SDL getting multiple key imputs at once

Hey all I am new here, so I have a problem, I am trying to get multiple key imputs in sdl at once, but I am only to in few presses 2 key impust...

I need to get few imputs at once for moving object down + left, or left + up.

Here is the short code for moving an object


 while( SDL_PollEvent( &event ) ) {
 
 if(event.type == SDL_KEYDOWN)
 {
 switch(event.key.keysym.sym) {
 case SDLK_UP: yVel = -1; break;
 case SDLK_DOWN: yVel = 1; break;
 case SDLK_RIGHT: xVel = 1; break;
 case SDLK_LEFT: xVel = -1; break;
 }
 }
 else if(event.type == SDL_KEYUP)
 {
 switch(event.key.keysym.sym) {
 case SDLK_UP: yVel = 0; break;
 case SDLK_DOWN: yVel = 0; break;
 case SDLK_RIGHT: xVel = 0; break;
 case SDLK_LEFT: xVel = 0; break;
 }
 } 
 
 if( event.type == SDL_QUIT ) {
 quit = true;
 }
 
 }
 y += yVel;
 
 x += xVel;
 
 if (( x < 0 ) || ( x + DOT_WIDTH > SCREEN_WIDTH )) {
 x -= xVel;
 }
 
 if( ( y < 0 ) || ( y + DOT_HEIGHT > SCREEN_HEIGHT ) ) {
 y -= yVel;
 }

static bool isLeftPressed = false; static bool isRightPressed = false; // etc while(SDL_PollEvent(&event)) { if(event.type == SDL_KEYDOWN) { switch(event.key.keysm.sym) { case SDLK_LEFT: isLeftPressed = true; break; case SDLK_RIGHT: isRightPressed = true; break; // etc } } else if(event.type == SDL_KEYUP) { switch(event.key.keysm.sym) { case SDLK_LEFT: isLeftPressed = false; break; case SDLK_RIGHT: isRightPressed = false; break; // etc } } } if(isLeftPressed) { // ... } if(isRightPressed) { // ... }

didnt work maybe I have some problems in my whole code...


 #include "SDL/SDL.h"
 #include "SDL/SDL_image.h"
 #include <string>
 const int SCREEN_WIDTH = 300;
 const int SCREEN_HEIGHT = 300;
 const int SCREEN_BPP = 32;
 const int FRAMES_PER_SECOND = 10;
 const int DOT_WIDTH = 12;
 const int DOT_HEIGHT = 12;
 SDL_Surface *block = NULL;
 SDL_Surface *background = NULL;
 SDL_Surface *screen = NULL;
 SDL_Event event;
 
 class Timer
 {
 private:
 int startTicks;
 int pausedTicks;
 bool paused;
 bool started;
 public:
 Timer();
 void start();
 void stop();
 void pause();
 void unpause();
 int get_ticks();
 bool is_started();
 bool is_paused();
 };
 
 SDL_Surface *load_image( std::string filename ) {
 
 SDL_Surface* loadedImage = NULL;
 SDL_Surface* optimizedImage = NULL;
 
 loadedImage = IMG_Load( filename.c_str() );
 
 if( loadedImage != NULL ) {
 
 optimizedImage = SDL_DisplayFormat( loadedImage );
 SDL_FreeSurface( loadedImage );
 
 if( optimizedImage != NULL) {
 Uint32 colorkey = SDL_MapRGB( optimizedImage->format, 53, 255, 255 );
 SDL_SetColorKey( optimizedImage, SDL_SRCCOLORKEY, colorkey );
 } 
 }
 
 return optimizedImage;
 }
 void apply_surface( int x, int y, SDL_Surface* source, SDL_Surface* destination) {
 SDL_Rect offset;
 offset.x = x;
 offset.y = y;
 SDL_BlitSurface( source, NULL, destination, &offset );
 }
 bool init() {
 
 if( SDL_Init( SDL_INIT_EVERYTHING ) == -1 ) {
 return false;
 }
 
 screen = SDL_SetVideoMode( SCREEN_WIDTH, SCREEN_HEIGHT, SCREEN_BPP, SDL_SWSURFACE );
 
 if( screen == NULL ) {
 return false;
 }
 
 SDL_WM_SetCaption( "Project", NULL );
 return true;
 }
 bool load_files() {
 
 background = load_image( "Background.png" );
 block = load_image( "block.png" );
 
 if( (background == NULL)||(block == NULL)) {
 return false;
 }
 
 return true;
 }
 
 void clean_up() {
 SDL_FreeSurface( background );
 SDL_FreeSurface( block );
 SDL_Quit();
 }
 
 
 Timer::Timer()
 {
 startTicks = 0;
 pausedTicks = 0;
 paused = false;
 started = false;
 }
 void Timer::start()
 {
 started = true;
 paused = false;
 startTicks = SDL_GetTicks();
 }
 void Timer::stop()
 {
 started = false;
 paused = false;
 }
 void Timer::pause()
 {
 if( ( started == true ) && ( paused == false ) )
 {
 paused = true;
 pausedTicks = SDL_GetTicks() - startTicks;
 }
 }
 void Timer::unpause()
 {
 if( paused == true )
 {
 paused = false;
 startTicks = SDL_GetTicks() - pausedTicks;
 pausedTicks = 0;
 }
 }
 int Timer::get_ticks()
 {
 if( started == true )
 {
 if( paused == true )
 {
 return pausedTicks;
 }
 else
 {
 return SDL_GetTicks() - startTicks;
 }
 }
 return 0;
 }
 bool Timer::is_started()
 {
 return started;
 }
 bool Timer::is_paused()
 {
 return paused;
 }
 int main( int argc, char* args[] ) {
 
 int x,y;
 static bool isLeftPressed = false;
 static bool isRightPressed = false;
 static bool isUpPressed = false;
 static bool isDownPressed = false;
 bool quit = false;
 int frame = 0;
 bool cap = true;
 Timer fps;
 
 x = 140;
 y = 140;
 
 if( init() == false ) {
 return 1;
 }
 
 if( load_files() == false ) {
 return 1;
 }
 
 
 while( quit == false ) {
 
 fps.start();
 while( SDL_PollEvent( &event ) ) {
 
 if(event.type == SDL_KEYDOWN)
 {
 switch(event.key.keysym.sym) {
 case SDLK_UP: isUpPressed = true; break;
 case SDLK_DOWN: isDownPressed = true; break;
 case SDLK_RIGHT: isRightPressed = true; break;
 case SDLK_LEFT: isLeftPressed = true; break;
 }
 }
 else if(event.type == SDL_KEYUP)
 {
 switch(event.key.keysym.sym) {
 case SDLK_UP: isUpPressed = false; break;
 case SDLK_DOWN: isDownPressed = false; break;
 case SDLK_RIGHT: isRightPressed = false; break;
 case SDLK_LEFT: isLeftPressed = false; break;
 }
 } 
 
 if( event.type == SDL_QUIT ) {
 quit = true;
 }
 
 }
 if(isLeftPressed)
 {
 x -= 1;
 }
 if(isUpPressed)
 {
 y -= 1;
 }
 if(isRightPressed)
 {
 x += 1;
 }
 if(isDownPressed)
 {
 y += 1;
 } 
 
 
 
 
 apply_surface( 0, 0, background, screen );
 apply_surface( x, y, block, screen );
 
 if( SDL_Flip( screen ) == -1 ) {
 return 1;
 }
 
 
 frame++;
 
 if( ( cap == true ) && ( fps.get_ticks() < 1000 / FRAMES_PER_SECOND ) )
 {
 SDL_Delay( ( 1000 / FRAMES_PER_SECOND ) - fps.get_ticks() );
 }
 } 
 clean_up();
 return 0;
 }

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