<!--
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 Scissor FBO 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="canvas" width="16" height="16" style="width: 40px; height: 40px;"> </canvas>
<canvas id="canvas2" width="16" height="16" style="width: 40px; height: 40px;"> </canvas>
<div id="description"></div>
<div id="console"></div>
<script>
"use strict";
description("Checks the scissor does not change when switching framebuffers.");

var wtu = WebGLTestUtils;
var gl;

function makeFramebuffer(width, height) {
  var tex = gl.createTexture();
  gl.bindTexture(gl.TEXTURE_2D, tex);
  gl.texImage2D(gl.TEXTURE_2D, 0, gl.RGBA, width, height, 0, gl.RGBA, gl.UNSIGNED_BYTE, null);
  gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_WRAP_S, gl.CLAMP_TO_EDGE);
  gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_WRAP_T, gl.CLAMP_TO_EDGE);
  gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_MIN_FILTER, gl.NEAREST);
  gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_MAG_FILTER, gl.NEAREST);
  var fb = gl.createFramebuffer();
  gl.bindFramebuffer(gl.FRAMEBUFFER, fb);
  gl.framebufferTexture2D(gl.FRAMEBUFFER, gl.COLOR_ATTACHMENT0, gl.TEXTURE_2D, tex, 0);
  shouldBe('gl.checkFramebufferStatus(gl.FRAMEBUFFER)', 'gl.FRAMEBUFFER_COMPLETE');
  gl.bindFramebuffer(gl.FRAMEBUFFER, null);
  return fb;
}

function checkCanvasRect(x, y, width, height, color, msg) {
  debug("checking: " + x + ", " + y + ", " + width + ", " + height);
  wtu.checkCanvasRect(gl, x, y, width, height, color, msg);
}

function runEntireTest(canvasName, antialias) {
  debug("");
  debug("== Running scissor fbo test with antialias:" + antialias + " ==");
  debug("");

  gl = wtu.create3DContext(canvasName, {antialias: antialias});
  if (!gl) {
    testFailed("context does not exist");
    return;
  }
  testPassed("context exists");

  var fb8x8 = makeFramebuffer(8, 8);
  var fb32x32 = makeFramebuffer(32, 32);

  var testScissor = function(scissorX, scissorY, scissorWidth, scissorHeight, msg) {
    debug("");
    debug(msg);

    var test = function(fb, size) {
      debug("");
      debug("checking size: " + size);
      gl.bindFramebuffer(gl.FRAMEBUFFER, fb);
      gl.clearColor(0, 1, 0, 1);
      gl.clear(gl.COLOR_BUFFER_BIT);
      var scissorRight = Math.min(scissorX + scissorWidth, size);
      var scissorTop = Math.min(scissorY + scissorHeight, size);
      var scWidth = scissorRight - scissorX;
      var scHeight = scissorTop - scissorY;
      var rightWidth = Math.min(size - scissorRight, 0);
      var topHeight = Math.max(size - scissorTop, 0);
      checkCanvasRect(scissorX, scissorY, scWidth, scHeight, [0, 255, 0, 255], "should be green");
      checkCanvasRect(0, 0, size, scissorY, [255, 0, 0, 255], "should be red");
      checkCanvasRect(0, scissorTop, size, topHeight, [255, 0, 0, 255], "should be red");
      checkCanvasRect(0, 0, scissorX, size, [255, 0, 0, 255], "should be red");
      checkCanvasRect(scissorRight, 0, scissorX, rightWidth, [255, 0, 0, 255], "should be red");
    };

    gl.disable(gl.SCISSOR_TEST);
    gl.clearColor(1, 0, 0, 1);
    gl.bindFramebuffer(gl.FRAMEBUFFER, null);
    gl.clear(gl.COLOR_BUFFER_BIT);
    gl.bindFramebuffer(gl.FRAMEBUFFER, fb8x8);
    gl.clear(gl.COLOR_BUFFER_BIT);
    gl.bindFramebuffer(gl.FRAMEBUFFER, fb32x32);
    gl.clear(gl.COLOR_BUFFER_BIT);

    gl.bindFramebuffer(gl.FRAMEBUFFER, fb32x32);
    gl.enable(gl.SCISSOR_TEST);
    gl.scissor(scissorX, scissorY, scissorWidth, scissorHeight);
    test(null, 16);
    test(fb8x8, 8);
    test(fb32x32, 32);
    test(null, 16);
  };

  testScissor(2, 4, 12, 10, "test scissor in middle");
  testScissor(0, 0, 12, 10, "test scissor at 0,0");
  testScissor(0, 0, 16, 16, "test scissor with size that matches drawingbuffer");

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

runEntireTest("canvas", false);
runEntireTest("canvas2", true);

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

</body>
</html>
