From 3a1ce1fe2073e3dc5c25cf4f1802fb589d92f1ab Mon Sep 17 00:00:00 2001
From: Michael Hayes <michael.hayes@canterbury.ac.nz>
Date: Thu, 3 Oct 2013 16:40:02 +1300
Subject: [PATCH] Use a finite state machine

---
 apps/gobble7/gobble7.c | 59 ++++++++++++++++++++++++++----------------
 1 file changed, 37 insertions(+), 22 deletions(-)

diff --git a/apps/gobble7/gobble7.c b/apps/gobble7/gobble7.c
index 3cbe5ef..1a8cccb 100644
--- a/apps/gobble7/gobble7.c
+++ b/apps/gobble7/gobble7.c
@@ -15,17 +15,24 @@
 #include "things.h"
 
 
-#define DISPLAY_RATE 200
+#define DISPLAY_TASK_RATE 200
 
-#define NAVSWITCH_RATE 50
+#define NAVSWITCH_TASK_RATE 50
 
-#define THINGS_MOVE_RATE 10
+#define THINGS_MOVE_TASK_RATE 10
 
-#define MONSTER_FLASH_RATE 5
+#define MONSTER_FLASH_TASK_RATE 5
 
 
-static bool running = 0;
-static bool game_over = 1;
+typedef enum game_state
+{
+    GAME_WAIT,                  /* Waiting to start.  */
+    GAME_RUNNING,               /* Things running around.   */
+    GAME_PAUSED                 /* Things paused.  */
+} game_state_t;
+
+
+static game_state_t game_state = GAME_WAIT;
 static int duration = 0;
 
 
@@ -38,7 +45,7 @@ static void display_task (__unused__ void *data)
 static void monster_flash_task (__unused__ void *data)
 {
     /* Flash the monster.  */
-    if (running)
+    if (game_state == GAME_RUNNING)
         things_monster_toggle ();
 }
 
@@ -46,7 +53,7 @@ static void monster_flash_task (__unused__ void *data)
 static void things_move_task (__unused__ void *data)
 {
     /* Move the things.  */
-    if (running)
+    if (game_state == GAME_RUNNING)
     {
         duration++;
         things_move ();
@@ -70,26 +77,34 @@ static void navswitch_task (__unused__ void *data)
     /* Pause/resume things running around.  */
     if (navswitch_push_event_p (NAVSWITCH_PUSH))
     {
-        if (! running && game_over)
+        switch (game_state)
         {
+        case GAME_WAIT:
+            game_state = GAME_RUNNING;
             srand (timer_get ());
             tinygl_clear ();
             things_create ();
-            
             duration = 0;
-            game_over = 0;
+            led_set (LED1, 1);
+            break;
+            
+        case GAME_RUNNING:
+            game_state = GAME_PAUSED;
+            led_set (LED1, 0);
+            break;
+
+        case GAME_PAUSED:
+            game_state = GAME_RUNNING;
+            led_set (LED1, 1);
+            break;
         }
-        
-        running = !running;
-        led_set (LED1, running);
     }
     
-    if (running && things_killed_p ())
+    if (game_state == GAME_RUNNING && things_killed_p ())
     {
         char buffer[6];
         
-        running = 0;
-        game_over = 1;
+        game_state = GAME_WAIT;
         led_set (LED1, 0);
         sprintf (buffer, "%d", duration);
         tinygl_text (buffer);
@@ -101,10 +116,10 @@ int main (void)
 {
     task_t tasks[] =
     {
-        {.func = display_task, .period = TASK_RATE / DISPLAY_RATE},
-        {.func = navswitch_task, .period = TASK_RATE / NAVSWITCH_RATE},
-        {.func = things_move_task, .period = TASK_RATE / THINGS_MOVE_RATE},
-        {.func = monster_flash_task, .period = TASK_RATE / MONSTER_FLASH_RATE},
+        {.func = display_task, .period = TASK_RATE / DISPLAY_TASK_RATE},
+        {.func = navswitch_task, .period = TASK_RATE / NAVSWITCH_TASK_RATE},
+        {.func = things_move_task, .period = TASK_RATE / THINGS_MOVE_TASK_RATE},
+        {.func = monster_flash_task, .period = TASK_RATE / MONSTER_FLASH_TASK_RATE},
     };
 
 
@@ -113,7 +128,7 @@ int main (void)
     led_init ();
     led_set (LED1, 0);
 
-    tinygl_init (DISPLAY_RATE);
+    tinygl_init (DISPLAY_TASK_RATE);
     tinygl_font_set (&font3x5_1);
     tinygl_text_mode_set (TINYGL_TEXT_MODE_SCROLL);
     tinygl_text_dir_set (TINYGL_TEXT_DIR_ROTATE);