HTML three.js Texture Mapping

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テクスチャマッピングとは?
地球儀
D3.js で書いた地図をテクスチャとして使う

テクスチャマッピングとは? †

2Dの画像を3Dオブジェクトの表面に貼り付けること
NASAの正距円筒図法の世界地図を球に貼り付けてみる
- http://visibleearth.nasa.gov/view.php?id=57752

WebGL では、Canvas を 3D オブジェクトの表面に貼り付ける。 cf. Javascript canvas, HTML three.js Fog

// Canvas
var canvas = document.createElement("canvas");
cv.width = 400;
cv.height = 400;

var context = cv.getContext("2d");
context.fillStyle = "red";
context.fillRect = (0, 0, cv.width, cv.height);

// Texture
var texture = new THREE.Texture(cv);
texture.needUpdate = true;

// 球に Texture を貼り付ける
var geometry = new THREE.SphereGeometry(1, 32, 32);

var material = new THREE.MeshPhongMaterial({ map: texture });

var sphere = new THREE.Mesh(geometry, material);

単純に画像を貼り付ける場合には、Three.js のユーティリティ関数を使える

var geometry = new THREE.SphereGeometry(1, 32, 32);

var material = new THREE.MeshPhongMaterial({
    map: THREE.ImageUtils.loadTexture('land_shallow_topo_2048.jpg') });

var sphere = new THREE.Mesh(geometry, material);

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地球儀 †

https://github.com/kagyuu/ThreeJSExam/blob/master/globe.html

<!DOCTYPE html>
<html lang="ja">
<head>
    <meta charset="utf-8">
    <title>Globe and Texture</title>
    <style>
        div {
            border : 1px solid;
        }
    </style>
</head>
<body>
    <div id="webgl_view"></div>
    <script type="text/javascript" src="three.js" charset="utf-8"></script>
    <script type="text/javascript" src="https://ajax.googleapis.com/ajax/libs/jquery/2.0.3/jquery.min.js"></script>
    <script>

var height = 640;
var width  = 640;

var container = $('#webgl_view');
container.css({
    height :  height + "px",
    width  : width + "px"});

// (1) 球体
var geometry = new THREE.SphereGeometry(1, 32, 32);

var material = new THREE.MeshPhongMaterial({
    map: THREE.ImageUtils.loadTexture('land_shallow_topo_2048.jpg') });

var sphere = new THREE.Mesh(geometry, material);
      
// (2) ライト（平行光)
var light = new THREE.DirectionalLight(0xffffff);
light.position.x = Math.sin(Math.PI * 23.4 / 180.0);
light.position.y = Math.cos(Math.PI * 23.4 / 180.0);
light.position.z = 0;

// (3) 環境光
var alight = new THREE.AmbientLight(0x444444);

// (4) Scene
var scene = new THREE.Scene();
scene.add(sphere);
scene.add(light);
scene.add(alight);

// (5) Camera (視野角, アスペクト比(縦横比), 描画対象(最小距離), 描画対象(最大距離)
var camera = new THREE.PerspectiveCamera(90, (height / width), 0.1, 10);

// (6) WebGL Renderer
var renderer = new THREE.WebGLRenderer();
renderer.setSize(height, width);
renderer.setClearColor(0x101010);
renderer.clear(true);

container.append(renderer.domElement);

// (7) Animation (Rotate)
function animation() {
    var time = (new Date()).getTime();
    
    sphere.rotation.y = time / 3000;
    
    camera.position.x = 1.5 * Math.sin(-1.0 * time / 10000);
    camera.position.y = 1.0 * Math.sin(time / 10000);
    camera.position.z = 1.5 * Math.cos(-1.0 * time / 10000);
    
    camera.lookAt(new THREE.Vector3(-1.0 * camera.position.x,-1.0 * camera.position.y,-1.0 * camera.position.z));

    renderer.render(scene, camera);
    
    requestAnimationFrame(animation);
}

animation();


    </script>
</body>
</html>

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D3.js で書いた地図をテクスチャとして使う †

[Fabric.js]SVGをcanvasに転写する, GUNMA GIS GEEK, http://shimz.me/blog/d3-js/2892
で、SVG を Canvas に変換して、テクスチャとして使えば良さそう

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