poly_wave4（ブログ用）

const divNum = 12;//波の分割数
const waveNum = 1;//波の数

//ベジェ曲線の制御点の座標
var p1 = new THREE.Vector3();
var p2 = new THREE.Vector3();
var s1 = new THREE.Vector3();
var s2 = new THREE.Vector3();

function bezer(p1,p2,s1,s2,t){//三次ベジェ曲線の座標を返す
    var x = (1-t)*(1-t)*(1-t)*p1.x + 3*(1-t)*(1-t)*t*s1.x + 3*(1-t)*t*t*s2.x + t*t*t*p2.x;
    var y = (1-t)*(1-t)*(1-t)*p1.y + 3*(1-t)*(1-t)*t*s1.y + 3*(1-t)*t*t*s2.y + t*t*t*p2.y;
    return new THREE.Vector3(x,y,0);
}

function planeAnim(){
    p1.setX(-60);
    p1.setY(Math.sin(clock.getElapsedTime())*0);
    p2.setX(60);
    p2.setY(Math.sin(clock.getElapsedTime())*0);
    s1.setX(-30);
    s1.setY(Math.sin(clock.getElapsedTime())*20);
    s2.setX(30);
    s2.setY(Math.sin(clock.getElapsedTime()+60)*20);

    for (var i = 0; i < planeGeo.vertices.length; i++) {
        var divNumIndex  = i % divNum;//波の節のインデックス（左から0番~[divNum]番）
        var waveNumIndex = Math.floor(i/(divNum+1)) ;//波の数のインデックス（0番~[waveNum]番）
        if(waveNumIndex==1){//波ごとに処理
            var tmp = bezer(p1,p2,s1,s2,(i-12)/divNum);
            planeGeo.vertices[i].copy(tmp);
        }else{
            //planeGeo.vertices[i].y=Math.sin((clock.getElapsedTime()+(i/6))*2)*20;
        }
    }
    planeGeo.verticesNeedUpdate=true;
}