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Frame time
From FenixWiki
[edit] Definition
FLOAT frame_time
Frame_time is a global variable, holding the time passed the last frame. In other words: the difference in time between the start of the last frame and the current frame.
Doing a bit of physics, we see that:
- FPS = 1 / frame_time
Be advised that frame_time is in milliseconds accurate, so it can be 0 at times, so one might prevent such a case from happening:
- FPS = 1 / ( frame_time + (frame_time==0)*0.0001 );
This gives a sort of FPS which is accurate every frame.
[edit] Example
Display how long the program has been running, by use of frame_time:
Program timers;
Private
int ft; // Help variable
int i; // how long the program has been running in 1/100s
float f; // how long the program has been running in 1/100s
Begin
set_mode(320,400,8);
write_int (0,0,300,0,&timer);
write_int (0,0,310,0,&i);
write_float (0,0,320,0,&f);
Repeat
// Calculate how long the program has been running in 1/100s without a float
ft %= 10; // keep the milliseconds from last time
ft += frame_time*1000; // add the last passed time to it in milliseconds
i += ft/10; // add it to the integer without the milliseconds
// Calculate how long the program has been running in 1/100s with a float
f+=frame_time*100;
frame;
Until(key(_ESC))
End
Used in example: set_mode(), write_int(), write_float(), key(), timer
Let a process wait for a certain time by calling this function:
Function int wait(float seconds)
Begin
While( (seconds-=frame_time) > 0 ) frame; End
return -seconds;
End
This can be done with a timer too, as is displayed here.
| Global variables | |
| • Argc • Argv • Cdinfo • Dump_type • Fading • Fileinfo • Fps • Frame_time • Full_screen • Graph_mode • Mouse • Os_id • Restore_type • Scale_mode • Scroll • Sound_channels • Sound_freq • Sound_mode • Text_flags • Text_z • Timer • | |
