File content as of revision 34:85ccc16f24d2:

#include "Alien.h"

const int k_alien_sprite[6][7] = {
    { 0,0,1,1,1,1,0,},
    { 0,1,0,1,1,0,1,},
    { 0,1,0,1,1,0,1,},
    { 0,0,1,1,1,1,0,},
    { 0,1,0,1,0,1,0,},
    { 1,0,0,1,0,0,1,},
};

Alien::Alien() {

}
 
Alien::~Alien() {
    
}

void Alien::init(Gamepad &pad, int position_x_start, int position_y_start) {
    position_x_ = position_x_start;
    position_y_ = position_y_start;
    alien_move_counter_ = 0;
    srand(pad.read_adc()*64000);
    random_move_counter_ = 0;
    random_direction_ = 0;
    direction_ = rand()%2;
    collision_people_element_ = -1; 
    track_flag_ = false;
}
 
void Alien::draw_alien(N5110 &lcd,Vector2D spaceship_pos,Direction d_, 
int map_length_, int position_x_map_, bool alien_collision) {
    //moves alien spaceship movemen 
    position_x_ += calc_sprite_movement(d_);
    
    //Alien moves on its own but at half speed of spaceship 
    if (alien_move_counter_%2 == 0) {
        if(track_flag_){
            move_hunt_mode(spaceship_pos);
            //printf("tack_flag =  %d\n", track_flag_);
            //printf("pos_x = %d : pos y = %d\n",position_x_, position_y_);
        }else if (random_move_counter_ == 0 || alien_collision){
            if(alien_collision){
                //move alien to top of screen
                random_direction_ = 6;   
                random_move_counter_ = 42;
                alien_collision = false;
            }else{
                set_random_move();
            }
            
        }
        if(!track_flag_){
            move_direction();  
        }
        off_screen_x_y_checker(map_length_, position_x_map_);
        random_move_counter_ --; 
        alien_fire_counter_++;
         
        
    }
    alien_move_counter_++;

    lcd.drawSprite(position_x_, position_y_, 6, 7, (int*)k_alien_sprite);
}

void Alien::off_screen_x_y_checker(int map_length_, int position_x_map_){
    // checks y postion of alien and then alters alien movement direction if at 
    // edge  of map
    if (position_y_ < 0) {
        // sets alien direction to one that increces y value 
        if(direction_){
            random_direction_ = 1;
        }else{
            random_direction_ = 4;
        }
    }else if (position_y_ > 40) {
        // sets alien direction to one that decreces y value 
        if(direction_){
            random_direction_ = 2;
        }else{
            random_direction_ = 5;
        }
    } 
    
    // loops the alien round if it reaches the end of the map 
    if(position_x_ <= (84 - map_length_)){
       position_x_ += map_length_; 
    }else if (position_x_ >= map_length_){
        position_x_ -= map_length_ + 10;
    }   
    
    // Debug and check variables when defined  
    #ifdef CALCULATE_ALIEN_MOVEMENT_DEBUG   
        printf("\nposition_x_map_ =  %d\n", position_x_map_);
        printf("map_length_  =  %d\n", map_length_ );
        printf("map_length_ + position_x_map_ =  %d\n", map_length_ + 
        position_x_map_);
    #endif
}   

void Alien::move_hunt_mode(Vector2D spaceship_pos){
    if(spaceship_pos.x < position_x_){
        position_x_ --;
    }else if(spaceship_pos.x > position_x_){
        position_x_ ++;
    }
    
    if(spaceship_pos.y > position_y_){
        position_y_ ++;
    }else if(spaceship_pos.y < position_y_){
        position_y_ --;
    }
}

bool Alien::check_collision(Weapons bullet) {
    bool collision = false; 
    //printf ("Collision 1 = %d\n", collision);
    Vector2D bullet_pos = bullet.get_pos();
    // checks collision if bullet is going in east direction 
    if(bullet.get_direction()){
        //int bullet_pos_twox = bullet_pos.x;
        //int bullet_pos_twoy = bullet_pos.y;
        //printf ("alien x = %d, bullet x = %d\n", position_x_,bullet_pos_twox);
        //printf ("alien y = %d, bullet y = %d\n", position_y_,bullet_pos_twoy);
        
        if((bullet_pos.x + 1) >= position_x_ && 
        (bullet_pos.x + 1) <= (position_x_ + 6) && 
        position_y_ <= bullet_pos.y && 
        bullet_pos.y <= (position_y_ + 7)){
            collision = true;
        }
    //printf ("Collision 2 = %d\n", collision);  
      
    // checks collision if bullet is going in west direction 
    }else if(!bullet.get_direction()){
        
        if(bullet_pos.x <= (position_x_ + 6) && 
        bullet_pos.x >= position_x_ && 
        position_y_ <= bullet_pos.y && 
        bullet_pos.y <= (position_y_ + 7)){
            collision = true;
        }
        
     //printf ("Collision 3 = %d\n", collision);   
    }
    
    //printf ("Collision 4 = %d\n", collision);   
    return collision;
}


int Alien::get_alien_fire_counter(){
    return alien_move_counter_;
} 

void Alien::set_alien_x_pos(int position_x){
    position_x_ = position_x;
}

void Alien::set_collision_people_element(int people_element){
    collision_people_element_ = people_element;
}

int Alien::get_collision_people_element(){
    return collision_people_element_;
} 

void Alien::set_track_flag(bool track_flag){
    track_flag_ = track_flag;
}