This allows you to bind surfaceless contexts on a background thread to, for
example, load assets in a separate context, for platforms that have different
requirements about sharing surfaces, etc.
Martin's notes on the matter:
"Here's a patch that enables passing NULL windows to SDL_GL_MakeCurrent, if
the involved APIs allow it. Currently, this is only the case for EGL, and
even then only if some specific extensions are present (which they usually
are).
If "surfaceless" contexts are not supported, SDL_GL_MakeCurrent continues to
generate an error (albeit with a more specific error message than it used to),
so this should not break anything that wasn't broken before."
(Please see https://bugzilla.libsdl.org/show_bug.cgi?id=3695 for more
discussion.)
Fixes Bugzilla #3695.
Caleb Cornett's comments:
"A few weeks ago, Alex added a partial Metal API to SDL2:
https://hg.libsdl.org/SDL/rev/22c8e7cd8d38
I noticed it was missing a few features that would help Metal become a
first-class citizen in SDL, so I went ahead and wrote them! Here are the new
APIs:
1. SDL_WINDOW_METAL flag for SDL_CreateWindow(). This allows the programmer
to specify that they intend to create a window for use with SDL_MetalView.
The flag is used to ensure correct usage of the API and to prevent
accidentally defaulting to OpenGL on iOS.
2. SDL_Metal_GetLayer(). This function takes a SDL_MetalView and returns a
pointer to the view's backing CAMetalLayer. This simplifies things
considerably, since in the current version of the SDL_Metal API the
programmer is required to bridge-cast a SDL_MetalView handle to an NSView or
UIView (depending on the platform) and then extract the layer from there.
SDL_Metal_GetLayer automatically handles all of that, making the operation
simple and cross-platform.
3. SDL_Metal_GetDrawableSize(). This function already exists in the current
SDL_Metal API (and is used behind-the-scenes for SDL_Vulkan_GetDrawableSize
on Apple platforms) but was not publicly exposed. My patch exposes this
function for public use. It works just like you'd expect.
Tested on macOS 10.14 and iOS 12.4."
Fixes Bugzilla #4796.
Aaron Barany
Add SDL_HINT_VIDEO_EXTERNAL_CONTEXT hint to notify SDL that the graphics context is external. This disables the automatic context save/restore behavior on Android and avoids using OpenGL by default when SDL_WINDOW_VUKLAN isn't set.
When the application wishes to manage the OpenGL contexts on Android, this avoids cases where SDL unbinds the context and creates new contexts, which can interfere with the application's operation.
When using Vulkan and Metal renderer implementations, this avoids SDL forcing OpenGL to be enabled on certain platforms. While using the SDL_WINDOW_VULKAN flag can be used to achieve the same thing, it also causes Vulkan to be loaded. If the application uses Vulkan directly, this is not necessary, and fails window creation when using Metal due to Vulkan not being present. (assuming MoltenVK isn't installed)
The Offscreen video driver is intended to be used for headless rendering
as well as allows for multiple GPUs to be used for headless rendering
Currently only supports EGL (OpenGL / ES) or Framebuffers
Adds a hint to specifiy which EGL device to use: SDL_HINT_EGL_DEVICE
Adds testoffscreen.c which can be used to test the backend out
Disabled by default for now
First: disable d'n'd events by default; most apps don't need these at all, and
if an app doesn't explicitly handle these, each drop on the window will cause
a memory leak if the events are enabled. This follows the guidelines we have
for SDL_TEXTINPUT events already.
Second: when events are enabled or disabled, signal the video layer, as it
might be able to inform the OS, causing UI changes or optimizations (for
example, dropping a file icon on a Cocoa app that isn't accepting drops will
cause macOS to show a rejection animation instead of the drop operation just
vanishing into the ether, X11 might show a different cursor when dragging
onto an accepting window, etc).
Third: fill in the drop event details in the test library and enable the
events in testwm.c for making sure this all works as expected.
SDL now builds with gcc 7.2 with the following command line options:
-Wall -pedantic-errors -Wno-deprecated-declarations -Wno-overlength-strings --std=c99
This is necessary because the Raspberry Pi is a strange beast, that believes
it has OpenGL support (through glX?) but generally has GLES2 support.
So when using the raspberry video target, we need to force this to default
to a GLES2 context, or by default SDL_CreateWindow() will fail, deep down
when it tries to load the proper GL library.
Fixes testsprite2 (and basically everything else that wasn't testgles2) when
run on a Raspberry Pi without a X server.
Please note that other targets might also need this filled in, the Raspberry
Pi is just the most prominent and readily-available System-On-A-Chip style
thing on my desk. :)
This patch was originally written by Marc Di Luzio for glX and enhanced by
Maximilian Malek for WGL, etc. Thanks to both of you!
Fixes Bugzilla #3643.
Fixes Bugzilla #3735.
Edward Rudd
Device: Logitech Rumble Gamepad F510 in Xinput mode.
Upon opening the joystick the values of the axes are queried via PollAllValues are not actually set on the device all the time.
This can easily be seen in the testjoystick or testgamecontroller test programs,as the testjoystick shows all axes in the center until one 'tickles' the triggers., and the testgamecontroller will show the triggers as 'on' until on 'tickles' the triggers.
Upon further research the culprit is the SDL_HINT_JOYSTICK_ALLOW_BACKGROUND_EVENTS hint. In the default value events are ignored until there is an active window, Thus in cases where the joystick system is initialized and controllers opened before the initial window is created & focuses, the initial values will be incorrect.
Here is my current workaround in the game I'm working on porting..
SDL_SetHint(SDL_HINT_JOYSTICK_ALLOW_BACKGROUND_EVENTS, "1");
SDL_GameController* gamepad = SDL_GameControllerOpen(index);
SDL_SetHint(SDL_HINT_JOYSTICK_ALLOW_BACKGROUND_EVENTS, "0");
Manuel
The attached patch adds support for KMS/DRM context graphics.
It builds with no problem on X86_64 GNU/Linux systems, provided the needed libraries are present, and on ARM GNU/Linux systems that have KMS/DRM support and a GLES2 implementation.
Tested on Raspberry Pi: KMS/DRM is what the Raspberry Pi will use as default in the near future, once the propietary DispmanX API by Broadcom is overtaken by open graphics stack, it's possible to boot current Raspbian system in KMS mode by adding "dtoverlay=vc4-kms-v3d" to config.txt on Raspbian's boot partition.
X86 systems use KMS right away in every current GNU/Linux system.
Simple build instructions:
$./autogen.sh
$./configure --enable-video-kmsdrm
$make
Volumetric
In X11 the SDL error "Unknown touch device" can occur after which the application stops recognizing touch events. For a kiosk-type application this results in a hang as far as the user is concerned. This is reproducible on HP Z220/Z230/Z240 workstations by swapping USB cables for a while and it also occurs with no physical changes, probably due to USB device power management. A workaround is to make SDL re-enumerate the touch devices like it does at startup. A patch is attached.
Mark Callow
The attached patch does the following for the X11 and Windows platforms, the only ones where SDL attempts to use context_create_es_profile:
- Adds SDL_HINT_OPENGL_ES_DRIVER by which the application can
say to use the OpenGL ES driver & EGL rather than the Open GL
driver. (For bug #2570)
- Adds code to {WIN,X11}_GL_InitExtensions to determine the maximum
OpenGL ES version supported by the OpenGL driver (for bug #3145)
- Modifies the test that determines whether to use the OpenGL
driver or the real OpenGL ES driver to take into account the
hint, the requested and supported ES version and whether ES 1.X
is being requested. (For bug #2570 & bug #3145)
- Enables the testgles2 test for __WINDOWS__ and __LINUX__ and adds
the test to the VisualC projects.
With the fix in place I have run testdraw2, testgl and testgles2 without any issues and have run my own apps that use OpenGL, OpenGL ES 3 and OpenGL ES 1.1.
This is currently implemented for X11, Cocoa, Windows, and DirectFB.
This patch is based on work in Unreal Engine 4's fork of SDL,
compliments of Epic Games.
This allows an app to know when a set of drops are coming in a grouping of
some sort (for example, a user selected multiple files and dropped them all
on the window with a single drag), and when that set is complete.
This also adds a window ID to the drop events, so the app can determine to
which window a given drop was delivered. For application-level drops (for
example, you launched an app by dropping a file on its icon), the window ID
will be zero.
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().
