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<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<title>GLSL function nodes Test</title>
<link rel="stylesheet" href="../../../resources/js-test-style.css"/>
<link rel="stylesheet" href="../../resources/glsl-feature-tests.css"/>
<script src="../../../resources/js-test-pre.js"></script>
<script src="../../resources/webgl-test-utils.js"> </script>

<script id="vshaderFunction" type="x-shader/x-vertex">
attribute vec4 aPosition;
varying vec4 vColor;

float sign_emu(float value) {
  if (value == 0.0) return 0.0;
  return value > 0.0 ? 1.0 : -1.0;
}

void main()
{
   gl_Position = aPosition;
   vec2 texcoord = vec2(aPosition.xy * 0.5 + vec2(0.5, 0.5));
   vec4 color = vec4(
       texcoord,
       texcoord.x * texcoord.y,
       (1.0 - texcoord.x) * texcoord.y * 0.5 + 0.5);
   vColor = vec4(
    sign_emu(color.x * 2.0 - 1.0) * 0.5 + 0.5,
    sign_emu(color.y * 2.0 - 1.0) * 0.5 + 0.5,
    0,
    1);
}
</script>

<script id="vshaderMacro" type="x-shader/x-vertex">
attribute vec4 aPosition;
varying vec4 vColor;

#define sign_emu(value) ((value) == 0.0 ? 0.0 : ((value) > 0.0 ? 1.0 : -1.0))

void main()
{
   gl_Position = aPosition;
   vec2 texcoord = vec2(aPosition.xy * 0.5 + vec2(0.5, 0.5));
   vec4 color = vec4(
       texcoord,
       texcoord.x * texcoord.y,
       (1.0 - texcoord.x) * texcoord.y * 0.5 + 0.5);
   vColor = vec4(
    sign_emu(color.x * 2.0 - 1.0) * 0.5 + 0.5,
    sign_emu(color.y * 2.0 - 1.0) * 0.5 + 0.5,
    0,
    1);
}
</script>

<script id="fshader" type="x-shader/x-fragment">
precision mediump float;
varying vec4 vColor;
void main()
{
   gl_FragColor = vColor;
}
</script>
</head>
<body>
<canvas id="canvasFunction" width="50" height="50"></canvas>
<canvas id="canvasMacro" width="50" height="50"></canvas>
<div id="description">This tests against a Mac driver bug related to function calls.</div>
<div id="console"></div>
<script>
"use strict";
var width = 50;
var height = 50;
var wtu = WebGLTestUtils;

function drawAndRead(canvasID, vshaderID, buffer)
{
    var gl = wtu.create3DContext(canvasID);
    var program = wtu.setupProgram(gl, [vshaderID, "fshader"], ["aPosition"]);
    var vertexObject = gl.createBuffer();
    gl.bindBuffer(gl.ARRAY_BUFFER, vertexObject);
    gl.bufferData(gl.ARRAY_BUFFER, new Float32Array([ 0,0.5,0, -0.5,-0.5,0, 0.5,-0.5,0 ]), gl.STATIC_DRAW);
    gl.enableVertexAttribArray(0);
    gl.vertexAttribPointer(0, 3, gl.FLOAT, false, 0, 0);

    gl.clear(gl.COLOR_BUFFER_BIT | gl.DEPTH_BUFFER_BIT);
    gl.drawArrays(gl.TRIANGLES, 0, 3);
    gl.readPixels(0, 0, width, height, gl.RGBA, gl.UNSIGNED_BYTE, buffer);
    if (gl.getError() != gl.NO_ERROR)
        return false;
    return true;
}

function compareRendering(buffer1, buffer2, tol)
{
    for (var i = 0; i < width * height * 4; ++i) {
        if (Math.abs(buffer1[i] - buffer2[i]) > tol)
            return false;
    }
    return true;
}

function init()
{
    description("tests function nodes");

    var bufFunction = new Uint8Array(width * height * 4);
    var bufMacro = new Uint8Array(width * height * 4);

    if (drawAndRead("canvasFunction", "vshaderFunction", bufFunction) == false ||
        drawAndRead("canvasMacro", "vshaderMacro", bufMacro) == false) {
        testFailed("Setup failed");
    } else {
        if (compareRendering(bufFunction, bufMacro, 4) == false)
            testFailed("Rendering results are different");
        else
            testPassed("Rendering results are the same");
    }
}

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

