|author||wm4 <wm4@nowhere>||2013-03-28 21:44:27 +0100|
|committer||wm4 <wm4@nowhere>||2013-03-28 21:46:17 +0100|
vo_opengl: add alpha output
Allows playing video with alpha information on X11, as long as the video contains alpha and the window manager does compositing. See vo.rst. Whether a window can be transparent is decided by the choice of the X Visual used for window creation. Unfortunately, there's no direct way to request such a Visual through the GLX or the X API, and use of the XRender extension is required to find out whether a Visual implies a framebuffer with alpha used by XRender (see for example ). Instead of depending on the XRender wrapper library (which would require annoying configure checks, even though XRender is virtually always supported), use a simple heuristics to find out whether a Visual has alpha. Since getting it wrong just means an optional feature will not work as expected, we consider this ok.  http://stackoverflow.com/questions/4052940/how-to-make-an-opengl- rendering-context-with-transparent-background/9215724#9215724
Diffstat (limited to 'DOCS')
1 files changed, 8 insertions, 0 deletions
diff --git a/DOCS/man/en/vo.rst b/DOCS/man/en/vo.rst
index e3b8723966..dcfcb05278 100644
@@ -430,6 +430,14 @@ opengl
dimension. Default is 128x256x64.
Sizes must be a power of two, and 256 at most.
+ Try to create a framebuffer with alpha component. This only makes sense
+ if the video contains alpha information (which is extremely rare). May
+ not be supported on all platforms. If alpha framebuffers are
+ unavailable, it silently falls back to a normal framebuffer. Note
+ that when using FBO indirections (such as with ``opengl-hq``), a FBO
+ format with alpha must be specified with the ``fbo-format`` option.
Same as ``opengl``, but with default settings for high quality rendering.