webgl/public/gl/math/Vec3.js

export class Vec3 {

    constructor(x = 0, y = 0, z = 0) {
        this.x = x
        this.y = y
        this.z = z
    }

    set(x,y,z) {
        this.x = x
        this.y = y
        this.z = z
        return this
    }

    clone() {
        return new Vec3(this.x, this.y, this.z)
    }

    add(v) {
        this.x += v.x
        this.y += v.y
        this.z += v.z
        return this
    }

    sub(v) {
        this.x -= v.x
        this.y -= v.y
        this.z -= v.z
        return this
    }

    copy(v) {
        this.x = v.x
        this.y = v.y
        this.z = v.z
        return this
    }

    multV(v) {
        this.x *= v.x
        this.y *= v.y
        this.z *= v.z
        return this
    }

    multS(s) {
        this.x *= s
        this.y *= s
        this.z *= s
        return this
    }

    divV(v) {
        this.x *= (1 / v.x)
        this.y *= (1 / v.y)
        this.z *= (1 / v.z)
        return this
    }

    divS(s) {
        this.x *= (1 / s)
        this.y *= (1 / s)
        this.z *= (1 / s)
        return this
    }

    invert() {
        this.x = this.x == 0 ? 0 : (1 / this.x)
        this.y = this.y == 0 ? 0 : (1 / this.y)
        this.z = this.z == 0 ? 0 : (1 / this.z)
        return this
    }

    normalize() {
        return this.divS(this.length() || 1)
    }
    
	dot(v) {
		return this.x * v.x + this.y * v.y + this.z * v.z;
	}

    cross(v) {
        return this.crossV(this, v)
    }

    crossV(a, b) {
		const ax = a.x, ay = a.y, az = a.z;
		const bx = b.x, by = b.y, bz = b.z;

		this.x = ay * bz - az * by;
		this.y = az * bx - ax * bz;
		this.z = ax * by - ay * bx;

		return this;
	}
    
    length() {
		return Math.sqrt(this.x * this.x + this.y * this.y + this.z * this.z);
	}

}