12 replies to this topic

[DarkHorseKnight]

Hello how in this code would I make things happen on its own without doing anything without doing a while loop outside the application which would crash the rest of the program?

///////////////////////////////////////////////
//Main Libary
///////////////////////////////////////////////
#include "SDL/SDL.h"
#include "SDL/SDL_image.h"
//////////////////////////////////////////////

//Main Entry
int main(int argc, char *argv[])
{  
	 //Done setup
	 bool done = false;
	
	 //Surface For Screen
	 SDL_Surface *Screen = NULL;
	
	 //Screen Setup
	 Screen = SDL_SetVideoMode(640,480,32,SDL_SWSURFACE);
	
	 SDL_Event event;
	
	 //While Done = false
	 while(!done)
	 {  
	
		   //While SDL is continous
		   SDL_PollEvent(&event)

		{
		   case SDL_QUIT:

			 return 0;

			break;
		 }
   }
}

[reodor]

The simplest solution is to add whatever code you need to execute after the event switch statement. This will run without any key input.

An alternative is to create a background thread that does the work. This solution requires that you know multi threaded programing

[DarkHorseKnight]

Ty so much

[DarkHorseKnight]

Okay I tried what you said and non of it worked this is what I did

///////////////////////////////////////////////
//Main Libary
///////////////////////////////////////////////
#include "SDL/SDL.h"
#include "SDL/SDL_image.h"
//////////////////////////////////////////////
//Main Entry
int main(int argc, char *argv[])
{
		 //Done setup
		 bool done = false;
	  
		 //Surface For Screen
		 SDL_Surface *Screen = NULL;
	  
		 //Screen Setup
		 Screen = SDL_SetVideoMode(640,480,32,SDL_SWSURFACE);
	  
		 SDL_Event event;
		int enemyfunction(void *unused)
	   {
		  //////////////////////////////////////////////////
					 //Orange Ghost Knight Logic
		 /////////////////////////////////////////////////

		 SDL_Rect OrangeGhostKnightRect;
		 SDL_Rect StorageRect10;
		StorageRect10.x = 400;
		StorageRect10.y = 320;

		 ///////////////////////////////////////////////

			if(StorageRect10.x == 400)
						{
                         StorageRect10.x += 40;
                         OrangeGhostKnightRect = StorageRect10;
                         SDL_BlitSurface(OrangeGhostKnightSurf,NULL,Screen,&OrangeGhostKnightRect);
						}

					 if(StorageRect10.x == 2000)
						{
						   StorageRect10.x -=40;
						   OrangeGhostKnightRect = StorageRect10;
						   SDL_BlitSurface(OrangeGhostKnightSurf,NULL,Screen,&OrangeGhostKnightRect);
						}
	   }
		 //While Done = false
		 while(!done)
		 {
	  
				   //While SDL is continous
				   SDL_PollEvent(&event)
				{
				 SDL_Thread *EnemyThread;
				EnemyThread = SDL_CreateThread(Enemyfunction,NULL);
				   case SDL_QUIT:
						 return 0;
						break;
				 }
   }
}

And then the orangeghostknight only shows once and then dissappears on the background blitting

[SimonForsman]

You don't have a switch statement for your case SDL_QUIT: so the return 0; break; part will always run.

[DarkHorseKnight]

Oh yea sorry let me redo that

///////////////////////////////////////////////
//Main Libary
///////////////////////////////////////////////
#include "SDL/SDL.h"
#include "SDL/SDL_image.h"
//////////////////////////////////////////////
//Main Entry
int main(int argc, char *argv[])
{
				 //Done setup
				 bool done = false;
		
				 //Surface For Screen
				 SDL_Surface *Screen = NULL;
		
				 //Screen Setup
				 Screen = SDL_SetVideoMode(640,480,32,SDL_SWSURFACE);
		
				 SDL_Event event;
				int enemyfunction(void *unused)
		   {
				  //////////////////////////////////////////////////
				  //Orange Ghost Knight Logic
				 /////////////////////////////////////////////////
				 SDL_Rect OrangeGhostKnightRect;
				 SDL_Rect StorageRect10;
				StorageRect10.x = 400;
				StorageRect10.y = 320;
				 ///////////////////////////////////////////////
						if(StorageRect10.x == 400)
												{
						 StorageRect10.x += 40;
						 OrangeGhostKnightRect = StorageRect10;
						 SDL_BlitSurface(OrangeGhostKnightSurf,NULL,Screen,&OrangeGhostKnightRect);
					   }
						 if(StorageRect10.x == 2000)
					   {
					  StorageRect10.x -=40;
					  OrangeGhostKnightRect = StorageRect10;
					  SDL_BlitSurface(OrangeGhostKnightSurf,NULL,Screen,&OrangeGhostKnightRect);
					   }
		   }
				 //While Done = false
				 while(!done)
				 {
		
		 //While SDL is continous
	 SDL_PollEvent(&event)
								{
		switch(event.type)
		{
		  SDL_Thread *EnemyThread;
		EnemyThread = SDL_CreateThread(Enemyfunction,NULL);
		   case SDL_QUIT:
			return 0;
				break;
								 }
   }
}

[Madhed]

So? What's happening?

http://wiki.libsdl.o...i/SDL_PollEvent

Actually I'm not sure what SDL_PollEvent does to "event" when there are no events in the queue, but you should definitely check if it returns 1.

[BeerNutts]

Undergrowth, go back to learning how to program. Start with C++ Tutorial #1 (just pick a good C++ tutorial). When you're finished with all the tutorials, you might could come back to this, and you'll laugh at everything you are doing wrong.

It's obvious you don't know how to program yet. Learn how to program properly 1st, then try some graphics stuff.

[DarkHorseKnight]

That code is messed up above the real code is alot better I can ashore you

[SimonForsman]

That code is messed up above the real code is alot better I can ashore you

Then post the real code so we can help you instead of posting something different that only sidetracks the discussion.

[rip-off]

You appear to be declaring a function inside another. This is illegal in standard C and C++. I recommend avoiding threads for the moment if you're still having trouble with things like this. Threads are very advanced topics that trip up even the most experienced programmer. They are totally unsuitable for someone posting in "For Beginners".

[DarkHorseKnight]

Okay lets simplify this I want my enemy to move and do things on his own

how would I do that? .

If you can show some code if possible that would exactly replicate this result in SDL then I can learn from it otherwise I will be stuck in a endless race of trying to figure it out for myself in which I will fail many times.

on that note been doing that already and the closest I have gotten is having the image come on the screen at the start of the level and then the code doesn't loop even tho I tried a for loop with the drawing and a while loop also with the drawing both of which failed then tried it with updating the screen with SDL_UpdateRect and also SDL_Flip() which if I Remember correctly caused the awesome flicker bug which I hate oh so very much.

so what are the common causes of problems of this nature where most drawing and updating doesn't work constantly even when the image is loaded on the surface?

[BeerNutts]

Okay lets simplify this I want my enemy to move and do things on his own

how would I do that? .

If you can show some code if possible that would exactly replicate this result in SDL then I can learn from it otherwise I will be stuck in a endless race of trying to figure it out for myself in which I will fail many times.

on that note been doing that already and the closest I have gotten is having the image come on the screen at the start of the level and then the code doesn't loop even tho I tried a for loop with the drawing and a while loop also with the drawing both of which failed then tried it with updating the screen with SDL_UpdateRect and also SDL_Flip() which if I Remember correctly caused the awesome flicker bug which I hate oh so very much.

so what are the common causes of problems of this nature where most drawing and updating doesn't work constantly even when the image is loaded on the surface?

Undergrowth, I didn't suggest you start from the beginning just for fun. If you did start from scratch, learn C++ programming, how functions, loops, conditionals, etc. are supposed to work, you'd know exactly what you were doing wrong. It will be the best thing for you in the long run, i promise.