They're not needed and GLES doesn't technically support them, even
though GTK had been using them via epoxy sneakily using the
GL_OES_vertex_array_object extension behind our back.
We cheat and just set the texture parameters instead and hope nothing
explodes.
So far it didn't.
This is only needed to support GLES 2.0 so it's quite a limited set of
hardware these days.
Instead of uploading a texture once per filter, ensure textures are
uploaded as little as possible and use samplers instead to switch
different filters.
Sometimes we have to reupload a texture unfortunately, when it is an
external one and we want to create mipmaps.
Allow to set max texture size using the
GSK_MAX_TEXTURE_SIZE environment variable.
We only allow to lower the max (for obvious
reasons), and we don't allow values smaller
than 512 (since our atlases use that size).
When we truncate the command queue because it
is too big, we were messing up our state accounting
and running into criticals as a consequence.
This can be reproduced by opening a well-populated
fishbowl demo in the inspectors recorder.
Fixes: #5188
There are situations where our "default framebuffer" is not actually
zero, yet we still want to apply a scissor rect.
Generally, 0 is the default framebuffer. But on platforms where we need
to bind a platform-specific feature to a GL_FRAMEBUFFER, we might have a
default that is not 0. For example, on macOS we bind an IOSurfaceRef to
a GL_TEXTURE_RECTANGLE which then is assigned as the backing store for a
framebuffer. This is different than using gsk_gl_renderer_render_texture()
in that we don't want to incur an extra copy to the destination surface
nor do we even have a way to pass a texture_id into render_texture().
Instead of just passing major/minor, pass them twice, once for GL and
once for GLES. This way, we don't need to check for GL and GLES
separately.
If something is supported unconditionally, passing 0/0 works fine.
That said, I'd like to group the arguments somehow, because otherwise
it's just a confusing list of numbers - but I have no idea how to do
that.
Don't pass texture + rect, but instead have
gdk_memory_texture_new_subtexture()
and use it to generate subtextures and pass them.
This has the advantage of downloading the a too large texture only once
instead of N times.
It does not belong in GdkGLContext, it's a renderer thing.
It's also the only user of that API.
Introduce gdk_gl_context_check_version() private API to make version
checks simpler.
