| <html> | 
 | <head> | 
 | <script src="../../js/resources/js-test-pre.js"></script> | 
 | <script src="resources/webgl-test.js"></script> | 
 | </head> | 
 | <body> | 
 | <canvas id="example" width="1px" height="1px"></canvas> | 
 | <div id="description"></div> | 
 | <div id="console"></div> | 
 |  | 
 | <script id="vs" type="x-shader/x-vertex"> | 
 | attribute vec4 vPosition; | 
 | attribute vec4 vColor; | 
 | varying vec4 color; | 
 | void main() { | 
 |     gl_Position = vPosition; | 
 |     color = vColor; | 
 | } | 
 | </script> | 
 | <script id="fs" type="x-shader/x-fragment"> | 
 | #if defined(GL_ES) | 
 | precision mediump float; | 
 | #endif | 
 | varying vec4 color; | 
 | void main() { | 
 |   gl_FragColor = color; | 
 | } | 
 | </script> | 
 | <script> | 
 | description('Test that updating the size of a vertex buffer is properly noticed by the WebGL implementation.') | 
 |  | 
 | var gl = initWebGL("example", "vs", "fs", ["vPosition", "vColor"], [0, 0, 0, 1], 1); | 
 | glErrorShouldBe(gl, gl.NO_ERROR, "after initialization"); | 
 |  | 
 | gl.useProgram(gl.program); | 
 | var vertexObject = gl.createBuffer(); | 
 | gl.bindBuffer(gl.ARRAY_BUFFER, vertexObject); | 
 | gl.bufferData(gl.ARRAY_BUFFER, new Float32Array( | 
 |     [-1,1,0, 1,1,0, -1,-1,0, | 
 |      -1,-1,0, 1,1,0, 1,-1,0]), gl.STATIC_DRAW); | 
 | gl.enableVertexAttribArray(0); | 
 | gl.vertexAttribPointer(0, 3, gl.FLOAT, false, 0, 0); | 
 | glErrorShouldBe(gl, gl.NO_ERROR, "after vertex setup"); | 
 |  | 
 | var texCoordObject = gl.createBuffer(); | 
 | gl.bindBuffer(gl.ARRAY_BUFFER, vertexObject); | 
 | gl.bufferData(gl.ARRAY_BUFFER, new Float32Array( | 
 |     [0,0, 1,0, 0,1, | 
 |      0,1, 1,0, 1,1]), gl.STATIC_DRAW); | 
 | gl.enableVertexAttribArray(1); | 
 | gl.vertexAttribPointer(1, 2, gl.FLOAT, false, 0, 0); | 
 | glErrorShouldBe(gl, gl.NO_ERROR, "after texture coord setup"); | 
 |  | 
 | // Now resize these buffers because we want to change what we're drawing. | 
 | gl.bindBuffer(gl.ARRAY_BUFFER, vertexObject); | 
 | gl.bufferData(gl.ARRAY_BUFFER, new Float32Array([ | 
 |     -1,1,0, 1,1,0, -1,-1,0, 1,-1,0, | 
 |     -1,1,0, 1,1,0, -1,-1,0, 1,-1,0]), gl.STATIC_DRAW); | 
 | glErrorShouldBe(gl, gl.NO_ERROR, "after vertex redefinition"); | 
 | gl.bindBuffer(gl.ARRAY_BUFFER, texCoordObject); | 
 | gl.bufferData(gl.ARRAY_BUFFER, new Uint8Array([ | 
 |     255, 0, 0, 255, | 
 |     255, 0, 0, 255, | 
 |     255, 0, 0, 255, | 
 |     255, 0, 0, 255, | 
 |     0, 255, 0, 255, | 
 |     0, 255, 0, 255, | 
 |     0, 255, 0, 255, | 
 |     0, 255, 0, 255]), gl.STATIC_DRAW); | 
 | gl.vertexAttribPointer(1, 4, gl.UNSIGNED_BYTE, false, 0, 0); | 
 | glErrorShouldBe(gl, gl.NO_ERROR, "after texture coordinate / color redefinition"); | 
 |  | 
 | var numQuads = 2; | 
 | var indices = new Uint8Array(numQuads * 6); | 
 | for (var ii = 0; ii < numQuads; ++ii) { | 
 |     var offset = ii * 6; | 
 |     var quad = (ii == (numQuads - 1)) ? 4 : 0; | 
 |     indices[offset + 0] = quad + 0; | 
 |     indices[offset + 1] = quad + 1; | 
 |     indices[offset + 2] = quad + 2; | 
 |     indices[offset + 3] = quad + 2; | 
 |     indices[offset + 4] = quad + 1; | 
 |     indices[offset + 5] = quad + 3; | 
 | } | 
 | var indexObject = gl.createBuffer(); | 
 | gl.bindBuffer(gl.ELEMENT_ARRAY_BUFFER, indexObject); | 
 | gl.bufferData(gl.ELEMENT_ARRAY_BUFFER, indices, gl.STATIC_DRAW); | 
 | glErrorShouldBe(gl, gl.NO_ERROR, "after setting up indices"); | 
 | gl.drawElements(gl.TRIANGLES, numQuads * 6, gl.UNSIGNED_BYTE, 0); | 
 | glErrorShouldBe(gl, gl.NO_ERROR, "after drawing"); | 
 |  | 
 | debug("") | 
 | </script> | 
 |  | 
 | <script src="../../js/resources/js-test-post.js"></script> | 
 | </body> | 
 | </html> |