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	== Example ==		== Example ==
		+	Display how long the program has been running, by use of frame_time:
		+	<pre>
		+	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
		+	</pre>
		+	Used in example: [[set_mode]](), [[write_int]](), [[write_float]](), [[key]](), [[frame_time]]
		+
	Let a [[process]] wait for a certain time by calling this function:		Let a [[process]] wait for a certain time by calling this function:
	<pre>		<pre>

---

Revision as of 00:18, 21 January 2008

Up to Global Variables

---

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.

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(), frame_time

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, along with an example on how to measure time using frame_time.

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 •