UNTESTED! DO NOT USE - PC speaker passthrough

src/engine/platform/pcspkr.cpp

@@ -21,6 +21,12 @@
 #include "../engine.h"
 #include <math.h>
 
+#ifdef __linux__
+#include <sys/ioctl.h>
+#include <unistd.h>
+#include <linux/kd.h>
+#endif
+
 #define PCSPKR_DIVIDER 4
 #define CHIP_DIVIDER 1
 
@@ -106,6 +112,19 @@ void DivPlatformPCSpeaker::acquire_piezo(short* bufL, short* bufR, size_t start,
   }
 }
 
+void DivPlatformPCSpeaker::acquire_real(short* bufL, short* bufR, size_t start, size_t len) {
+#ifdef __linux__
+  if (lastOn!=on || lastFreq!=freq) {
+    lastOn=on;
+    lastFreq=freq;
+    ioctl(STDOUT_FILENO,KIOCSOUND,on?freq:0);
+  }
+#endif
+  for (size_t i=start; i<start+len; i++) {
+    bufL[i]=0;
+  }
+}
+
 void DivPlatformPCSpeaker::acquire(short* bufL, short* bufR, size_t start, size_t len) {
   switch (speakerType) {
     case 0:
@@ -117,6 +136,9 @@ void DivPlatformPCSpeaker::acquire(short* bufL, short* bufR, size_t start, size_
     case 2:
       acquire_piezo(bufL,bufR,start,len);
       break;
+    case 3:
+      acquire_real(bufL,bufR,start,len);
+      break;
   }
 }
 
@@ -282,12 +304,20 @@ void DivPlatformPCSpeaker::reset() {
   }
 
   on=false;
+  lastOn=false;
   freq=0;
+  lastFreq=0;
   pos=0;
   flip=false;
   low=0;
   band=0;
 
+  if (speakerType==3) {
+#ifdef __linux__
+    ioctl(STDOUT_FILENO,KIOCSOUND,0);
+#endif
+  }
+
   memset(regPool,0,2);
 }
 
@@ -329,6 +359,11 @@ int DivPlatformPCSpeaker::init(DivEngine* p, int channels, int sugRate, unsigned
 }
 
 void DivPlatformPCSpeaker::quit() {
+  if (speakerType==3) {
+#ifdef __linux__
+    ioctl(STDOUT_FILENO,KIOCSOUND,0);
+#endif
+  }
 }
 
 DivPlatformPCSpeaker::~DivPlatformPCSpeaker() {

src/engine/platform/pcspkr.h

@@ -52,12 +52,12 @@ class DivPlatformPCSpeaker: public DivDispatch {
   };
   Channel chan[1];
   bool isMuted[1];
-  bool on, flip;
+  bool on, flip, lastOn;
   int pos, speakerType;
   float low, band;
   float low2, high2, band2;
   float low3, band3;
-  unsigned short freq;
+  unsigned short freq, lastFreq;
   unsigned char regPool[2];
 
   friend void putDispatchChan(void*,int,int);
@@ -65,6 +65,7 @@ class DivPlatformPCSpeaker: public DivDispatch {
   void acquire_unfilt(short* bufL, short* bufR, size_t start, size_t len);
   void acquire_cone(short* bufL, short* bufR, size_t start, size_t len);
   void acquire_piezo(short* bufL, short* bufR, size_t start, size_t len);
+  void acquire_real(short* bufL, short* bufR, size_t start, size_t len);
 
   public:
     void acquire(short* bufL, short* bufR, size_t start, size_t len);

src/gui/gui.cpp

@@ -17,7 +17,6 @@
  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  */
 
-#include <SDL_video.h>
 #define _USE_MATH_DEFINES
 #include "gui.h"
 #include "util.h"
@@ -4894,12 +4893,10 @@ bool FurnaceGUI::loop() {
                   e->setSysFlags(i,(flags&(~3))|2,restart);
                   updateWindowTitle();
                 }
-                /*
-                if (ImGui::RadioButton("Use system beeper",(flags&3)==3)) {
+                if (ImGui::RadioButton("Use system beeper (Linux only!)",(flags&3)==3)) {
                   e->setSysFlags(i,(flags&(~3))|3,restart);
                   updateWindowTitle();
                 }
-                */
                 break;
               }
               case DIV_SYSTEM_QSOUND: {