Automagically determine ideal integer scale

src/sdl_render.c

@@ -57,12 +57,20 @@ static int sdl_render_init(nes_Renderer* rend) {
         fprintf(stderr, "SDL: Failed to initialize\n");
 
     } else {
+        SDL_DisplayMode mode = {0};
+
+        SDL_GetCurrentDisplayMode(0, &mode);
+
+        int yscale = (mode.h - 1) / nes_ppu_scan_h;
+        int xscale = mode.w / nes_ppu_scan_w;
+        int scale = (xscale < yscale ? xscale : yscale);
+
         data->window = SDL_CreateWindow(
                 "NESe",
                 SDL_WINDOWPOS_UNDEFINED,
                 SDL_WINDOWPOS_UNDEFINED,
-                nes_ppu_scan_w * 4,
-                nes_ppu_scan_h * 4,
+                nes_ppu_scan_w * scale,
+                nes_ppu_scan_h * scale,
                 0
             );
         if (NULL == data->window) {