The gltestsrc element was refactored to inherit from this base class which
handles the GL context. The sub-class only needs to implement the gl_start,
gl_stop and fill_gl_memory vfuncs, along with properly advertizing the GL APIs
it supports through the supported_gl_api GstGLBaseSrc class attribute.
If we do, then multiple disjoint OpenGL contexts will not perform the
necessary download and reupload of data that is necessary to cross between
each OpenGL context sharegroup.
gst_gl_shader_string_get_highest_precision needs to make an OpenGL call
so execution outside the OpenGL thread and context results in undefined
behaviour.
Doing so involves retrieving the current viewport from OpenGL which as
with any glGet operation, is expensive.
This means that the various sinks need to reset the viewport on draw.
In the process, fix resizing on cocoa.
If we only ever make it to READY, transform_caps can create an
internal convert object that will never be freed by basetransform's
stop vmethod (PAUSED->READY).
The use of mediump as a specifier in GLSL shaders will have limited
resolution and when used as texture coordinates may become inaccurate
over texture sizes of 1024.
Binding the vertex array to 0 will unbind everything else already.
In the previous order older versions of the Intel GL driver caused
errors to be printed for every single call when disabling the vertex
attrib arrays after binding the vertex array to 0.
It might be the case that glgsinkbin would try to set a property to
its internal sink which doesn't exist in it, leading to a glib's
warning. For example, when playsink sets 'force-aspect-ratio' property
and glsinkbin has, as internal sink, appsink, which doesn't handle
that property.
The patch validates the incoming property to forward to internal sink
if it exists in the internal sink and both properties has the same
type.
Running the context query in _start and during the NULL->READY state transition
can fail because downstream elements might not be able to answer and thus the
source element would not be able to reuse downstream GLContext and GLDisplay.
This issue happened specifically when trying to use gltestsrc in playbin.
Without this, a buffer is dropped if glupload indicates that it is
necessary to reconfigure.
Avoid this by explicitly reconfiguring immediately and uploading the buffer
again.
https://bugzilla.gnome.org/show_bug.cgi?id=783521
Fixes the internal viewconvert to not scale buffers for output with the
following pipeline:
gltestsrc ! glimagesink
It also fixes overlay composition with a resized output with an OpenGL
upstream:
gltestsrc ! timeoverlay ! glimagesink
Attempting to use the MAX(1, display_rect) would result in the overlay
composition attempting to draw into 1x1 buffer and calculate some
grossly incorrect sizes.
previously failing case:
gltestsrc ! textoverlay text=GStreamer ! glimagesinkelement
Without this, a buffer is dropped if glupload indicates that it is
necessary to reconfigure.
Avoid this by explicitly reconfiguring immediately and uploading the buffer
again.
https://bugzilla.gnome.org/show_bug.cgi?id=783521
This effectively (but optionally) requires libjpeg-turbo which
ships with a .pc file and is what pretty much everyone these days
uses anyway for libjpeg, so shouldn't be a problem hopefully.
https://bugzilla.gnome.org/show_bug.cgi?id=796947
