General comments about graphics:
BOINC supports process structures where graphics is done:
In this approach, graphics are generated by a thread within your main application. The application must call either
int boinc_init_graphics(WORKER_FUNC_PTR worker);
// for simple applications
int boinc_init_options_graphics(BOINC_OPTIONS&, WORKER_FUNC_PTR worker);
// for compound applications
where worker() is the main function of your application.
Do NOT call boinc_init() or boinc_init_options().
Your application must be linked with libboinc_graphics_api.a,
and with your rendering and input-handling functions (see below).
It should be linked dynamically with glut and opengl.
boinc_init_graphics() creates a worker thread
that runs the main application function.
The original thread becomes the graphics thread,
which handles GUI events and does rendering.
The two threads communicate through application-defined
shared memory structures.
Typically these structures contain information about the computation,
which is used to generate graphics.
You must initialize the shared data structure
before calling boinc_init_graphics().
Unix/Linux applications that use graphics should compile
all files with -D_REENTRANT,
since graphics uses multiple threads.
In this structure your application consists of two parts:
a main program and a shared library.
The main program calls either
The shared library must have the same name as the
executable followed by '.so'.
It must be linked with libboinc_graphics_impl.a,
with your rendering and input-handling functions,
and (dynamically) with glut and opengl.
You must bundle the main program and the shared library together as a
multi-file application version.
A typical linking line in building the main program might look like
this:
A typical linking line in building the shared library might
look like this: In order to communicate data between the worker thread and the
graphics thread, the worker() function can call functions from within
the shared library. To do this, it makes use of the global variable
graphics_lib_handle. If NULL, this means that the host lacks graphics
capabilities. If not NULL, the worker can use
In this approach, an application bundles a
'main program' and a 'graphics program'.
The main program executes the graphics program,
and kills it when done.
The main and graphics programs typically communicate using shared memory;
you can use the functions in boinc/lib/shmem.C for this.
The graphics application can be implemented
using the BOINC framework, in which case it must initialize with
Either the graphics or the main program can handle
graphics messages from the core client.
It's easiest to have the graphics program handle them;
if the main program handles them, it must convey them to the graphics program.
Programs that use BOINC graphics must supply the following functions:
The application must supply the following input-handling functions:
The following global variables control frame rate:
boinc_max_fps is an upper bound on the number of frames per second
(default 30).
boinc_max_gfx_cpu_frac is an upper bound on the fraction
of CPU time used for graphics (default 0.5).
Several graphics-related classes were developed for SETI@home.
They may be of general utility.
An application can display a pre-existing image file
(JPEG, GIFF, BMP or Targa) as its graphic.
This is the simplest approach since you
don't need to develop any code.
You must include the image file with each workunit.
To do this, link the application with api/static_graphics.C
(edit this file to use your filename).
You can change the image over time,
but you must change the (physical, not logical)
name of the file each time.
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Shared-library structure
int boinc_init_graphics_lib(WORKER_FUNC_PTR worker, char* argv0);
// for simple apps
int boinc_init_options_graphics_lib(
BOINC_OPTIONS&, WORKER_FUNC_PTR worker, char* argv0
)
// for compound apps
where worker() is as above, and argv0 is the name of the
executable as passed in the second argument of main() as argv[0].
The main program must be linked with libboinc_graphics_lib.a
g++ -pthread -o einstein_4.01_i686-pc-linux-gnu app1.o
app2.o -lboinc_zip -lboinc_api -lboinc -lboinc_graphics_lib -ldl
-lm
where app1.o and app2.o contain the definitions of main() and worker().
g++ -pthread -o
einstein_4.01_i686-pc-linux-gnu.so -shared -fPIC app_graphics1.o
app_graphics2.o -lboinc_graphics_impl -lboinc -lglut -lGLU -lGL -lX11
-lXmu -ldl -lm
where app_graphics1.o and app_graphics2.o contain the definitions
of app_graphics_init(), app_graphics_render(), etc.
communications_function_hook = dlsym(graphics_lib_handle,\"communications_function\");
to resolve pointers to functions which are defined in the graphics
code app_graphicsN.o. In turn, such functions can modify data used by
the graphics code.
Separate-program structure
int boinc_init_options_graphics(BOINC_OPTIONS&, NULL);
and supply rendering and input-handling functions.
Rendering and input-handling functions
bool app_graphics_render(int xs, ys, double time_of_day);
This will be called periodically in the graphics thread.
It should generate the current graphic.
xs and ys are the X and Y sizes of the window,
and time_of_day is the relative time in seconds.
The function should return true if it actually drew anything.
It can refer to the user name, CPU time etc. obtained from
boinc_get_init_data().
Applications that don't do graphics must also supply a
dummy app_graphics_render() to link with the API.
void app_graphics_init();
This is called in the graphics thread when a window is created.
It must make any calls needed to initialize graphics in the window.
void app_graphics_resize(int x, int y);
Called when the window size changes.
void app_graphics_reread_prefs();
This is called, in the graphics thread, whenever
the user's project preferences change.
It can call
boinc_parse_init_data_file();
boinc_get_init_data(APP_INIT_DATA&);
to get the new preferences.
void boinc_app_mouse_move(
int x, int y, // new coords of cursor
bool left, // whether left mouse button is down
bool middle,
bool right
);
void boinc_app_mouse_button(
int x, int y, // coords of cursor
int which, // which button (0/1/2)
bool is_down // true iff button is now down
);
void boinc_app_key_press(
int, int // system-specific key encodings
)
void boinc_app_key_release(
int, int // system-specific key encodings
)
Limiting frame rate
Support classes
Static graphics