feat: add bomb mechanic with explosion to kill rats

src/bomb.c

@@ -0,0 +1,109 @@
+#include "bomb.h"
+#include "maze.h"
+#include "rat.h"
+#include "music.h"
+#include <gb/gb.h>
+
+extern const unsigned char BombSpriteData[];
+
+#define BOMB_STATE_INACTIVE 0
+#define BOMB_STATE_TICKING 1
+#define BOMB_STATE_EXPLODING 2
+
+typedef struct {
+    uint8_t state;
+    uint8_t x;
+    uint8_t y;
+    uint16_t timer;
+} Bomb;
+
+static Bomb bomb;
+
+void init_bombs(void) {
+    bomb.state = BOMB_STATE_INACTIVE;
+    set_sprite_data(5, 6, BombSpriteData);
+    for(uint8_t i = 34; i <= 38; i++) {
+        move_sprite(i, 0, 0);
+    }
+}
+
+void drop_bomb(uint8_t x, uint8_t y) {
+    if (bomb.state == BOMB_STATE_INACTIVE) {
+        bomb.state = BOMB_STATE_TICKING;
+        bomb.x = x;
+        bomb.y = y;
+        bomb.timer = 180; // 3 seconds
+        play_sfx_plop(); // Generic drop sound
+    }
+}
+
+static void hide_explosion() {
+    for(uint8_t i = 34; i <= 38; i++) {
+        move_sprite(i, 0, 0);
+    }
+}
+
+static void do_explosion_damage(uint8_t ex, uint8_t ey) {
+    kill_rats_at(ex, ey);
+}
+
+void update_bombs(void) {
+    if (bomb.state == BOMB_STATE_TICKING) {
+        bomb.timer--;
+        
+        uint8_t px = bomb.x * 8 + 12;
+        uint8_t py = bomb.y * 8 + 20;
+        
+        if (bomb.timer > 120) {
+            set_sprite_tile(38, 5); // bomb_3
+        } else if (bomb.timer > 60) {
+            set_sprite_tile(38, 6); // bomb_2
+        } else {
+            if (bomb.timer & 4) {
+                set_sprite_tile(38, 7); // bomb_1
+            } else {
+                set_sprite_tile(38, 5);
+            }
+        }
+        
+        move_sprite(38, px, py);
+        
+        if (bomb.timer == 0) {
+            bomb.state = BOMB_STATE_EXPLODING;
+            bomb.timer = 30; // 0.5s explosion
+            
+            play_sfx_explosion();
+            
+            set_sprite_tile(38, 8);
+            move_sprite(38, px, py);
+            do_explosion_damage(bomb.x, bomb.y);
+            
+            if (bomb.y > 0 && maze[bomb.y - 1][bomb.x] == 0) {
+                set_sprite_tile(34, 10);
+                move_sprite(34, px, py - 8);
+                do_explosion_damage(bomb.x, bomb.y - 1);
+            }
+            if (bomb.y < MAZE_HEIGHT - 1 && maze[bomb.y + 1][bomb.x] == 0) {
+                set_sprite_tile(35, 10);
+                move_sprite(35, px, py + 8);
+                do_explosion_damage(bomb.x, bomb.y + 1);
+            }
+            if (bomb.x > 0 && maze[bomb.y][bomb.x - 1] == 0) {
+                set_sprite_tile(36, 9);
+                move_sprite(36, px - 8, py);
+                do_explosion_damage(bomb.x - 1, bomb.y);
+            }
+            if (bomb.x < MAZE_WIDTH - 1 && maze[bomb.y][bomb.x + 1] == 0) {
+                set_sprite_tile(37, 9);
+                move_sprite(37, px + 8, py);
+                do_explosion_damage(bomb.x + 1, bomb.y);
+            }
+        }
+    } else if (bomb.state == BOMB_STATE_EXPLODING) {
+        bomb.timer--;
+        if (bomb.timer == 0) {
+            bomb.state = BOMB_STATE_INACTIVE;
+            hide_explosion();
+        }
+    }
+}

src/bomb.h

@@ -0,0 +1,10 @@
+#ifndef BOMB_H
+#define BOMB_H
+
+#include <stdint.h>
+
+void init_bombs(void);
+void drop_bomb(uint8_t x, uint8_t y);
+void update_bombs(void);
+
+#endif

src/bomb_gfx.c

@@ -0,0 +1,14 @@
+const unsigned char BombSpriteData[] = {
+    // bomb_3
+    0x18, 0x18, 0x3C, 0x3C, 0x7E, 0x7E, 0x7E, 0x7E, 0x7E, 0x7E, 0x7E, 0x7E, 0x3C, 0x3C, 0x00, 0x00,
+    // bomb_2
+    0x00, 0x00, 0x18, 0x18, 0x3C, 0x3C, 0x7E, 0x7E, 0x7E, 0x7E, 0x3C, 0x3C, 0x00, 0x00, 0x00, 0x00,
+    // bomb_1
+    0x00, 0x00, 0x00, 0x00, 0x18, 0x18, 0x3C, 0x3C, 0x3C, 0x3C, 0x18, 0x18, 0x00, 0x00, 0x00, 0x00,
+    // exp_center
+    0xC3, 0xC3, 0xA5, 0xA5, 0x3C, 0x3C, 0x7E, 0x7E, 0x7E, 0x7E, 0x3C, 0x3C, 0xA5, 0xA5, 0xC3, 0xC3,
+    // exp_horiz
+    0x00, 0x00, 0x00, 0x00, 0xFF, 0xFF, 0x7E, 0x7E, 0x7E, 0x7E, 0xFF, 0xFF, 0x00, 0x00, 0x00, 0x00,
+    // exp_vert
+    0x3C, 0x3C, 0x3C, 0x3C, 0x7E, 0x7E, 0x7E, 0x7E, 0x7E, 0x7E, 0x7E, 0x7E, 0x3C, 0x3C, 0x3C, 0x3C,
+};

src/cursor.c

@@ -1,6 +1,7 @@
 #include "cursor.h"
 #include "maze.h"
 #include <gb/gb.h>
+#include "bomb.h"
 
 const unsigned char CursorSpriteData[] = {
     // Bordo quadrato 8x8 (Nero, colore 3 -> 11)
@@ -44,6 +45,11 @@ void update_cursor(void) {
         if (cursor_x < MAZE_WIDTH - 1) cursor_x++;
     }
     
+    // Tasto A per sganciare la bomba
+    if ((keys & J_A) && !(previous_keys & J_A)) {
+        drop_bomb(cursor_x, cursor_y);
+    }
+    
     previous_keys = keys;
     
     // Effetto lampeggiante: nascondi il cursore per metà del ciclo (ogni 16 frame)

src/main.c

@@ -20,6 +20,7 @@
 #include "rat.h"
 #include "music.h"
 #include "cursor.h"
+#include "bomb.h"
 
 void main(void) {
     uint8_t y, x;
@@ -86,6 +87,8 @@ void main(void) {
     // Inizializza il cursore controllato dal giocatore
     init_cursor();
     
+    init_bombs();
+    
     // Inizializza il sequencer musicale
     init_music();
     
@@ -126,6 +129,9 @@ void main(void) {
         // Aggiorna l'input del cursore del giocatore
         update_cursor();
         
+        // Aggiorna le bombe
+        update_bombs();
+        
         // Attendi la sincronizzazione con il monitor
         wait_vbl_done();
     }

src/music.c

@@ -422,3 +422,10 @@ void play_game_over_music(void) {
     
     NR22_REG = 0x00; NR32_REG = 0x00; NR42_REG = 0x00; // Zittisce tutto
 }
+
+void play_sfx_explosion(void) {
+    // Esplosione forte e lunga sul canale 4
+    NR42_REG = 0xF7; 
+    NR43_REG = 0x6E; 
+    NR44_REG = 0xC0;
+}

src/music.h

@@ -6,6 +6,7 @@ void update_music(void);
 
 void play_sfx_moan(void);
 void play_sfx_plop(void);
+void play_sfx_explosion(void);
 
 void play_game_over_music(void);
 

src/rat.c

@@ -297,3 +297,18 @@ void update_rats(void) {
         }
     }
 }
+
+void kill_rats_at(uint8_t x, uint8_t y) {
+    for (uint8_t i = 0; i < MAX_RATS; i++) {
+        if (rats[i].active) {
+            // Uccidi se il topo è esattamente sulla cella esplosa
+            // Oppure se ci stava andando.
+            if ((rats[i].rat_x == x && rats[i].rat_y == y) ||
+                (rats[i].target_x == x && rats[i].target_y == y)) {
+                rats[i].active = 0;
+                move_sprite(rats[i].sprite_base_idx, 0, 0);
+                move_sprite(rats[i].sprite_base_idx + 1, 0, 0);
+            }
+        }
+    }
+}

src/rat.h

@@ -9,5 +9,6 @@ extern uint8_t game_over_flag;
 
 void init_rats(void);
 void update_rats(void);
+void kill_rats_at(uint8_t x, uint8_t y);
 
 #endif