Multiple SDL windows with YUV Overlay - c

Question

Does anyone know, how to create two Windows ans both should have an own YUV Overlay with the SDL 1.3 Library?
It is possible or do I try to use a wrong strategy?
If I tried the following source, i got an error message:
[!] can't create local overlay YUV display is only supported on the screen surface
#include <SDL/SDL.h>
#include <stdio.h>
#include <stdlib.h>
static bool running = true;
static SDL_Window* win_local;
static SDL_Window* win_remote;
int main(int argc, char** argv) {
// SDL_SetVideoMode
if((SDL_Init(SDL_INIT_VIDEO) != 0))
{
printf("[!] can't initialize SDL %s\n", SDL_GetError());
exit(-1);
}
if(!(win_local = SDL_CreateWindow("Local Video", 0, 0, 640, 480, SDL_WINDOW_SHOWN | SDL_WINDOW_BORDERLESS)))
{
printf("[!] can't create Window %s\n", SDL_GetError());
exit(-1);
}
if(!(win_remote = SDL_CreateWindow("Remote Video", 700, 0, 640, 480, SDL_WINDOW_SHOWN)))
{
printf("[!] can't create Window %s\n", SDL_GetError());
exit(-1);
}
SDL_Surface* surface_local;
SDL_Surface* surface_remote;
if(!(surface_local = SDL_GetWindowSurface(win_local)))
{
printf("[!] can't get local surface %s\n", SDL_GetError());
exit(-1);
}
if(!(surface_remote = SDL_GetWindowSurface(win_remote)))
{
printf("[!] can't get remote surface %s", SDL_GetError());
exit(-1);
}
SDL_Overlay* overlay_local;
SDL_Overlay* overlay_remote;
if(!(overlay_local = SDL_CreateYUVOverlay(640, 480, SDL_IYUV_OVERLAY, surface_local)))
{
printf("[!] can't create local overlay %s\n", SDL_GetError());
exit(-1);
}
//
// if(!(overlay_remote = SDL_CreateYUVOverlay(640, 480, SDL_IYUV_OVERLAY, surface_remote)))
// {
// printf("[!] can't create remote overlay %s\n", SDL_GetError());
// exit(-1);
// }
SDL_Event event;
while(running)
{
while(SDL_PollEvent(&event))
{
switch(event.type)
{
case SDL_KEYDOWN:
if (event.key.keysym.sym == SDLK_ESCAPE)
running = false;
break;
case SDL_QUIT:
running = false;
break;
}
}
SDL_Delay(20);
}
//SDL_FreeSurface(local);
//SDL_FreeSurface(remote);
SDL_DestroyWindow(win_local);
SDL_DestroyWindow(win_remote);
SDL_Quit();
exit(0);
return 0;
}

Answer 1

SDL_CreateYUVOverlay doesn't work well with multiple windows, because it's not part of 1.3 API, it was left for reverse compatibility with SDL 1.2.
I see three possible solutions:
Call SDL_CreateYUVOverlay just after SDL_CreateWindow for each surface. You will probably avoid the error but I'm not sure if it will work correctly.
See how SDL_CreateYUVOverlay is implemented using 1.3 API and do something similar.
Use OpenGL and shaders.