Improvement #7: Add double buffering

Add double buffering with X DBE extension in hope to get rid of the
tearing issue. Thanks to cairo-compmgr for providing hints. Could be
enabled with --dbe. Only very limited tests have been done, I don't know
if it actually solves the tearing issue. My estimation is it is harmful
for performance, but I found no clear evidence. Experimental, so no
configuration file option is available for it.

MONITOR_REPAINT is broken if --dbe is turned on, this is intended for
testing whether DBE is actually working.
This commit is contained in:
Richard Grenville 2012-10-23 13:42:20 +08:00
parent fe2146f1a5
commit 5dd544d29d
2 changed files with 82 additions and 10 deletions

View File

@ -39,8 +39,14 @@ Display *dpy = NULL;
int scr;
Window root;
Picture root_picture;
Picture root_buffer;
/// Picture of root window. Destination of painting in no-DBE painting
/// mode.
Picture root_picture = None;
/// Temporary buffer to paint to before sending to display.
Picture root_buffer = None;
/// DBE back buffer for root window. Used in DBE painting mode.
XdbeBackBuffer root_dbe = None;
Picture black_picture;
Picture cshadow_picture;
/// Picture used for dimming inactive windows.
@ -109,6 +115,8 @@ Bool glx_exists = False;
int glx_event, glx_error;
#endif
Bool dbe_exists = False;
/* shadows */
conv *gaussian_map;
@ -163,6 +171,7 @@ static options_t opts = {
.refresh_rate = 0,
.vsync = VSYNC_NONE,
.dbe = False,
.wintype_shadow = { False },
.shadow_red = 0.0,
@ -1557,18 +1566,29 @@ paint_all(Display *dpy, XserverRegion region, win *t) {
}
#ifdef MONITOR_REPAINT
// Note: MONITOR_REPAINT cannot work with DBE right now.
root_buffer = root_picture;
#else
if (!root_buffer) {
Pixmap root_pixmap = XCreatePixmap(
dpy, root, root_width, root_height,
DefaultDepth(dpy, scr));
// DBE painting mode: Directly paint to a Picture of the back buffer
if (opts.dbe) {
root_buffer = XRenderCreatePicture(dpy, root_dbe,
XRenderFindVisualFormat(dpy, DefaultVisual(dpy, scr)),
0, 0);
}
// No-DBE painting mode: Paint to an intermediate Picture then paint
// the Picture to root window
else {
Pixmap root_pixmap = XCreatePixmap(
dpy, root, root_width, root_height,
DefaultDepth(dpy, scr));
root_buffer = XRenderCreatePicture(dpy, root_pixmap,
XRenderFindVisualFormat(dpy, DefaultVisual(dpy, scr)),
0, 0);
root_buffer = XRenderCreatePicture(dpy, root_pixmap,
XRenderFindVisualFormat(dpy, DefaultVisual(dpy, scr)),
0, 0);
XFreePixmap(dpy, root_pixmap);
XFreePixmap(dpy, root_pixmap);
}
}
#endif
@ -1674,7 +1694,16 @@ paint_all(Display *dpy, XserverRegion region, win *t) {
XFixesDestroyRegion(dpy, reg_tmp);
XFixesDestroyRegion(dpy, reg_tmp2);
if (root_buffer != root_picture) {
// DBE painting mode, only need to swap the buffer
if (opts.dbe) {
XdbeSwapInfo swap_info = {
.swap_window = root,
// Is it safe to use XdbeUndefined?
.swap_action = XdbeCopied
};
XdbeSwapBuffers(dpy, &swap_info, 1);
}
else if (root_buffer != root_picture) {
XFixesSetPictureClipRegion(dpy, root_buffer, 0, 0, None);
XRenderComposite(
dpy, PictOpSrc, root_buffer, None,
@ -3240,6 +3269,9 @@ usage(void) {
"--alpha-step val\n"
" Step for pregenerating alpha pictures. 0.01 - 1.0. Defaults to\n"
" 0.03.\n"
"--dbe\n"
" Enable DBE painting mode, intended to use with VSync to\n"
" (hopefully) eliminate tearing.\n"
"\n"
"Format of a condition:\n"
"\n"
@ -3624,6 +3656,7 @@ get_cfg(int argc, char *const *argv) {
{ "refresh-rate", required_argument, NULL, 269 },
{ "vsync", required_argument, NULL, 270 },
{ "alpha-step", required_argument, NULL, 271 },
{ "dbe", no_argument, NULL, 272 },
// Must terminate with a NULL entry
{ NULL, 0, NULL, 0 },
};
@ -3810,6 +3843,10 @@ get_cfg(int argc, char *const *argv) {
// --alpha-step
opts.alpha_step = atof(optarg);
break;
case 272:
// --dbe
opts.dbe = True;
break;
default:
usage();
break;
@ -4190,6 +4227,19 @@ init_alpha_picts(Display *dpy) {
}
}
/**
* Initialize double buffer.
*/
static void
init_dbe(void) {
if (!(root_dbe = XdbeAllocateBackBufferName(dpy, root, XdbeCopied))) {
fprintf(stderr, "Failed to create double buffer. Double buffering "
"turned off.\n");
opts.dbe = False;
return;
}
}
int
main(int argc, char **argv) {
XEvent ev;
@ -4279,6 +4329,22 @@ main(int argc, char **argv) {
}
#endif
// Query X DBE extension
if (opts.dbe) {
int dbe_ver_major = 0, dbe_ver_minor = 0;
if (XdbeQueryExtension(dpy, &dbe_ver_major, &dbe_ver_minor))
if (dbe_ver_major >= 1)
dbe_exists = True;
else
fprintf(stderr, "DBE extension version too low. Double buffering "
"impossible.\n");
else {
fprintf(stderr, "No DBE extension. Double buffering impossible.\n");
}
if (!dbe_exists)
opts.dbe = False;
}
register_cm((VSYNC_OPENGL == opts.vsync));
// Initialize software/DRM/OpenGL VSync
@ -4287,6 +4353,9 @@ main(int argc, char **argv) {
|| (VSYNC_OPENGL == opts.vsync && !vsync_opengl_init()))
opts.vsync = VSYNC_NONE;
if (opts.dbe)
init_dbe();
if (opts.fork_after_register) fork_after();
get_atoms();

View File

@ -75,6 +75,7 @@
#include <X11/extensions/Xrender.h>
#include <X11/extensions/shape.h>
#include <X11/extensions/Xrandr.h>
#include <X11/extensions/Xdbe.h>
#ifdef CONFIG_VSYNC_DRM
#include <fcntl.h>
@ -314,6 +315,8 @@ typedef struct _options {
int refresh_rate;
/// VSync method to use;
vsync_t vsync;
/// Whether to enable double buffer.
Bool dbe;
// Shadow
Bool wintype_shadow[NUM_WINTYPES];