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Use a constant frame rate (25 fps) in test/cube demo

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The old version was "synchronized" by calling Fl::check() in a loop
which resulted in the highest speed possible on any platform.

It turned out that this was way too fast on the Wayland platform as
`valerius` posted on IRC/Matrix on Nov 30, 2024. Citation:
"anyone else notice the cube demo on Wayland is mega ultra hyper speed?".

I took the opportunity to change the demo to use a timer with a given
frame rate (see constant 'FPS') to synchronize drawing.
Note: the 'speed' slider is independent of the drawing frequency.

Finally this commit adds statistics output when the 'Stats / Exit' button
is pressed like

  Iterations =  304, runtime = 12.167 sec, fps = 24.99, requested: 25

with the requested frame rate (default = 25) and allows the user to
continue to see more statistics.

To do (very likely not in 1.4.x):
 1. integrate running statistics in the display
 2. make the desired frame rate variable at runtime (new slider)
This commit is contained in:
Albrecht Schlosser 2024-12-01 15:07:12 +01:00 committed by Albrecht Schlosser
parent 12ea6a0288
commit 5160567728
1 changed files with 124 additions and 38 deletions
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162
test/cube.cxx
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@ -16,7 +16,18 @@
// https://www.fltk.org/bugs.php
//
#include <config.h>
// Define 'HAVE_GL=1' on the compiler commandline to build this program
// w/o 'config.h' (needs FLTK lib with GL).
// $ fltk-config --use-gl --compile cube.cxx -DHAVE_GL=1
// Use '-DHAVE_GL=0' to build and test w/o OpenGL support.
#ifndef HAVE_GL
#include <config.h> // needed only for 'HAVE_GL'
#endif
// ... or uncomment the next line to test w/o OpenGL (see also above)
// #undef HAVE_GL
#include <FL/Fl.H>
#include <FL/fl_ask.H>
#include <FL/Fl_Window.H>
@ -27,7 +38,23 @@
#include <FL/Fl_Sys_Menu_Bar.H>
#include <FL/Fl_Printer.H> // demo printing
#include <FL/Fl_Grid.H> // grid layout
#include <stdlib.h>
// Glocal constants and variables
const int FPS = 25; // desired frame rate (independent of speed slider)
const int MAX_LOOP = 0; // <= 0: no limit, >0: max. timer (draw) iterations
int iters = 0; // total loop (draw) iterations
int done = 0; // set to 1 in exit button callback
Fl_Timestamp start; // taken at start of main
// Pointers to widgets
class cube_box; // forward declaration
Fl_Window *form;
Fl_Slider *speed, *size;
Fl_Button *exit_button, *wire, *flat;
cube_box *lt_cube, *rt_cube;
#if !HAVE_GL
class cube_box : public Fl_Box {
@ -36,7 +63,7 @@ public:
int wire;
double size;
double speed;
cube_box(int x,int y,int w,int h,const char *l=0) :Fl_Box(FL_DOWN_BOX,x,y,w,h,l) {
cube_box(int x,int y,int w,int h,const char *l=0) : Fl_Box(FL_DOWN_BOX,x,y,w,h,l) {
label("This demo does\nnot work without GL");
}
};
@ -95,7 +122,7 @@ void drawcube(int wire) {
}
void cube_box::draw() {
lasttime = lasttime+speed;
lasttime = lasttime + speed;
if (!valid()) {
glLoadIdentity();
glViewport(0,0,pixel_w(),pixel_h());
@ -153,15 +180,59 @@ void overlay_button(cube_box *cube) {
#endif // HAVE_GL
Fl_Window *form;
Fl_Slider *speed, *size;
Fl_Button *exit_button, *wire, *flat;
cube_box *lt_cube, *rt_cube;
int done = 0; // set to 1 in exit button callback
void exit_cb(Fl_Widget *w = NULL, void *v = NULL) {
// exit button callback
void exit_cb(Fl_Widget *w, void *) {
done = 1;
// display performance data on stdout and (for Windows!) in a message window
double runtime = Fl::seconds_since(start);
char buffer[120];
sprintf(buffer, "Iterations = %4d, runtime = %7.3f sec, fps = %5.2f, requested: %d",
iters, runtime, iters / runtime, FPS);
printf("%s\n", buffer);
fflush(stdout);
int choice = fl_choice(buffer, "Continue", "Exit", NULL);
if (choice == 1) {
// exit program, close all windows
done = 1;
Fl::hide_all_windows(); // return from Fl::run()
}
}
#if HAVE_GL
void timer_cb(void *data) {
iters++;
if (done || (MAX_LOOP > 0 && iters >= MAX_LOOP)) {
exit_cb();
return;
}
lt_cube->redraw();
rt_cube->redraw();
Fl::repeat_timeout(1.0/FPS, timer_cb);
}
#endif // HAVE_GL
void speed_cb(Fl_Widget *w, void *) {
lt_cube->speed = rt_cube->speed = ((Fl_Slider *)w)->value();
}
void size_cb(Fl_Widget *w, void *) {
lt_cube->size = rt_cube->size = ((Fl_Slider *)w)->value();
}
void flat_cb(Fl_Widget *w, void *) {
int flat = ((Fl_Light_Button *)w)->value();
lt_cube->wire = 1 - flat;
rt_cube->wire = flat;
}
void wire_cb(Fl_Widget *w, void *) {
int wire = ((Fl_Light_Button *)w)->value();
lt_cube->wire = wire;
rt_cube->wire = 1 - wire;
}
// print screen demo
@ -234,8 +305,9 @@ void makeform(const char *name) {
flat = new Fl_Radio_Light_Button( 0, 0, 100, 25, "Flat");
speed = new Fl_Slider(FL_VERT_SLIDER, 0, 0, 40, 90, "Speed");
size = new Fl_Slider(FL_VERT_SLIDER, 0, 0, 40, 90, "Size");
exit_button = new Fl_Button( 0, 0, 100, 25, "Exit");
exit_button = new Fl_Button( 0, 0, 100, 25, "Stats / Exit");
exit_button->callback(exit_cb);
exit_button->tooltip("Display statistics (fps) and\nchoose to exit or continue\n");
// right GL window
rt_cube = new cube_box(0, 0, 350, 350);
@ -263,43 +335,57 @@ int main(int argc, char **argv) {
Fl::use_high_res_GL(1);
Fl::set_color(FL_FREE_COLOR, 255, 255, 0, 75);
makeform(argv[0]);
speed->bounds(4, 0);
speed->value(lt_cube->speed = rt_cube->speed = 1.0);
speed->bounds(6, 0);
speed->value(lt_cube->speed = rt_cube->speed = 2.0);
speed->callback(speed_cb);
size->bounds(4, 0.2);
size->value(lt_cube->size = rt_cube->size = 2.0);
flat->value(1); lt_cube->wire = 0; rt_cube->wire = 1;
size->callback(size_cb);
flat->value(1);
flat->callback(flat_cb);
wire->value(0);
wire->callback(wire_cb);
form->label("Cube Demo");
form->show(argc,argv);
lt_cube->show();
rt_cube->show();
#if 0
lt_cube->wire = wire->value();
rt_cube->wire = !wire->value();
lt_cube->size = rt_cube->size = size->value();
lt_cube->speed = rt_cube->speed = speed->value();
lt_cube->redraw();
rt_cube->redraw();
#if HAVE_GL
#if (0) // share OpenGL contexts
// This demonstrates how to manipulate OpenGL contexts.
// In this case the same context is used by multiple windows (I'm not
// sure if this is allowed on Win32, can somebody check?).
// This fixes a bug on the XFree86 3.0 OpenGL where only one context per
// program seems to work, but there are probably better uses for this!
lt_cube->make_current(); // causes context to be created
rt_cube->context(lt_cube->context()); // share the contexts
#endif
#if HAVE_GL
for (;;) {
if (form->visible() && speed->value()) {
if (!Fl::check()) break; // returns immediately
} else {
if (!Fl::wait()) break; // waits until something happens
}
lt_cube->wire = wire->value();
rt_cube->wire = !wire->value();
lt_cube->size = rt_cube->size = size->value();
lt_cube->speed = rt_cube->speed = speed->value();
lt_cube->redraw();
rt_cube->redraw();
if (done) break; // exit button was clicked
}
return 0;
#else
while (!done) Fl::wait();
lt_cube->make_current(); // causes context to be created
rt_cube->context(lt_cube->context()); // share the contexts
#endif // share OpenGL contexts
// with GL: use a timer for drawing and measure performance
Fl::add_timeout(0.01, timer_cb); // start timer
start = Fl::now();
int ret = Fl::run();
return ret;
#else // w/o GL: no timer, no performance report
return Fl::run();
#endif
}