Small program to trigger a bug(?) in SDL2 on Windows 11 using default direct3d renderer.

sdltest.cpp

#include <string_view>

#include <SDL2/SDL.h>

void setColour(SDL_Renderer *renderer, uint8_t red, uint8_t green, uint8_t blue) {
	if (SDL_SetRenderDrawColor(renderer, red, green, blue, SDL_ALPHA_OPAQUE) < 0) {
		SDL_Log(SDL_GetError());
	}
}

void recreateRenderer(SDL_Window *window, SDL_Renderer *&renderer, uint32_t flags, std::string_view message) {
	SDL_DestroyRenderer(renderer);
	renderer = SDL_CreateRenderer(window, -1, flags);
	if (renderer == nullptr) {
		SDL_Log(SDL_GetError());
	}

	SDL_RendererInfo info{};
	if (SDL_GetRendererInfo(renderer, &info) < 0) {
		SDL_Log(SDL_GetError());
	}
	else {
		SDL_Log("Recreated %s renderer %s", message.data(), info.name);
	}
}

int main(int argc, char* argv[])
{
	if (SDL_InitSubSystem(SDL_INIT_VIDEO) < 0) {
		SDL_Log(SDL_GetError());
	}

	auto window = SDL_CreateWindow("Test SDL Window", SDL_WINDOWPOS_UNDEFINED, SDL_WINDOWPOS_UNDEFINED, 640, 480, /*::SDL_WINDOW_ALLOW_HIGHDPI | ::SDL_WINDOW_RESIZABLE*/0);
	if (window == nullptr) {
		SDL_Log(SDL_GetError());
	}

	auto renderer = SDL_CreateRenderer(window, -1, 0);
	if (renderer == nullptr) {
		SDL_Log(SDL_GetError());
	}

	if (SDL_InitSubSystem(SDL_INIT_EVENTS) < 0) {
		SDL_Log(SDL_GetError());
	}

	SDL_Event event{};
	while (true) {
		while (SDL_PollEvent(&event) != 0) {
			if (event.type == ::SDL_KEYUP) {
				switch (event.key.keysym.sym) {
				case ::SDLK_ESCAPE: {
					SDL_Quit();
					return 0;
				}
				case ::SDLK_r: {
					setColour(renderer, 255, 0, 0);
					break;
				}
				case ::SDLK_g: {
					setColour(renderer, 0, 255, 0);
					break;
				}
				case ::SDLK_b: {
					setColour(renderer, 0, 0, 255);
					break;
				}
				case ::SDLK_RETURN: {
					recreateRenderer(window, renderer, ::SDL_RENDERER_ACCELERATED | ::SDL_RENDERER_PRESENTVSYNC, "accelerated vsync");
					break;
				}
				case ::SDLK_SLASH: {
					recreateRenderer(window, renderer, ::SDL_RENDERER_ACCELERATED, "accelerated");
					break;
				}
				case ::SDLK_BACKSLASH: {
					recreateRenderer(window, renderer, ::SDL_RENDERER_PRESENTVSYNC, "vsync");
					break;
				}
				case ::SDLK_QUOTE: {
					recreateRenderer(window, renderer, 0, "no-flags");
					break;
				}
				}
			}
		}

		if (SDL_RenderClear(renderer) < 0) {
			SDL_Log(SDL_GetError());
		}
		SDL_RenderPresent(renderer);
	}
	return 1;
}