I have a simple piece of code that successfully creates pbuffers when compiled against the macOS 10.12 SDK, but an update to the 10.13 SDK breaks things. I know that this tech is very deprecated.
#import <Cocoa/Cocoa.h>
#import <OpenGL/OpenGL.h>
#import <OpenGL/gl3.h>
#import <OpenGL/glext.h>
int main( int argc, const char* argv[] )
{
GLsizei width = 1024;
GLsizei height = 1024;
GLenum target = GL_TEXTURE_RECTANGLE_EXT;
GLenum internalFormat = GL_RGBA;
GLint maxLevel = 0;
CGLPBufferObj pBuffer = NULL;
CGLError error = kCGLNoError;
error = CGLCreatePBuffer( width, height, target, internalFormat, maxLevel, &pBuffer );
if( error )
{
NSLog(#"CGL Error %# : %s", #(error), CGLErrorString( error ) );
}
return 0;
}
Using the 10.12 SDK, I get kCGLNoError, but using 10.13 it delivers kCGLBadDrawable.
Beyond transitioning to using e.g. framebuffer objects, what can I do to keep this piece of code going for a little bit longer?
Note: it's not even necessary to fully recompile the generated binary against a different macOS SDK. Changing the Mach-O load command (changing a single byte) around VERSION_MIN_MAC_OSX to point to 10.12.0 rather than 10.13.0 also fixes things.
I'm experimenting with XReparentWindow with the end goal to aggregate windows of multiple processes into one "cockpit" simulating process. Experiments with XReparentWindow works sporadically; sometimes the window is reparented successfully, sometimes not. When unsuccessfully reparented the (not) grabbed window flickers for a second and then proceedes as usual, and the grabber show undefined window content. It is successfull every other time (tempted to brute-force the problem away by always trying two times).
Edit 1: Checking output of XQueryTree right after XReparentWindow shows the grabbed window is properly reparented, but would appear to keep its frame origin where grabbed from on display rather than being moved to the grabber window.
The grabbed window is from a real-time OpenGL rendering application, compiled from source. The application does not anticipate the grabbing in any way (maybe it should?). I have also tried grabbing glxgears and a GNOME Terminal, same result.
The experimental code, taking window to grab as program argument (e.g. using xwininfo | grep "Window id"):
#include <X11/Xlib.h>
#include <stdio.h>
#include <assert.h>
#include <unistd.h> // usleep
int main(int argc, char** argv) {
assert(argc==2);
Window window, extwin;
sscanf(argv[1], "%p", &extwin);
Display* display = XOpenDisplay(0);
window = XCreateWindow(display, RootWindow(display, 0), 0, 0, 500, 500, 0, DefaultDepth(display, 0), InputOutput, DefaultVisual(display, 0), 0, 0);
XMapWindow(display, window);
XReparentWindow(display, extwin, window, 0, 0);
while(1) {
XFlush(display);
usleep(3e5);
}
return 0;
}
(Code is manually exported from a restricted environment. Sorry for any typos made during export.)
Looking forward for suggestions of what to try out next.
Edit 2: Having captured the event stream of the grabbed window using xev I notice something odd; after being reparented to the grabber window, it reparents itself back to root window after less than a second (restricted environment, typing what's seen on other window with anticipated significance):
UnmapNotify event ...
ReparentNotify event ... parent 0x4000001 (grabber window)
MapNotify event ...
ConfigureNotify event ... synthetic YES (what is this?)
UnmapNotify event ...
ReparentNotify event ... parent 0xed (reparenting back to parent window, but why?)
MapNotify event ...
VisibilityNotify event ...
Expose event ...
PropertyNotify event ... _NET_WM_DESKTOP state PropertyDelete
PropertyNotify event ... _NET_WM_STATE state PropertyDelete
PropertyNotify event ... WM_STATE state PropertyNewValue
I quit the program and try again a second time, at which the output that continues is:
UnmapNotify event ...
ReparentNotify event ... parent 0x4000001 (grabber window)
MapNotify event ...
VisibilityNotify event ...
Expose event ...
What is going on?
I am a newbie in the GUI world and I don't know X11 internals. But I've just read a very interesting documentation (https://www.x.org/releases/current/doc/libX11/libX11/libX11.html)
Most of the functions in Xlib just add requests to an output buffer. These requests later execute asynchronously on the X server. Functions that return values of information stored in the server do not return (that is, they block) until an explicit reply is received or an error occurs. You can provide an error handler, which will be called when the error is reported.
If a client does not want a request to execute asynchronously, it can follow the request with a call to XSync, which blocks until all previously buffered asynchronous events have been sent and acted on. As an important side effect, the output buffer in Xlib is always flushed by a call to any function that returns a value from the server or waits for input.
So I guess what you have is a race condition between reparenting and something.
This works for me:
// gcc -lX11 -lXcomposite a.c && ./a.out 0x1a00001
// IDs can be gotten from
// `wmctrl -l` (shows only the parent windows) or `xwininfo`.
#include <stdio.h>
#include <stdlib.h>
#include <stdint.h>
#include <stdbool.h>
#include <unistd.h>
#include <X11/Xlib.h> // -lX11
#include <X11/Xutil.h>
#include <X11/Xatom.h>
#include <X11/extensions/Xcomposite.h> // optional, -lXcomposite
void reparent (Display *d, Window child, Window new_parent)
{
XUnmapWindow(d, child);
XMapWindow(d, new_parent);
XSync(d, False);
XReparentWindow(d, child, new_parent, 0, 0);
XMapWindow(d, child);
// 1 ms seems to be enough even during `nice -n -19 stress -c $cpuThreadsCount` (pacman -S stress) on linux-tkg-pds.
// Probably can be decreased even further.
usleep(1e3);
XSync(d, False);
}
int main (int argc, char **argv)
{
Display *d = XOpenDisplay(XDisplayName(NULL));
int s = DefaultScreen(d);
Window root = RootWindow(d, s);
if (argc != 2)
{
printf("Wrong number of arguments, exiting.");
exit(1);
}
Window child = strtol(argv[1], NULL, 0);
Window new_parent = XCreateSimpleWindow(
d, root, 0, 0, 500, 500, 0, 0, 0
);
// (Optional)
// Allow grabbing by `ffmpeg -f x11grab -window_id`
// while being on the same virtual screen
// AND (focused or unfocused)
// AND (seen or unseen)
// AND no other window is both fullscreen and focused.
XCompositeRedirectWindow(d, child, CompositeRedirectAutomatic);
// After `new_parent` is destroyed (when the program exists),
// don't make `child` unmapped/invisible.
XAddToSaveSet(d, child);
reparent(d, child, new_parent);
XEvent e;
while (1)
{
XNextEvent(d, &e);
}
return 0;
}
Also it's possible to use xdotool:
xdotool windowunmap $CHID
xdotool windowreparent $CHID $NEWPID
xdotool windowmap --sync $CHID
Brute force solution, grabbing the window repeatedly:
#include <X11/Xlib.h>
#include <stdio.h>
#include <assert.h>
#include <unistd.h> // usleep
int main(int argc, char** argv) {
assert(argc==2);
Window window, extwin;
sscanf(argv[1], "%p", &extwin);
Display* display = XOpenDisplay(0);
window = XCreateWindow(display, RootWindow(display, 0), 0, 0, 500, 500, 0, DefaultDepth(display, 0), InputOutput, DefaultVisual(display, 0), 0, 0);
XMapWindow(display, window);
while(1) {
Window root, parent, *ch;
unsigned int nch;
XQueryTree(display, extwin, &root, &parent, &ch, &nch);
if(parent!=window) {
XReparentWindow(display, extwin, window, 0, 0);
}
if(nch>0) { XFree(ch); }
XFlush(display);
usleep(3e5);
}
return 0;
}
Assuming this only happens once the clause can be disabled after two calls to reparent. Works on my machine. Would appreciate full explaination of what is really going on.
I have never tried with an OpenGL application and do not have the environment here.
Maybe try first with a simple X app (like xclock) and observe if you get the same behaviour.
If yes, that's your code, if no, probably OpenGL interaction.
From your snippset, two comments though:
In the while loop, you should consume the X events
XEvent e;
while(1) {
XNextEvent(d, &e);
}
Then the XAddToSaveSet function does not work properly.
You will need to use the XFixes in order to properly restore that window in case of a crash.
#include <X11/extensions/Xfixes.h>
...
// The Xorg API is buggy in certain areas.
// Need to use the XFixes extensions to address them
// Initializes these extensions
int event_base_return = 0;
int error_base_return = 0;
Bool result = XFixesQueryExtension(display, &event_base_return);
printf("XFixesQueryExtension result: %d. eventbase: %d - errorbase: %d\n", result, event_base_return, error_base_return);
// We actually only need version 1.0. But if 4.0 is not there then something is really wrong
int major = 4;
int minor = 0;
result = XFixesQueryVersion(display, &major, &minor);
printf("XFixesQueryVersion result: %d - version: %d.%d\n", result, major, minor);
...
XReparentWindow(display, childWindowId, parentWindowId, 0, 0);
XFixesChangeSaveSet(display, childWindowId, SetModeInsert, SaveSetRoot, SaveSetUnmap);
...
I tried to play a video using OpenCV-2.4.7 in Visual Studio 2010, Win 7
Code is as follow-
#include<opencv\cv.h>
#include <opencv\highgui.h>
using namespace cv;
int main( int argc, char** argv ) {
cvNamedWindow( "Window", CV_WINDOW_AUTOSIZE );
CvCapture* capture = cvCreateFileCapture( "C:/Users/17/Desktop/Wildlife.avi" );
IplImage* frame;
while(1) {
frame = cvQueryFrame( capture );
if( !frame ) break;
cvShowImage( "Window", frame );
char c = cvWaitKey(33);
if( c == 27 ) break;
}
cvReleaseCapture( &capture );
cvDestroyWindow( "Window" );
}
Debugs is fine but on running, a waring window opens saying "The program can't start because libiconv-2.dll is missing from your computer".
I tried to download libiconv-2.dll into system package then it showed the error "C:\Windows\System32\libiconv-2.dll', Binary was not built with debug information".
Is there any possible missing setting?? what should be done to run this code?
It's an issue with opencv_ffmpeg247.dll in the latest release (2.4.7) as described here
I'm having the same issue, though with the fix earmarked for 2.4.8 I'd suggest either installing an earlier version (2.4.6) or using the latest copy from the repo here
I've been trying to find a way of grabbing video directly from an X window and got pointed to Xlib and the compositing extension.
So far, I've been able to listen to change events and grab a Pixmap with this code:
#include <X11/Intrinsic.h>
#include <X11/extensions/Xcomposite.h>
#include <X11/extensions/Xdamage.h>
#include <iostream>
#include <fstream>
using namespace std;
int main(int argc, char ** argv) {
int br, base;
Window win = 0x3400003;
Display *dsp = XOpenDisplay(0);
XCompositeQueryExtension(dsp, &base, &br);
XDamageQueryExtension(dsp,&base, &br);
cout << base << endl;
Damage damage = XDamageCreate(dsp, win, XDamageReportRawRectangles);
XCompositeRedirectWindow(dsp, win, CompositeRedirectAutomatic);
XEvent ev;
while(true) {
XNextEvent(dsp, &ev);
if(ev.type == base + XDamageNotify) {
Pixmap pm = XCompositeNameWindowPixmap(dsp, win);
XWindowAttributes attr;
XGetWindowAttributes(dsp, win, &attr);
XWriteBitmapFile(dsp, "test.bmp", pm, attr.width, attr.height, -1, -1);
return 0;
}
}
XCompositeUnredirectWindow(dsp, win, CompositeRedirectAutomatic);
XDamageDestroy(dsp, damage);
return 0;
}
The problem here is that the resulting bmp (created by XWriteBitmapFile) is black&white horribleness. Disregarding the fact that I don't want to write the data to file anyway, I am apparently doing something wrong in reading it.
I would love to convert the Pixmap to either a framebuffer in opengl or a binary blob in ram.
Thanks in advance for any help you can give me on this.
Best regards.
"Bitmaps" in X world refer to two-colored images. I guess XWriteBitmapFile does internally GetImage request and transforms server pixmap to a bitmap. Note that file format is it's own 'X11 bitmap', not windows bitmap.
Use XGetImage function If you actually need image's binary blob.
I am a beginner for Eclipse. I now have Eclipse C/C++ IDE with OpenCV library running on Windows 7. So far it works after spending hours trying to get it running. But then I realize that Eclipse does not pop up a command prompt as VS2010 does while debugging. And moreover Eclipse's debug mode is just stuck in there and refuse to output anything. But if the code doesn't involve the OpenCV things it works again.
Below is the code I use for testing. It captures images from webcam and output it to the screen. The infinite loop (until you press 'q') makes sure it constantly grabs new inputs from the camera.
I browsed through the workspace and run the exe just compiled and it worked flawlessly. So I don't think there's anything wrong in the code (it's an example code anyway
In brief, can I just pop up a command prompt window in debug mode? And why is Eclipse console stuck when the code involves some OpenCV functions?
#include <stdio.h>
#include <stdlib.h>
#include <tchar.h>
#include <cv.h>
#include <cxcore.h>
#include <highgui.h>
#include <iostream>
int _tmain(int argc, _TCHAR* argv[])
{
CvCapture *capture = 0;
IplImage *frame = 0;
int key = 0;
/* initialize camera */
capture = cvCaptureFromCAM( 0 );
/* always check */
if ( !capture ) {
printf("Cannot open initialize webcam!\n");
return 1;
}
/* create a window for the video */
cvNamedWindow( "result", CV_WINDOW_AUTOSIZE );
while( key != 'q' ) {
/* get a frame */
frame = cvQueryFrame( capture );
/* always check */
if( !frame ) break;
/* display current frame */
cvShowImage( "result", frame );
/* exit if user press 'q' */
key = cvWaitKey( 1 );
}
/* free memory */
cvDestroyWindow( "result" );
cvReleaseCapture( &capture );
return 0;
}
This is because you have already set the windows 7 system variable PATH to your MinGw/bin and compiled opencv bin directories. So when you run the program from your folder your system automatically take the required binaries from its PATH and the program runs correctly.
I don't know why but Eclipse does not take it directly from the system environment PATH variable. So we have to set it ourself.
go to Preferences > C/C++ (Expand it) > Environment > Add:
"Name:PATH"
"Value:C:\MinGW\bin;C:\opencv_MinGW\bin"
where opencv_MinGW is the folder where I compiled my opencv