add gl-swapbuffer-framelock option

panda/src/wgldisplay/config_wgldisplay.cxx

@@ -47,6 +47,9 @@ bool bResponsive_minimized_fullscreen_window = config_wgldisplay.GetBool("respon
 // will crab out WireGL.
 bool support_wiregl = config_wgldisplay.GetBool("support-wiregl", false);
 
+// Set this true to enable HW swapbuffer frame-lock on 3dlabs cards
+bool gl_swapbuffer_framelock = config_wgldisplay.GetBool("gl-swapbuffer-framelock", false);
+
 // if true, use ddraw's GetAvailVidMem to fail if driver says it has too little video mem
 bool gl_do_vidmemsize_check = config_wgldisplay.GetBool("do-vidmemsize-check", true);
 

panda/src/wgldisplay/config_wgldisplay.h

@@ -34,6 +34,7 @@ extern Filename get_mono_cursor_filename_2();
 extern bool gl_show_fps_meter;
 extern float gl_fps_meter_update_interval;
 extern bool gl_sync_video;
+extern bool gl_swapbuffer_framelock;
 extern int gl_forced_pixfmt;
 extern bool bResponsive_minimized_fullscreen_window;
 extern bool gl_do_vidmemsize_check;

panda/src/wgldisplay/wglGraphicsWindow.cxx

@@ -620,6 +620,31 @@ void wglGraphicsWindow::config() {
   if (wgldisplay_cat.is_spam())
      wgldisplay_cat.spam() << "GL extensions: " << _extensions_str << endl;
 
+  if(gl_swapbuffer_framelock) {
+     // utilize HW-assisted framelocking if available (3dLabs ext)
+     WGLENABLEFRAMELOCKI3DFUNCPTR wglEnableFrameLock = (WGLENABLEFRAMELOCKI3DFUNCPTR) wglGetProcAddress("wglEnableFrameLockI3D");
+
+     if(wglEnableFrameLock==NULL) {
+         wgldisplay_cat.fatal() << "wglEnableFrameLockI3D not found in OpenGL ICD, cannot implement gl-swapbuffer-framelock!\n";
+         exit(1);
+     } else {
+         BOOL result = wglEnableFrameLock();
+         if(!result) {
+             wgldisplay_cat.fatal() << "wglEnableFrameLockI3D failed, error=" << GetLastError() << endl;
+             exit(1);
+         }
+     }
+
+     if(wgldisplay_cat.is_debug()) {
+         WGLQUERYFRAMELOCKMASTERI3DFUNCPTR wglQueryFrameLockMasterI3D = (WGLQUERYFRAMELOCKMASTERI3DFUNCPTR) wglGetProcAddress("wglQueryFrameLockMasterI3D");
+         BOOL bIsMaster;
+         if((wglQueryFrameLockMasterI3D!=NULL) && wglQueryFrameLockMasterI3D(&bIsMaster))
+             wgldisplay_cat.debug() << "SwapBuffer Frame-locking Enabled, HW wired as framelock " << (bIsMaster ? "Master" : "Slave") << endl;
+     }
+
+     gl_sync_video=true;       // you want gl_sync_video if you want framelock, right?
+  }
+
   if (gl_sync_video) {
       // set swapbuffers to swap no more than once per monitor refresh
       // note sometimes the ICD advertises this ext, but it still doesn't seem to work

panda/src/wgldisplay/wglext.h

@@ -391,6 +391,21 @@ typedef void * (APIENTRY * PFNWGLALLOCATEMEMORYNVPROC) (int size, float readfreq
 typedef void (APIENTRY * PFNWGLFREEMEMORYNVPROC) (void *pointer);
 #endif
 
+// added from 3dlabs glext.h
+/*
+ * Constants and typedefs for the WGL swap_frame_usage extension.
+ */
+typedef BOOL (APIENTRY *WGLGETFRAMEUSAGEI3DFUNCPTR)(float *);
+
+
+/*
+ * Constants and typedefs for the WGL swap_frame_lock extension.
+ */
+typedef BOOL (APIENTRY *WGLENABLEFRAMELOCKI3DFUNCPTR)(VOID);
+typedef BOOL (APIENTRY *WGLDISABLEFRAMELOCKI3DFUNCPTR)(VOID);
+typedef BOOL (APIENTRY *WGLISENABLEDFRAMELOCKI3DFUNCPTR)(BOOL *);
+typedef BOOL (APIENTRY *WGLQUERYFRAMELOCKMASTERI3DFUNCPTR)(BOOL *);
+
 
 #ifdef __cplusplus
 }