| <!DOCTYPE html> |
| <html> |
| <head> |
| <title>WebGL Enable Vertex Attrib Zero Test</title> |
| <script src="../../../resources/js-test.js"></script> |
| <script src="resources/webgl-test.js"> </script> |
| <script src="resources/webgl-test-utils.js"> </script> |
| </head> |
| <body> |
| <canvas id="example" width="50" height="50"> |
| </canvas> |
| <div id="description"></div> |
| <div id="console"></div> |
| <script id="vshader" type="x-shader/x-vertex"> |
| attribute vec4 vPosition; |
| void main() |
| { |
| gl_Position = vPosition; |
| } |
| </script> |
| |
| <script id="fshader" type="x-shader/x-fragment"> |
| void main() |
| { |
| gl_FragColor = vec4(0.0,0.0,0.0,0.0); |
| } |
| </script> |
| |
| <script> |
| description("Test some of the issues of the difference between attrib 0 on OpenGL vs WebGL"); |
| debug(""); |
| var wtu = WebGLTestUtils; |
| var canvas = document.getElementById("example"); |
| var gl = wtu.create3DContext(canvas); |
| |
| function setup(numVerts, attribIndex) { |
| var program = wtu.setupProgram( |
| gl, |
| [wtu.loadShaderFromScript(gl, 'vshader', gl.VERTEX_SHADER), |
| wtu.loadShaderFromScript(gl, 'fshader', gl.FRAGMENT_SHADER)], |
| ['vPosition'], [attribIndex]); |
| // draw with something on attrib zero with a small number of vertices |
| var vertexObject = gl.createBuffer(); |
| g_program = program; |
| g_attribLocation = attribIndex; |
| shouldBe("g_attribLocation", "gl.getAttribLocation(g_program, 'vPosition')"); |
| gl.bindBuffer(gl.ARRAY_BUFFER, vertexObject); |
| gl.bufferData( |
| gl.ARRAY_BUFFER, new Float32Array(numVerts * 3), gl.STATIC_DRAW); |
| gl.vertexAttribPointer(attribIndex, 3, gl.FLOAT, false, 0, 0); |
| var indices = new Uint16Array(numVerts); |
| for (var ii = 0; ii < numVerts; ++ii) { |
| indices[ii] = ii; |
| } |
| var indexBuffer = gl.createBuffer(); |
| gl.bindBuffer(gl.ELEMENT_ARRAY_BUFFER, indexBuffer); |
| gl.bufferData(gl.ELEMENT_ARRAY_BUFFER, indices, gl.STATIC_DRAW); |
| return program; |
| } |
| |
| var p1 = setup(3, 0); |
| var p2 = setup(60000, 3); |
| |
| for (var ii = 0; ii < 5; ++ii) { |
| gl.useProgram(p1); |
| gl.enableVertexAttribArray(0); |
| gl.drawElements(gl.TRIANGLES, 3, gl.UNSIGNED_SHORT, 0); |
| glErrorShouldBe( |
| gl, gl.NO_ERROR, |
| "drawing using attrib 0 with 3 verts"); |
| |
| gl.useProgram(p2); |
| gl.enableVertexAttribArray(3); |
| gl.drawArrays(gl.LINES, 0, 60000); |
| glErrorShouldBe( |
| gl, gl.NO_ERROR, |
| "drawing using attrib 3 with 60000 verts"); |
| } |
| |
| wtu.checkCanvas(gl, [0, 0, 0, 0], "canvas should be 0, 0, 0, 0"); |
| </script> |
| </body> |
| </html> |
| |
