The read format is dependent on the output, so we first need to make it
current. This fixes a race condition in wlr-screencopy-v1 where a dmabuf
client would cause EGL_NO_SURFACE to be bound at the time when
screencopy needs to query for the preferred format, causing GL errors.
We were assuming GL_BGRA_EXT was always supported.
We now check that it's supported for rendering. We fail if it isn't because
this format is specified as "always supported" by the Wayland protocol.
We also check if it's supported for reading pixels. A new preferred_read_format
function returns the preferred format that can be used to read pixels. This is
used by the screencopy protocol.
This removes any assumptions about how the libdrm headers are installed,
and uses the pkg-config include directories as we're "supposed to".
This only adds a partial dependency, since we don't actually need to
link against libdrm.
This PR broke a private nixpkgs definition I have for wlroots: https://github.com/swaywm/wlroots/pull/1304
It is fixed by changing `#include <drm_fourcc.h>` to `#include <libdrm/drm_fourcc.h>`, which follows what is already done in the dmabuf example.
If a client uses an older version of the dmabuf protocol, use the
`formats` event instead of `modifiers` (since that didn't exist in older
versions).
With a bit of necessary guessing, support dmabuf importing even when
EGL_EXT_image_dma_buf_import_modifiers isn't present instead of
failing up front.
Detecting whether eglSwapBuffersWithDamageEXT or
eglSwapBuffersWithDamageKHR is used should be based on the extension
string, not only on the availability of the function.
Compositors now have more control over how the backend creates its
renderer. Currently all backends create an EGL/GLES2 renderer, so
the necessary attributes for creating the context are passed to a
user-provided callback function. It is responsible for initializing
provided wlr_egl and to return a renderer. On fail, return 0.
Fixes#987