<!--
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">
<title>WebGL Vertex Buffer Updated After Draw 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="example" width="50" height="50">
</canvas>
<div id="description"></div>
<div id="console"></div>
<script id="vshader" type="x-shader/x-vertex">
attribute vec2 a_position;
attribute vec4 a_color;
varying vec4 v_outcolor;
void main() {
  gl_Position = vec4(a_position, 0, 1);
  v_outcolor = a_color;
}
</script>

<script id="fshader" type="x-shader/x-fragment">
varying mediump vec4 v_outcolor;
void main() {
    gl_FragColor = v_outcolor;
}
</script>

<script>
// Tests that D3D11 dirty bit updates don't forget about BufferSubData attrib updates.
// Based on ANGLE test (StateChangeTest, VertexBufferUpdatedAfterDraw) from https://github.com/google/angle/blob/f7f0b8c3ab21c52cc2915048959361cf628d95f0/src/tests/gl_tests/StateChangeTest.cpp
"use strict";
var wtu = WebGLTestUtils;
description();

var gl = wtu.create3DContext("example");

var program = wtu.setupProgram(gl, ['vshader', 'fshader']);

var colorLoc = gl.getAttribLocation(program, "a_color");
var green = new Uint8Array(4 * 6);
var red = new Uint8Array(4 * 6);

for (var i = 0; i < 6; ++i) {
  var ci = i * 4;

  green[ci] = 0;
  red[ci] = 255;

  green[ci + 1] = 255;
  red[ci + 1] = 0;

  green[ci + 2] = red[ci + 2] = 0;

  green[ci + 3] = red[ci + 3] = 255;
}

var positionLoc = gl.getAttribLocation(program, "a_position");

var gridRes = 1;
wtu.setupIndexedQuad(gl, gridRes, positionLoc);

var colorBuf = gl.createBuffer();
gl.bindBuffer(gl.ARRAY_BUFFER, colorBuf);
gl.bufferData(gl.ARRAY_BUFFER, green, gl.STATIC_DRAW);
gl.vertexAttribPointer(colorLoc, 4, gl.UNSIGNED_BYTE, true, 0, 0);
gl.enableVertexAttribArray(colorLoc);

wtu.clearAndDrawIndexedQuad(gl, gridRes);
wtu.checkCanvas(gl, [0, 255, 0, 255], "should be green");

gl.bufferSubData(gl.ARRAY_BUFFER, 0, red);

wtu.clearAndDrawIndexedQuad(gl, gridRes);
wtu.checkCanvas(gl, [255, 0, 0, 255], "should be red");

wtu.glErrorShouldBe(gl, gl.NO_ERROR, "should be no errors");

var successfullyParsed = true;
</script>
<script src="../../js/js-test-post.js"></script>

</body>
</html>

