[gstreamer-bugs] [Bug 572767] Should error out instead of doing nothing if an OpenGL feature is not present

[GStreamer (bugzilla.gnome.org)]

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  GStreamer | gst-plugins-gl | Ver: 0.10.x




------- Comment #5 from Filippo Argiolas  2009-08-05 08:11 UTC -------
IMHO, this could be solved in the following way.

1. gldisplay should provide some kind of "feature checking" infrastructure:
  - a flag structure (GstGLFeatureFlags flags)
  - a bunch of feature checks in gldisplay init function, something like:

     if (GLEW_ARB_shading_language_100) flags |= GST_GL_FEATURE_GLSL;
     if (some more complex check) flags |= GST_GL_FEATURE_FBO;

  - some public utility method for feature checking
(gst_gl_feature(s)_available?) that just check the flags structure
  - replace all "if (GLEW_stuff)" calls with custom flags checking

2. all base elements (upload, filter, download) could then check needed
features (glfilter should provide a vmethod for custom subclasses dependencies)
in the prepare_output_buffer function return FLOW_ERROR on fail

3. Maybe we could manually handle state changes and do the checks in
NULL->READY as Olivier suggested, but 1 and 2 should be enough for now.


Note that we could just use glew everywhere but this way we could have some
more complex custom check if needed and eventually get rid of glew in the
future.


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