CODEWITHSUNDEEP
sdl-2
Topological Sort
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Reputation: 2898

SDL_SetWindowSize gives a new window, that can't be written to

In the program below, SDL_SetWindowSize does make the window itself bigger... but it doesn't let SDL_RenderClear (or other functions) display anything in that new area.

The platform is CentOS running on VMWare. I don't get this problem in my Visual Studio version, FWIW.

In this screenshot, the window with the grey top bar is the new window created by the resize; it's cleared to red, but only in the area delimited by the old size. enter image description here

I know I could create the window the right size from the beginning, but I really do need the ability to resize later. 

#include <SDL.h>
#include <SDL_ttf.h>
#include <SDL_image.h>

SDL_Window*   sdlWindow;
SDL_Renderer* sdlRenderer;

class myException {};

void initialize ()
{
  if (SDL_Init (SDL_INIT_EVERYTHING) < 0)
    throw myException ();  

  sdlWindow = SDL_CreateWindow ("",     
                 SDL_WINDOWPOS_UNDEFINED, SDL_WINDOWPOS_UNDEFINED,
                 640, 480,
                 0);        
  if (! sdlWindow) throw myException ();

  int rendererIndex = -1, rendererFlags =  0;
  sdlRenderer = SDL_CreateRenderer (sdlWindow, rendererIndex, rendererFlags);

  if (! sdlRenderer) throw myException ();

  SDL_ClearError ();
}

int main (int argc, char** argv)
{
  initialize ();

  SDL_SetWindowSize (sdlWindow, 800, 400);

  SDL_SetRenderDrawColor (sdlRenderer, 255, 0, 0, 255); //now we'll clear to red

  SDL_RenderClear   (sdlRenderer);
  SDL_RenderPresent (sdlRenderer); //update screen now

  SDL_Delay (2000);                 //Delay, then quit
  SDL_Quit ();

  return 0;
}

Upvotes: 1

Views: 1154

Answers (1)

pabdulin
pabdulin

Reputation: 35255

The rendering surface is invalidated on windows resize, quote from SDL wiki on SDL_GetWindowSurface:

This surface will be invalidated if the window is resized. After resizing a window this function must be called again to return a valid surface.

So you must get window surface again after resizing window, in general.

Upvotes: 1

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