<!DOCTYPE html> <html> <head> <meta charset='utf-8'> <title>Bug 1426289 - vertexAttrib4f should actually update.</title> <script src='/tests/SimpleTest/SimpleTest.js'></script> <link rel='stylesheet' href='/tests/SimpleTest/test.css'> <script src='webgl-util.js'></script> </head> <body> <script id='eVertSource' type='none'> attribute vec4 aColor; varying vec4 vColor; void main() { gl_PointSize = 64.0; gl_Position = vec4(vec3(0.0), 1.0); vColor = aColor; } </script> <script id='eFragSource' type='none'> precision mediump float; varying vec4 vColor; void main() { gl_FragColor = vColor; } </script> <script> const canvas = document.createElement('canvas'); canvas.width = 1; canvas.height = 1; const gl = canvas.getContext('webgl'); const prog = WebGLUtil.linkProgramByIds(gl, eVertSource, eFragSource); gl.useProgram(prog); function getRgb() { const data = new Uint32Array(1); gl.readPixels(0, 0, 1, 1, gl.RGBA, gl.UNSIGNED_BYTE, new Uint8Array(data.buffer)); return data[0] & 0xffffff; } gl.clearColor(0.0, 0.0, 0.0, 1.0); gl.clear(gl.COLOR_BUFFER_BIT); let was = getRgb(); ok(was == 0x000000, '0x'+was.toString(16)); gl.disableVertexAttribArray(prog.aColor); gl.vertexAttrib4f(prog.aColor, 1, 0, 0, 1); gl.drawArrays(gl.POINTS, 0, 1); was = getRgb(); ok(was == 0x0000ff, '0x'+was.toString(16)); gl.vertexAttrib4f(prog.aColor, 0, 1, 0, 1); gl.drawArrays(gl.POINTS, 0, 1); was = getRgb(); ok(was == 0x00ff00, '0x'+was.toString(16)); </script> </body> </html>