SDL3 Event Handling: Renamed Enumerations Break Existing Switch Logic

Answer

SDL3 renames most SDL2 event type constants to the SDL_EVENT_* prefix, removes the aggregate SDL_WINDOWEVENT constant, and splits window events into distinct types. The sdl2-compat layer provides macro mappings for many of the renamed constants, but it does not forward SDL3‑only events and does not map the removed SDL_WINDOWEVENT aggregate.

Confirmed facts

• SDL_QUIT → SDL_EVENT_QUIT
• SDL_KEYDOWN → SDL_EVENT_KEY_DOWN
• SDL_KEYUP → SDL_EVENT_KEY_UP
• SDL_MOUSEMOTION → SDL_EVENT_MOUSE_MOTION
• SDL_MOUSEBUTTONDOWN → SDL_EVENT_MOUSE_BUTTON_DOWN
• SDL_MOUSEBUTTONUP → SDL_EVENT_MOUSE_BUTTON_UP
• SDL_WINDOWEVENT is removed; window events are now:
• SDL_EVENT_WINDOW_SHOWN
• SDL_EVENT_WINDOW_HIDDEN
• SDL_EVENT_WINDOW_EXPOSED
• SDL_EVENT_WINDOW_MOVED
• SDL_EVENT_WINDOW_RESIZED
• SDL_EVENT_WINDOW_SIZE_CHANGED
• SDL_EVENT_WINDOW_MINIMIZED
• SDL_EVENT_WINDOW_MAXIMIZED
• SDL_EVENT_WINDOW_RESTORED
• SDL_EVENT_WINDOW_ENTER
• SDL_EVENT_WINDOW_LEAVE
• SDL_EVENT_WINDOW_FOCUS_GAINED
• SDL_EVENT_WINDOW_FOCUS_LOST
• SDL_EVENT_WINDOW_CLOSE_REQUESTED
• The sdl2-compat header defines macros such as #define SDL_QUIT SDL_EVENT_QUIT for the renamed constants that have a direct counterpart.

Likely explanation

The compatibility layer maps many SDL2 names to SDL3 equivalents, but it cannot map SDL3‑only events (e.g., SDL_EVENT_DISPLAY_ORIENTATION) and it does not provide a macro for the removed SDL_WINDOWEVENT aggregate. Consequently, a switch statement compiled against SDL3 headers with sdl2-compat will:

• Still match the mapped SDL2 constants via macros.
• Fall through to the default case for any SDL3‑only event or for a window event that relied on the subcode field, causing silent drops or incorrect handling.
• Potentially read wrong data if the code accesses SDL_Event.window fields assuming the SDL2 layout.

Steps needed for this case

1. Compile a minimal test program against SDL3 headers (with and without sdl2-compat) and log event.type for each generated event to verify the actual constant values.
2. Add a default case to your event switch that logs unknown event.type values; run the application under both builds to detect unmapped events.
3. Inspect the sdl2-compat compatibility headers to confirm which SDL2 constants are mapped and which SDL3 events lack a macro.
4. Replace any remaining SDL_WINDOWEVENT cases with explicit handling of the discrete SDL_EVENT_WINDOW_* events, using the appropriate union member (event.window) as defined in SDL3.
5. Update the switch to use the SDL_EVENT_* constants directly (or retain the sdl2-compat macros if you wish to keep SDL2 source compatibility).
6. Re‑test the application, verifying that all expected events are processed and that no unknown types appear in the log.

Missing diagnostic detail

To determine whether the current sdl2-compat mapping is sufficient for your codebase, please provide the list of SDL2 event types your code currently handles (e.g., from your existing switch statement). This will let us confirm if any of those are unmapped or if SDL3‑only events need to be added.