<!--
Copyright (c) 2020 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>WebGL2 can render to framebuffer attachments with different targets</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>
<script id="vshader" type="x-shader/x-vertex">#version 300 es
void main(void) {
  gl_Position = vec4(-0.5, -0.5, 0, 1);
  gl_PointSize = 1.0;
}
</script>
<script id="fshader" type="x-shader/x-fragment">#version 300 es
precision mediump float;
out vec4 outColor;
void main() {
  outColor = vec4(0, 1, 0, 1);
}
</script>
</head>
<body>
<canvas id="example" width="1", height="1"></canvas>
<div id="description"></div>
<div id="console"></div>
<script>
"use strict";
debug("");

description("Test framebuffer attachments with different targets");

const wtu = WebGLTestUtils;
const gl = wtu.create3DContext("example", undefined, 2);

if (!gl) {
    testFailed("WebGL context creation failed");
} else {
    testPassed("WebGL context creation succeeded");
    runTest();
}

function newResource(target, mipLevels, format, size) {
  let ret;
  switch (target) {
    case gl.RENDERBUFFER: {
      ret = gl.createRenderbuffer();
      ret.mips = [ ret ];
      for (let i = 1; i < mipLevels; i++) {
        ret.mips.push(gl.createRenderbuffer());
      }
      for (const i in ret.mips) {
        const rb = ret.mips[i];
        gl.bindRenderbuffer(target, rb);
        gl.renderbufferStorage(target, format, size>>i, size>>i);
      }
      ret.attach = (attachEnum, mipLevel) => {
        const rb = ret.mips[mipLevel];
        gl.framebufferRenderbuffer(gl.FRAMEBUFFER, attachEnum, gl.RENDERBUFFER, rb);
      };
      break;
    }
    case gl.TEXTURE_2D:
    case gl.TEXTURE_CUBE_MAP: {
      ret = gl.createTexture();
      gl.bindTexture(target, ret);
      gl.texStorage2D(target, mipLevels, format, size, size);
      let imageTarget = target;
      if (imageTarget == gl.TEXTURE_CUBE_MAP) {
        imageTarget = gl.TEXTURE_CUBE_MAP_POSITIVE_X+2; // Deliberately don't choose the first image.
      }
      ret.attach = (attachEnum, mipLevel) => {
        gl.framebufferTexture2D(gl.FRAMEBUFFER, attachEnum, imageTarget, ret, mipLevel);
      };
      break;
    }
    case gl.TEXTURE_3D:
    case gl.TEXTURE_2D_ARRAY: {
      ret = gl.createTexture();
      gl.bindTexture(target, ret);
      gl.texStorage3D(target, mipLevels, format, size, size, 1);
      ret.attach = (attachEnum, mipLevel) => {
        gl.framebufferTextureLayer(gl.FRAMEBUFFER, attachEnum, ret, mipLevel, 0);
      };
      break;
    }
    default:
      throw new Error();
  }
  ret.target = wtu.glEnumToString(gl, target);
  ret.format = wtu.glEnumToString(gl, format);
  return ret;
}

function runTest() {
  const MIP_LEVELS = 2;
  const SIZE = 2;

  gl.clearColor(1, 0, 0, 1);

  const program = wtu.setupProgram(gl, ['vshader','fshader'], [], console.log.bind(console));
  gl.useProgram(program);

  const colorResList = [
    newResource(gl.RENDERBUFFER, MIP_LEVELS, gl.RGBA8, SIZE),
    newResource(gl.TEXTURE_2D, MIP_LEVELS, gl.RGBA8, SIZE),
    newResource(gl.TEXTURE_CUBE_MAP, MIP_LEVELS, gl.RGBA8, SIZE),
    newResource(gl.TEXTURE_3D, MIP_LEVELS, gl.RGBA8, SIZE),
    newResource(gl.TEXTURE_2D_ARRAY, MIP_LEVELS, gl.RGBA8, SIZE),
  ];

  const depthResList = [
    newResource(gl.RENDERBUFFER, MIP_LEVELS, gl.DEPTH_COMPONENT16, SIZE),
    newResource(gl.TEXTURE_2D, MIP_LEVELS, gl.DEPTH_COMPONENT16, SIZE),
    newResource(gl.TEXTURE_CUBE_MAP, MIP_LEVELS, gl.DEPTH_COMPONENT16, SIZE),
    //newResource(gl.TEXTURE_3D, MIP_LEVELS, gl.DEPTH_COMPONENT16, SIZE), // Depth formats forbidden for TEXTURE_3D.
    newResource(gl.TEXTURE_2D_ARRAY, MIP_LEVELS, gl.DEPTH_COMPONENT16, SIZE),
  ];

  const fb = gl.createFramebuffer();
  gl.bindFramebuffer(gl.FRAMEBUFFER, fb);
  for (const color of colorResList) {
    for (const depth of depthResList) {
      debug(`\ncolor: ${color.target}; depth: ${depth.target}`);
      for (let mipLevel = 0; mipLevel < MIP_LEVELS; mipLevel++) {
        debug(`mipLevel: ${mipLevel}`);
        color.attach(gl.COLOR_ATTACHMENT0, mipLevel);
        depth.attach(gl.DEPTH_ATTACHMENT, mipLevel);
        const maybeStatus = wtu.framebufferStatusShouldBe(gl, gl.FRAMEBUFFER, [gl.FRAMEBUFFER_COMPLETE, gl.FRAMEBUFFER_UNSUPPORTED]);
        if (!maybeStatus || maybeStatus[0] != gl.FRAMEBUFFER_COMPLETE) {
          continue;
        }

        gl.clear(gl.COLOR_BUFFER_BIT);
        wtu.checkCanvas(gl, [255, 0, 0, 255], `framebuffer layer ${mipLevel} should be cleared red`);

        gl.drawArrays(gl.POINTS, 0, 1);
        wtu.checkCanvas(gl, [0, 255, 0, 255], `framebuffer layer ${mipLevel} should be drawn green`);

        wtu.glErrorShouldBe(gl, gl.NO_ERROR, `No errors`);
      }
    }
  }

  // make sure we were not rendering to the canvas.
  gl.bindFramebuffer(gl.FRAMEBUFFER, null)
  wtu.checkCanvas(gl, [0, 0, 0, 0], "canvas should be zero");
}

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

</body>
</html>
