starship/enemy.c

//    Copyright 2025 Bill Rossi
//    
//    This file is part of Starship Futuretime
//
//    Starship Futuretime is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version.
//
//    Starship Futuretime is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.
//
//    You should have received a copy of the GNU General Public License along with Starship Futuretime. If not, see <https://www.gnu.org/licenses/>. 
#include <stdlib.h>

#include <raylib.h>

#include "enemy.h"
#include "entity.h"

Texture2D *enemy_sprite = NULL;

Entity *spawn_enemy(void) {
  if (enemy_sprite == NULL) {
    enemy_sprite = malloc(sizeof(Texture2D));
    Image sprite_img = LoadImage("img/enemy.png");
    *enemy_sprite = LoadTextureFromImage(sprite_img);
    UnloadImage(sprite_img);
  }
  Entity *e = malloc(sizeof(Entity));
  e->name = "Enemy";
  e->properties = malloc(sizeof(Entity));
  e->timer = 1.0;
  EnemyProperties *props = (EnemyProperties*)e->properties;
  props->position.x = 400;
  props->position.y = 50;
  props->position.width = 25;
  props->position.height = 25;
  props->velocity.x = 3;
  props->velocity.y = 0;
  props->bullet_timer = rand() % 4;
  e->draw = &draw_enemy;
  e->tick = &tick_enemy;
  e->free = &free_enemy;
  return e;
}

void draw_enemy(Entity *e) {
  EnemyProperties *props = e->properties;
  // DrawRectangleRec(props->position, RED);
  DrawTextureRec(*enemy_sprite, (Rectangle) { props->velocity.x > 0 ? 32 : 0, 0, 32, 32 }, (Vector2) { props->position.x, props->position.y }, WHITE);
}

void update_position_enemy(Entity *e, float dt) {
  EnemyProperties *props = e->properties;
  if (props->position.x < 200) props->velocity.x = 3;
  if (props->position.x > 600) props->velocity.x = -3;

  props->position.x += props->velocity.x;
}

void tick_enemy(Game *g, Entity *e, float dt) {
  EnemyProperties *props = e->properties;
  update_position_enemy(e, dt);
  props->bullet_timer -= dt;
  if (props->bullet_timer < 0.) {
    props->bullet_timer = (float)(rand() % 4);

    add_entity(g->bullets, spawn_bullet((Vector2) { props->position.x, props->position.y }, props->velocity, true));
  }
}

void free_enemy(Entity *e) {
  free(e->properties);
  free(e);
}