<!--
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 BindAttribLocation Conformance Tests</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>
<div id="description"></div>
<div id="console"></div>
<canvas style="border: 1px solid black;" id="canvas" width="50" height="50"></canvas>
<script id="vshader" type="text/something-not-javascript">
attribute vec4 vPosition;
attribute vec4 vColor;
varying vec4 color;
void main()
{
  gl_Position = vPosition;
  color = vColor;
}
</script>
<script id="fshader" type="text/something-not-javascript">
precision mediump float;

varying vec4 color;
void main()
{
  gl_FragColor = color;
}
</script>
<script>
"use strict";
description("This test ensures WebGL implementations don't allow names that start with 'gl_' when calling bindAttribLocation.");

debug("");
debug("Canvas.getContext");

var wtu = WebGLTestUtils;
var gl = wtu.create3DContext("canvas");
shouldBeNonNull("gl");

debug("");
debug("Checking gl.bindAttribLocation.");

var program = gl.createProgram();
gl.bindAttribLocation(program, 0, "gl_foo");
wtu.glErrorShouldBe(gl, gl.INVALID_OPERATION,
    "bindAttribLocation should return INVALID_OPERATION if name starts with 'gl_'");
gl.bindAttribLocation(program, 0, "gl_TexCoord0");
wtu.glErrorShouldBe(gl, gl.INVALID_OPERATION,
    "bindAttribLocation should return INVALID_OPERATION if name starts with 'gl_'");

var vs = wtu.loadShaderFromScript(gl, 'vshader', gl.VERTEX_SHADER);
var fs = wtu.loadShaderFromScript(gl, 'fshader', gl.FRAGMENT_SHADER);
gl.attachShader(program, vs);
gl.attachShader(program, fs);

var positions = gl.createBuffer();
gl.bindBuffer(gl.ARRAY_BUFFER, positions);
gl.bufferData(gl.ARRAY_BUFFER, new Float32Array([ 0,0.5,0, -0.5,-0.5,0, 0.5,-0.5,0 ]), gl.STATIC_DRAW);

var colors = gl.createBuffer();
gl.bindBuffer(gl.ARRAY_BUFFER, colors);
gl.bufferData(gl.ARRAY_BUFFER, new Float32Array([
    0,1,0,1,
    0,1,0,1,
    0,1,0,1]), gl.STATIC_DRAW);

function setBindLocations(colorLocation, positionLocation) {
  gl.bindAttribLocation(program, positionLocation, "vPosition");
  gl.bindAttribLocation(program, colorLocation, "vColor");
  gl.linkProgram(program);
  gl.useProgram(program);
  var linked = (gl.getProgramParameter(program, gl.LINK_STATUS) != 0);
  assertMsg(linked, "program linked successfully");

  debug("vPosition:" + gl.getAttribLocation(program, "vPosition"))
  debug("vColor   :" + gl.getAttribLocation(program, "vColor"))
  assertMsg(gl.getAttribLocation(program, "vPosition") == positionLocation,
            "location of vPosition should be " + positionLocation);
  assertMsg(gl.getAttribLocation(program, "vColor") == colorLocation,
            "location of vColor should be " + colorLocation);

  var ploc = gl.getAttribLocation(program, "vPosition");
  var cloc = gl.getAttribLocation(program, "vColor");
  gl.bindBuffer(gl.ARRAY_BUFFER, positions);
  gl.enableVertexAttribArray(positionLocation);
  gl.vertexAttribPointer(positionLocation, 3, gl.FLOAT, false, 0, 0);
  gl.bindBuffer(gl.ARRAY_BUFFER, colors);
  gl.enableVertexAttribArray(colorLocation);
  gl.vertexAttribPointer(colorLocation, 4, gl.FLOAT, false, 0, 0);
}

function checkDraw(colorLocation, positionLocation, r, g, b, a) {
  gl.clearColor(0, 0, 0, 1);
  gl.clear(gl.COLOR_BUFFER_BIT | gl.DEPTH_BUFFER_BIT);
  gl.drawArrays(gl.TRIANGLES, 0, 3);

  var width = 50;
  var height = 50;

  // Test several locations
  wtu.checkCanvasRect(gl, 0, 0, width, 1, [0, 0, 0, 255],
      "First line should be all black");
  wtu.checkCanvasRect(gl, 20, 15, 10, 1, [r, g, b, a],
      "Line 15 should be red for at least 10 rgba pixels starting 20 pixels in");
  wtu.checkCanvasRect(gl, 0, height - 1, width, 0, [0, 0, 0, 255],
      "Last line should be all black");

  gl.disableVertexAttribArray(positionLocation);
  gl.disableVertexAttribArray(colorLocation);
}

setBindLocations(2, 3);
checkDraw(2, 3, 0, 255, 0, 255);

setBindLocations(0, 3);
gl.disableVertexAttribArray(0);
gl.vertexAttrib4f(0, 1, 0, 0, 1);
checkDraw(0, 3, 255, 0, 0, 255);

wtu.glErrorShouldBe(gl, gl.NO_ERROR);

debug("");
var successfullyParsed = true;

</script>
<script src="../../js/js-test-post.js"></script>

</body>
</html>
