Laser Engraved Art

#include <Servo.h>
#include <math.h>

#define MOTOR_SPEED 1161 //RPM: took 310ms to rotate 6 times
#define CIRCLE 2*M_PI/360
#define PERIOD 50 //how many milliseconds pass before calling main
#define MAX_SPEED 0 //if 1, will go as fast as possible
#define MOTOR_SPEED 5 //how quickly the motor moves through its motions //also dependant on period
#define FUNC_SWITCH_PERIOD 5000 //in milliseconds
#define DIRECTION_SWITCH_PERIOD 10000
#define FUNC_SWITCH_SHIFT 2500 //the shift forward of the function switcher so that it doesn't switch at thr same time as the direction switch

int motor_angle = 0; //the motor angle can point between 0 (pointing directly down) and about 45 (pointing midway down to the horizontal plane)
int servo_pin = 11; //digital
int laser_pin = 10; //digital
double x = 360;
double millis_time = millis();
int laser_on = 0;
int dir = 0;
int function_type = 0;
double switch_func_timer = FUNC_SWITCH_SHIFT;
double switch_dir_timer = 0;

Servo servo;

void laser_switch() {
  if (laser_on) {
    digitalWrite(laser_pin, 0);
    laser_on = 0;
  }
  else {
    digitalWrite(laser_pin, 1);
    laser_on = 1;
  }
}

//### functions
double sine_waveform(double x) {
  double angle = 22.5+22.5*sin(x);  //need to generate a sin wave with peak to peak amplitude of 45 and a vertical shift of 22.5 degrees
  return(angle);
}

double square_waveform(double x) {
  double angle = 0;
  angle += 45*(((int)x % 360) % 2);
  return(angle);
}

double stepwise_waveform(double x) {
  double angle = 0;
  angle += 15*(((int)x % 360) % 4);
  return(angle);
}

//###

void function_switch() {
  function_type++;
  function_type = function_type % 3;
}

void dir_switch() {
  dir += 1;
  dir = dir % 2;
}

void setup() {
  // put your setup code here, to run once:
  pinMode(laser_pin, OUTPUT);
  Serial.begin(9600);
  servo.attach(servo_pin);
  servo.write(0); //starting angle is pointing midway between max and min angle
  delay(100);
  laser_switch();
}

void loop() {
  // put your main code here, to run repeatedly:
  if (MAX_SPEED || (millis()-millis_time) > PERIOD) {
    millis_time = millis();

    //direction change using y
    if (dir = 0) {
      x += MOTOR_SPEED * CIRCLE;
    }
    else {
      x -= MOTOR_SPEED * CIRCLE;
    }

    //function call based on current function type
    if (function_type == 0) {
      motor_angle = sine_waveform(x);
    } else if (function_type == 1) {
      motor_angle = square_waveform(x);
    } else if (function_type == 2) {
      motor_angle = stepwise_waveform(x);
    }
    servo.write(motor_angle);
  }
  if (millis()-switch_func_timer > FUNC_SWITCH_PERIOD) {
    function_switch();
    switch_func_timer = millis();
  }
  if (millis() - switch_dir_timer > DIRECTION_SWITCH_PERIOD) {
    dir_switch();
    switch_dir_timer = millis();
  }
}