Thread: While thing

Hi!

I'm making a game, just to learn SDL. But i seem to have some trouble with my code. If i cpoy and paste my code from the while into the switch it works. It is the same code. But if i do like that, the piece wouldn't move if you hold down the button. It would only move when you press the button.

How can i make this work?

Code:

    //While the user hasn't quit
    while( quit == false )
    {  
        //If there's an event to handle
        if( SDL_PollEvent( &event ) )
        {
            //If a key was pressed
            if( event.type == SDL_KEYDOWN )
            {
                //Set the proper holder surface
                switch( event.key.keysym.sym )
                {                       
                    case SDLK_LEFT: 
                         left = true;
                         break;
                         
                    case SDLK_RIGHT:
                         right = true;
                         break;
                         
                    case SDLK_ESCAPE: 
                         quit = true; 
                         break;    
                }
            } 
            
            //Check if the right is pressed
            while (right == true)
            {
                         x = x + 10; 
                         SDL_FillRect( screen, NULL, NULL ); 
                         apply_surface( 0, 0, background, screen );
                         piece = load_image( "piece-right.png" ); 
                         apply_surface( x, y, piece, screen ); 
            }
            
            //Check if the left is pressed
            while (left == true)
            {
                         x = x - 10; 
                         SDL_FillRect( screen, NULL, NULL ); 
                         apply_surface( 0, 0, background, screen );
                         piece = load_image( "piece-left.png" ); 
                         apply_surface( x, y, piece, screen ); 
            }
            
            }    
            //If the user has Xed out the window
            else if( event.type == SDL_QUIT )
            {
                //Quit the program
                quit = true;
            }
    
        //Update the screen
        if( SDL_Flip( screen ) == -1 )
        {
            return 1;    
        }
    }

Hmm... I didn't thought of that. That was a very good question. My answer is: I don't know! Do you have a suggestion?

No, cause if i do that. It would only happen 1 time. You see?

If i recall correctly, SDL only signals when keys are pressed or released. If you want to check if a key is *held down* for a longer time, you'd have to do it manually by also checking for KEYUP events. I'm too busy right now to dust off my SDL-fu and write an example, sorry.

Okey, meanwhile i wait for you to write an example, i'll search on internet.

But i want the game to work. This is the way im learning stuff. Doing it first, so i know how they work. And after that, i read about them. But if you know somewhere hey have KEYUP or something like that, tell me!

Here's the first thing that popped up when I typed "SDL KEYUP" in google:
http://gpwiki.org/index.php/SDL:Tuto...Keyboard_Input

> This is the way im learning stuff. Doing it first, so i know how they work. And after that, i read about them.

I think you might benefit from switching up the paradigm a little bit.

Well, actuallt i learn better from first testing, then reading. It's a fact.

I played around with your link but didn't get it to work. You can see my whole main-function here:

Code:

int main( int argc, char* args[] )
{
    //The pieces coordinates
    int x = 200;
    int y = 200;
    
    //Left flag
    bool left = false;
    
    //Right flag
    bool right = false;
    
    //Quit flag
    bool quit = false;
    
    //Initialize
    if( init() == false )
    {
        return 1;
    }
    
    //Load the files
    if( load_files() == false )
    {
        return 1;
    }
    
    //Apply the background
    apply_surface( 0, 0, background, screen );
    
    //Apply the piece
    apply_surface( 70, 178, piece, screen );
    
    //While the user hasn't quit
    while( quit == false )
    {  
        //If there's an event to handle
        while (SDL_PollEvent(&event))
        {
              if (event.type == SDL_KEYDOWN)
              {
                                switch(event.key.keysym.sym)
                                {
                                                               case SDLK_LEFT:
                                                                     left = true;
                                                                     break;
                                                                     
                                                               case SDLK_RIGHT:
                                                                     right = true;
                                                                     break;
                                                                     
                                                               case SDLK_ESCAPE:
                                                                    quit = true;
                                                                    break;
               }                 }
               
               if (event.type == SDL_KEYUP)
               {
                                 switch(event.key.keysym.sym)
                                 {
                                                                case SDLK_LEFT:
                                                                      left = false;
                                                                      break;
                                                                
                                                                case SDLK_RIGHT:
                                                                     right = false;
                                                                     break;
                                 }
               }      
            //Check if the right is pressed
            while (right == true)
            {
                         x = x + 10; 
                         SDL_FillRect( screen, NULL, NULL ); 
                         apply_surface( 0, 0, background, screen );
                         piece = load_image( "piece-right.png" ); 
                         apply_surface( x, y, piece, screen ); 
            }
            
            //Check if the left is pressed
            while (left == true)
            {
                         x = x - 10; 
                         SDL_FillRect( screen, NULL, NULL ); 
                         apply_surface( 0, 0, background, screen );
                         piece = load_image( "piece-left.png" ); 
                         apply_surface( x, y, piece, screen ); 
            }
            
            }    
            //If the user has Xed out the window
            if( event.type == SDL_QUIT )
            {
                //Quit the program
                quit = true;
            }
    
        //Update the screen
        if( SDL_Flip( screen ) == -1 )
        {
            return 1;    
        }
    }
        
        
    //Clean up
    clean_up();
    
    return 0;    
}