three.js BufferGeometryのサイズ設定

resizeBufferGeometry.js

geo = new THREE.BufferGeometry();
geo.setIndex(new THREE.BufferAttribute(new Uint16Array(3 * 2), 1));
geo.addAttribute('position', new THREE.BufferAttribute(new Float32Array(3 * 4), 3));
geo.addAttribute('uv', new THREE.BufferAttribute(new Float32Array(2 * 4), 2));

// サイズ
w = 1000;
h = 1000;

// 頂点インデックス
index = geo.index.array;
index[0] = 0;
index[1] = 1;
index[2] = 2;
index[3] = 0;
index[4] = 2;
index[5] = 3;

// UV座標
uv = geo.attributes.uv.array;
uv[0] = 0;
uv[1] = 0;
uv[2] = 1;
uv[3] = 0;
uv[4] = 1;
uv[5] = 1;
uv[6] = 0;
uv[7] = 1;

// 頂点位置
pos = geo.attributes.position.array;
pos[0]  = -w * 0.5;
pos[1]  = -h * 0.5;
pos[2]  = 0;
pos[3]  = w * 0.5;
pos[4]  = -h * 0.5;
pos[5]  = 0;
pos[6]  = w * 0.5;
pos[7]  = h * 0.5;
pos[8]  = 0;
pos[9]  = -w * 0.5;
pos[10] = h * 0.5;
pos[11] = 0;

// 動的に変えるときは忘れずに
geo.attributes.position.needsUpdate = true;