struct vec2 {
    public float x, y;

    public static vec2 create(float x, float y) {
        return vec2.allocate().set(x, y);
    }
    public static vec2 createByUnit(unit u) {
        return vec2.create(GetUnitX(u), GetUnitY(u));
    }
    public static vec2 createByAngle(float angle) {
        return vec2.create(CosBJ(angle), SinBJ(angle));
    }

    public vec2 set(float x, float y) {
        .x = x;
        .y = y;
        return this;
    }

    public vec2 plus(vec2 v) {
        return .set(x + v.x, y + v.y);
    }

    public vec2 minus(vec2 v) {
        return .set(x - v.x, y - v.y);
    }
    public vec2 mult(float num) {
        return .set(x*num, y*num);
    }
    public vec2 div(float num) {
        return .mult(1/num);
    }
    public vec2 normalize() {
        return .mult(1/SquareRoot(x*x + y*y));
    }
    public vec2 rotate(float angle) {
        return .rotateHelper(CosBJ(angle), SinBJ(angle));    
    }
    public float dot(vec2 v) {
        return x*v.x + y*v.y;
    }
    public float radius() {
        return SquareRoot(x*x + y*y);
    }
    public float radiusSqr() {
        return x*x + y*y;
    }

    private vec2 rotateHelper(float aCos, float aSin) {
        return .set(x*aCos - y*aSin, y*aCos + x*aSin);
    }
}

#define DUMMY_ID = 'u001';
#define DEG2RAD = 0.017453292;

unit CreateSpellParticleUnit(unit source, float offsetAngle, float offsetRadius) {
    float spawnAngle = (offsetAngle + GetUnitFacing(source))*DEG2RAD;
    vec2 pivot = vec2.createByUnit(source);
    vec2 spawn = vec2.createByAngle(spawnAngle).mult(offsetRadius).plus(pivot);

    unit particle = CreateUnit(GetOwningPlayer(source), DUMMY_ID, spawn.x, spawn.y, 0);
    pivot.destroy();
    spawn.destroy();
    return particle;
}

struct vec2 {
	public float x, y;

	public static vec2 create(float x, float y) {
		return vec2.allocate().set(x, y);
	}
	public static vec2 createByUnit(unit u) {
		return vec2.create(GetUnitX(u), GetUnitY(u));
	}

	public vec2 plus(vec2 v) {
		return .set(x + v.x, y + v.y);
	}
	public vec2 minus(vec2 v) {
		return .set(x - v.x, y - v.y);
	}
	public vec2 mult(float num) {
		return .set(x*num, y*num);
	}
	public vec2 div(float num) {
		return .mult(1/num);
	}
	public vec2 normalize() {
		return this.div(SquareRoot(x*x + y*y));
	}
	private vec2 set(float x, float y) {
		this.x = x;
		this.y = y;
		return this;
	}
}

#define DUMMY_ID = 'u001'
#define SPAWN_DISTANCE = 100.0

unit createParticle(unit source, unit target) {
	vec2 va = vec2.createByUnit(source);
	vec2 vb = vec2.createByUnit(target).minus(va).normalize().mult(SPAWN_DISTANCE).plus(va);
	unit result = CreateUnit(GetOwningPlayer(source), DUMMY_ID, vb.x, vb.y, 0);
	va.destroy();
	vb.destroy();
	return result;
}