The two are only ever called together, and combining them makes it possible
to eliminate redundant symbol loading and redundant attempts to connect
to a display server.
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.
This behavior matches SDL_RecreateWindow and makes it less likely that
another piece of code (e.g. a DestroyWindowFramebuffer implementation)
will attempt to use or free the stale surface pointer.
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.
If a driver's implementation of CreateWindowFramebuffer sets the window
surface, use that rather than overwriting it. A driver may set the window
surface if data cannot be passed via the CreateWindowFramebuffer output
parameters (e.g. surface palette colors).
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)
fix building with Mesa 19.2
With Mesa 19.2 building fails with:
/include/GLES/gl.h:63:25: error: conflicting types for 'GLsizeiptr'
The same type is defined in include/SDL_opengl.h for OpenGL and the two
headers should not be included at the same time.
This was just never noticed because the same header guard '__gl_h_' was
used. This was changed in Mesa. The result is this error.
Fix this the same way GLES2 already handles this: Don't include the GLES
header when the OpenGL header was already included.
(https://hg.libsdl.org/SDL/rev/6a3670d6108d)
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
Sylvain
On Android, if you set no attribute using SDL_GL_SetAttribute(), and try to create a SDL Render OpenGLES 1:
- it loads first by default GLESv2 libraries
- creates the rendere OpenGLES 1
- recreates the Window to have a context 1.1 ( https://hg.libsdl.org/SDL/file/4db4cfd59470/src/render/opengles/SDL_render_gles.c#l298 )
But it doesn't unload libraries, then reload GLESv1 lib. So the SDL_Renderer OpenGLES 1 is working with GLES 2 libs, which seems inconsistent.
If you, at first, set
SDL_GL_SetAttribute(SDL_GL_CONTEXT_PROFILE_MASK, SDL_GL_CONTEXT_PROFILE_ES);
SDL_GL_SetAttribute(SDL_GL_CONTEXT_MAJOR_VERSION, 1);
SDL_GL_SetAttribute(SDL_GL_CONTEXT_MINOR_VERSION, 1);
It will correctly load GLES v1 libraries.
Here's a small patch to reload egl libs when SDL_RecreateWindow() is called.
It fixes the issue, also the case from bug 4042
( SDL_RecreateWindow() is used by SDL_Renderer gl, gles1, gles2. )
Removed incorrect call to SDL_SendWindowEvent(window, SDL_WINDOWEVENT_MOVED, x, y);
If the position of the window isn't adjusted in the SetWindowPosition() call, then sending the window event would have no effect because x and y equals the window x and y. If the position of the window is adjusted in the SetWindowPosition() call, then we don't want to clobber it with values that the user passed in.
Switching between renderers "software -> opengl -> opengles2 -> software" fails.
"opengl -> opengles2" calls SDL_RecreateWindow() and frees "window->surface"
without marking it as "surface_invalid".
This prevents us from clearing the clip rect globally when another application has set it.
There's also an experimental change to regularly update the clip rect for a window defensively, in case someone else has reset it. It works well, but I don't know if it's cheap enough to call as frequently as it would be called now, and might have other undesirable side effects.
Also fixed whitespace and SDL coding style
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.
This means we have to consider SDL_WINDOW_MINIMIZED a window creation flag, but on non-windows platforms we just remove it and let the normal FinishWindowCreation re-apply and do the minimize as I have no idea what is right on them or if anything should change.
CR: Phil
Simon Hug
I just wanted to fix a simple compiler warning in SDL_ShowMessageBox on Windows (which Sam fixed recently) and ended up finding some issues.
Attached patch fixes these issues:
- Because Windows only reports the lower 16 bits of the control identifier that was pushed, the button IDs used by SDL (C type int, most likely 32 bits) can get cut off.
- The documentation states (somewhat ambiguously) that the button ID will be -1 if the dialog was closed, but the current code sets 0. For SDL 2.1, I think this should be a return code of SDL_ShowMessageBox itself. That will free up the button ID and it seems a more appropriate place for signaling this event.
- Ampersands in controls will create mnemonics on Windows (underlined letters that, if combined with the Alt key, will push the button). I was thinking of adding a hint or flag to let the users enable it, but that might have unexpected results.
- When the size of the text gets calculated, it doesn't use the same parameters as the static control. This can cut off text or wrap it weirdly.
- On Windows, the Tab key is used to switch between control groups and sometimes between buttons in dialogs. This didn't seem to work correctly.
Attached patch also adds:
- Icons. Just the system ones that can be loaded with the ordinals IDI_ERROR, IDI_WARNING and IDI_INFORMATION.
- A button limit of 2^16 - 101.
- Some more specific error messages, but they never reach the user because how SDL_ShowMessageBox handles them if an implementation returns with an error.
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 is necessary because we need to see if GLES compat extensions exist.
All of this code (including ShouldUseTextureFramebuffer()) should be
revisited after 2.0.6 ships; ideally we don't make throwaway contexts if
we can avoid it...but maybe we can't. I hear Vulkan is pretty cool.
Fixes Bugzilla #3725.
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.
Sam Lantinga
Ryan C. Gordon
M Stoeckl
Jay Petacat
EXL
Sylvain Becker
Brandon Schaefer
Alex Szpakowski
Jeremy Ong
sezero
Conn O'Griofa