• Emmanuele Bassi's avatar
    GL: Split GL context creation in two phases · 22e6f37c
    Emmanuele Bassi authored
    One of the major requests by OpenGL users has been the ability to
    specify settings when creating a GL context, like the version to use
    or whether the debug support should be enabled.
    We have a couple of requirements in terms of API:
     • avoid, if at all possible, the "C arrays of integers with
       attribute, value pairs", which are hard to write and hard
       to bind in non-C languages.
     • allow failing in a recoverable way.
     • do not make the GL context creation API a mess of arguments.
    Looking at prior art, it seems that a common pattern is to split the
    construction phase in two:
     • a first phase that creates a GL context wrapper object and
       does preliminary checks on the environment.
     • a second phase that creates the backend-specific GL object.
    We adopted a similar pattern:
     • gdk_window_create_gl_context() creates a GdkGLContext
     • gdk_gl_context_realize() creates the underlying resources
    Calling gdk_gl_context_make_current() also realizes the context, so
    simple GL users do not need to care. Advanced users will want to
    call gdk_window_create_gl_context(), set up the optional requirements,
    and then call gdk_gl_context_realize(). If either of these two steps
    fails, it's possible to recover by changing the requirements, or simply
    creating a new GdkGLContext instance.
gdkwindow.c 329 KB