readbuffer.html - mozsearch

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<title>Test readBuffer Against WebGL 2</title>

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<canvas id="canvas" width="20" height="20"> </canvas>

<script>

"use strict";

description("This tests reading from fbo");

var clearDrawingbuffer = function(color) {

  gl.clearColor(color[0] / 255, color[1] / 255, color[2] / 255, color[3] / 255);

  gl.clear(gl.COLOR_BUFFER_BIT);

var validateReadingFromFramebuffer = function(color, expected, msg) {

  var pixels = new Uint8Array(1 * 1 * 4);

  gl.readPixels(0, 0, 1, 1, gl.RGBA, gl.UNSIGNED_BYTE, pixels);

  wtu.glErrorShouldBe(gl, expected, msg);

  if (expected == gl.NO_ERROR)

    wtu.checkCanvasRect(gl, 0, 0, canvas.width, canvas.height, color,

    "the color should be [" + color + "]");

var setupRenderbuffer = function(attachment) {

  var renderbuffer = gl.createRenderbuffer();

  gl.bindRenderbuffer(gl.RENDERBUFFER, renderbuffer);

  gl.framebufferRenderbuffer(gl.FRAMEBUFFER, attachment, gl.RENDERBUFFER, renderbuffer);

  gl.renderbufferStorage(gl.RENDERBUFFER, gl.RGBA8, canvas.width, canvas.height);

  return renderbuffer;

var testReadBufferOnDefaultFB = function() {

  gl.readBuffer(gl.NONE);

  wtu.glErrorShouldBe(gl, gl.NO_ERROR,

      "calling readBuffer with GL_NONE on the default framebuffer should succeed.");

  var pixels = new Uint8Array(1 * 1 * 4);

  gl.readPixels(0, 0, 1, 1, gl.RGBA, gl.UNSIGNED_BYTE, pixels);

  wtu.glErrorShouldBe(gl, gl.INVALID_OPERATION,

      "should generate INVALID_OPERATION when reading from framebuffer and read buffer is GL_NONE.");

  gl.readBuffer(gl.BACK);

  wtu.glErrorShouldBe(gl, gl.NO_ERROR,

      "calling readBuffer with GL_BACK on the default framebuffer should succeed.");

  gl.readBuffer(gl.COLOR_ATTACHMENT0);

  wtu.glErrorShouldBe(gl, gl.INVALID_OPERATION,

      "calling readBuffer with GL_COLOR_ATTACHMENT0 on the default framebuffer should generate INVALID_OPERATION.");

var testReadBufferOnFBO = function() {

  gl.readBuffer(gl.BACK);

  wtu.glErrorShouldBe(gl, gl.INVALID_OPERATION,

      "calling readBuffer with GL_BACK on fbo should generate INVALID_OPERATION.");

  gl.readBuffer(gl.NONE);

  wtu.glErrorShouldBe(gl, gl.NO_ERROR,

      "calling readBuffer with GL_NONE on fbo should succeed.");

  var pixels = new Uint8Array(1 * 1 * 4);

  gl.readPixels(0, 0, 1, 1, gl.RGBA, gl.UNSIGNED_BYTE, pixels);

  wtu.glErrorShouldBe(gl, gl.INVALID_OPERATION,

      "should generate INVALID_OPERATION when reading from framebuffer and read buffer is GL_NONE.");

  gl.readBuffer(gl.COLOR_ATTACHMENT0);

  wtu.glErrorShouldBe(gl, gl.NO_ERROR,

      "calling readBuffer with GL_COLOR_ATTACHMENT0 on fbo should succeed.");

  var maxColorAttachments = gl.getParameter(gl.MAX_COLOR_ATTACHMENTS);

  gl.readBuffer(gl.COLOR_ATTACHMENT0 + maxColorAttachments);

  wtu.glErrorShouldBe(gl, gl.INVALID_OPERATION,

      "calling readBuffer with GL_COLOR_ATTACHMENTi that exceeds MAX_COLOR_ATTACHMENT on fbo should generate INVALID_OPERATION.");

  gl.readBuffer(gl.COLOR_ATTACHMENT1);

  wtu.glErrorShouldBe(gl, gl.NO_ERROR,

      "calling readBuffer with GL_COLOR_ATTACHMENT1 on the fbo should succeed.");

  shouldBe('gl.getParameter(gl.READ_BUFFER)', 'gl.COLOR_ATTACHMENT1');

debug("");

debug("Canvas.getContext");

var wtu = WebGLTestUtils;

var canvas = document.getElementById("canvas");

var gl = wtu.create3DContext(canvas, undefined, 2);

if (!gl) {

  testFailed("context does not exist");

} else {

  testPassed("context exists");

  debug("");

  debug("Checking reading from framebuffer.");

  // Test on the default framebuffer. Read buffer is GL_BACK by default.

  var backColor = [0, 0, 0, 255];

  clearDrawingbuffer(backColor);

  validateReadingFromFramebuffer(backColor, gl.NO_ERROR,

      "should be no errors when reading from GL_BACK on the default framebuffer.");

  shouldBe('gl.getParameter(gl.READ_BUFFER)', 'gl.BACK');

  testReadBufferOnDefaultFB();

  // Test on fbo. Read buffer is GL_COLOR_ATTACHMENT0 by default

  var fb = gl.createFramebuffer();

  gl.bindFramebuffer(gl.FRAMEBUFFER, fb);

  var colorbuffer = setupRenderbuffer(gl.COLOR_ATTACHMENT0);

  var red = [255, 0, 0, 255];

  clearDrawingbuffer(red);

  validateReadingFromFramebuffer(red, gl.NO_ERROR,

      "should be no errors when reading from GL_COLOR_ATTACHMENT0 on fbo.");

  shouldBe('gl.getParameter(gl.READ_BUFFER)', 'gl.COLOR_ATTACHMENT0');

  testReadBufferOnFBO();

  // Test on user defined read buffer (GL_COLOR_ATTACHMENT1) with or without corresponding image on fbo.

  gl.bindFramebuffer(gl.FRAMEBUFFER, fb);

  var colorbuffer1 = setupRenderbuffer(gl.COLOR_ATTACHMENT1);

  var green = [0, 255, 0, 255];

  gl.drawBuffers([gl.NONE, gl.COLOR_ATTACHMENT1]);

  clearDrawingbuffer(green);

  wtu.glErrorShouldBe(gl, gl.NO_ERROR, "should be no error after setup and clear render buffer");

  gl.readBuffer(gl.COLOR_ATTACHMENT1);

  validateReadingFromFramebuffer(green, gl.NO_ERROR,

      "should be no errors when reading from GL_COLOR_ATTACHMENT1 on fbo.");

  shouldBe('gl.getParameter(gl.READ_BUFFER)', 'gl.COLOR_ATTACHMENT1');

  // Need to reset draw buffers, otherwise it triggers a mac driver bug.

  // We add a separate test for that bug: conformance2/rendering/framebuffer-completeness-unaffected.html

  gl.drawBuffers([gl.COLOR_ATTACHMENT0]);

  gl.framebufferRenderbuffer(gl.FRAMEBUFFER, gl.COLOR_ATTACHMENT1, gl.RENDERBUFFER, null)

  gl.readBuffer(gl.COLOR_ATTACHMENT1);

  validateReadingFromFramebuffer(null, gl.INVALID_OPERATION,

      "should generate INVALID_OPERATION when reading from GL_COLOR_ATTACHMENT1 but this attachment has no image currently.");

  // switch to another fbo, read buffer is GL_COLOR_ATTACHMENT0, not GL_COLOR_ATTACHMENT1

  var fb1 = gl.createFramebuffer();

  gl.bindFramebuffer(gl.FRAMEBUFFER, fb1);

  var buffer = setupRenderbuffer(gl.COLOR_ATTACHMENT0);

  shouldBe('gl.getParameter(gl.READ_BUFFER)', 'gl.COLOR_ATTACHMENT0');

  var blue = [0, 0, 255, 255];

  clearDrawingbuffer(blue);

  validateReadingFromFramebuffer(blue, gl.NO_ERROR,

      "should be no errors when reading from GL_COLOR_ATTACHMENT0 on another fbo.");

  // switch from fbo to default fb, read buffer will switch to GL_BACK from GL_COLOR_ATTACHMENT0

  gl.bindFramebuffer(gl.FRAMEBUFFER, null);

  shouldBe('gl.getParameter(gl.READ_BUFFER)', 'gl.BACK');

  validateReadingFromFramebuffer(backColor, gl.NO_ERROR,

      "should be no errors when reading from GL_BACK on the default framebuffer.");

  gl.deleteFramebuffer(fb);

  gl.deleteRenderbuffer(colorbuffer);

  gl.deleteRenderbuffer(colorbuffer1);

  gl.deleteFramebuffer(fb1);

  gl.deleteRenderbuffer(buffer);

debug("");

var successfullyParsed = true;

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