This allows the client to work when the OpenGL implementation fails if
EGL_RENDER_BUFFER is passed, printing a warning. This should fix issues
with Nvidia proprietary drivers on Wayland.
According to the documentation for eglQueryString:
> EGL_BAD_DISPLAY is generated if display is not an EGL display connection,
> unless display is EGL_NO_DISPLAY and name is EGL_EXTENSIONS.
Therefore, we should check EGL by doing:
eglQueryString(EGL_NO_DISPLAY, EGL_EXTENSIONS)
Indeed, the old way of eglQueryString(EGL_NO_DISPLAY, EGL_VERSION) works on
libglvnd but not using mesa's libEGL.so directly.
Also added a warning to make it more obvious that EGL is not available.
Due to the way assert is defined in standard C, compilers in release mode
will not treat it as unreachable. This explains a lot about those pesky
uninitialized variable bugs, actually.
This uses the same line sweep algorithm originally created to copy DXGI
textures to IVSHMEM to implement the copy from IVSHMEM to memory-mapped
pixel buffer objects.
This replaces the scaled `destRect` with a version that uses doubles
correcting the rounding error that is causing a failure to properly
clear the black bar areas.
This mesh will later be used to render only damaged portions of the desktop.
We also moved the coordinate transformation for damage overlay into a matrix
and computed by the shader.
After the damage queue PR, EGL damage count 0 means no change, and -1 means
invalidate the entire window. However, several other places have different
semantics, and we are not handling them correctly:
1. KVMFR uses 0 to signal invalidating the entire frame, so if we receive 0
rectangles in egl_on_frame, we should set damage count to -1.
2. The damage overlay treated 0 as full damage, which is now incorrect. This
is fixed, and now it treats 0 as no update, and -1 as full damage.
The way things were handled in EGLTexture is not only very hard to
follow, but broken. This change set breaks up EGLTexture into a modular
design making it easier to implement the various versions.
Note that DMABUF is currently broken and needs to be re-implemented.
There used to be a possible race when a bunch of rectangle is appended, but
the total count is not updated before it's read. Using a lock eliminates
all such races.
