﻿<!--
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 Conformance Tests: Verify validation for active built-in attribs</title>
<link rel="stylesheet" href="../../resources/js-test-style.css"/>
<script src="../../js/desktop-gl-constants.js"></script>
<script src="../../js/js-test-pre.js"></script>
<script src="../../js/webgl-test-utils.js"></script>
</head>
<body>
<div id="description"></div>
<canvas id="canvas" style="width: 64px; height: 64px;"> </canvas>
<div id="console"></div>
<script id="vs" type="x-shader/x-vertex">#version 300 es
void main() {
  gl_Position = vec4(gl_VertexID % 2, (gl_VertexID/2) % 2, 0, 1);
}
</script>

<script id="fs" type="x-shader/x-fragment">#version 300 es
precision mediump float;
out vec4 fragColor;
void main() {
  fragColor = vec4(0, 1, 0, 1);
}
</script>

<script>
"use strict";
description("This test verifies validation for active built-in attribs.");

debug("");

var wtu = WebGLTestUtils;
var canvas = document.getElementById("canvas");
var gl = wtu.create3DContext(canvas, null, 2);

if (!gl) {
  testFailed("WebGL context does not exist");
} else {
  testPassed("WebGL context exists");
  runTests();
}

var activeInfo, attribLoc;

function runTests() {
  var prog = wtu.setupProgram(gl, ["vs", "fs"]);
  if (!prog) {
    testFailed("Set up program failed");
    return;
  }
  wtu.glErrorShouldBe(gl, gl.NO_ERROR, "No GL error from set up");

  var numActive = gl.getProgramParameter(prog, gl.ACTIVE_ATTRIBUTES);
  if (numActive != 1) {
    testFailed('ACTIVE_ATTRIBUTES should be 1.');
    return;
  }
  testPassed('ACTIVE_ATTRIBUTES should be 1.');

  activeInfo = gl.getActiveAttrib(prog, 0);
  if (!activeInfo) {
    testFailed('getActiveAttrib should return an info object.');
    return;
  }

  shouldBe('activeInfo.name', '"gl_VertexID"');
  attribLoc = gl.getAttribLocation(prog, 'gl_VertexID');
  wtu.glErrorShouldBe(gl, gl.NO_ERROR, "Should be able to request the location of a built-in.");
  shouldBe('attribLoc', '-1');
}

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

</body>
</html>
