Intro #

How Chapter 5 works? #

1. init()
   1. SDL_Init()
   2. SDL_CreateWindow()
   3. SDL_GetWindowSurface()
2. loadMedia()
   1. loadSurface()
      1. load BMP file on intermediate surface with SDL_LoadBMP().
      2. optimize loaded intermediate surface into optimized surface with SDL_ConvertSurface().
         • free memory of intermediate surface with SDL_FreeSurface().
3. start loop untill variable quit is true.
   1. start loop that calls SDL_PollEvent() untill it returns 0.
      1. if SDL_Event.type is SDL_QUIT, quit is true( which means first loop will end).
      2. copy screen(Blit) scaled one with SDL_BlitScaled().
      3. update window with SDL_UpdateWindowSurface() to refresh and show what we’ve done.
4. close()
   1. SDL_FreeSurface()
   2. SDL_DestroyWindow()
   3. SDL_Quit()

Function #

SDL_ConvertSurface() #

SDL_Surface* SDL_ConvertSurface( SDL_Surface* src, const SDL_PixelFormat* fmt, Uint32 flags );

• param
  • src : the existing SDL_Surface structure to convert
  • fmt : the SDL_PixelFormat structure that the new surface is optimized for
  • flags : the flags are unused and should be set to 0; this is a leftover from SDL 1.2’s API
• return
  • new surface on success
  • NULL on failure

get surface src and convert it into specific format that fmt indicating.

SDL_BlitScaled() #

int SDL_BlitScaled( SDL_Surface* src, const SDL_Rect* srcrect, SDL_Surface* dst, SDL_Rect* dstrect );

• param
  • src : the SDL_Surface structure to be copied from
  • srcrect : the SDL_Rect structure representing the rectangle to be copied, or NULL to copy entire surface
  • dst : the SDL_Surface structure that is the blit target
  • dstrect : the SDL_Rect structure representing the rectangle that is copied into, or NULL to copy into the entire surface
• return
  • 0 on success
  • negative integer as error code on failure

Simiral with SDL_BlitSurface() but blit scaled surface.
this function call SDL_LowerBlitScaled() internally.

Struct #

SDL_PixelFormat #

Term #

• nothing new