1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
|
<!--
Copyright (c) 2019 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">
<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>
<title>WebGL Out-of-Bounds Index Buffer Conformance Test</title>
</head>
<body>
<canvas id="canvas" width="8" height="8" style="width: 100px; height: 100px;"></canvas>
<div id="description"></div>
<div id="console"></div>
<script id="vsCheckOutOfBounds" type="x-shader/x-vertex">
precision mediump float;
attribute vec2 position;
attribute vec4 vecRandom;
varying vec4 v_color;
// Per the spec, each component can either contain existing contents
// of the buffer or 0.
bool testFloatComponent(float component) {
return (component == 0.2 || component == 0.0);
}
// The last component is additionally allowed to be 1.0.
bool testLastFloatComponent(float component) {
return testFloatComponent(component) || component == 1.0;
}
void main() {
if (testFloatComponent(vecRandom.x) &&
testFloatComponent(vecRandom.y) &&
testFloatComponent(vecRandom.z) &&
testLastFloatComponent(vecRandom.w)) {
v_color = vec4(0.0, 1.0, 0.0, 1.0); // green -- We're good
} else {
v_color = vec4(1.0, 0.0, 0.0, 1.0); // red -- Unexpected value
}
gl_Position = vec4(position, 0.0, 1.0);
}
</script>
<script>
"use strict";
description("This test verifies that out-of-bounds index buffers behave according to spec.");
// Prepare an element array buffer that indexes out-of-bounds beginning with the start index passed in.
// Ensure that drawElements flags either no error or INVALID_OPERATION. In the case of INVALID_OPERATION,
// no canvas pixels can be touched. In the case of NO_ERROR, all written values must either be the
// zero vertex or a value in the vertex buffer. See vsCheckOutOfBounds shader.
function drawAndVerifyOutOfBoundsIndex(gl, startIndex) {
gl.clearColor(0.0, 0.0, 1.0, 1.0); // Start with blue to indicate no pixels touched.
gl.clear(gl.COLOR_BUFFER_BIT | gl.DEPTH_BUFFER_BIT);
prepareElementArrayBuffer(gl, /*StartIndex*/startIndex);
gl.drawElements(gl.TRIANGLE_STRIP, 4, gl.UNSIGNED_SHORT, /*offset*/0);
var error = gl.getError();
if (error === gl.INVALID_OPERATION) {
testPassed("drawElements flagged INVALID_OPERATION, which is valid so long as all canvas pixels were not touched.");
wtu.checkCanvas(gl, [0, 0, 255, 255]);
} else if (error === gl.NO_ERROR) {
testPassed("drawElements flagged NO_ERROR, which is valid so long as all canvas pixels are green.");
wtu.checkCanvas(gl, [0, 255, 0, 255]);
} else {
testFailed("Invalid error flagged by drawElements. Should be INVALID_OPERATION or NO_ERROR");
}
}
// Create an element array buffer with a tri-strip that starts at startIndex and make
// it the active element array buffer.
function prepareElementArrayBuffer(gl, startIndex) {
var glElementArrayBuffer = gl.createBuffer();
gl.bindBuffer(gl.ELEMENT_ARRAY_BUFFER, glElementArrayBuffer);
var quadIndices = new Uint16Array(4);
for (var i = 0; i < quadIndices.length; i++) {
quadIndices[i] = startIndex + i;
}
gl.bufferData(gl.ELEMENT_ARRAY_BUFFER, quadIndices, gl.STATIC_DRAW);
}
var wtu = WebGLTestUtils;
var canvas = document.getElementById("canvas");
var gl = wtu.create3DContext(canvas, {antialias: false});
var numberOfQuads = 200;
// Create a vertex buffer with 200 properly formed tri-strip quads. These quads will cover the canvas texture
// such that every single pixel is touched by the fragment shader.
var glQuadBuffer = gl.createBuffer();
gl.bindBuffer(gl.ARRAY_BUFFER, glQuadBuffer);
var quadPositions = new Float32Array(numberOfQuads * /*ComponentsPerQuad*/2 * /*VerticesPerQuad*/4);
for (var i = 0; i < quadPositions.length; i += /*ComponentsPerQuad*/2 * /*VerticesPerQuad*/4) {
quadPositions[i+0] = -1.0; // upper left
quadPositions[i+1] = 1.0;
quadPositions[i+2] = 1.0; // upper right
quadPositions[i+3] = 1.0;
quadPositions[i+4] = -1.0; // lower left
quadPositions[i+5] = -1.0;
quadPositions[i+6] = 1.0; // lower right
quadPositions[i+7] = -1.0;
}
gl.bufferData(gl.ARRAY_BUFFER, quadPositions, gl.STATIC_DRAW);
gl.enableVertexAttribArray(0);
gl.vertexAttribPointer(0, 2, gl.FLOAT, false, 0, 0);
// Create a small vertex buffer with determined-ahead-of-time "random" values (0.2). This buffer will be
// the one indexed off the end.
var glVertexBuffer = gl.createBuffer();
gl.bindBuffer(gl.ARRAY_BUFFER, glVertexBuffer);
gl.bufferData(gl.ARRAY_BUFFER, new Float32Array([0.2, 0.2, 0.2, 0.2]), gl.STATIC_DRAW);
gl.enableVertexAttribArray(1);
gl.vertexAttribPointer(1, 4, gl.FLOAT, false, 0, 0);
// Setup the verification program.
var glProgram = wtu.setupProgram(gl, ["vsCheckOutOfBounds", wtu.simpleVertexColorFragmentShader], ["position", "vecRandom"]);
wtu.glErrorShouldBe(gl, gl.NO_ERROR, "Shader and buffer setup should not generate errors");
debug("Test -- Index off the end of the vertex buffer near the beginning of the out of bounds area.");
drawAndVerifyOutOfBoundsIndex(gl, /*StartIndex*/4);
debug("");
debug("Test -- Index off the end of the vertex buffer near the end of the out of bounds area.")
drawAndVerifyOutOfBoundsIndex(gl, /*StartIndex*/numberOfQuads - 4);
var successfullyParsed = true;
</script>
<script src="../../js/js-test-post.js"></script>
</body>
</html>
|
