// forked from Rihei Endo's "WaveEquation Neumann" http://www.natural-science.or.jp/WebGL/WaveEquation_Neumann.html

var DOT_SIZE = 8;
var X_START_POS = 4;
var Y_START_POS = 4;
var Z_START_POS = 0;

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var dataSet = [
    "BK","BK","BK","BK","BK","BK","BK","BK","BK","BK","BK","BK","BK","BG","BG","BG",
    "BK","BK","BK","BK","BK","BK","RD","RD","RD","RD","RD","BK","BK","BG","BG","BG",
    "BK","BK","BK","BK","BK","RD","RD","RD","RD","RD","RD","RD","RD","RD","BG","BG",
    "BK","BK","BK","BK","BK","BR","BR","BR","BG","BG","BR","BG","BK","RD","RD","RD",
    "BK","BK","BK","BK","BR","BG","BR","BG","BG","BG","BR","BG","BG","RD","RD","RD",
    "BK","BK","BK","BK","BR","BG","BR","BR","BG","BG","BG","BR","BG","BG","BG","RD",
    "BK","BK","BK","BK","BR","BR","BG","BG","BG","BG","BR","BR","BR","BR","RD","BK",
    "BK","BK","BK","BK","BK","BK","BG","BG","BG","BG","BG","BG","BG","RD","BK","BK",
    "BK","BK","RD","RD","RD","RD","RD","BL","RD","RD","RD","BL","RD","BK","BK","BK",
    "BK","RD","RD","RD","RD","RD","RD","RD","BL","RD","RD","RD","BL","BK","BK","BR",
    "BG","BG","RD","RD","RD","RD","RD","RD","BL","BL","BL","BL","BL","BK","BK","BR",
    "BG","BG","BG","BK","BL","BL","RD","BL","BL","YL","BL","BL","YL","BL","BR","BR",
    "BK","BG","BK","BR","BL","BL","BL","BL","BL","BL","BL","BL","BL","BL","BR","BR",
    "BK","BK","BR","BR","BR","BL","BL","BL","BL","BL","BL","BL","BL","BL","BR","BR",
    "BK","BR","BR","BR","BL","BL","BL","BL","BL","BL","BL","BK","BK","BK","BK","BK",
    "BK","BR","BK","BK","BL","BL","BL","BL","BK","BK","BK","BK","BK","BK","BK","BK"
];

function getRgbColor(colorType)
{
    var colorHash = {
        "BK":"#000000", // black
        "WH":"#FFFFFF", // white
        "BG":"#FFCCCC", // beige
        "BR":"#800000", // brown
        "RD":"#FF0000", // red
        "YL":"#FFFF00", // yellow
        "GN":"#00FF00", // green
        "WT":"#00FFFF", // water
        "BL":"#0000FF", // blue
        "PR":"#800080"  // purple
    };
    return colorHash[colorType];
}

var N = 24;
var l = 5.0;

var dt = 0.1;
var dd = 1.0;
var v = 4;

var BC = "Dirichlet";

var peakPosition = {
    x: 0,
    y: 0,
    z: 75,
    sigma2: 50
};
var peakPosition_bound = {
    x_min: -50,
    x_max: 50,
    y_min: -50,
    y_max: 50,
    z_min: -50,
    z_max: 100,
    sigma2_min: 10,
    sigma2_max: 100
};

var restartFlag = false;
var stopFlag = false;

var Tn = 3;
var f = new Array(Tn);

function initialCondition(parameter) {
    var x0 = parameter.x;
    var y0 = parameter.y;
    var z0 = parameter.z;
    var sigma2 = parameter.sigma2;
    for (var t = 0; t < Tn; t++) {
        f[t] = new Array(N);
        for (i = 0; i <= N; i++) {
            f[t][i] = new Array(N);
            for (j = 0; j <= N; j++) {
                var x = (-N / 2 + i) * l;
                var y = (-N / 2 + j) * l;
                var z = z0 * Math.exp(-(Math.pow(x - x0, 2) + Math.pow(y - y0, 2)) / (2 * sigma2));
                f[0][i][j] = z;
            }
        }
    }
    for (var i = 1; i <= N - 1; i++) {
        for (var j = 1; j <= N - 1; j++) {
            f[1][i][j] = f[0][i][j] + v * v / 2.0 * dt * dt / (dd * dd) * (f[0][i + 1][j] + f[0][i - 1][j] + f[0][i][j + 1] + f[0][i][j - 1] - 4.0 * f[0][i][j]);
        }
    }
    if (BC == "Dirichlet") {
        for (var i = 0; i <= N; i++) {
            f[1][i][0] = f[1][i][N] = f[1][0][i] = f[1][N][i] = 0.0;
        }
    } else if (BC == "Neumann") {
        for (var i = 1; i <= N - 1; i++) {
            f[1][i][0] = f[1][i][1];
            f[1][i][N] = f[1][i][N - 1];
            f[1][0][i] = f[1][1][i];
            f[1][N][i] = f[1][N - 1][i];
        }
        f[1][0][0] = (f[1][0][1] + f[1][1][0]) / 2;
        f[1][0][N] = (f[1][0][N - 1] + f[1][1][N]) / 2;
        f[1][N][0] = (f[1][N - 1][0] + f[1][N][1]) / 2;
        f[1][N][N] = (f[1][N - 1][N] + f[1][N][N - 1]) / 2;
    }
}

window.addEventListener("load", function() {
    initialCondition(peakPosition);
    threeStart();
});


function threeStart() {
    initThree();
    initCamera();
    initLight();
    initObject();
    loop();
}

var renderer,
    scene,
    canvasFrame;

function initThree() {
    canvasFrame = document.getElementById('canvas-frame');
    renderer = new THREE.WebGLRenderer({
        antialias: true
    });
    if (!renderer) alert('Failed to initialize Three.js');
    renderer.setSize(canvasFrame.clientWidth, canvasFrame.clientHeight);
    canvasFrame.appendChild(renderer.domElement);

    renderer.setClearColor(0x000000, 1.0);

    scene = new THREE.Scene();
}

var camera;
var theta = 0;

function initCamera() {
    camera = new THREE.PerspectiveCamera(45, canvasFrame.clientWidth / canvasFrame.clientHeight, 1, 10000);
    camera.position.set(160, 0, 100);
    camera.up.set(0, 0, 1);
    camera.lookAt({
        x: 0,
        y: 0,
        z: 0
    });
}

var directionalLight,
    ambientLight;

function initLight() {
    directionalLight = new THREE.DirectionalLight(0xDDDDDD, 1.0, 0);
    directionalLight.position.set(30, 30, 100);

    ambientLight = new THREE.AmbientLight(0x222222);
    scene.add(ambientLight);

    scene.add(directionalLight);
}

var axis,
    lattice,
    cubes = [];

function initObject() {
    initialCondition(peakPosition);

    var geometry = new THREE.Geometry();
    var colors = [];
    for (i = 0; i <= N; i++) {
        for (j = 0; j <= N; j++) {
            var x = (-N / 2 + i) * l;
            var y = (-N / 2 + j) * l;
            var z = f[0][i][j];

            geometry.vertices.push(new THREE.Vector3(x, y, z));

            var ii = i - X_START_POS;
            var jj = j - Y_START_POS;
            var color = new THREE.Color();
            if ((ii >= 0 && ii < 16) && (jj >= 0 && jj < 16)) {
                var pos = jj * 16 + (15 - ii);
                if (dataSet[pos] != "BK") {
                    color.setStyle(getRgbColor(dataSet[pos]));
                }
            }
            colors.push(color);
        }
    }

    geometry.colors = colors;
    geometry.computeFaceNormals();
    geometry.computeVertexNormals();

    // ball.png  
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    var sprite = THREE.ImageUtils.loadTexture(dataUrl);

    var material = new THREE.PointCloudMaterial({
        map: sprite,
        size: DOT_SIZE * 2.0,
        transparent: true,
        opacity: 0.7,
        vertexColors: true
    });
    //立方体オブジェクトの生成
    lattice = new THREE.PointCloud(geometry, material);
}

var step = 0;

function loop() {
    camera.lookAt(scene.position);
    camera.position.x = 200 * Math.sin(theta * Math.PI / 180);
    camera.position.y = 100;
    camera.position.z = 200 * Math.cos(theta * Math.PI / 180);
    theta += 0.5;

    var time = step * dt;
    if (stopFlag == false) {
        step++;
        time = step * dt;
        for (var i = 1; i <= N - 1; i++) {
            for (var j = 1; j <= N - 1; j++) {
                f[2][i][j] = 2.0 * f[1][i][j] - f[0][i][j] + v * v * dt * dt / (dd * dd) * (f[1][i + 1][j] + f[1][i - 1][j] + f[1][i][j + 1] + f[1][i][j - 1] - 4.0 * f[1][i][j]);
            }
        }
        if (BC == "Dirichlet") {
            for (var i = 0; i <= N; i++) {
                f[2][i][0] = f[2][i][N] = f[2][0][i] = f[2][N][i] = 0.0;
            }
        } else if (BC == "Neumann") {
            for (var i = 1; i <= N - 1; i++) {
                f[2][i][0] = f[2][i][1];
                f[2][i][N] = f[2][i][N - 1];
                f[2][0][i] = f[2][1][i];
                f[2][N][i] = f[2][N - 1][i];
            }
            f[2][0][0] = (f[2][0][1] + f[2][1][0]) / 2;
            f[2][0][N] = (f[2][0][N - 1] + f[2][1][N]) / 2;
            f[2][N][0] = (f[2][N - 1][0] + f[2][N][1]) / 2;
            f[2][N][N] = (f[2][N - 1][N] + f[2][N][N - 1]) / 2;

        }
        for (var i = 0; i <= N; i++) {
            for (var j = 0; j <= N; j++) {
                f[0][i][j] = f[1][i][j];
                f[1][i][j] = f[2][i][j];
            }
        }
    }

    var a = 0;
    for (i = 0; i <= N; i++) {
        for (j = 0; j <= N; j++) {
            var x = (-N / 2 + i) * l;
            var y = (-N / 2 + j) * l;
            var z = f[1][i][j];
            lattice.geometry.vertices[a].z = z;
            a++;
        }
    }

    lattice.geometry.normalsNeedUpdate = true;
    lattice.geometry.verticesNeedUpdate = true;
    lattice.geometry.computeFaceNormals();
    lattice.geometry.computeVertexNormals();

    scene.add(lattice);

    renderer.clear();
    renderer.render(scene, camera);

    scene.remove(lattice);

    requestAnimationFrame(loop);
}