The surface-to-GL upload logic has become more complicated with the
addition of the GLES code paths; it's more logical to have a public
utility function that can be called from GDK users, instead of copy
pasting the whole thing multiple times.
This allows us to decide when the R and B color channels should be
flipped with a much better granularity.
For instance, when using GLX_EXT_texture_from_pixmap to create a GL
texture from a surface we don't need to swap the R and B channels, as
the internal representation of the texture data will already have the
appropriate colors.
We also don't need to flip color channels when blitting from a texture.
We cannot use GL_BGRA and GL_UNSIGNED_INT_8_8_8_8_REV when reading back
from the frame buffer in the software fallback path, as they do not
exist on OpenGL ES.
This will make the slow path a bit slower, because of the implicit
format conversion.
If we're using modern GLSL, then we should stop using deprecated
modifiers, like 'varying' and 'attribute', as well as deprecated global
variables, like 'gl_FragColor'.
On the other hand, with legacy contexts we should be using older GLSL
shaders, to maximize compatibility.
https://bugzilla.gnome.org/show_bug.cgi?id=756142
Using version 1.20 with a forward compatible 3.2 core context is incorrect
since OpenGL 3.2 deprecates shader version 1.20 (See section E.2). The latest
fglrx drivers will not compile these shaders.
https://bugzilla.gnome.org/show_bug.cgi?id=744203
- Specifically request GL version when creating context. Just specifying core
profile bit results in the requested version defaulting to 1.0 which causes
the core profile bit to be ignored and an arbitrary compatability context to be
returned.
- Fix GL painting by removing GL calls that have been depricated by the 3.2 core
profile.
- Additionally remove glInvalidateFramebuffer() call, it is not supported by 3.2
core.
https://bugzilla.gnome.org/show_bug.cgi?id=742953
As the alignments, strides and image formats may be different across
platforms, make the texture upload a vfunc to allow backends to override
the GL commands for uploading textures for the software implementation for
gdk_gl_texture_from_surface(), if necessary.
Suggested by Alex to avoid copying non-trivial portions of code which would
then add maintainenace burden.
https://bugzilla.gnome.org/show_bug.cgi?id=740795
We can't combine multiple draws into one for the software fallback,
because each quad has a different texture. And we generally don't
want to make a larger single texture because then we would have
to upload more data.
NULL-plus-something could be seen by the compiler to attempt to do
arithmetic with void *, which is a GCCism. Instead, do the math normally
and cast the results as a void *.
https://bugzilla.gnome.org/show_bug.cgi?id=740605
This requires us to use GL_TRIANGLES and six verts per quad instead
of four, which makes me think it might not be worth it on
well-optimized GL drivers. However, from talking to some driver
developers about it, the GL_TRIANGLES should be faster, since this
means that there's one giant contiguous buffer instead of many small
buffers.
If we were really rendering a lot of quads, I'd use an element buffer
and GL_PRIMITIVE_RESTART, but we're really not ever rendering that
many quads, and the setup cost for that would just be too annoying.
This is needed in the edge case where the X11 backend rounded the actual
size, and the GL flipping really needs the correct window height to
do proper Y coordinate flipping.
https://bugzilla.gnome.org/show_bug.cgi?id=739750
This moves the GDK_ALWAYS_USE_GL env var to GDK_GL=always.
It also changes GDK_DEBUG=nogl to GDK_GL=disable, as GDK_DEBUG
is really only about debug loggin.
It also adds some completely new flags:
software-draw-gl:
Always use software fallback for drawing gl content to a cairo_t.
This disables the fastpaths that exist for drawing directly to
a window and instead reads back the pixels into a cairo image
surface.
software-draw-surface:
Always use software fallback for drawing cairo surfaces onto a
gl-using window. This disables e.g. texture-from-pixmap on X11.
software-draw:
Enables both the above.
This was unnecessarily creating a framebuffer in the texture case,
and it was not properly setting up a framebuffer with the texture
as source in the software fallback w/ texture source case.
Its not really reasonable to handle failures to make_current, it
basically only happens if you pass invalid arguments to it, and
thats not something we trap on similar things on the X drawing side.
If GL is not supported that should be handled by the context creation
failing, and anything going wrong after that is essentially a critical
(or an async X error).
