Add entity system, add new enemy (snake)

13 files changed, 358 insertions, 19 deletions

diff --git a/TODO.md b/TODO.md
index 556dfb2..792c458 100644
--- a/TODO.md
+++ b/TODO.md
@@ -1,7 +1,5 @@
 # TODO
 
-- entity system
-  - free/used lists
 - pick ups
   - extra time
   - bonuses
@@ -9,7 +7,6 @@
   - key / doors
 - end of stage
 - enemies
-  - pattern (snake)
   - flying (bat)
   - free
   - tracker
diff --git a/data/stage.json b/data/stage.json
index 2ae131e..9095400 100644
--- a/data/stage.json
+++ b/data/stage.json
@@ -41,6 +41,118 @@
                  "width":16,
                  "x":16,
                  "y":128
+                }, 
+                {
+                 "height":16,
+                 "id":2,
+                 "name":"Snake",
+                 "rotation":0,
+                 "type":"",
+                 "visible":true,
+                 "width":16,
+                 "x":216,
+                 "y":128
+                }, 
+                {
+                 "height":16,
+                 "id":3,
+                 "name":"Snake",
+                 "properties":[
+                        {
+                         "name":"dir",
+                         "type":"string",
+                         "value":"left"
+                        }],
+                 "rotation":0,
+                 "type":"",
+                 "visible":true,
+                 "width":16,
+                 "x":288,
+                 "y":128
+                }, 
+                {
+                 "height":16,
+                 "id":4,
+                 "name":"Snake",
+                 "rotation":0,
+                 "type":"",
+                 "visible":true,
+                 "width":16,
+                 "x":184,
+                 "y":152
+                }, 
+                {
+                 "height":16,
+                 "id":5,
+                 "name":"Snake",
+                 "rotation":0,
+                 "type":"",
+                 "visible":true,
+                 "width":16,
+                 "x":32,
+                 "y":152
+                }, 
+                {
+                 "height":16,
+                 "id":6,
+                 "name":"Snake",
+                 "properties":[
+                        {
+                         "name":"dir",
+                         "type":"string",
+                         "value":"left"
+                        }],
+                 "rotation":0,
+                 "type":"",
+                 "visible":true,
+                 "width":16,
+                 "x":280,
+                 "y":152
+                }, 
+                {
+                 "height":16,
+                 "id":7,
+                 "name":"Snake",
+                 "properties":[
+                        {
+                         "name":"dir",
+                         "type":"string",
+                         "value":"left"
+                        }],
+                 "rotation":0,
+                 "type":"",
+                 "visible":true,
+                 "width":16,
+                 "x":112,
+                 "y":152
+                }, 
+                {
+                 "height":16,
+                 "id":8,
+                 "name":"Snake",
+                 "rotation":0,
+                 "type":"",
+                 "visible":true,
+                 "width":16,
+                 "x":144,
+                 "y":32
+                }, 
+                {
+                 "height":16,
+                 "id":9,
+                 "name":"Snake",
+                 "properties":[
+                        {
+                         "name":"dir",
+                         "type":"string",
+                         "value":"left"
+                        }],
+                 "rotation":0,
+                 "type":"",
+                 "visible":true,
+                 "width":16,
+                 "x":112,
+                 "y":80
                 }],
          "opacity":1,
          "type":"objectgroup",
@@ -49,7 +161,7 @@
          "y":0
         }],
  "nextlayerid":4,
- "nextobjectid":2,
+ "nextobjectid":10,
  "orientation":"orthogonal",
  "renderorder":"right-down",
  "tiledversion":"1.7.2",
diff --git a/src/Makefile b/src/Makefile
index 8f3c13a..4c26b5b 100644
--- a/src/Makefile
+++ b/src/Makefile
@@ -1,6 +1,6 @@
 BIN	:= ../game.exe
 CC	:= i586-pc-msdosdjgpp-gcc
-CFLAGS	:= -I. -c -Wall -Werror -pedantic -O2 -march=i386
+CFLAGS	:= -I. -c -Wall -Werror -pedantic -O2 -march=i386 -DDEBUG
 LDFLAGS := -s
 
 IMGS		:= $(wildcard ../data/*.png)
diff --git a/src/entities.c b/src/entities.c
new file mode 100644
index 0000000..be976ea
--- /dev/null
+++ b/src/entities.c
@@ -0,0 +1,72 @@
+#include <stdint.h>
+#include <string.h>
+
+#include "vga.h"
+#include "map.h"
+#include "data.h"
+
+#include "entities.h"
+
+#define MAX_ENTITY 32
+
+static Entity entities[MAX_ENTITY];
+static uint8_t last;
+
+void entities_init()
+{
+    memset(entities, 0, sizeof(Entity) * MAX_ENTITY);
+    last = 0;
+}
+
+Entity *entities_new()
+{
+    for (uint8_t i = 0; i < MAX_ENTITY; i++)
+    {
+        if (entities[i].used == 0)
+        {
+            memset(&entities[i], 0, sizeof(Entity));
+            entities[i].used = 1;
+
+            if (i >= last)
+                last = i + 1;
+
+            return &entities[i];
+        }
+    }
+
+    return NULL;
+}
+
+void entities_update()
+{
+    Entity *e = entities;
+
+    for (uint8_t i = 0; i < last; i++, e++)
+        if (e->used)
+            e->update(e);
+}
+
+void entities_erase()
+{
+    Entity *e = entities + last - 1;
+
+    for (uint8_t i = 0; i < last; i++, e--)
+        if (e->used)
+        {
+            Rect dst = { e->x, e->y + MAP_OFFS_Y, 16, 16 };
+            blit(e->bg, &dst);
+        }
+}
+
+void entities_draw()
+{
+    Entity *e = entities;
+
+    for (uint8_t i = 0; i < last; i++, e++)
+        if (e->used)
+        {
+            Rect dst = { e->x, e->y + MAP_OFFS_Y, 16, 16 };
+            read_buffer(e->bg, &dst);
+            blitrc(binary_sprites_start, &e->frames[e->dir * 4 + e->frame], &dst);
+        }
+}
diff --git a/src/entities.h b/src/entities.h
new file mode 100644
index 0000000..e553390
--- /dev/null
+++ b/src/entities.h
@@ -0,0 +1,34 @@
+#ifndef _ENTITIES_H
+#define _ENTITIES_H
+
+#define DIR_RIGHT 0
+#define DIR_LEFT 1
+
+#define WALK_DELAY 8
+
+typedef struct entity_s
+{
+    uint8_t used;
+    uint16_t x;
+    uint16_t y;
+    uint8_t dir;
+    uint8_t frame;
+    uint8_t delay;
+    uint8_t gravity;
+    uint8_t flag;
+    uint8_t bg[16 * 16];
+    /* expected to be 2 directions per 4 frames max; 8 Rect */
+    const Rect *frames;
+    void (*update)(struct entity_s *e);
+} Entity;
+
+void entities_init();
+
+Entity *entities_new();
+
+void entities_update();
+
+void entities_erase();
+void entities_draw();
+
+#endif /* _ENTITIES_H */
diff --git a/src/game.c b/src/game.c
index c489417..001ce21 100644
--- a/src/game.c
+++ b/src/game.c
@@ -7,6 +7,7 @@
 #include "map.h"
 #include "data.h"
 #include "timer.h"
+#include "entities.h"
 
 #include "player.h"
 
@@ -114,6 +115,7 @@ void run_game()
     map_init(binary_stage_start);
     map_render();
 
+    entities_draw();
     player_draw();
 
     timer_start(GAME_TIME_MAX, &clock_updated);
@@ -129,10 +131,14 @@ void run_game()
         if (hud)
             hud_render();
 
+        /* erase first the last we draw */
         player_erase();
+        entities_erase();
 
         player_update();
+        entities_update();
 
+        entities_draw();
         player_draw();
 
         wait_vsync();
diff --git a/src/map.c b/src/map.c
index 4c5390f..c62c5c1 100644
--- a/src/map.c
+++ b/src/map.c
@@ -1,18 +1,33 @@
 #include <stdint.h>
+#include <stdio.h>
 #include <string.h>
+#include <stdlib.h>
 
 #include "vga.h"
 #include "data.h"
 
+#include "entities.h"
 #include "player.h"
+#include "snake.h"
 
 #include "map.h"
 
+typedef enum
+{
+    Player = 0,
+    Snake,
+} EntityType;
+
 /* current map; set via map_init */
 static const uint8_t *cmap;
 static uint8_t gold[MAP_W * MAP_H];
 static uint8_t total_gold;
 
+static void (* const init[])(Entity *) =
+{
+    snake_init,
+};
+
 void map_init(const uint8_t map[])
 {
     cmap = map;
@@ -27,18 +42,40 @@ void map_init(const uint8_t map[])
         if (gold[i] != 0xff)
             total_gold++;
 
+    entities_init();
+
+    Entity *e;
+
     /* spawn entities, 0xff is the list terminator */
     for (
         const uint8_t *ent = map + MAP_W * MAP_H * 2;
         *ent != 0xff;
         ent += 4
     )
-        switch (*ent)
+    {
+        /* the player is not part of the entity system */
+        if (*ent == Player)
         {
-            case Player:
-                player_init(ent[1] * MAP_TILE_W, ent[2] * MAP_TILE_H, ent[3] & 1);
-                break;
+            player_init(ent[1] * MAP_TILE_W, ent[2] * MAP_TILE_H, ent[3] & 1);
+            continue;
         }
+
+        e = entities_new();
+#ifdef DEBUG
+        if (!e)
+        {
+            set_mode(3);
+            fprintf(stderr, "ERROR: run out of entities\n");
+            exit(1);
+        }
+#endif
+
+        e->x = ent[1] * MAP_TILE_W;
+        e->y = ent[2] * MAP_TILE_H;
+        e->dir = ent[3] & 1;
+
+        init[*ent - 1](e);
+    }
 }
 
 void map_render()
diff --git a/src/map.h b/src/map.h
index 992c982..42f8da7 100644
--- a/src/map.h
+++ b/src/map.h
@@ -14,11 +14,6 @@
 #define MAP_FIRST_BLOCKED 40
 #define MAP_FIRST_DEADLY 100
 
-typedef enum
-{
-    Player = 0,
-} EntityType;
-
 void map_init(const uint8_t map[]);
 void map_render();
 
diff --git a/src/player.c b/src/player.c
index 856cafd..ae50348 100644
--- a/src/player.c
+++ b/src/player.c
@@ -6,17 +6,14 @@
 #include "data.h"
 #include "game.h"
 
+#include "entities.h"
 #include "player.h"
 
-#define DIR_RIGHT 0
-#define DIR_LEFT 1
-
 #define FRAME_STANDING 0
 #define FRAME_JUMPING 4
 #define FRAME_DYING 5
 
 #define WALK_CYCLE_FRAMES 4
-#define WALK_DELAY 8
 
 #define GRAVITY_OFF 0
 /* XXX: subtract 1 to get the value from gravity_seq */
@@ -298,6 +295,18 @@ void player_draw()
     blitrc(binary_sprites_start, &frames[dir][frame], &dst);
 }
 
+uint8_t player_collision(Entity *e)
+{
+    if (invuln || dying)
+        return 0;
+
+    if (y < e->y + 16 && e->y < y + 16
+            && x < e->x + 8 && e->x < x + 8)
+        return 1;
+
+    return 0;
+}
+
 void player_hit()
 {
     /* TODO: pickaxe */
diff --git a/src/player.h b/src/player.h
index 9767fbe..104bfee 100644
--- a/src/player.h
+++ b/src/player.h
@@ -7,6 +7,7 @@ void player_update();
 void player_erase();
 void player_draw();
 
+uint8_t player_collision(Entity *e);
 void player_hit();
 
 #endif /* _PLAYER_H */
diff --git a/src/snake.c b/src/snake.c
new file mode 100644
index 0000000..e81a1c8
--- /dev/null
+++ b/src/snake.c
@@ -0,0 +1,69 @@
+#include <stdint.h>
+
+#include <vga.h>
+#include "map.h"
+#include "entities.h"
+
+#include "player.h"
+
+#include "snake.h"
+
+static const Rect frames[2 * 4] =
+{
+    /* right */
+    { 0, 32, 144, 144 },
+    { 16, 32, 144, 144 },
+    /* not used */
+    { 0, 0, 144, 144 },
+    { 0, 0, 144, 144 },
+
+    /* left */
+    { 32, 32, 144, 144 },
+    { 48, 32, 144, 144 },
+    /* not used */
+    { 0, 0, 144, 144 },
+    { 0, 0, 144, 144 }
+};
+
+void snake_init(Entity *e)
+{
+    e->frames = (const Rect *)frames;
+    e->update = snake_update;
+}
+
+void snake_update(Entity *e)
+{
+    if (e->delay & 1)
+    {
+        if (e->dir == DIR_RIGHT)
+        {
+            if (map_is_blocked(e->x + 16, e->y + 15)
+                    || !map_is_blocked(e->x + 16, e->y + 16))
+                e->dir = DIR_LEFT;
+            else
+                e->x++;
+        }
+        else
+        {
+            /* dir is LEFT */
+            if (map_is_blocked(e->x - 1, e->y + 15)
+                    || !map_is_blocked(e->x - 1, e->y + 16))
+                e->dir = DIR_RIGHT;
+            else
+                e->x--;
+        }
+    }
+
+    if (player_collision(e))
+    {
+        player_hit();
+        /* change direction */
+        e->dir ^= 1;
+    }
+
+    if (e->delay++ == WALK_DELAY + 4)
+    {
+        e->delay = 0;
+        e->frame ^= 1;
+    }
+}
diff --git a/src/snake.h b/src/snake.h
new file mode 100644
index 0000000..48f22e9
--- /dev/null
+++ b/src/snake.h
@@ -0,0 +1,7 @@
+#ifndef _SNAKE_H
+#define _SNAKE_H
+
+void snake_init(Entity *e);
+void snake_update(Entity *e);
+
+#endif /* _SNAKE_H */
diff --git a/tools/map.py b/tools/map.py
index 7e0210f..8464c28 100755
--- a/tools/map.py
+++ b/tools/map.py
@@ -10,7 +10,7 @@ __version__ = "1.0"
 ld = os.environ.get("LD", "i586-pc-msdosdjgpp-ld")
 strip = os.environ.get("STRIP", "i586-pc-msdosdjgpp-strip")
 
-entity_types = ("Player",)
+entity_types = ("Player", "Snake")
 
 
 def get_layer(data, name):