Resize on windows scales input weirdly on first present.

doocman commented 2 weeks ago

Compile the following code with SDL3:


#include <SDL3/SDL.h>

#include "stdlib.h"
#include "stdio.h"

#define SHOW_SDL_BUG_WORKAROUND 0

void show_sld_bug_render_rect(SDL_Window*w, SDL_Renderer* r) {
  SDL_RenderClear(r);
#if SHOW_SDL_BUG_WORKAROUND
  SDL_RenderPresent(r);
#endif
  SDL_Rect total_size{};
  SDL_GetWindowSize(w, &total_size.w, &total_size.h);
  SDL_FRect left{0.f, 0.f, (float)total_size.w / 2, (float)total_size.h};
  SDL_FRect right{left.w, 0.f, left.w, left.h};
  SDL_SetRenderDrawColor(r, 255, 0, 0, 255);
  SDL_RenderFillRect(r, &left);
  SDL_SetRenderDrawColor(r, 0, 0, 255, 255);
  SDL_RenderFillRect(r, &right);
  SDL_RenderPresent(r);
}

void show_sdl_bug_cleanup() {
  SDL_QuitSubSystem(SDL_INIT_VIDEO);
  SDL_Quit();
}

int main() {
  SDL_Init(0);
  SDL_InitSubSystem(SDL_INIT_VIDEO);
  SDL_Window* w = SDL_CreateWindow("Hello", 500, 500, SDL_WINDOW_RESIZABLE);
  if(!w) {
    printf("Error: %s\n", SDL_GetError());
    return EXIT_FAILURE;
  }

  SDL_Renderer* r = SDL_GetRenderer(w);
  if(!r) {
    r = SDL_CreateRenderer(w, nullptr);
  }
  show_sld_bug_render_rect(w, r);
  SDL_Event e;
  while(SDL_WaitEvent(&e)) {
    switch (e.type) {
    case SDL_EVENT_WINDOW_RESIZED:
      show_sld_bug_render_rect(w, r);
      break;
    case SDL_EVENT_QUIT:
      show_sdl_bug_cleanup();
      return EXIT_SUCCESS;
    }
  }
  show_sdl_bug_cleanup();
  return EXIT_FAILURE;
}

and resize the window in width. The rectangles does not scale the way you would expect. Change SHOW_SDL_BUG_WORKAROUND to 1 and things will seem to work again.

Error is seen on commit 615d2dcd5b6352aea50372745a05779e24ff8d31 and 802686699449289109f58b9ec4e6200f061e9dd2 . I have not experienced similar behaviour in SDL2.

System information: OS - Windows 11 Processor: Intel I7 1280P Graphics: Integrated Screen: Laptop screen with 2880x1600 (2x scaling in windows)

AntTheAlchemist commented 2 weeks ago

Sam bug as #11324 ?

doocman commented 2 weeks ago

Seems very similar at least. I see it on Windows and the referenced report is Android. I can say that querying the size of the window gives the expected result.

// Robin

On Sun, Nov 3, 2024, 18:29 Anthony @.***> wrote:

Sam bug as #11324 https://github.com/libsdl-org/SDL/issues/11324 ?

— Reply to this email directly, view it on GitHub https://github.com/libsdl-org/SDL/issues/11401#issuecomment-2453504308, or unsubscribe https://github.com/notifications/unsubscribe-auth/AHEBBRVIZXQTG564XOHEKY3Z6ZMOVAVCNFSM6AAAAABRCXEIY6VHI2DSMVQWIX3LMV43OSLTON2WKQ3PNVWWK3TUHMZDINJTGUYDIMZQHA . You are receiving this because you authored the thread.Message ID: @.***>

libsdl-org / SDL

Resize on windows scales input weirdly on first present. #11401