<!--
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.
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<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<title>WebGL ActiveTexture BindTexture conformance 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="2" height="2" style="width: 40px; height: 40px;"></canvas>
<canvas id="canvas2d" width="1" height="1" style="width: 40px; height: 40px;"></canvas>
<div id="description"></div>
<div id="console"></div>
<script id="vshader" type="x-shader/x-vertex">
uniform mat4 world;
attribute vec3 vPosition;
attribute vec2 texCoord0;
varying vec2 texCoord;
void main()
{
  gl_Position = world * vec4(vPosition, 1);
  texCoord = texCoord0;
}
</script>
<script id="trivial-vs" type="text/plain">
void main()
{
  gl_Position = vec4(0,0,0,1);
  gl_PointSize = 1.0;
}
</script>
<script id="tex-point-fs" type="text/plain">
precision mediump float;
uniform sampler2D uSampler;
void main()
{
  gl_FragColor = texture2D(uSampler, vec2(0));
}
</script>
<script>
"use strict";
var gl;

function init()
{
  description(
      "Tests that glActiveTexture and glBindTexture work as expected" +
      "Specifically texture targets are per active texture unit.");

  var canvas2d = document.getElementById("canvas2d");
  var ctx2d = canvas2d.getContext("2d");

  var wtu = WebGLTestUtils;
  gl = wtu.create3DContext("example");
  var program = wtu.setupProgram(
      gl,
      ["vshader", wtu.simpleTextureFragmentShader],
      ['vPosition', 'texCoord0']);
  wtu.setupUnitQuad(gl);
  gl.disable(gl.DEPTH_TEST);
  gl.disable(gl.BLEND);
  wtu.glErrorShouldBe(gl, gl.NO_ERROR);

  var colors = [
      [0,192,128,255],
      [128,64,255,255],
      [192,255,64,255],
      [200,0,255,255]];

  // Make 4 textures by using 4 active texture units if available.
  var texunits = Math.min(colors.length, gl.getParameter(gl.MAX_COMBINED_TEXTURE_IMAGE_UNITS))
  var textures = [];
  for (var ii = 0; ii < texunits; ++ii) {
    var tex = gl.createTexture();
    gl.activeTexture(gl.TEXTURE0 + ii);
    gl.bindTexture(gl.TEXTURE_2D, tex);
    textures[ii] = tex;
  }
  wtu.glErrorShouldBe(gl, gl.NO_ERROR);

  // now use each texture unit to write into the textures,
  for (var ii = 0; ii < texunits; ++ii) {
    var c = colors[ii];
    ctx2d.fillStyle =
        "rgba(" + c[0] + "," + c[1] + "," + c[2] + "," + c[3] + ")";
    ctx2d.fillRect(0, 0, 1, 1);
    gl.activeTexture(gl.TEXTURE0 + ii);
    gl.texImage2D(gl.TEXTURE_2D, 0, gl.RGBA, gl.RGBA, gl.UNSIGNED_BYTE, canvas2d);
  }
  wtu.glErrorShouldBe(gl, gl.NO_ERROR);

  var textureLoc = gl.getUniformLocation(program, "tex");
  var worldLoc = gl.getUniformLocation(program, "world");
  wtu.glErrorShouldBe(gl, gl.NO_ERROR);

  gl.clearColor(1,0,0,1);
  gl.clear(gl.COLOR_BUFFER_BIT | gl.DEPTH_BUFFER_BIT);

  for (var ii = 0; ii < texunits; ++ii) {
    var x = ii % 2;
    var y = Math.floor(ii / 2);
    gl.uniform1i(textureLoc, ii);
    gl.uniformMatrix4fv(
        worldLoc, false,
        [0.5, 0, 0, 0,
         0, 0.5, 0, 0,
         0, 0, 1, 0,
         -0.5 + x, -0.5 + y, 0, 1]);
    gl.drawArrays(gl.TRIANGLES, 0, 6);
  }
  wtu.glErrorShouldBe(gl, gl.NO_ERROR);

  for (var ii = 0; ii < texunits; ++ii) {
    var x = ii % 2;
    var y = Math.floor(ii / 2);
    wtu.checkCanvasRect(gl, x, y, 1, 1, colors[ii]);
  }

  debug("");
  debug("Swizzle applied to correct ActiveTexture index");

  {
    const prog = wtu.setupProgram(
        gl,
        ["trivial-vs", "tex-point-fs"]);
    prog.uSampler = gl.getUniformLocation(prog, "uSampler");
    gl.useProgram(prog);
    gl.viewport(0, 0, 1, 1);
    gl.activeTexture(gl.TEXTURE0);
    wtu.glErrorShouldBe(gl, gl.NO_ERROR);

    const tex0_rgba8 = gl.createTexture();
    gl.bindTexture(gl.TEXTURE_2D, tex0_rgba8);
    const tex0_rgba8_data = new Uint8Array([10, 20, 30, 40]);
    gl.texImage2D(gl.TEXTURE_2D, 0, gl.RGBA, 1, 1, 0, gl.RGBA, gl.UNSIGNED_BYTE, tex0_rgba8_data);

    const tex2_a8 = gl.createTexture();
    gl.bindTexture(gl.TEXTURE_2D, tex2_a8);
    gl.texImage2D(gl.TEXTURE_2D, 0, gl.ALPHA, 1, 1, 0, gl.ALPHA, gl.UNSIGNED_BYTE, null);

    window.control = new Uint8Array(4);
    window.after_swizzle_applied = new Uint8Array(4);

    gl.bindTexture(gl.TEXTURE_2D, tex0_rgba8);
    gl.drawArrays(gl.POINTS, 0, 1);
    gl.readPixels(0, 0, 1, 1, gl.RGBA, gl.UNSIGNED_BYTE, window.control);
    shouldBeString("window.control", tex0_rgba8_data.toString());

    gl.activeTexture(gl.TEXTURE2);
    gl.bindTexture(gl.TEXTURE_2D, tex2_a8);
    gl.uniform1i(prog.uSampler, 2);
    gl.activeTexture(gl.TEXTURE0);
    gl.drawArrays(gl.POINTS, 0, 1);
    // Firefox would apply the A8-on-R8 swizzle to whatever tex-unit was active.

    gl.uniform1i(prog.uSampler, 0);
    gl.drawArrays(gl.POINTS, 0, 1);
    gl.readPixels(0, 0, 1, 1, gl.RGBA, gl.UNSIGNED_BYTE, window.after_swizzle_applied);
    shouldBeString("window.after_swizzle_applied", tex0_rgba8_data.toString());
    // Firefox would then get 0,0,0,10 here, as the [ZERO,ZERO,ZERO,RED] swizzle was applied to our
    // 10,20,30,40 texture.
  }
}

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

</body>
</html>

