Timing in Games - GameCreators Forum

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HumanMan

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Posted: 11th Apr 2010 23:17

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I want to have a "see how many things you can get in the time limit" kinda game
here is the relevant part of my code :

+ Code Snippet

dbSetTextSize(30);
	char ctime [9],stime [9];
	_strtime( stime );	
    
	// imgages
	dbLoadImage("pacman.png",1);
	dbLoadImage("box.bmp",2);
	
	// sprites
	dbSprite(1,200,200,1); //pac man 1
	dbOffsetSprite(1,dbSpriteWidth(1) / 2,dbSpriteHeight(1) / 2);
	dbSprite(2,rand()%550,rand()%375,2); // random block 2

     
    
	while(LoopGDK())
	{	
		// Text
		_strtime( ctime );
		dbText(0,0,dbStr(ctime-stime));

you can ignore the middle part the aim in the end is to have a timer that reaches 0 when 10s are up but when i take time(current ctime) from start time( stime) i get 20 constantly and also i get this error once the game has quitted ever since the time addition

i need to know a). a totally different take on the time thing
or b). a fix for my time thing
and c). an explanation to the error (image attached)

help??

-James

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Bran flakes91093

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Joined: 13th Sep 2008

Location: Crazy Land

Posted: 11th Apr 2010 23:44 Edited at: 11th Apr 2010 23:47

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You're subtracting two pointers here:
dbText(0,0,dbStr(ctime-stime));

I'd use clock() and clock_t from <ctime> if you need seconds. Look to GetTickCount if you need higher resolution timing.
http://www.cplusplus.com/reference/clibrary/ctime/clock/

The error is probably caused by you trying to read memory that is not yours through the use of dbStr when you subtract those two pointers.

By the way, you're causing a memory leak by using dbStr since you don't use it correctly. Use it like this:

+ Code Snippet

char* str = dbStr(...);
dbText(0, 0, str);
delete[] str;

Or you can use sprintf:

+ Code Snippet

char str[32];
sprintf(str, "FPS: %d", dbScreenFPS());
dbText(0, 0, str);

http://www.cplusplus.com/reference/clibrary/cstdio/sprintf/

"A computer once beat me at chess, but it was no match for me at kick boxing."
Emo Philips

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HumanMan

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Posted: 12th Apr 2010 10:35

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can you show me the usage please

e.g. a timer that's updated every loop showing seconds since program start

thanks

-James

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HumanMan

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Posted: 12th Apr 2010 10:46

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actualy i apear to have found a solution

code dump:

+ Code Snippet

	clock_t begin,end,dif;
	char showtime[32];
	begin = clock();
	
	while(LoopGDK())
	{	
		// Text
		end = clock();
		dif = end - begin;
		sprintf(showtime,"Timer: %d",dif);
		dbText(0,0,showtime);

hope this helps anyone that has the same problem

-James

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MadBit

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Joined: 25th Jun 2009

Location: Germany

Posted: 12th Apr 2010 14:53

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Why you don't use the DarkGDK-Function dbTimer(); The Sample above looks like this ...

+ Code Snippet

	int begin,end,dif;
	char showtime[32];
	begin = dbTimer();
	
	while(LoopGDK())
	{	
		// Text
		end = dbTimer();
		dif = end - begin;
		sprintf(showtime,"Timer: %.3f sec.", ((float)dif/1000.0));
		dbText(0,0,showtime);

With Computers you can solve Problems that you have never befor.

My English is so BAD ;(

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Dark GDK / Timing in Games

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