import { Vec3 } from '../math/Vec3.js'
import { Mat4 } from '../math/Mat4.js'

export class Camera {

    constructor() {
        this.position = new Vec3()
        this.rotation = new Vec3()
    }

    view() {
        const view = new Mat4()
        const d = view.data

        const c3 = Math.cos(this.rotation.z * (Math.PI / 180))
        const s3 = Math.sin(this.rotation.z * (Math.PI / 180))
        const c2 = Math.cos(this.rotation.x * (Math.PI / 180))
        const s2 = Math.sin(this.rotation.x * (Math.PI / 180))
        const c1 = Math.cos(this.rotation.y * (Math.PI / 180))
        const s1 = Math.sin(this.rotation.y * (Math.PI / 180))

        const u = new Vec3((c1 * c3 + s1 * s2 * s3), (c2 * s3), (c1 * s2 * s3 - c3 * s1));
        const v = new Vec3((c3 * s1 * s2 - c1 * s3), (c2 * c3), (c1 * c3 * s2 + s1 * s3));
        const w = new Vec3((c2 * s1), (-s2), (c1 * c2));
      
        d[0] = u.x;
        d[1] = v.x;
        d[2] = w.x;
        d[3] = 0
        d[4] = u.y;
        d[5] = v.y;
        d[6] = w.y;
        d[7] = 0
        d[8] = u.z;
        d[9] = v.z;
        d[10] = w.z;
        d[11] = 0
        d[12] = -u.dot(this.position)
        d[13] = -v.dot(this.position)
        d[14] = -w.dot(this.position)
        d[15] = 1

        return view
    }

}