Avoid SDL_GetMouseState(), which returns raw coordinates (fixes #318) #320
Conversation
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
sdl12-compat tracks the mouse position in the MousePosition variable, even when we're not in relative mouse mode. We therefore don't need to call SDL20_GetMouseState() to update it before entering relative mouse mode: we already have it from the last SDL_MOUSEMOTION event, and have already applied any scaling we need. This is important, because SDL_GetMouseState() returns the _raw_ mouse coordinates, not the ones scaled by SDL_RenderSetLogicalSize(). So we end up with a mismatch. This results in a mouse offset on non-OpenGL, scaled games, like Alpha Centauri in fullscreen (see libsdl-org#318). We could fix this by calling SDL_RenderWindowToLogical() instead, but that complicates the codepath as we don't always have an SDL_Renderer (we might be using OpenGL), so this seems cleaner. I've tested this with SMAC (where it fixes the bug) and Wolf4SDL (which was cited in the commit which introduced this check). Both work fine.
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
Add this suggestion to a batch that can be applied as a single commit.
This suggestion is invalid because no changes were made to the code.
Suggestions cannot be applied while the pull request is closed.
Suggestions cannot be applied while viewing a subset of changes.
Only one suggestion per line can be applied in a batch.
Add this suggestion to a batch that can be applied as a single commit.
Applying suggestions on deleted lines is not supported.
You must change the existing code in this line in order to create a valid suggestion.
Outdated suggestions cannot be applied.
This suggestion has been applied or marked resolved.
Suggestions cannot be applied from pending reviews.
Suggestions cannot be applied on multi-line comments.
Suggestions cannot be applied while the pull request is queued to merge.
Suggestion cannot be applied right now. Please check back later.
sdl12-compat tracks the mouse position in the MousePosition variable, even when we're not in relative mouse mode. We therefore don't need to call SDL20_GetMouseState() to update it before entering relative mouse mode: we already have it from the last SDL_MOUSEMOTION event, and have already applied any scaling we need.
This is important, because SDL_GetMouseState() returns the raw mouse coordinates, not the ones scaled by SDL_RenderSetLogicalSize(). So we end up with a mismatch. This results in a mouse offset on non-OpenGL, scaled games, like Alpha Centauri in fullscreen (see #318).
We could fix this by calling SDL_RenderWindowToLogical() instead, but that complicates the codepath as we don't always have an SDL_Renderer (we might be using OpenGL), so this seems cleaner.
I've tested this with SMAC (where it fixes the bug) and Wolf4SDL (which was cited in the commit which introduced this check). Both work fine.