molstar
Version:
A comprehensive macromolecular library.
44 lines (43 loc) • 1.75 kB
JavaScript
/**
* Copyright (c) 2018 mol* contributors, licensed under MIT, See LICENSE file for more info.
*
* @author Alexander Rose <alexander.rose@weirdbyte.de>
*/
import { Vec3 } from '../../mol-math/linear-algebra';
import { PrimitiveBuilder } from './primitive';
export const DefaultStarProps = {
pointCount: 5,
outerRadius: 1,
innerRadius: 0.5,
thickness: 0.3
};
const op = Vec3.zero(), on = Vec3.zero();
const a = Vec3.zero(), b = Vec3.zero(), c = Vec3.zero();
export function Star(props) {
const { outerRadius, innerRadius, thickness, pointCount } = { ...DefaultStarProps, ...props };
const triangleCount = pointCount * 2 * 2;
const builder = PrimitiveBuilder(triangleCount);
const innerPoints = new Float32Array(pointCount * 2);
const outerPoints = new Float32Array(pointCount * 2);
for (let i = 0; i < pointCount; ++i) {
const io = i * 2, ii = i * 2 + 1;
const co = (io + 1) / pointCount * Math.PI, ci = (ii + 1) / pointCount * Math.PI;
outerPoints[io] = Math.cos(co) * outerRadius;
outerPoints[ii] = Math.sin(co) * outerRadius;
innerPoints[io] = Math.cos(ci) * innerRadius;
innerPoints[ii] = Math.sin(ci) * innerRadius;
}
Vec3.set(op, 0, 0, thickness / 2);
Vec3.set(on, 0, 0, -thickness / 2);
for (let i = 0; i < pointCount; ++i) {
const ni = (i + 1) % pointCount;
Vec3.set(a, outerPoints[i * 2], outerPoints[i * 2 + 1], 0);
Vec3.set(b, innerPoints[i * 2], innerPoints[i * 2 + 1], 0);
Vec3.set(c, outerPoints[ni * 2], outerPoints[ni * 2 + 1], 0);
builder.add(op, a, b);
builder.add(b, a, on);
builder.add(op, b, c);
builder.add(c, b, on);
}
return builder.getPrimitive();
}