Fix SDL2 window creation on Wayland

See this post: https://github.com/libsdl-org/SDL/issues/6074

It seems like SDL2 does not show an empty window on Wayland systems
if there is nothing drawn on this. Thus this commit adds an empty white
pixel buffer.

1 files changed, 17 insertions, 2 deletions

diff --git a/sdl2.c b/sdl2.c
index e8a12f9..6b30891 100644
--- a/sdl2.c
+++ b/sdl2.c
@@ -2,8 +2,6 @@
 
 /* mention the SDL2 documentation at http://wiki.libsdl.org/APIByCategory */
 
-/* WARNING this seems to be not working on Wayland! */
-
 
 #include <SDL2/SDL.h>
 #include <stdbool.h>
@@ -17,6 +15,9 @@ void gui_run(void) {
 	bool quit = false;
 	SDL_Event event;
 	SDL_Window* window;
+	SDL_Renderer* renderer;
+	SDL_Texture* texture;
+	uint32_t* pixels;
 
 	// init SDL2 and create window
 	SDL_Init(SDL_INIT_VIDEO);
@@ -28,12 +29,20 @@ void gui_run(void) {
 	// output video driver to stderr
 	fprintf(stderr, "SDL2 video driver: %s\n", SDL_GetCurrentVideoDriver());
 
+	// create and initialize renderer, texture and pixel buffer
+	renderer = SDL_CreateRenderer(window, -1, 0);
+	texture = SDL_CreateTexture(renderer, SDL_PIXELFORMAT_ARGB8888,
+	                            SDL_TEXTUREACCESS_STATIC, 640, 480);
+	pixels = malloc(sizeof(uint32_t) * 640 * 480);
+	memset(pixels, 255, 640 * 480 * sizeof(uint32_t));
+
 	// handle failed window creation
 	if (window == NULL) {
 		fprintf(stderr, "Failed to create SDL2 window!\n");
 		return;
 	} else {
 		while (!quit) {
+			SDL_UpdateTexture(texture, NULL, pixels, 640 * sizeof(uint32_t));
 			SDL_WaitEvent(&event);
 			switch (event.type)
 			{
@@ -41,10 +50,16 @@ void gui_run(void) {
 					quit = true;
 					break;
 			}
+			SDL_RenderClear(renderer);
+			SDL_RenderCopy(renderer, texture, NULL, NULL);
+			SDL_RenderPresent(renderer);
 		}
 		SDL_DestroyWindow(window);
 	}
 
+	free(pixels);
+	SDL_DestroyTexture(texture);
+	SDL_DestroyRenderer(renderer);
 	SDL_Quit();
 
 }