Implement pausing of music.

Subversion-branch: /branches/opl-branch
Subversion-revision: 1688

7 files changed, 79 insertions, 10 deletions

diff --git a/opl/opl.c b/opl/opl.c
index 6e75c951..9d73fe0e 100644
--- a/opl/opl.c
+++ b/opl/opl.c
@@ -33,7 +33,7 @@
 #include "opl.h"
 #include "opl_internal.h"
 
-//#define OPL_DEBUG_TRACE
+#define OPL_DEBUG_TRACE
 
 #ifdef HAVE_IOPERM
 extern opl_driver_t opl_linux_driver;
@@ -195,3 +195,11 @@ void OPL_Delay(unsigned int ms)
     SDL_DestroyCond(delay_data.cond);
 }
 
+void OPL_SetPaused(int paused)
+{
+    if (driver != NULL)
+    {
+        driver->set_paused_func(paused);
+    }
+}
+
diff --git a/opl/opl.h b/opl/opl.h
index a0998404..f5b93a64 100644
--- a/opl/opl.h
+++ b/opl/opl.h
@@ -96,5 +96,9 @@ void OPL_Unlock(void);
 
 void OPL_Delay(unsigned int ms);
 
+// Pause the OPL callbacks.
+
+void OPL_SetPaused(int paused);
+
 #endif
 
diff --git a/opl/opl_internal.h b/opl/opl_internal.h
index 384b96f8..78cbe7b2 100644
--- a/opl/opl_internal.h
+++ b/opl/opl_internal.h
@@ -39,6 +39,7 @@ typedef void (*opl_set_callback_func)(unsigned int ms,
 typedef void (*opl_clear_callbacks_func)(void);
 typedef void (*opl_lock_func)(void);
 typedef void (*opl_unlock_func)(void);
+typedef void (*opl_set_paused_func)(int paused);
 
 typedef struct
 {
@@ -52,6 +53,7 @@ typedef struct
     opl_clear_callbacks_func clear_callbacks_func;
     opl_lock_func lock_func;
     opl_unlock_func unlock_func;
+    opl_set_paused_func set_paused_func;
 } opl_driver_t;
 
 #endif /* #ifndef OPL_INTERNAL_H */
diff --git a/opl/opl_linux.c b/opl/opl_linux.c
index 8a61dbf7..089192c9 100644
--- a/opl/opl_linux.c
+++ b/opl/opl_linux.c
@@ -94,7 +94,8 @@ opl_driver_t opl_linux_driver =
     OPL_Timer_SetCallback,
     OPL_Timer_ClearCallbacks,
     OPL_Timer_Lock,
-    OPL_Timer_Unlock
+    OPL_Timer_Unlock,
+    OPL_Timer_SetPaused
 };
 
 #endif /* #ifdef HAVE_IOPERM */
diff --git a/opl/opl_sdl.c b/opl/opl_sdl.c
index ffbe6820..e38f9f6e 100644
--- a/opl/opl_sdl.c
+++ b/opl/opl_sdl.c
@@ -60,6 +60,15 @@ static SDL_mutex *callback_queue_mutex = NULL;
 
 static int current_time;
 
+// If non-zero, playback is currently paused.
+
+static int opl_sdl_paused;
+
+// Time offset (in samples) due to the fact that callbacks
+// were previously paused.
+
+static unsigned int pause_offset;
+
 // OPL software emulator structure.
 
 static FM_OPL *opl_emulator = NULL;
@@ -96,11 +105,16 @@ static void AdvanceTime(unsigned int nsamples)
 
     current_time += nsamples;
 
+    if (opl_sdl_paused)
+    {
+        pause_offset += nsamples;
+    }
+
     // Are there callbacks to invoke now?  Keep invoking them
     // until there are none more left.
 
     while (!OPL_Queue_IsEmpty(callback_queue)
-        && current_time >= OPL_Queue_Peek(callback_queue))
+        && current_time >= OPL_Queue_Peek(callback_queue) + pause_offset)
     {
         // Pop the callback from the queue to invoke it.
 
@@ -180,13 +194,13 @@ static void OPL_Mix_Callback(void *udata,
         // the callback queue must be invoked.  We can then fill the
         // buffer with this many samples.
 
-        if (OPL_Queue_IsEmpty(callback_queue))
+        if (opl_sdl_paused || OPL_Queue_IsEmpty(callback_queue))
         {
             nsamples = buffer_len - filled;
         }
         else
         {
-            next_callback_time = OPL_Queue_Peek(callback_queue);
+            next_callback_time = OPL_Queue_Peek(callback_queue) + pause_offset;
 
             nsamples = next_callback_time - current_time;
 
@@ -260,7 +274,7 @@ static void TimerHandler(int channel, double interval_seconds)
 
     SDL_LockMutex(callback_queue_mutex);
     OPL_Queue_Push(callback_queue, TimerOver, (void *) channel,
-                   current_time + interval_samples);
+                   current_time - pause_offset + interval_samples);
     SDL_UnlockMutex(callback_queue_mutex);
 }
 
@@ -297,6 +311,9 @@ static int OPL_SDL_Init(unsigned int port_base)
         sdl_was_initialised = 0;
     }
 
+    opl_sdl_paused = 0;
+    pause_offset = 0;
+
     // Queue structure of callbacks to invoke.
 
     callback_queue = OPL_Queue_Create();
@@ -370,7 +387,7 @@ static void OPL_SDL_SetCallback(unsigned int ms,
 {
     SDL_LockMutex(callback_queue_mutex);
     OPL_Queue_Push(callback_queue, callback, data,
-                   current_time + (ms * mixing_freq) / 1000);
+                   current_time - pause_offset + (ms * mixing_freq) / 1000);
     SDL_UnlockMutex(callback_queue_mutex);
 }
 
@@ -391,6 +408,11 @@ static void OPL_SDL_Unlock(void)
     SDL_UnlockMutex(callback_mutex);
 }
 
+static void OPL_SDL_SetPaused(int paused)
+{
+    opl_sdl_paused = paused;
+}
+
 opl_driver_t opl_sdl_driver =
 {
     "SDL",
@@ -401,6 +423,7 @@ opl_driver_t opl_sdl_driver =
     OPL_SDL_SetCallback,
     OPL_SDL_ClearCallbacks,
     OPL_SDL_Lock,
-    OPL_SDL_Unlock
+    OPL_SDL_Unlock,
+    OPL_SDL_SetPaused
 };
 
diff --git a/opl/opl_timer.c b/opl/opl_timer.c
index e254a5e2..35b2092f 100644
--- a/opl/opl_timer.c
+++ b/opl/opl_timer.c
@@ -41,6 +41,15 @@ static SDL_Thread *timer_thread = NULL;
 static thread_state_t timer_thread_state;
 static int current_time;
 
+// If non-zero, callbacks are currently paused.
+
+static int opl_timer_paused;
+
+// Offset in milliseconds to adjust time due to the fact that playback
+// was paused.
+
+static unsigned int pause_offset = 0;
+
 // Queue of callbacks waiting to be invoked.
 // The callback queue mutex is held while the callback queue structure
 // or current_time is being accessed.
@@ -59,6 +68,17 @@ static SDL_mutex *timer_mutex;
 
 static int CallbackWaiting(unsigned int *next_time)
 {
+    // If paused, just wait in 50ms increments until unpaused.
+    // Update pause_offset so after we unpause, the callback 
+    // times will be right.
+
+    if (opl_timer_paused)
+    {
+        *next_time = current_time + 50;
+        pause_offset += 50;
+        return 0;
+    }
+
     // If there are no queued callbacks, sleep for 50ms at a time
     // until a callback is added.
 
@@ -72,7 +92,7 @@ static int CallbackWaiting(unsigned int *next_time)
     // If the time for the callback has not yet arrived,
     // we must sleep until the callback time.
 
-    *next_time = OPL_Queue_Peek(callback_queue);
+    *next_time = OPL_Queue_Peek(callback_queue) + pause_offset;
 
     return *next_time <= current_time;
 }
@@ -169,6 +189,8 @@ int OPL_Timer_StartThread(void)
 
     timer_thread_state = THREAD_STATE_RUNNING;
     current_time = SDL_GetTicks();
+    opl_timer_paused = 0;
+    pause_offset = 0;
 
     timer_thread = SDL_CreateThread(ThreadFunction, NULL);
 
@@ -198,7 +220,8 @@ void OPL_Timer_StopThread(void)
 void OPL_Timer_SetCallback(unsigned int ms, opl_callback_t callback, void *data)
 {
     SDL_LockMutex(callback_queue_mutex);
-    OPL_Queue_Push(callback_queue, callback, data, current_time + ms);
+    OPL_Queue_Push(callback_queue, callback, data,
+                   current_time + ms - pause_offset);
     SDL_UnlockMutex(callback_queue_mutex);
 }
 
@@ -219,3 +242,10 @@ void OPL_Timer_Unlock(void)
     SDL_UnlockMutex(timer_mutex);
 }
 
+void OPL_Timer_SetPaused(int paused)
+{
+    SDL_LockMutex(callback_queue_mutex);
+    opl_timer_paused = paused;
+    SDL_UnlockMutex(callback_queue_mutex);
+}
+
diff --git a/opl/opl_timer.h b/opl/opl_timer.h
index e8657a90..f03fc499 100644
--- a/opl/opl_timer.h
+++ b/opl/opl_timer.h
@@ -36,6 +36,7 @@ void OPL_Timer_SetCallback(unsigned int ms,
 void OPL_Timer_ClearCallbacks(void);
 void OPL_Timer_Lock(void);
 void OPL_Timer_Unlock(void);
+void OPL_Timer_SetPaused(int paused);
 
 #endif /* #ifndef OPL_TIMER_H */