[SDL] Flashing window
Matthew Johnson
levifiction at gmail.com
Sun Aug 19 18:15:09 PDT 2007
It's actually been forever since I've used C++ but wouldn't putting a
";" at the end of an if statement end the if statement altogether? So
that once it reaches
if( SDL_Init(SDL_INIT_EVERYTHING) != 0 );
return 1;
it automatically returns 1? Here's a similar trial I did
int a = 2;
if(a == 3);
cout << "Hello World";
And it displays Hello World.
It might be that simple.
On 8/19/07, justin <kokotusu at hotmail.com> wrote:
> Brian <brian.ripoff <at> gmail.com> writes:
>
> >
> > Why do you undefine main? SDL #defines main for a reason - unless you
> > know what you are doing.
> >
> > Also, it makes it easier for us if you give a description of the
> > symptoms seen versus expected output. I don't know how "screen
> > flashing" relates to your program, you have not described it fully.
> >
> > HTH
> >
> > On 19/08/07, justin <kokotusu <at> hotmail.com> wrote:
> > > Hello my fellow SDL comrades, well i have a problem with my program im
> confuse
> > > if it's either my code or my linking. im sure it probably not my linking
> seen
> > > i check it and it's in a GUI form and main( int argc, char* args[] ) is
> > > present.
> >
>
> first of all, the use of
> #ifdef main
> #undef main
> #endif
>
> is to take off the additional output of
> stdout and stderr....
>
> another thing by mean of flashing window is that the screen fully
> creates but closes instantly.. i debug more of it resulting in my code to look
> like this
> #include "SDL/SDL.h"
> #include "SDL/SDL_image.h"
> #include<iostream>
> #include<string>
> using namespace std;
>
>
> #define SCREENWIDTH 160
>
> #define SCREENHEIGHT 240
>
> #ifdef main
> #undef main
> #endif
>
>
> int const Size = 16;
>
>
> class Rocket
> {
> SDL_Surface *Picture;
>
> SDL_Surface *Optimize;
>
> int dx;
>
> int dy;
>
> public:
>
> Rocket();
> ~Rocket();
> SDL_Surface * LoadPicture(std::string filename);
>
> void move( int x, int y);
>
> int GetX();
>
> int GetY();
>
> };
>
> Rocket::Rocket()
> {
> Picture = NULL;
>
> Optimize = NULL;
>
> dx = SCREENWIDTH / 2;
>
> dy = SCREENHEIGHT / 2;
>
> }
>
> Rocket::~Rocket()
> {
> Picture = NULL;
>
> Optimize = NULL;
>
> dx = 0;
>
> dy = 0;
> }
>
> SDL_Surface * Rocket::LoadPicture(std::string filename)
> {
> Picture = IMG_Load(filename.c_str());
>
> if(Picture != NULL)
> {
> Optimize = SDL_DisplayFormat(Picture);
>
> SDL_FreeSurface(Picture);
>
> }
>
> return Optimize;
>
> }
>
> void Rocket::move( int x, int y)
> {
> dx += x;
>
> dy += y;
>
> }
>
> int Rocket::GetX()
> {
> return(dx);
> }
>
> int Rocket::GetY()
> {
> return(dy);
> }
>
> Rocket rocket;
>
> SDL_Surface * screen;
>
> SDL_Surface * background;
>
> SDL_Surface * user;
>
> SDL_Event event;
>
> int X; int Y;
>
> int pre_x; int pre_y;
>
> int position =0;
>
> Uint32 StartTime;
>
> Uint32 Timediffer;
>
> int XMovement =0;
>
> int YMovement =0;
>
> void DrawMap(int sprite);
>
> int GameInit();
>
> void GameLoop();
>
> void Collision();
>
> void GameDone();
>
> bool GAMESTARTED = false;
>
>
> int main( int argc, char* args[] )
> {
>
>
>
> GameInit();
>
>
> bool quit = false;
>
> while( quit != true)
> {
> GameLoop();
>
>
>
> while( SDL_PollEvent( &event ) )
>
> { switch(event.type)
> {case SDL_KEYDOWN:
> { switch(event.key.keysym.sym)
> {
> case SDLK_UP:
> {
> rocket.move(0,-2);
> position = 0;
> }
> break;
> case SDLK_DOWN:
> {
> rocket.move(2,0);
> position = 1;
> }
> break;
> case SDLK_RIGHT:
> {
> rocket.move(2,0);
> position = 2;
> }
> break;
> case SDLK_LEFT:
> {
> rocket.move(-2,0);
> position = 3;
> }
> break;
> }// end of key switch
> }break;
>
> case SDL_QUIT:
> quit = true;
> break;
> }// end of event switch
>
> }
>
>
> }
>
>
>
> GameDone();
>
> SDL_Quit();
>
> return 0;
>
> }//end of main
>
> void DrawMap( int sprite)
> {
> //takes our previous movement's rect
> if( GAMESTARTED == true)
> {
> SDL_Rect PreRect; //destination postioning
> SDL_Rect PreSRCRect; //which part of our picture to put into the game
> PreRect.x = pre_x;
> PreRect.y = pre_y;
> PreRect.w = Size;
> PreRect.h = Size;
> PreSRCRect.x = 0;
> PreSRCRect.y = 16 * 4;;
> PreSRCRect.w = Size;
> PreSRCRect.h = Size;
> SDL_BlitSurface(user,&PreSRCRect,background,&PreRect);
> }
> //plots current position
> SDL_Rect Rect;//destination postioning
> SDL_Rect SRCRect;//which part of our picture to put into the game
> Rect.x = X;
> Rect.y = Y;
> Rect.w = Size;
> Rect.h = Size;
> SRCRect.x = sprite * Size;
> SRCRect.y = sprite * Size;
> SRCRect.w = Size;
> SRCRect.h = Size;
>
> SDL_BlitSurface(user,&SRCRect,background,&Rect);
>
> SDL_BlitSurface(background,NULL,screen,NULL);
>
>
>
> }
>
>
> int GameInit()
> {
>
> if( SDL_Init(SDL_INIT_EVERYTHING) != 0 );
>
> return 1;
>
> screen = SDL_SetVideoMode(SCREENWIDTH,SCREENHEIGHT,32,
> SDL_HWSURFACE|SDL_DOUBLEBUF);
> if(screen == NULL)
> return 1;
>
> SDL_PixelFormat *fmt = screen->format;
>
> Uint32 desiredcolor = SDL_MapRGB(fmt, 0,0,0);
>
> SDL_FillRect(background,NULL,desiredcolor);
>
> SDL_WM_SetCaption( "Game test", NULL );
>
> user = rocket.LoadPicture("ship.bmp");
>
> X = rocket.GetX();
>
> Y = rocket.GetY();
>
> StartTime = SDL_GetTicks();
>
> DrawMap(position);
>
> SDL_Flip( screen );
>
> }
>
>
> void GameLoop()
> {
>
> pre_x = XMovement;
>
> pre_y = YMovement;
>
> Timediffer = StartTime - SDL_GetTicks();
>
> float spf = (float) Timediffer / 1000.0;
>
>
> XMovement = (int) (2 / (1/spf));
> YMovement = (int) ( 2 / (1/spf));
>
> rocket.move(XMovement,YMovement);
>
> Collision();
>
> X += rocket.GetX();
>
>
> Y += rocket.GetY();
>
> DrawMap(position);
>
> SDL_Flip( screen );
> }
>
> void Collision()
> {
> if( X > SCREENWIDTH)
> XMovement =-8 * 2;
> position = 3;
> if(X < 0 )
> XMovement = 8;
> position = 2;
> if( Y > SCREENHEIGHT)
> YMovement = -8 * 2;
> position = 3;
> if(Y < 0 )
> YMovement = 8;
> position = 2;
> }
>
>
> void GameDone()
> {
>
>
>
> SDL_FreeSurface(background);
>
> SDL_FreeSurface(user);
>
>
>
> SDL_Surface * background = NULL;
>
> SDL_Surface * user=NULL;
>
> int X=0;
>
> int Y=0;
>
> int pre_x=0;
>
> int pre_y=0;
>
> int position=0;
>
> Uint32 StartTime=0;
>
> Uint32 Timediffer=0;
>
> int XMovement=0;
>
> int YMovement=0;
> }
>
> i suspect it has something to do with my gameInit but i would liek advice in
> this thought....
>
>
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