<!--

/*
** Copyright (c) 2016 The Khronos Group Inc.
**
** Permission is hereby granted, free of charge, to any person obtaining a
** copy of this software and/or associated documentation files (the
** "Materials"), to deal in the Materials without restriction, including
** without limitation the rights to use, copy, modify, merge, publish,
** distribute, sublicense, and/or sell copies of the Materials, and to
** permit persons to whom the Materials are furnished to do so, subject to
** the following conditions:
**
** The above copyright notice and this permission notice shall be included
** in all copies or substantial portions of the Materials.
**
** THE MATERIALS ARE PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
** EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
** MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
** IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
** CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
** TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
** MATERIALS OR THE USE OR OTHER DEALINGS IN THE MATERIALS.
*/

-->

<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<title>WebGL Rendering and Sampling Feedback Loop 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>
<canvas id="example" width="8" height="8"></canvas>
<div id="description"></div>
<div id="console"></div>

<script id="vshader" type="x-shader/x-vertex">#version 300 es
in highp vec4 aPosition;
in vec2 aTexCoord;
out vec2 texCoord;
void main() {
    gl_Position = aPosition;
    texCoord = aTexCoord;
}
</script>

<script id="fshader" type="x-shader/x-fragment">#version 300 es
precision mediump float;
uniform sampler2D tex;
in vec2 texCoord;
out vec4 oColor;
void main() {
    oColor = texture(tex, texCoord);
}
</script>

<script>
"use strict";

var wtu = WebGLTestUtils;
description("This test verifies the functionality of rendering to the same texture where it samples from.");

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

var width = 8;
var height = 8;
var tex0;
var tex1;
var fbo;
var program;
var positionLoc;
var texCoordLoc;

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

    init();

    // The sampling texture is bound to COLOR_ATTACHMENT1 during resource allocation
    allocate_resource();

    rendering_sampling_feedback_loop([gl.NONE, gl.COLOR_ATTACHMENT1], gl.INVALID_OPERATION);
    rendering_sampling_feedback_loop([gl.COLOR_ATTACHMENT0, gl.COLOR_ATTACHMENT1], gl.INVALID_OPERATION);
    rendering_sampling_feedback_loop([gl.COLOR_ATTACHMENT0, gl.NONE], gl.NO_ERROR);
}

function init() {
    program = wtu.setupProgram(gl, ['vshader', 'fshader'], ['aPosition', 'aTexCoord'], [0, 1]);
    positionLoc = gl.getAttribLocation(program, "aPosition");
    texCoordLoc = gl.getAttribLocation(program, "aTexCoord");
    if (!program || positionLoc < 0 || texCoordLoc < 0) {
        testFailed("Set up program failed");
        return;
    }
    testPassed("Set up program succeeded");

    wtu.setupUnitQuad(gl, 0, 1);
    gl.viewport(0, 0, width, height);
}

function allocate_resource() {
    tex0 = gl.createTexture();
    tex1 = gl.createTexture();
    fbo = gl.createFramebuffer();
    wtu.fillTexture(gl, tex0, width, height, [0xff, 0x0, 0x0, 0xff], 0, gl.RGBA, gl.UNSIGNED_BYTE, gl.RGBA);
    wtu.fillTexture(gl, tex1, width, height, [0x0, 0xff, 0x0, 0xff], 0, gl.RGBA, gl.UNSIGNED_BYTE, gl.RGBA);

    gl.bindTexture(gl.TEXTURE_2D, tex1);
    var texLoc = gl.getUniformLocation(program, "tex");
    gl.uniform1i(texLoc, 0);

    gl.bindFramebuffer(gl.FRAMEBUFFER, fbo);
    gl.framebufferTexture2D(gl.FRAMEBUFFER, gl.COLOR_ATTACHMENT0, gl.TEXTURE_2D, tex0, 0);
    gl.framebufferTexture2D(gl.FRAMEBUFFER, gl.COLOR_ATTACHMENT1, gl.TEXTURE_2D, tex1, 0);
}

function rendering_sampling_feedback_loop(draw_buffers, error) {
    gl.drawBuffers(draw_buffers);

    // Make sure framebuffer is complete before feedback loop detection
    if (gl.checkFramebufferStatus(gl.FRAMEBUFFER) != gl.FRAMEBUFFER_COMPLETE) {
        testFailed("Framebuffer incomplete.");
        return;
    }

    wtu.clearAndDrawUnitQuad(gl);
    wtu.glErrorShouldBe(gl, error, "Rendering to a texture where it samples from should geneates INVALID_OPERATION. Otherwise, it should be NO_ERROR");
}

gl.bindTexture(gl.TEXTURE_2D, null);
gl.bindFramebuffer(gl.FRAMEBUFFER, null);
gl.deleteTexture(tex0);
gl.deleteTexture(tex1);
gl.deleteFramebuffer(fbo);

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

</body>
</html>
