Throttle overlapping screen updates
We need to make sure the display server has finished reading our
previous update before we overwrite the buffer with the next update.
diff --git a/vncviewer/X11PixelBuffer.cxx b/vncviewer/X11PixelBuffer.cxx
index 9196fdc..046676e 100644
--- a/vncviewer/X11PixelBuffer.cxx
+++ b/vncviewer/X11PixelBuffer.cxx
@@ -21,8 +21,10 @@
#include <config.h>
#endif
+#include <assert.h>
#include <stdlib.h>
+#include <FL/Fl.H>
#include <FL/x.H>
#include <rfb/LogWriter.h>
@@ -35,6 +37,8 @@
static rfb::LogWriter vlog("X11PixelBuffer");
+std::list<X11PixelBuffer*> X11PixelBuffer::shmList;
+
static PixelFormat display_pf()
{
int i;
@@ -97,7 +101,7 @@
X11PixelBuffer::X11PixelBuffer(int width, int height) :
PlatformPixelBuffer(display_pf(), width, height, NULL, 0),
- shminfo(NULL), xim(NULL)
+ shminfo(NULL), xim(NULL), pendingPutImage(0)
{
// Might not be open at this point
fl_open_display();
@@ -122,6 +126,8 @@
{
if (shminfo) {
vlog.debug("Freeing shared memory XImage");
+ shmList.remove(this);
+ Fl::remove_system_handler(handleSystemEvent);
shmdt(shminfo->shmaddr);
shmctl(shminfo->shmid, IPC_RMID, 0);
delete shminfo;
@@ -137,12 +143,18 @@
void X11PixelBuffer::draw(int src_x, int src_y, int x, int y, int w, int h)
{
- if (shminfo)
- XShmPutImage(fl_display, fl_window, fl_gc, xim, src_x, src_y, x, y, w, h, False);
- else
+ if (shminfo) {
+ XShmPutImage(fl_display, fl_window, fl_gc, xim, src_x, src_y, x, y, w, h, True);
+ pendingPutImage++;
+ } else {
XPutImage(fl_display, fl_window, fl_gc, xim, src_x, src_y, x, y, w, h);
+ }
}
+bool X11PixelBuffer::isRendering(void)
+{
+ return pendingPutImage > 0;
+}
static bool caughtError;
@@ -202,6 +214,11 @@
if (caughtError)
goto free_shmaddr;
+ // FLTK is a bit stupid and unreliable if you register the same
+ // callback with different data values.
+ Fl::add_system_handler(handleSystemEvent, NULL);
+ shmList.push_back(this);
+
vlog.debug("Using shared memory XImage");
return 1;
@@ -222,3 +239,31 @@
return 0;
}
+
+int X11PixelBuffer::handleSystemEvent(void* event, void* data)
+{
+ XEvent* xevent;
+ XShmCompletionEvent* shmevent;
+
+ std::list<X11PixelBuffer*>::iterator iter;
+
+ xevent = (XEvent*)event;
+ assert(xevent);
+
+ if (xevent->type != XShmGetEventBase(fl_display))
+ return 0;
+
+ shmevent = (XShmCompletionEvent*)event;
+
+ for (iter = shmList.begin();iter != shmList.end();++iter) {
+ if (shmevent->shmseg != (*iter)->shminfo->shmseg)
+ continue;
+
+ (*iter)->pendingPutImage--;
+ assert((*iter)->pendingPutImage >= 0);
+
+ return 1;
+ }
+
+ return 0;
+}