Help Beginner

**b-k24** · 02-21-2009

I already have the collision function working fine...now in the collision function i used target[i] (which at the time of testing i set i=0in which loads the image target[0] for my collision detection( I have 6 images target[0],target[1],target[2] etc). But now i want to use the collision function for all my array of images so i was wondering if i could get ("i" //variable) to equal to 0,1,2,3,4,5 which corresponds with all my images target[0],target[1],target[2] etc.So in the end all i will have in my collision function is target[i] which will cover collision for my 6 images.

its driving me nuts

**IceBall** · 02-21-2009

you want to use a for-loop

Code:

for(i = 0; i < 6; i++) {
// your code here
}

**b-k24** · 02-21-2009

i am not sure...i have been learning on my own so not much experience on how things work..how can i use the loop to get all objects of my target[] array to equal to (i)?

**IceBall** · 02-21-2009

the loop i posted will run 6 times - i will be 0 the first time (since it's initialized by i = 0; ) and incremented by 1 every run (i++; )

So you will be able to use target[i] inside of the loop to access all items of your array.

There is a nice tutorial on this site: here

**b-k24** · 02-21-2009

int x;

for(x = 0; x < 6; x++) {
i=x;

is this rite?

**IceBall** · 02-21-2009

it's missing a } at the end
If "i" is an int too, you would not need to use x - you can use i instead.

**b-k24** · 02-21-2009

OK thanks I'll give it a try now

**MK27** · 02-21-2009

Originally Posted by IceBall

it's missing a } at the end

Code:

If you only have {one command within brackets}, 
you can optionally leave them out:

for(x = 0; x < 6; x++) i=x;

**IceBall** · 02-21-2009

yeah MK27 thats correct
i was reffering to b-k24's code --> an opening-brace requires always a closing-brace.

**MK27** · 02-21-2009

There was no problem -- I was just mentioning a permissible alternative. Which that maddening avatar should not be. I may have to kill you if you don't come up with something more pleasant

**b-k24** · 02-21-2009

still not working

here is my code
am coding for the psp.

Code:

#include <oslib/oslib.h>
#include <stdio.h>



//Necessary to create eboot
PSP_MODULE_INFO("OSLib Sample", 0, 1, 1);
PSP_MAIN_THREAD_ATTR(THREAD_ATTR_USER | THREAD_ATTR_VFPU);

//declaration of the pointers of our images
OSL_IMAGE *background,*crosshair,*bg,*target[5],*gun,*hud;


 //variables
#define RIGHT  0


float j=0,sty,collision=0,collide=0;
int counter,target_choice=0,stretchx,stretchy,width,height;
int gun_march=0,gun_position;
int i;
int p;
void Hud();
void GAME();
void keys();
void target_AI();
void GunAnimate();

bool collisionHS( float targetposX, float targetposY, float crosshairposX, float crosshairposY)
{
int collision,collide=0;
collision = 0;
int *strhx=&stretchx;


target[i]->y=targetposY;
target[i]->x=targetposX;
crosshair->x=crosshairposX;
crosshair->y=crosshairposY;


float targetwidth = 35+*strhx;
float targetheight = sty;
float crosshairwidth = 10;
float crosshairheight = 10;

 
 if ((targetposX + targetwidth > crosshairposX) &&
(targetposX < crosshairposX + crosshairwidth) &&
(targetposY + targetheight+20 > crosshairposY) &&
(targetposY < crosshairposY + crosshairheight))
{
collision = 1; collide=2;
}


return collision;
}


bool collisionBD( float targetposX1, float targetposY1, float crosshairposX1, float crosshairposY1)
{
int collision1;
collision1 = 0;
int *strhx1=&stretchx;


target[i]->y=targetposY1;
target[i]->x=targetposX1;
crosshair->x=crosshairposX1;
crosshair->y=crosshairposY1;


float targetwidth1 = 35+*strhx1;
float targetheight1 = sty;
float crosshairwidth1 = 10;
float crosshairheight1 = 10;





 

           if((targetposX1 + targetwidth1 > crosshairposX1) &&
(targetposX1 < crosshairposX1 + crosshairwidth1) &&
(targetposY1+25 + targetheight1+50 > crosshairposY1) &&
(targetposY1+25 < crosshairposY1 + crosshairheight1)){ collision1 = 1;}
       


return collision1;
}

int GetRandomNum(int lo, int hi)
{
 SceKernelUtilsMt19937Context ctx;
 sceKernelUtilsMt19937Init(&ctx, time(NULL)); //SEED TO TIME
 u32 rand_val = sceKernelUtilsMt19937UInt(&ctx);
 rand_val = lo + rand_val % hi;
 return (int)rand_val;
}

void keys(){

           //crosshair movement
          if(osl_keys->held.right)crosshair->x+=4;
		  if(osl_keys->held.left)crosshair->x-=4;
		  if(osl_keys->held.up)crosshair->y-=4;
		  if(osl_keys->held.down)crosshair->y+=4;
		  //
		  if (osl_keys->held.circle){ target[i]->stretchX++; 
		  target[i]->stretchY++;
		    stretchx++;
	    stretchy++;
		  sty+=.80;} //zoom target
		  
		  if (osl_keys->held.cross){ target[i]->stretchX--; 
		  target[i]->stretchY--;
		    stretchx--;
	    stretchy--;
		  
		   sty-=.80;} //zoom target

}

void GAME(){

	
	    ///darw images
	    oslDrawImage(bg);
		oslDrawImage(target[0]);
		oslDrawImage(target[1]);
		oslDrawImage(crosshair);
		oslDrawImage(hud);
		oslDrawImage(gun);
		
		
		

		////keys
		keys();
		////
		GunAnimate();
		//
		Hud();
		//
		target_AI();


}

void target_AI(){
	//
	
	  if (collisionHS( target[i]->x , target[i]->y, crosshair->x, crosshair->y ))oslPrintf_xy(250,60,"headshot");
	  if (collisionBD( target[i]->x , target[i]->y, crosshair->x, crosshair->y ))oslPrintf_xy(250,70,"bodyshot");

   


}
void GunAnimate()
   {	
		

		//Moves the sprite constantly with no static position
		oslSetImageTileSize(gun,(gun_march * 36),gun_position,36,60);

		//resets the sprite movement in that row
		if(crosshair->x>145 && crosshair->x<345 && gun->y>86)gun_march = 0;
		if(crosshair->y<86 && crosshair->x<145)gun_march = 1;
		if(crosshair->x>345 && crosshair->y<86)gun_march = 2;
		if(crosshair->x<145 && crosshair->y>86)gun_march = 3;
		if(crosshair->x>345 && crosshair->y>86)gun_march = 4;

  
 }

void Hud(){

	//
	if(hud->x<0)hud->x+=8;


}
		
int main(int argc, char **argv)
{
	//Initialization of the Oslib library
	oslInit(0);

	//Initialization of the graphics mode
	oslInitGfx(OSL_PF_8888, 1);

	oslInitConsole();				//Text

	oslSetTransparentColor(RGB(255,0,255));
	
	//loads our images into memory
	crosshair = oslLoadImageFile("crosshair.png", OSL_IN_RAM, OSL_PF_5551);
	bg = oslLoadImageFile("bg.png", OSL_IN_RAM, OSL_PF_5551);
	 target[0] = oslLoadImageFile("target.png", OSL_IN_RAM, OSL_PF_5551);
     if(target[0]==NULL) oslFatalError("t didn't load in");
     target[1] = oslLoadImageFile("target1.png", OSL_IN_RAM, OSL_PF_5551);
     if(target[1]==NULL) oslFatalError("t1 didn't load in");
     target[2] = oslLoadImageFile("target2.png", OSL_IN_RAM, OSL_PF_5551);
     if(target[2]==NULL) oslFatalError("t2 didn't load in");
     target[3] = oslLoadImageFile("target3.png", OSL_IN_RAM, OSL_PF_5551);
     if(target[3]==NULL) oslFatalError("t3 didn't load in");
	  target[4] = oslLoadImageFile("target4.png", OSL_IN_RAM, OSL_PF_5551);
     if(target[4]==NULL) oslFatalError("t4 didn't load in");
	  target[5] = oslLoadImageFile("target5.png", OSL_IN_RAM, OSL_PF_5551);
     if(target[5]==NULL) oslFatalError("t5 didn't load in");
	 gun = oslLoadImageFile("gun.png", OSL_IN_RAM, OSL_PF_5551);
	  hud = oslLoadImageFile("hud.png", OSL_IN_RAM, OSL_PF_5551);



	
   
    
	//positions
   crosshair->x =100;
   crosshair->y =150;

   target[0]->x =200;
   target[0]->y =60;
   target[1]->x =250;
   target[1]->y =120;

   gun->x =300;
   gun->y =220;
   hud->x =-200;
   hud->y =237;

   //for loop
for(p=0; p < 6; p++ )i=p;
  
    
   
	 	//main while loop
	while (!osl_quit)
	{
		//To be able to draw on the screen
		oslStartDrawing();

		//Clear the screen
		oslCls();

		//initiate the PSP's buttons
		oslReadKeys();
		///
		GAME();




		




		//Ends drawing mode
		oslEndDrawing();

		//Synchronizes the screen
		oslSyncFrame();		
	}

	//Terminate the program
	oslEndGfx();
	oslQuit();
	return 0;
}

I tried this and the collision only worked for one of my targets(target[1])and not target[0]

//for loop
for(p=0; p < 2; p++ ){
if(p==0)i=0;
if(p==1)i=1;
}

**vart** · 02-21-2009

your problem - using of too many global vars

get rid of them and pass the data the function should work with as a parameters

**Adak** · 02-21-2009

You're going to want i and p to be local variables, so you can use them freely inside any function.

Code:

  //for loop
   for(p=0; p < 2; p++ ) {
      if(p==0)i=0;
      if(p==1)i=1;
   }

It seems like the above is doing this:

Code:

   //for loop
   for(p=0; p < 2; p++ ) {
      i = p;
   }

But since there is no other code in that for loop, it just results in:

Code:

  i = 1;

Which probably isn't what you want.

Working with i and p as local variables may seem more of a PITA right now, but it will definitely improve your programming - and we're right here if you need to ask something about it.

**b-k24** · 02-21-2009

plz explain more about this local variables of which u speak..and yea the for loop (i)is always equal to 1.when i want (i)value to equal 0then1then0then1 etc.

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