Add entities and enemies

enemy.c

@@ -0,0 +1,50 @@
+//    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"
+
+Entity *spawn_enemy(void) {
+  Entity *e = malloc(sizeof(Entity));
+  e->name = "Enemy";
+  e->properties = malloc(sizeof(Entity));
+  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;
+  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);
+}
+
+void tick_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 free_enemy(Entity *e) {
+  free(e->properties);
+  free(e);
+}

enemy.h

@@ -0,0 +1,26 @@
+//    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/>. 
+#ifndef ENEMY_H
+#define ENEMY_H
+#include <raylib.h>
+
+#include "entity.h"
+
+typedef struct EnemyProperties {
+  Rectangle position;
+  Vector2 velocity;
+} EnemyProperties;
+
+Entity *spawn_enemy(void);
+void draw_enemy(Entity *e);
+void tick_enemy(Entity *e, float dt);
+void free_enemy(Entity *e);
+
+#endif

entity.h

@@ -0,0 +1,31 @@
+//    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/>. 
+
+#ifndef ENTITY_H
+#define ENTITY_H
+
+typedef struct Entity Entity;
+typedef struct Entities Entities;
+
+struct Entity {
+  char *name;
+  void *properties;
+  void (*draw)(Entity *e);
+  void (*tick)(Entity *e, float dt);
+  void (*free)(Entity *e);
+};
+
+struct Entities {
+  Entity **entities;
+  size_t count;
+  size_t capacity;
+};
+
+#endif

game.c

@@ -10,27 +10,55 @@
 #include <stdlib.h>
 #include <stdbool.h>
 #include <raylib.h>
+
 #include "game.h"
+#include "enemy.h"
+
+#define FOREACH_ENTITY for (size_t i = 0; i < g->entities->count; i++)
+#define INIT_ENTITY Entity *e = g->entities->entities[i]
 
 void initialize_game(Game *g) {
   g->should_close = false;
   g->player = malloc(sizeof(Player));
   initialize_player(g->player);
+  g->entities = malloc(sizeof(Entities));
+  g->entities->entities = malloc(10 * sizeof(Entity*));
+  g->entities->count = 0;
+  g->entities->capacity = 10;
+}
+
+void add_entity(Game *g, Entity *e) {
+  if (g->entities->count >= g->entities->capacity) {
+    g->entities->capacity *= 2;
+    g->entities->entities = realloc(g->entities->entities, g->entities->capacity * sizeof(Entity*));
+  }
+  g->entities->entities[g->entities->count++] = e;
 }
 
 void handle_input(Game *g) {
   handle_player_input(g->player);
+  if (IsKeyPressed(KEY_S)) {
+    add_entity(g, spawn_enemy());
+  }
 }
 
 void run_frame(Game *g) {
   handle_input(g);
   move_player(g->player);
+  FOREACH_ENTITY {
+    INIT_ENTITY;
+    e->tick(e, GetFrameTime());
+  }
 }
 
 void draw_frame(Game *g) {
   BeginDrawing();
   ClearBackground(RAYWHITE);
   draw_player(g->player);
+  FOREACH_ENTITY {
+    INIT_ENTITY;
+    e->draw(e);
+  }
   EndDrawing();
 }
 

game.h

@@ -13,12 +13,13 @@
 
 #include <stdlib.h>
 #include "player.h"
+#include "entity.h"
 
 typedef struct Game {
   Player *player;
+  Entities *entities;
   /*
   Levels levels;
-  Entities entities;
   */
   bool should_close;
 } Game;