Andreas Ragnerstam
I have two windows where one has a renderer where the logical size has been changed with SDL_RenderSetLogicalSize. When I get SDL_MOUSEMOTION events belonging to the non-scaled window these will have been scaled with the factor of the scaled window, which is not expected.
Adding some printf debugging to SDL_RendererEventWatch of SDL_render.c, where (event->type == SDL_MOUSEMOTION), I found that for every mouse motion SDL_RendererEventWatch is called twice and the event->motion.x and event.motion.y are set twice for the event, once for each renderer where only the last one set will be saved to the event struct. This will work fine if both renderers have the same scale, but otherwise the motion coordinates will be scaled for the renderer belonging to another window than the mouse was moved in.
I guess one solution would be to check that window == renderer->window for SDL_MOUSEMOTION events, similar to what is done for when SDL_WINDOWEVENT events.
I get the same error on both X11 and Windows.
The same problem also exists for SDL_MOUSEBUTTONDOWN and SDL_MOUSEBUTTONUP events.
The internal function SDL_EGL_LoadLibrary() did not delete and remove a mostly
uninitialized data structure if loading the library first failed. A later try to
use EGL then skipped initialization and assumed it was previously successful
because the data structure now already existed. This led to at least one crash
in the internal function SDL_EGL_ChooseConfig() because a NULL pointer was
dereferenced to make a call to eglBindAPI().
The expected use case is for games that are designed with multiple aspect ratios already in mind and leave optional margins on the edges of the game which won't hurt if they are cut off.
An example use case is a game is designed for wide-screen/16:9, but then wants to deploy on an iPad which is 4:3. Normally, SDL will letterbox, which will shrink things and result in wasted space. But the designer already thought about 4:3 and designed the edges of the game so they could be cut off without any functional loss. So rather than wasting space with letterboxing, "overscan" mode will zoom the rendering to fill up the entire screen. Parts on the edges will be drawn offscreen, but since the game was already designed with this in mind, it is fine. The end result is the iPad (4:3) experience is much better since it feels like a game designed for that screen aspect ratio.
This patch introduces a new SDL_hint: SDL_HINT_RENDER_LOGICAL_SIZE_MODE.
Valid values are "letterbox" or "0" for letterboxing and "overscan" or "1" for overscan.
The default mode is letterbox to preserve existing behavior.
// Example usage:
SDL_SetHint(SDL_HINT_RENDER_LOGICAL_SIZE_MODE, "overscan");
SDL_RenderSetLogicalSize(renderer, SCREEN_WIDTH, SCREEN_HEIGHT);
An existing hint lets apps that don't need the timer resolution changed avoid
this, to save battery, etc, but this fixes several problems in timing, audio
callbacks not firing fast enough, etc.
Fixes Bugzilla #2944.
Sam Lantinga
David Ludwig
Philipp Wiesemann
Ryan C. Gordon
Eric Wing