{SDL}Displaying multiple images at once

I cleaned it up for you a little bit, but you have what seems like some really unnecessary code in there.

A more detailed description of what you want might help a little too.

#ifdef WIN32
#pragma comment(lib, "SDL.lib")
#pragma comment(lib, "SDLmain.lib")
#endif
#include "SDL.h"

int main( int argc, char* argv[] )
{
  SDL_Init( SDL_INIT_VIDEO );  
  atexit( SDL_Quit );  
  SDL_Surface * screen = SDL_SetVideoMode( 800,600, 24, SDL_ANYFORMAT|SDL_DOUBLEBUF );  
  SDL_Surface * img = SDL_LoadBMP( "filename.bmp" );   
  SDL_Rect dest;  
  dest.x = 200;  
  dest.y = 300;  
  SDL_Event event;
  SDL_Rect coord;
  coord.x = 100;
  coord.y = 100;
  SDL_Surface * tdi
splay;

  while(true)
  {
     SDL_BlitSurface(img,NULL,screen, &dest);  
     SDL_Flip( screen );

     SDL_PollEvent(&event);
     if(event.type == SDL_MOUSEBUTTONDOWN)
     {      
         if(event.button.button == SDL_BUTTON_LEFT)   
         {

	    // this code doesn''t really accompilish much 

	    // and you should free the surface as well

	    SDL_Surface *imi =SDL_LoadBMP("ad.bmp");
	  				                                             SDL_BlitSurface(imi,NULL,tdisplay,&coord);
	    SDL_Flip(screen);
         }
     }
     else if(event.type == SDL_QUIT)
	return 0;
   }
   
   return -1;
}

i''ll try to do it even a little better. Flip() should come at the very end IMHO. The imi image should be pre-loaded first, then blitted when the button is pressed. You should only Flip() once in the loop as well.

Please excuse my exotic code indentation

#ifdef WIN32
#pragma comment(lib, "SDL.lib")
#pragma comment(lib, "SDLmain.lib")
#endif
#include "SDL.h"

int main( int argc, char* argv[] ) {
	SDL_Init( SDL_INIT_VIDEO );
	atexit( SDL_Quit );
	SDL_Surface * screen = SDL_SetVideoMode( 800,600, 24, SDL_ANYFORMAT|SDL_DOUBLEBUF );
	SDL_Surface * img = SDL_LoadBMP( "filename.bmp" );
	SDL_Surface *imi =SDL_LoadBMP("ad.bmp"); // NEW

	SDL_Rect dest;
	dest.x = 200;
	dest.y = 300;
	SDL_Event event;
	SDL_Rect coord;
	coord.x = 100;
	coord.y = 100;
	SDL_Surface * tdisplay;

	while(true) {
		SDL_BlitSurface(img,NULL,screen, &dest);

		SDL_PollEvent(&event);
		if(event.type == SDL_MOUSEBUTTONDOWN) {
			if(event.button.button == SDL_BUTTON_LEFT) {
				SDL_BlitSurface(imi,NULL,tdisplay,&coord);
				}
			}
		else if(event.type == SDL_QUIT) { return 0; }

		SDL_Flip( screen );
		}

   return 0;
}
[source]

how do i set the width,hight,ect

#ifdef WIN32
#pragma comment(lib, "SDL.lib")
#pragma comment(lib, "SDLmain.lib")
#endif
#include "SDL.h"

int main( int argc, char* argv[] )
{
  SDL_Init( SDL_INIT_VIDEO );  
  atexit( SDL_Quit );  
  SDL_Surface * screen = SDL_SetVideoMode( 800,600, 24, SDL_ANYFORMAT|SDL_DOUBLEBUF );  
  SDL_Surface * img = SDL_LoadBMP( "filename.bmp" );   
  SDL_Rect dest;  
  dest.x = 200;  
  dest.y = 300;  
  SDL_Event event;
  SDL_Event a;
  SDL_Event b;
  SDL_Event Event              
	 ;SDL_Rect coord;
			 coord.x = 100;
			 coord.y = 100;
			 SDL_Surface * tdisplay;
  while(true);

Your code enters tight infinite loop here and doesn''t get to any of the actual function calls. This is not the first time you''ve had this problem IIRC. Don''t put the blasted semicolon here if you actually want to *do* something in your while loop. This form is only useful if the while condition does something useful. "true" does not do anything useful on its own.

Your indentation is rather strange too. It won''t harm anything but it makes it harder for others (and yourself) to figure out what''s going on.

  {
SDL_BlitSurface(img,NULL,screen, &dest);  
  SDL_Flip( screen );// wait for user exit

  }

Even after fixing that, you won''t get past this point.

  while( !( SDL_PollEvent(&event) && event.type == SDL_QUIT ) )  {}

This is probably what you want as your condition for the previous while loop, or something along those lines.

SDL_PollEvent(&Event);

This re-polls for no good reason, the event you want to look at is already in ''event''. Having two variables whose names differ only in capitalization is bad idea, too. You *will* get them mixed up eventually even if you do need them both, which you don''t seem to here.

if(Event.type == SDL_MOUSEBUTTONDOWN)
{      
	if(Event.button.button == SDL_BUTTON_LEFT)   
         {
			 SDL_Surface *imi =SDL_LoadBMP("ad.bmp")
            
 ;while(true);

Another one of these extra semicolons. You don''t want to enter a separate tight loop once you receive a click. I get the general impression that you really don''t have any good concept of how the whole "control flow" thing is supposed to work.

			 {
				 SDL_BlitSurface(imi,NULL,tdisplay,&coord)
				;SDL_Flip(screen);
			 }
		 }
}
		 
        return 0;
  }

You didn''t initialize ''tdisplay'' to anything, so it''s not pointing at any particular SDL_Surface.

The reason why I put the semicolon the is because it gives me "missing ; BEFORE whatever." I need to set the w,h,ect for tdisplay because when i cliked it gave me a run-time error

If you get an error abour "missing ; before XXX" then look at the line of code (not braces etc) directly above it and add in the semi-colon.

EDIT: calling Flip() changes the surface to which you are drawing to so only call this after you have drawn all the images you need .

[edited by - Spudder on April 13, 2004 7:17:09 PM]

Run-Time Check Failure #3 - The variable ''tdisplay'' is being used without being defined.

Replace tdisplay with screen. Since you're having some problems, you may want to rewrite the code to use a single buffer.

#ifdef WIN32
#pragma comment(lib, "SDL.lib")
#pragma comment(lib, "SDLmain.lib")
#endif
#include "SDL.h"

int main( int argc, char* argv[] )
{
SDL_Init( SDL_INIT_VIDEO );  
atexit( SDL_Quit );  
SDL_Surface * screen = SDL_SetVideoMode( 800,600, 24, SDL_ANYFORMAT );  
SDL_Surface * img = SDL_LoadBitmap("filename.bmp");

SDL_Rect coords;
coords.x = 0;
coords.y = 0;

while(!( SDL_PollEvent(&event) && event.type == SDL_QUIT))
{
SDL_BlitSurface(img,NULL,screen,&coords);
}
}
  

[edited by - Onemind on April 17, 2004 1:30:50 PM]

Is ther somting wrong with the coordinants

Cords count in from the top left I think

filename shows up but ad dosn''t.

Can anyone help?

I''m thinking maybe you should try starting out with a simpler language? I seem to recall that you''ve been trying this for a long time now, but you''re still not grasping the basic concepts of C++. You''re just copying and pasting code without understanding how it works at all.

You might consider starting with one of those game-related flavors of Basic.

hehe, i didnt put .bmp at the end, sorry.