- Added SDL_WINDOW_TRANSPARENT to request a window with transparent framebuffer

- Remove SDL_VIDEO_EGL_ALLOW_TRANSPARENCY hint, EGL now checks 'window->flags & SDL_WINDOW_TRANSPARENT'

include/SDL3/SDL_hints.h

@@ -1602,17 +1602,6 @@ extern "C" {
  */
 #define SDL_HINT_VIDEO_DOUBLE_BUFFER      "SDL_VIDEO_DOUBLE_BUFFER"
 
-/**
- * \brief A variable controlling whether the EGL window is allowed to be
- * composited as transparent, rather than opaque.
- *
- * Most window systems will always render windows opaque, even if the surface
- * format has an alpha channel. This is not always true, however, so by default
- * SDL will try to enforce opaque composition. To override this behavior, you
- * can set this hint to "1".
- */
-#define SDL_HINT_VIDEO_EGL_ALLOW_TRANSPARENCY "SDL_VIDEO_EGL_ALLOW_TRANSPARENCY"
-
 /**
  * \brief If eglGetPlatformDisplay fails, fall back to calling eglGetDisplay.
  *

include/SDL3/SDL_video.h

@@ -152,6 +152,7 @@ typedef enum
     SDL_WINDOW_KEYBOARD_GRABBED     = 0x00100000,   /**< window has grabbed keyboard input */
     SDL_WINDOW_VULKAN               = 0x10000000,   /**< window usable for Vulkan surface */
     SDL_WINDOW_METAL                = 0x20000000,   /**< window usable for Metal view */
+    SDL_WINDOW_TRANSPARENT          = 0x40000000,   /**< window with transparent buffer */
 
 } SDL_WindowFlags;