File content as of revision 36:92d131695e7c:

#include "Headless.h"
#include "math.h"
#include <complex>

Headless::Headless(float pos_x, float pos_y)
{
    _damage_self_upon_collision = false;
    _hp_drop_chance = 10; // out of 100
    moving = true;
    face = 0;
    hp = 4;
    attack = 1;
    hitbox.width = 6;
    hitbox.height = 5;
    position.x = pos_x;
    position.y = pos_y;
    sprite_size.width = 6;
    sprite_size.height = 9;
    sprite_size.offset_x = 0;
    sprite_size.offset_y = -4;
    frame.count = 0;
    frame.number = 0;
    frame.max = 4;
    velocity = 0.25;
}

void Headless::move(float player_x, float player_y, char * map, bool * doorways)
{
    std::complex<double> pos_diff(player_x - position.x, player_y - position.y); // defining difference in position as a vector
    position.x += velocity * pos_diff.real() / std::abs(pos_diff);
    position.y += velocity * pos_diff.imag() / std::abs(pos_diff);

    if (abs(pos_diff.real()) > abs(pos_diff.imag())) {
        if (pos_diff.real() > 0) {
            face = 1;
        } else {
            face = 3;
        }
    } else {
        if (pos_diff.imag() > 0) {
            face = 2;
        } else {
            face = 0;
        }
    }

    undo_move_x(entity_to_map_collision_test(position.x, prev_pos.y, map, doorways));
    undo_move_y(entity_to_map_collision_test(prev_pos.x, position.y, map, doorways));

    if (frame.number < frame.max) {
        frame.count++;
    } else {
        frame.count = 0;
    }
    frame.number = (frame.count/16) % frame.max;
}

void Headless::draw(N5110 &lcd)
{
    lcd.drawSpriteTransparent(position.x+sprite_size.offset_x,
                              position.y+sprite_size.offset_y,
                              sprite_size.height,
                              sprite_size.width,
                              get_frame());
}

void Headless::take_damage(int damage)
{
    hp -= damage;
}

char * Headless::get_frame()
{
    return (char *) sprite_headless[face][frame.number];
}