> |
| attribute vec2 a_position; |
| varying vec2 v_uv; |
| void main() |
| { |
| v_uv = a_position.xy * vec2(0.5, 0.5) + vec2(0.5, 0.5); |
| gl_Position = vec4(a_position.xy, 0.0, 1.0); |
| } |
| </script> |
| |
| <script id="fshader" type="x-shader/x-fragment"> |
| precision mediump float; |
| varying vec2 v_uv; |
| uniform sampler2D u_texture; |
| uniform vec4 u_color; |
| void main() |
| { |
| vec4 tex = texture2D(u_texture, v_uv); |
| gl_FragColor = tex * u_color; |
| } |
| </script> |
| |
| <script> |
| "use strict"; |
| // This test exposes an Intel driver issue on macOS. |
| var wtu = WebGLTestUtils; |
| var gl = wtu.create3DContext("canvas"); |
| |
| var program; |
| var offscreen_tex; |
| var fbo; |
| |
| function init() |
| { |
| // Init program |
| program = wtu.setupProgram(gl, ["vshader", "fshader"], ["a_position"]); |
| |
| // Init offscreen render targets and specify the format of offscreen texture to be RGB. |
| offscreen_tex = gl.createTexture(); |
| gl.activeTexture(gl.TEXTURE0); |
| gl.bindTexture(gl.TEXTURE_2D, offscreen_tex); |
| gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_MIN_FILTER, gl.NEAREST); |
| gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_MIN_FILTER, gl.NEAREST); |
| gl.texImage2D(gl.TEXTURE_2D, 0, gl.RGB, canvas.width, canvas.height, 0, gl.RGB, gl.UNSIGNED_BYTE, null); |
| |
| fbo = gl.createFramebuffer(); |
| gl.bindFramebuffer(gl.FRAMEBUFFER, fbo); |
| gl.framebufferTexture2D(gl.FRAMEBUFFER, gl.COLOR_ATTACHMENT0, gl.TEXTURE_2D, offscreen_tex, 0); |
| |
| // Init blend state |
| gl.blendFunc(gl.SRC_ALPHA, gl.ONE_MINUS_SRC_ALPHA); |
| } |
| |
| function draw_rect() |
| { |
| gl.useProgram(program); |
| |
| gl.bindTexture(gl.TEXTURE_2D, offscreen_tex); |
| var u_tex_loc = gl.getUniformLocation(program, 'u_texture'); |
| gl.uniform1i(u_tex_loc, 0); |
| |
| wtu.setupUnitQuad(gl); |
| wtu.drawFloatColorQuad(gl, [1.0, 1.0, 1.0, 1.0]); |
| } |
| |
| function test_canvas_alpha() { |
| init(); |
| |
| // Clear offscreen texture to Green |
| gl.bindFramebuffer(gl.FRAMEBUFFER, fbo); |
| gl.viewport(0, 0, canvas.width, canvas.height); |
| gl.clearColor(0.0, 1.0, 0.0, 1.0); |
| gl.clear(gl.COLOR_BUFFER_BIT); |
| |
| // Clear default framebuffer |
| gl.bindFramebuffer(gl.FRAMEBUFFER, null); |
| gl.viewport(0, 0, canvas.width, canvas.height); |
| gl.clearColor(1.0, 0.0, 0.0, 1.0); |
| gl.clear(gl.COLOR_BUFFER_BIT); |
| |
| // Enable alpha blending and render to default framebuffer |
| gl.enable(gl.BLEND); |
| draw_rect(); |
| wtu.checkCanvasRect(gl, 0, 0, gl.drawingBufferWidth, gl.drawingBufferHeight, [0, 255, 0, 255]); |
| } |
| |
| test_canvas_alpha(); |
| |
| description("Exposes alpha blending bug in Intel drivers on macOS - see https://crbug.com/886970"); |
| var successfullyParsed = true; |
| |
| </script> |
| <script src="../../js/js-test-post.js"></script> |
| |
| </body> |
| </html> |
