Add OPL library API function to set software emulation sample rate, and

set from snd_samplerate in the configuration file.

Subversion-branch: /branches/opl-branch
Subversion-revision: 1723

4 files changed, 32 insertions, 4 deletions

diff --git a/opl/opl.c b/opl/opl.c
index 8e57647e..2c8fd692 100644
--- a/opl/opl.c
+++ b/opl/opl.c
@@ -68,6 +68,8 @@ static opl_driver_t *drivers[] =
 static opl_driver_t *driver = NULL;
 static int init_stage_reg_writes = 1;
 
+unsigned int opl_sample_rate = 22050;
+
 //
 // Init/shutdown code.
 //
@@ -182,6 +184,13 @@ void OPL_Shutdown(void)
     }
 }
 
+// Set the sample rate used for software OPL emulation.
+
+void OPL_SetSampleRate(unsigned int rate)
+{
+    opl_sample_rate = rate;
+}
+
 void OPL_WritePort(opl_port_t port, unsigned int value)
 {
     if (driver != NULL)
diff --git a/opl/opl.h b/opl/opl.h
index 9f5d0a9f..04d3cf27 100644
--- a/opl/opl.h
+++ b/opl/opl.h
@@ -70,6 +70,10 @@ int OPL_Init(unsigned int port_base);
 
 void OPL_Shutdown(void);
 
+// Set the sample rate used for software emulation.
+
+void OPL_SetSampleRate(unsigned int rate);
+
 // Write to one of the OPL I/O ports:
 
 void OPL_WritePort(opl_port_t port, unsigned int value);
diff --git a/opl/opl_internal.h b/opl/opl_internal.h
index 78cbe7b2..4a46b060 100644
--- a/opl/opl_internal.h
+++ b/opl/opl_internal.h
@@ -56,5 +56,9 @@ typedef struct
     opl_set_paused_func set_paused_func;
 } opl_driver_t;
 
+// Sample rate to use when doing software emulation.
+
+extern unsigned int opl_sample_rate;
+
 #endif /* #ifndef OPL_INTERNAL_H */
 
diff --git a/opl/opl_sdl.c b/opl/opl_sdl.c
index 4a2e1ff8..2eb8288f 100644
--- a/opl/opl_sdl.c
+++ b/opl/opl_sdl.c
@@ -40,9 +40,6 @@
 
 #include "opl_queue.h"
 
-// TODO:
-#define opl_sample_rate 22050
-
 // When the callback mutex is locked using OPL_Lock, callback functions
 // are not invoked.
 
@@ -278,6 +275,20 @@ static void TimerHandler(int channel, double interval_seconds)
     SDL_UnlockMutex(callback_queue_mutex);
 }
 
+static unsigned int GetSliceSize(void)
+{
+    unsigned int slicesize;
+
+    slicesize = 1024 * (opl_sample_rate / 11025);
+
+    if (slicesize <= 1024)
+    {
+        slicesize = 1024;
+    }
+
+    return slicesize;
+}
+
 static int OPL_SDL_Init(unsigned int port_base)
 {
     // Check if SDL_mixer has been opened already
@@ -291,7 +302,7 @@ static int OPL_SDL_Init(unsigned int port_base)
             return 0;
         }
 
-        if (Mix_OpenAudio(opl_sample_rate, AUDIO_S16SYS, 2, 1024) < 0)
+        if (Mix_OpenAudio(opl_sample_rate, AUDIO_S16SYS, 2, GetSliceSize()) < 0)
         {
             fprintf(stderr, "Error initialising SDL_mixer: %s\n", Mix_GetError());