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Copyright (c) 2023 The Khronos Group Inc.
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<title>WebGL OES_shader_multisample_interpolation Conformance Tests</title>
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"use strict";
description("This test verifies the functionality of the OES_shader_multisample_interpolation extension, if it is available.");
debug("");
var wtu = WebGLTestUtils;
var gl = wtu.create3DContext("c", { antialias: false }, 2);
var ext;
function runShaderTests(extensionEnabled) {
debug("");
debug("Testing various shader compiles with extension " + (extensionEnabled ? "enabled" : "disabled"));
const macroVertex = `#version 300 es
in vec4 vPosition;
void main() {
#ifdef GL_OES_shader_multisample_interpolation
gl_Position = vPosition;
#else
#error no GL_OES_shader_multisample_interpolation;
#endif
}`;
const macroFragment = `#version 300 es
precision highp float;
out vec4 my_FragColor;
void main() {
#ifdef GL_OES_shader_multisample_interpolation
my_FragColor = vec4(1.0, 0.0, 0.0, 1.0);
#else
#error no GL_OES_shader_multisample_interpolation;
#endif
}`;
for (const shaders of [[wtu.simpleVertexShaderESSL300, macroFragment],
[macroVertex, wtu.simpleColorFragmentShaderESSL300]]) {
// Expect the macro shader to succeed ONLY if enabled
if (wtu.setupProgram(gl, shaders)) {
if (extensionEnabled) {
testPassed("Macro defined in shaders when extension is enabled");
} else {
testFailed("Macro defined in shaders when extension is disabled");
}
} else {
if (extensionEnabled) {
testFailed("Macro not defined in shaders when extension is enabled");
} else {
testPassed("Macro not defined in shaders when extension is disabled");
}
}
}
const missingVertex = `#version 300 es
sample out float interpolant;
in vec4 vPosition;
void main() {
gl_Position = vPosition;
}`;
const missingFragment = `#version 300 es
precision highp float;
sample in float interpolant;
out vec4 my_FragColor;
void main() {
my_FragColor = vec4(1.0, 0.0, 0.0, 1.0);
}`;
// Always expect the shader missing the #extension pragma to fail (whether enabled or not)
for (const shaders of [[missingVertex, wtu.simpleColorFragmentShaderESSL300],
[wtu.simpleVertexShaderESSL300, missingFragment],
[missingVertex, missingFragment]]) {
if (wtu.setupProgram(gl, shaders)) {
testFailed("Sample interpolation qualifier allowed without #extension pragma");
} else {
testPassed("Sample interpolation qualifier disallowed without #extension pragma");
}
}
const validVertex = `#version 300 es
#extension GL_OES_shader_multisample_interpolation : enable
sample out float interpolant;
in vec4 vPosition;
void main() {
gl_Position = vPosition;
}`;
const validFragment = `#version 300 es
#extension GL_OES_shader_multisample_interpolation : enable
precision highp float;
sample in float interpolant;
out vec4 my_FragColor;
void main() {
my_FragColor = vec4(1.0, 0.0, 0.0, 1.0);
}`;
// Try to compile a shader using a sample qualifier that should only succeed if enabled
if (wtu.setupProgram(gl, [validVertex, validFragment])) {
if (extensionEnabled) {
testPassed("Sample interpolation qualifier compiled successfully when extension enabled");
} else {
testFailed("Sample interpolation qualifier compiled successfully when extension disabled");
}
} else {
if (extensionEnabled) {
testFailed("Sample interpolation qualifier failed to compile when extension enabled");
} else {
testPassed("Sample interpolation qualifier failed to compile when extension disabled");
}
}
}
function runQueryTests(extensionEnabled) {
debug("");
debug("Testing parameters with extension " + (extensionEnabled ? "enabled" : "disabled"));
if (extensionEnabled) {
shouldBeGreaterThanOrEqual("gl.getParameter(ext.FRAGMENT_INTERPOLATION_OFFSET_BITS_OES)", "4");
wtu.glErrorShouldBe(gl, gl.NO_ERROR, "should be no errors");
const limit = 0.5 - Math.pow(2, -gl.getParameter(ext.FRAGMENT_INTERPOLATION_OFFSET_BITS_OES));
shouldBeLessThanOrEqual("gl.getParameter(ext.MIN_FRAGMENT_INTERPOLATION_OFFSET_OES)", `-${limit}`);
wtu.glErrorShouldBe(gl, gl.NO_ERROR, "should be no errors");
shouldBeGreaterThanOrEqual("gl.getParameter(ext.MAX_FRAGMENT_INTERPOLATION_OFFSET_OES)", `${limit}`);
wtu.glErrorShouldBe(gl, gl.NO_ERROR, "should be no errors");
} else {
shouldBeNull("gl.getParameter(0x8E5B /* MIN_FRAGMENT_INTERPOLATION_OFFSET_OES */)");
wtu.glErrorShouldBe(gl, gl.INVALID_ENUM, "parameter unknown without enabling the extension");
wtu.glErrorShouldBe(gl, gl.NO_ERROR, "should be no errors");
shouldBeNull("gl.getParameter(0x8E5C /* MAX_FRAGMENT_INTERPOLATION_OFFSET_OES */)");
wtu.glErrorShouldBe(gl, gl.INVALID_ENUM, "parameter unknown without enabling the extension");
wtu.glErrorShouldBe(gl, gl.NO_ERROR, "should be no errors");
shouldBeNull("gl.getParameter(0x8E5D /* FRAGMENT_INTERPOLATION_OFFSET_BITS_OES */)");
wtu.glErrorShouldBe(gl, gl.INVALID_ENUM, "parameter unknown without enabling the extension");
wtu.glErrorShouldBe(gl, gl.NO_ERROR, "should be no errors");
}
}
function checkEnums() {
debug("");
debug("Check enums");
shouldBe("ext.MIN_FRAGMENT_INTERPOLATION_OFFSET_OES", "0x8E5B");
shouldBe("ext.MAX_FRAGMENT_INTERPOLATION_OFFSET_OES", "0x8E5C");
shouldBe("ext.FRAGMENT_INTERPOLATION_OFFSET_BITS_OES", "0x8E5D");
}
/*
* This test renders a triangle using MSAAx4 and 1x1 viewport
* with the following vertex colors.
*
* | Position | Color |
* |==========|===========|
* | (-1, -1) | (0, 0, 0) |
* | (-1, +1) | (0, 1, 0) |
* | (+1, -1) | (1, 0, 0) |
*
* This triangle cannot cover all four samples.
*
* When default interpolation is used, the vertex color is interpolated
* once, most likely in the pixel center.
*
* When per-sample interpolation is used, the vertex color is interpolated
* several times, producing a distinct value for each covered sample.
* Due to the asymmetry of sample positions, the resolved pixel color must
* not match the color produced by default interpolation.
*
* OpenGL specs do not guarantee specific sample positions, so the test
* checks only that the resolved colors are different.
*/
function runInterpolationTest() {
debug("");
debug("Testing multisample interpolation");
function draw(program) {
gl.viewport(0, 0, 1, 1);
gl.useProgram(program);
const posLoc = gl.getAttribLocation(program, "position");
const buf = gl.createBuffer();
gl.bindBuffer(gl.ARRAY_BUFFER, buf);
gl.bufferData(
gl.ARRAY_BUFFER,
new Float32Array([
-1.0, -1.0,
-1.0, +1.0,
+1.0, -1.0]),
gl.STATIC_DRAW);
gl.vertexAttribPointer(posLoc, 2, gl.FLOAT, false, 0, 0);
gl.enableVertexAttribArray(posLoc);
const rbo = gl.createRenderbuffer();
gl.bindRenderbuffer(gl.RENDERBUFFER, rbo);
gl.renderbufferStorageMultisample(gl.RENDERBUFFER, 4, gl.RGBA8, 1, 1);
const fbo = gl.createFramebuffer();
gl.bindFramebuffer(gl.FRAMEBUFFER, fbo);
gl.framebufferRenderbuffer(gl.FRAMEBUFFER, gl.COLOR_ATTACHMENT0, gl.RENDERBUFFER, rbo);
wtu.framebufferStatusShouldBe(gl, gl.FRAMEBUFFER, gl.FRAMEBUFFER_COMPLETE);
gl.clear(gl.COLOR_BUFFER_BIT);
gl.drawArrays(gl.TRIANGLES, 0, 3);
gl.bindFramebuffer(gl.READ_FRAMEBUFFER, fbo);
gl.bindFramebuffer(gl.DRAW_FRAMEBUFFER, null);
gl.blitFramebuffer(0, 0, 1, 1, 0, 0, 1, 1, gl.COLOR_BUFFER_BIT, gl.NEAREST);
wtu.glErrorShouldBe(gl, gl.NO_ERROR, "should be no errors");
gl.bindFramebuffer(gl.READ_FRAMEBUFFER, null);
}
const vertexCenter = `#version 300 es
in vec4 position;
out vec4 interp_color;
void main() {
gl_Position = position;
interp_color = vec4(position.xy * 0.5 + 0.5, 0.0, 1.0);
}`;
const fragmentCenter = `#version 300 es
precision highp float;
in vec4 interp_color;
out vec4 fragColor;
void main() {
fragColor = interp_color;
}`;
const programCenter = wtu.setupProgram(gl, [vertexCenter, fragmentCenter]);
draw(programCenter);
const centerColor = new Uint8Array(4);
gl.readPixels(0, 0, 1, 1, gl.RGBA, gl.UNSIGNED_BYTE, centerColor);
const vertexSample = `#version 300 es
#extension GL_OES_shader_multisample_interpolation : require
in vec4 position;
sample out vec4 interp_color;
void main() {
gl_Position = position;
interp_color = vec4(position.xy * 0.5 + 0.5, 0.0, 1.0);
}`;
const fragmentSample = `#version 300 es
#extension GL_OES_shader_multisample_interpolation : require
precision highp float;
sample in vec4 interp_color;
out vec4 fragColor;
void main() {
fragColor = interp_color;
}`;
const programSample = wtu.setupProgram(gl, [vertexSample, fragmentSample]);
draw(programSample);
const sampleColor = new Uint8Array(4);
gl.readPixels(0, 0, 1, 1, gl.RGBA, gl.UNSIGNED_BYTE, sampleColor);
const message = `Pixel-center value: ${centerColor}, sample-average value: ${sampleColor}`;
if (centerColor[0] == sampleColor[0] && centerColor[1] == sampleColor[1]) {
testFailed(message);
} else {
testPassed(message);
}
}
function runTest() {
if (!gl) {
testFailed("WebGL context does not exist");
return;
}
testPassed("WebGL context exists");
runQueryTests(false);
runShaderTests(false);
debug("");
ext = gl.getExtension("OES_shader_multisample_interpolation");
wtu.runExtensionSupportedTest(gl, "OES_shader_multisample_interpolation", ext !== null);
if (!ext) {
testPassed("No OES_shader_multisample_interpolation support -- this is legal");
} else {
testPassed("Successfully enabled OES_shader_multisample_interpolation extension");
runQueryTests(true);
runShaderTests(true);
runInterpolationTest();
}
}
runTest();
var successfullyParsed = true;
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