1. 10 Dec, 2020 3 commits
    • Vlad Zahorodnii's avatar
      Prevent EGL headers from including Xlib headers · 6b2e6cfd
      Vlad Zahorodnii authored
      One of the annoying things about EGL headers is that they include
      platform headers by default, e.g. on X11, it's Xlib.h, etc.
      The problem with Xlib.h is that it uses the define compiler directive to
      declare constants and those constants have very generic names, e.g.
      'None', which typically conflict with enums, etc.
      In order to work around bad things coming from Xlib.h, we include
      fixx11.h file that contains some workarounds to redefine some Xlib's
      There's a flag or rather two flags (EGL_NO_PLATFORM_SPECIFIC_TYPES and
      EGL_NO_X11) that are cross-vendor and they can be used to prevent EGL
      headers from including platform specific headers, such as Xlib.h [1]
      The benefit of setting those two flags is that you can simply include
      EGL/egl.h or epoxy/egl.h and the world won't explode due to Xlib.h
      MESA_EGL_NO_X11_HEADERS is set to support older versions of Mesa.
      [1] https://github.com/KhronosGroup/EGL-Registry/pull/111
    • Vlad Zahorodnii's avatar
    • Vlad Zahorodnii's avatar
      Provide expected presentation time to effects · 9f2cb0ae
      Vlad Zahorodnii authored
      Effects are given the interval between two consecutive frames. The main
      flaw of this approach is that if the Compositor transitions from the idle
      state to "active" state, i.e. when there is something to repaint,
      effects may see a very large interval between the last painted frame and
      the current. In order to address this issue, the Scene invalidates the
      timer that is used to measure time between consecutive frames before the
      Compositor is about to become idle.
      While this works perfectly fine with Xinerama-style rendering, with per
      screen rendering, determining whether the compositor is about to idle is
      rather a tedious task mostly because a single output can't be used for
      the test.
      Furthermore, since the Compositor schedules pointless repaints just to
      ensure that it's idle, it might take several attempts to figure out
      whether the scene timer must be invalidated if you use (true) per screen
      Ideally, all effects should use a timeline helper that is aware of the
      underlying render loop and its timings. However, this option is off the
      table because it will involve a lot of work to implement it.
      Alternative and much simpler option is to pass the expected presentation
      time to effects rather than time between consecutive frames. This means
      that effects are responsible for determining how much animation timelines
      have to be advanced. Typically, an effect would have to store the
      presentation timestamp provided in either prePaint{Screen,Window} and
      use it in the subsequent prePaint{Screen,Window} call to estimate the
      amount of time passed between the next and the last frames.
      Unfortunately, this is an API incompatible change. However, it shouldn't
      take a lot of work to port third-party binary effects, which don't use the
      AnimationEffect class, to the new API. On the bright side, we no longer
      need to be concerned about the Compositor getting idle.
      We do still try to determine whether the Compositor is about to idle,
      primarily, because the OpenGL render backend swaps buffers on present,
      but that will change with the ongoing compositing timing rework.
  2. 09 Dec, 2020 9 commits
  3. 08 Dec, 2020 5 commits
  4. 07 Dec, 2020 3 commits
  5. 05 Dec, 2020 1 commit
  6. 04 Dec, 2020 2 commits
  7. 03 Dec, 2020 6 commits
  8. 02 Dec, 2020 11 commits