Add a basic enemy.

18 files changed, 258 insertions, 7 deletions

diff --git a/Makefile b/Makefile
index 02a40ff..581c027 100644
--- a/Makefile
+++ b/Makefile
@@ -89,6 +89,7 @@ sources = \
   animation_system.c \
   asset.c \
   bullet.c \
+  enemy.c \
   main.c \
   malware.c \
   platform.c \
diff --git a/asset.c b/asset.c
index b6e408b..5ae5419 100644
--- a/asset.c
+++ b/asset.c
@@ -8,7 +8,8 @@
 static const char* const asset_vpaths[] = {
 	/* asset_id_usr    */ "data/usr.img",
 	/* asset_id_char   */ "data/char.img",
-	/* asset_id_bullet */ "data/bullet.img"
+	/* asset_id_bullet */ "data/bullet.img",
+	/* asset_id_enemy  */ "data/enemy.img"
 };
 
 static struct {
diff --git a/asset.h b/asset.h
index e60ff4b..8c6e201 100644
--- a/asset.h
+++ b/asset.h
@@ -3,12 +3,13 @@
 
 #include "render.h"
 
-#define bitmap_asset_count 3
+#define bitmap_asset_count 4
 
 typedef enum {
 	asset_id_usr = 0,
 	asset_id_char,
 	asset_id_bullet,
+	asset_id_enemy,
 	asset_count
 } Asset_ID;
 
diff --git a/bullet.c b/bullet.c
index 9acefc2..a2f1c66 100644
--- a/bullet.c
+++ b/bullet.c
@@ -60,6 +60,43 @@ Entity new_player_bullet(
 	return e;
 }
 
+int new_enemy_bullet(
+	struct World* world,
+	int x,
+	int y,
+	int vx,
+	int vy
+) {
+	Entity e;
+	CBullet* bullet;
+	CPosition* pos;
+	CSprite* sprite;
+
+	e = new_entity(world);
+
+	add_components(
+		world,
+		e,
+		ctype_sprite        |
+		ctype_position      |
+		ctype_bullet        |
+		ctype_enemy_bullet
+	);
+	pos = &world->positions[e];
+	sprite = &world->sprites[e];
+	bullet = &world->bullets[e];
+	pos->x = x;
+	pos->y = y;
+
+	bullet->vx = vx;
+	bullet->vy = vy;
+	bullet->life = 500;
+
+	init_csprite(sprite, sprite_enemy_bullet);
+
+	return e;
+}
+
 void bullet_system(World* world) {
 	int i;
 	unsigned bits;
diff --git a/bullet.h b/bullet.h
index cd7a436..2c84840 100644
--- a/bullet.h
+++ b/bullet.h
@@ -12,4 +12,12 @@ int new_player_bullet(
 	int life
 );
 
+int new_enemy_bullet(
+	struct World* world,
+	int x,
+	int y,
+	int vx,
+	int vy
+);
+
 #endif
diff --git a/components.h b/components.h
index 66304df..d288ac5 100644
--- a/components.h
+++ b/components.h
@@ -29,13 +29,26 @@ typedef struct {
 	int vx, vy;
 } CBullet;
 
+typedef struct {
+	int hp;
+	int backpedal;
+	int shoot_timer;
+} CEnemy;
+
+typedef struct {
+	int vx, vy;
+} CDebris;
+
 typedef enum {
 	ctype_sprite        = 1 << 0,
 	ctype_position      = 1 << 1,
 	ctype_animated      = 1 << 2,
 	ctype_bullet        = 1 << 3,
 	ctype_player_bullet = 1 << 4,
-	ctype_enemy_bullet  = 1 << 5
+	ctype_enemy_bullet  = 1 << 5,
+	ctype_enemy         = 1 << 6,
+	ctype_skull         = 1 << 7,
+	ctype_debris        = 1 << 8
 } CType;
 
 #endif
diff --git a/enemy.c b/enemy.c
new file mode 100644
index 0000000..9a67cba
--- /dev/null
+++ b/enemy.c
@@ -0,0 +1,103 @@
+#include "bullet.h"
+#include "components.h"
+#include "game_config.h"
+#include "sprite.h"
+#include "standard.h"
+#include "world.h"
+
+Entity new_skull(World* world, int x, int y) {
+	CSprite* sprite;
+	CPosition* pos;
+	CEnemy* enemy;
+	Entity e;
+
+	e = new_entity(world);
+	add_components(
+		world,
+		e,
+		ctype_position |
+		ctype_sprite |
+		ctype_enemy |
+		ctype_skull
+	);
+	pos = &world->positions[e];
+	sprite = &world->sprites[e];
+	enemy = &world->enemies[e];
+
+	pos->x = x;
+	pos->y = y;
+
+	init_csprite(sprite, sprite_skull_right);
+
+	enemy->hp = skull_hp;
+	enemy->shoot_timer = 0;
+
+	return e;
+}
+
+void enemy_system(World* world) {
+	/* Skulls. */
+	int i;
+	unsigned bits;
+	CPosition* pos;
+	CEnemy* enemy;
+	Player* player;
+	CPosition* ppos;
+	int dpx, dpy, tpx, tpy, d;
+	char buf[32];
+
+	player = &world->player;
+	ppos = &world->positions[player->entity];
+
+	for (i = 0; i < world->entity_count; i++) {
+		bits = world->bitmask[i];
+		if (
+			(bits & ctype_position) &&
+			(bits & ctype_enemy) &&
+			(bits & ctype_skull)
+		) {
+			pos = &world->positions[i];
+			enemy = &world->enemies[i];
+
+			dpx = (ppos->x - pos->x) >> 4;
+			dpy = (ppos->y - pos->y) >> 4;
+			tpx = dpx;
+			tpy = dpy;
+			d = ((dpx * dpx) >> fbits) + ((dpy * dpy) >> fbits);
+
+			if (d < 10 << fbits) {
+				dpx = -dpx;
+				dpy = -dpy;
+				enemy->backpedal = 1;
+			} else if (enemy->backpedal) {
+				if (d > 30 << fbits) {
+					enemy->backpedal = 0;
+				} else {
+					dpx = -dpx;
+					dpy = -dpy;
+				}
+			}
+
+			dpx = (dpx < 0 ? -1 : 1);
+      dpy = (dpy < 0 ? -1 : 1);
+
+			pos->x += dpx * skull_speed;
+			pos->y += dpy * skull_speed;
+
+			if (enemy->shoot_timer > skull_shoot_cooldown) {
+				vec_nrmise(&tpx, &tpy);
+
+				new_enemy_bullet(
+					world,
+					pos->x,
+					pos->y,
+					tpx * enemy_bullet_speed,
+					tpy * enemy_bullet_speed
+				);
+				enemy->shoot_timer = 0;
+			}
+
+			enemy->shoot_timer++;
+		}
+	}
+}
diff --git a/enemy.h b/enemy.h
new file mode 100644
index 0000000..f968864
--- /dev/null
+++ b/enemy.h
@@ -0,0 +1,8 @@
+#ifndef enemy_h
+#define enemy_h
+
+struct World;
+
+int new_skull(struct World* world, int x, int y);
+
+#endif
diff --git a/game_config.h b/game_config.h
index 7bb6cdd..0c97a8d 100644
--- a/game_config.h
+++ b/game_config.h
@@ -4,4 +4,10 @@
 #define player_move_speed (3 << fbits)
 #define player_bullet_speed (10 << fbits)
 
+#define skull_hp 3
+#define skull_speed (1 << fbits)
+
+#define skull_shoot_cooldown 15
+#define enemy_bullet_speed 10
+
 #endif
diff --git a/intermediate/enemy.bmp b/intermediate/enemy.bmp
new file mode 100644
index 0000000..da1e068
--- /dev/null
+++ b/intermediate/enemy.bmp
diff --git a/main.c b/main.c
index e1fd29b..ef757b2 100644
--- a/main.c
+++ b/main.c
@@ -4,6 +4,7 @@
 #include "standard.h"
 #include "systems.h"
 #include "world.h"
+#include "enemy.h"
 
 World world;
 
@@ -17,11 +18,14 @@ void on_init(int argc, char** argv) {
 	init_world(&world);
 
 	init_player(&world.player, &world);
+
+	new_skull(&world, 0, 0);
 }
 
 void on_update() {
 	renderer_begin_frame();
 	update_player(&world.player, &world);
+	enemy_system(&world);
 	bullet_system(&world);
 	animation_system(&world);
 	sprite_system(&world);
diff --git a/player.c b/player.c
index cadb0dc..b723849 100644
--- a/player.c
+++ b/player.c
@@ -26,8 +26,8 @@ void init_player(Player* player, World* world) {
 	sprite = &world->sprites[e];
 	animated = &world->animateds[e];
 
-	pos->x = 32;
-	pos->y = 70;
+	pos->x = 32 << fbits;
+	pos->y = 70 << fbits;
 
 	sprite->id = asset_id_char;
 	sprite->rect = make_rect(0, 16, 16, 16);
diff --git a/sprite.c b/sprite.c
index 8289fd2..c14f717 100644
--- a/sprite.c
+++ b/sprite.c
@@ -20,6 +20,46 @@ static const Sprite sprites[] = {
 	{
 		asset_id_bullet,
 		{ 14, 14, 14, 9 }
+	},
+	/* sprite_skull_left */
+	{
+		asset_id_enemy,
+		{ 16, 0, 16, 16 }
+	},
+	/* sprite_skull_right */
+	{
+		asset_id_enemy,
+		{ 0, 0, 16, 16 }
+	},
+	/* sprite_skull_debris_1 */
+	{
+		asset_id_enemy,
+		{ 32, 0, 5, 8 }
+	},
+	/* sprite_skull_debris_2 */
+	{
+		asset_id_enemy,
+		{ 38, 0, 6, 6 }
+	},
+	/* sprite_skull_debris_3 */
+	{
+		asset_id_enemy,
+		{ 32, 8, 5, 8 }
+	},
+	/* sprite_skull_debris_4 */
+	{
+		asset_id_enemy,
+		{ 38, 11, 5, 5 }
+	},
+	/* sprite_skull_debris_5 */
+	{
+		asset_id_enemy,
+		{ 44, 10, 3, 6 }
+	},
+	/* sprite_enemy_bullet */
+	{
+		asset_id_bullet,
+		{ 18, 0, 5, 5 }
 	}
 };
 
diff --git a/sprite.h b/sprite.h
index a520b99..cf9d6e8 100644
--- a/sprite.h
+++ b/sprite.h
@@ -9,7 +9,15 @@ typedef enum {
 	sprite_player_bullet_left = 0,
 	sprite_player_bullet_right,
 	sprite_player_bullet_up,
-	sprite_player_bullet_down
+	sprite_player_bullet_down,
+	sprite_skull_left,
+	sprite_skull_right,
+	sprite_skull_debris_1,
+	sprite_skull_debris_2,
+	sprite_skull_debris_3,
+	sprite_skull_debris_4,
+	sprite_skull_debris_5,
+	sprite_enemy_bullet
 } Sprite_ID;
 
 typedef struct {
diff --git a/standard.c b/standard.c
index 5e464f6..9a87342 100644
--- a/standard.c
+++ b/standard.c
@@ -135,6 +135,20 @@ int flerp(int a, int b, int t) {
 	return a + ((t * (b - a)) >> fbits);
 }
 
+void vec_minise(int* x, int* y) {
+	if (
+		absolute(*x) <= fscale_lower_limit ||
+		absolute(*y) <= fscale_lower_limit) {
+		*x *= fscale_factor;
+		*y *= fscale_factor;
+	} else if (
+		absolute(*x) > fscale_upper_limit ||
+		absolute(*y) > fscale_upper_limit) {
+		*x /= fscale_factor;
+		*y /= fscale_factor;
+	}
+}
+
 void vec_nrmise(int* x, int* y) {
 	int l;
 
diff --git a/standard.h b/standard.h
index 6f56ebc..88918af 100644
--- a/standard.h
+++ b/standard.h
@@ -4,6 +4,9 @@
 int string_equal(const char* a, const char* b);
 
 #define fbits 9
+#define fscale_lower_limit 16
+#define fscale_upper_limit 900
+#define fscale_factor 16
 
 #define mini(a_, b_) ((a_) < (b_) ? (a_) : (b_))
 #define maxi(a_, b_) ((a_) > (b_) ? (a_) : (b_))
@@ -15,6 +18,7 @@ int ftan(int t);
 int flerp(int a, int b, int t);
 int fsqrt(int v);
 
+void vec_minise(int* x, int* y);
 void vec_nrmise(int* x, int* y);
 
 void seed_rng(unsigned seed);
diff --git a/systems.h b/systems.h
index 0e405dd..0cc55ec 100644
--- a/systems.h
+++ b/systems.h
@@ -6,5 +6,7 @@
 void animation_system(World* world);
 void bullet_system(World* world);
 void sprite_system(const World* world);
+void enemy_system(World* world);
+
 
 #endif
diff --git a/world.h b/world.h
index d9995ab..9709337 100644
--- a/world.h
+++ b/world.h
@@ -13,13 +13,14 @@ struct World {
 	int entity_count;
 	int recycle_bin_count;
 
-	unsigned char bitmask[max_entities];
+	unsigned short bitmask[max_entities];
 	Entity recycle_bin[max_entities];
 
 	CSprite        sprites       [max_entities];
 	CPosition      positions     [max_entities];
 	CAnimated      animateds     [max_entities];
 	CBullet        bullets       [max_entities];
+	CEnemy         enemies       [max_entities];
 
 	Player player;
 };