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Test multisampled framebuffer draws / copies / blends. (KhronosGroup#…
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…3379)

Mimics the call structure in the following two Three.js demos:
  https://threejs.org/examples/webgl_framebuffer_texture
  https://threejs.org/examples/webgl_decals

Draws a solid color quad to the center of the viewport, copies a
portion of it to a texture, and blends that texture with the contents
of the framebuffer.

On Intel Macs, reproduced the bug in ANGLE's Metal backend when the
browser was invoked with Metal debug layers and load/store action
validation enabled:
  MTL_DEBUG_LAYER=1 \
  MTL_DEBUG_LAYER_VALIDATE_LOAD_ACTIONS=1 \
  MTL_DEBUG_LAYER_VALIDATE_STORE_ACTIONS=1 \
  MTL_DEBUG_LAYER_VALIDATE_UNRETAINED_RESOURCES=4 [browser...]

A similarly structured test is being added to the ANGLE project.

Minimized test case for http://anglebug.com/6972 .
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@kenrussell
kenrussell authored Feb 10, 2022
1 parent cf04aeb commit 4429f45
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1 change: 1 addition & 0 deletions sdk/tests/conformance2/rendering/00_test_list.txt
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Expand Up @@ -31,6 +31,7 @@ framebuffer-completeness-unaffected.html
--min-version 2.0.1 framebuffer-render-to-layer-angle-issue.html
--min-version 2.0.1 framebuffer-texture-changing-base-level.html
--min-version 2.0.1 framebuffer-texture-level1.html
--min-version 2.0.1 framebuffer-to-texture.html
framebuffer-unsupported.html
--min-version 2.0.1 fs-color-type-mismatch-color-buffer-type.html
instanced-arrays.html
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201 changes: 201 additions & 0 deletions sdk/tests/conformance2/rendering/framebuffer-to-texture.html
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<!--
Copyright (c) 2022 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>WebGL framebuffer to texture conformance test.</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>
<canvas id="canvas"></canvas>
<div id="description"></div>
<div id="console"></div>
<script>
"use strict";
description("Test resolving and copying the framebuffer to a texture, and drawing the result.");
debug('Reduced test case for <a href="http://anglebug.com/6972">http://anglebug.com/6972</a>');

// Reproduces two behaviors:
//
// 1) The initial draw disappearing entirely from the default back
// buffer. The current test case does not show this behavior
// independently from the other, but a previous iteration, with the
// textured quad scaled to half size and translated (-0.5, -0.5), did.
//
// 2) With Metal debug layers and load/store validation turned on on
// Intel Macs, the transparent area of the texture prior to the bug
// fix was magenta = undefined. Similar behavior would presumably
// reproduce on M1 hardware without debug layers or validation.

const size = 64;
const halfSize = size / 2;
const green = [ 0, 255, 0, 255 ];
const transparent = [ 0, 0, 0, 0 ];

let wtu = WebGLTestUtils;
let canvas = document.getElementById("canvas");
canvas.width = size;
canvas.height = size;

let gl = wtu.create3DContext("canvas", {
// Antialiasing is crucial for reproducing the bug.
antialias: true,
// Depth testing is not.
depth: false,
}, 2);

function allocateTexture(sz) {
let texture = gl.createTexture();
gl.bindTexture(gl.TEXTURE_2D, texture);
gl.texStorage2D(gl.TEXTURE_2D, 1, gl.RGBA8, sz, sz);
gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_MIN_FILTER, gl.NEAREST);
gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_MAG_FILTER, gl.NEAREST);
gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_WRAP_S, gl.CLAMP_TO_EDGE);
gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_WRAP_T, gl.CLAMP_TO_EDGE);
gl.bindTexture(gl.TEXTURE_2D, null);
return texture;
}

// Allocate destination texture
let destTexture = allocateTexture(halfSize);

// Set up half-size solid color quad in center
let colorQuadVAO = gl.createVertexArray();
gl.bindVertexArray(colorQuadVAO);
let colorQuadProgram = wtu.setupColorQuad(gl, 0, { scale: 0.5 });

// Setup textured quad covering the entire renderable area
let quadVAO = gl.createVertexArray();
gl.bindVertexArray(quadVAO);
let quadProgram = wtu.setupTexturedQuad(gl, 0, 1);
gl.useProgram(quadProgram);
let quadTexLoc = gl.getUniformLocation(quadProgram, "tex");
gl.uniform1i(quadTexLoc, 0);

gl.blendFunc(gl.ONE, gl.ONE_MINUS_SRC_ALPHA);
gl.activeTexture(gl.TEXTURE0); // To match quadTexLoc=0

function runTest() {
gl.clearColor(0, 0, 0, 0);
gl.clear(gl.COLOR_BUFFER_BIT);
gl.disable(gl.BLEND);
gl.bindVertexArray(colorQuadVAO);
gl.useProgram(colorQuadProgram);
wtu.drawUByteColorQuad(gl, [ 0, 255, 0, 255 ]);

gl.bindTexture(gl.TEXTURE_2D, destTexture);
// Copy the upper right corner of the framebuffer to the texture.
gl.copyTexSubImage2D(gl.TEXTURE_2D, 0, 0, 0, halfSize, halfSize, halfSize, halfSize);
gl.bindTexture(gl.TEXTURE_2D, null);
gl.useProgram(quadProgram);
gl.enable(gl.BLEND);
gl.bindVertexArray(quadVAO);
gl.bindTexture(gl.TEXTURE_2D, destTexture);
// Magnify and blend this texture over the current framebuffer.
wtu.drawUnitQuad(gl);
}

function runUserDefinedFBOTest() {
let fbo1 = gl.createFramebuffer();
let fbo2 = gl.createFramebuffer();
let rb = gl.createRenderbuffer();
gl.bindFramebuffer(gl.FRAMEBUFFER, fbo1);
gl.bindRenderbuffer(gl.RENDERBUFFER, rb);
gl.renderbufferStorageMultisample(gl.RENDERBUFFER, 4, gl.RGBA8, size, size);
gl.framebufferRenderbuffer(gl.FRAMEBUFFER, gl.COLOR_ATTACHMENT0, gl.RENDERBUFFER, rb);
wtu.framebufferStatusShouldBe(gl, gl.FRAMEBUFFER, [ gl.FRAMEBUFFER_COMPLETE ]);

let tex = allocateTexture(size, size);
gl.bindFramebuffer(gl.FRAMEBUFFER, fbo2);
gl.framebufferTexture2D(gl.FRAMEBUFFER, gl.COLOR_ATTACHMENT0, gl.TEXTURE_2D, tex, 0);
wtu.framebufferStatusShouldBe(gl, gl.FRAMEBUFFER, [ gl.FRAMEBUFFER_COMPLETE ]);

// Same rendering steps as in the default-framebuffer test, with appropriate framebuffer blits interspersed.
gl.bindFramebuffer(gl.DRAW_FRAMEBUFFER, fbo1);
gl.clearColor(0, 0, 0, 0);
gl.clear(gl.COLOR_BUFFER_BIT);
gl.disable(gl.BLEND);
gl.bindVertexArray(colorQuadVAO);
gl.useProgram(colorQuadProgram);
wtu.drawUByteColorQuad(gl, [ 0, 255, 0, 255 ]);

gl.bindFramebuffer(gl.READ_FRAMEBUFFER, fbo1);
gl.bindFramebuffer(gl.DRAW_FRAMEBUFFER, fbo2);
gl.blitFramebuffer(0, 0, size, size, 0, 0, size, size, gl.COLOR_BUFFER_BIT, gl.NEAREST);
gl.bindFramebuffer(gl.FRAMEBUFFER, fbo2);

gl.bindTexture(gl.TEXTURE_2D, destTexture);
// Copy the upper right corner of the framebuffer to the texture.
gl.copyTexSubImage2D(gl.TEXTURE_2D, 0, 0, 0, halfSize, halfSize, halfSize, halfSize);
gl.bindTexture(gl.TEXTURE_2D, null);

gl.bindFramebuffer(gl.DRAW_FRAMEBUFFER, fbo1);

gl.useProgram(quadProgram);
gl.enable(gl.BLEND);
gl.bindVertexArray(quadVAO);
gl.bindTexture(gl.TEXTURE_2D, destTexture);
// Magnify and blend this texture over the current framebuffer.
wtu.drawUnitQuad(gl);

gl.bindFramebuffer(gl.READ_FRAMEBUFFER, fbo1);
gl.bindFramebuffer(gl.DRAW_FRAMEBUFFER, fbo2);
gl.blitFramebuffer(0, 0, size, size, 0, 0, size, size, gl.COLOR_BUFFER_BIT, gl.NEAREST);
gl.bindFramebuffer(gl.FRAMEBUFFER, fbo2);

// No longer easy to put these results on the canvas, because it's
// antialiased and we can't blitFramebuffer to it. Let's assume
// that if failures occur, they'll be straightforward to debug.
}

function checkRenderingResults(prefix) {
// Center quad should be rendered correctly.
wtu.checkCanvasRect(gl,
halfSize / 2 + 1, halfSize / 2 + 1,
halfSize - 2, halfSize - 2,
green,
prefix + ": center quad should be green");

// Overlapping lower-left quad should be green as well.
wtu.checkCanvasRect(gl,
1, 1,
halfSize - 2, halfSize - 2,
green,
prefix + ": lower left quad should be green");

// Leftmost area above the lower-left quad should be transparent.
wtu.checkCanvasRect(gl,
1, halfSize + 1,
halfSize / 2 - 2, halfSize / 2 - 2,
transparent,
prefix + ": leftmost area above lower left quad should be transparent");

// Bottommost area to the right of the lower-left quad should be transparent.
wtu.checkCanvasRect(gl,
halfSize + 1, 1,
halfSize / 2 - 2, halfSize / 2 - 2,
transparent,
prefix + ": bottommost area to the right of lower left quad should be transparent");
}

runTest();
checkRenderingResults("default back buffer");

runUserDefinedFBOTest();
checkRenderingResults("user-defined framebuffer");

wtu.glErrorShouldBe(gl, gl.NO_ERROR, "Should be no errors at the end of the test.");

finishTest();

var successfullyParsed = true;
</script>
</body>
</html>

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