[Libva] [RFC] OpenGL API extension (v3)

[Yuan, Shengquan]

On Fri, Aug 28, 2009 at 5:05 PM, Gwenole
Beauchesne<gbeauchesne at splitted-desktop.com> wrote:
> On Fri, 28 Aug 2009, Gwenole Beauchesne wrote:
>
>> The current implementation for NVIDIA shows the API is not very convenient
>> and probably inhibits some performance. MPlayer CPU usage for VO (video
>> output) now jumps to ~20% whereas it's under 1% in normal 2D display. Note
>> that a VA driver for another chipset can make this below 5% for both
>> cases. That is, 2D or GL rendering perform as well.
>
> In order to address this problem, and try to make implementations work
> more with their asynchronous functions, I will likely move this v2 API:
>
> vaCopySurfaceToTextureGLX()
> vaBindSurfaceToTextureGLX()
> vaReleaseSurfaceFromTextureGLX()
>
> to v3 API:
>
> vaCreateSurfaceGLX()
> vaDestroySurfaceGLX()
> vaAssociateSurfaceGLX()    (if TFP: vaPutSurface(Pixmap,...))
> vaDeassociateSurfaceGLX()
> vaSyncSurfaceGLX()
> vaBeginRenderSurfaceGLX()  (if TFP: glXBindTexImage())
> vaEndRenderSurfaceGLX()    (if TFP: glXReleaseTexImage())
> vaCopySurfaceGLX()         (if TFP and no direct impl. use FBO)
>
> This also makes it possible to implement TFP + FBO fallbacks effeciently
> since the problem of VA/GLX surface creation/destruction is delegated to
> specific functions. i.e. no lookup table or other trickery is required.
>
You can write a VA X11 driver using pure OpenGL, then:
Drv_Initialization()
{
      glx_context = glxCreateContext
      ..........
}

Drv_CreateSurface
{
      glGenTextures(...)
      glBindTextures(...)
      .....
}


Drv_PutSurface()
{
      glEnable(TEXTURE0)
      glBegin(xxxx)
      ......
      glEnd
}

Then when  a player call libva-core/libva-x11, it doesn't need to know
whether the lower level is a pure video driver, and the video
accelerate is actually achieved by 3D engine.

You may create a GLX backend, and pass "glx context" to
vaGetDisplay(), then it maybe more easy to share the frame buffer
information with 3D driver because they are in the same GLX context.

Just a cent, FYI.

Austin

> I have inlined the new <va/va_glx.h> header hereunder.
>
> TODO:
> - Cosmetics: right function names?
> - Add a VA/GLX specific function table?
> - Probably make vaCreateSurfaceGLX() take a pointer to a GLXContext?
>
> /**
>  * Return a suitable VADisplay for VA API
>  *
>  * @param[in] dpy the X11 display
>  * @return a VADisplay
>  */
> VADisplay vaGetDisplayGLX(
>     Display *dpy
> );
>
> /**
>  * Create a surface used for display to OpenGL
>  *
>  * The application shall maintain the live GLX context itself.
>  * Implementations are free to use glXGetCurrentContext() and
>  * glXGetCurrentDrawable() functions for internal purposes.
>  *
>  * @param[in]  dpy        the VA display
>  * @param[in]  target     the GL target to which the texture needs to be bound
>  * @param[in]  texture    the GL texture
>  * @param[out] gl_surface the VA surface
>  * @return VA_STATUS_SUCCESS if successful
>  */
> VAStatus vaCreateSurfaceGLX(
>     VADisplay dpy,
>     GLenum    target,
>     GLuint    texture,
>     void    **gl_surface
> );
>
> /**
>  * Destroy a VA/GLX surface
>  *
>  * The application shall maintain the live GLX context itself.
>  * Implementations are free to use glXGetCurrentContext() and
>  * glXGetCurrentDrawable() functions for internal purposes.
>  *
>  * @param[in]  dpy        the VA display
>  * @param[in]  gl_surface the VA surface
>  * @return VA_STATUS_SUCCESS if successful
>  */
> VAStatus vaDestroySurfaceGLX(
>     VADisplay dpy,
>     void     *gl_surface
> );
>
> /**
>  * Associate a VA surface to a VA/GLX surface
>  *
>  * The association is live until vaDeassociateSurfaceGLX(),
>  * vaCopySurfaceGLX() or the next call to vaBeginPicture() with the
>  * specificed VA surface.
>  *
>  * The application shall maintain the live GLX context itself.
>  * Implementations are free to use glXGetCurrentContext() and
>  * glXGetCurrentDrawable() functions for internal purposes.
>  *
>  * @param[in]  dpy        the VA display
>  * @param[in]  gl_surface the VA API surface
>  * @param[in]  surface    the VA API surface
>  * @param[in]  flags      the PutSurface flags
>  * @return VA_STATUS_SUCCESS if successful
>  */
> VAStatus vaAssociateSurfaceGLX(
>     VADisplay    dpy,
>     void        *gl_surface,
>     VASurfaceID  surface,
>     unsigned int flags
> );
>
> /**
>  * Deassociate a VA surface from a VA/GLX surface
>  *
>  * The application shall maintain the live GLX context itself.
>  * Implementations are free to use glXGetCurrentContext() and
>  * glXGetCurrentDrawable() functions for internal purposes.
>  *
>  * @param[in]  dpy        the VA display
>  * @param[in]  gl_surface the VA surface
>  * @return VA_STATUS_SUCCESS if successful
>  */
> VAStatus vaDeassociateSurfaceGLX(
>     VADisplay dpy,
>     void     *gl_surface
> );
>
> /**
>  * Synchronize a VA/GLX surface
>  *
>  * This function blocks until all pending operations on the VA/GLX
>  * surface have been completed.
>  *
>  * The application shall maintain the live GLX context itself.
>  * Implementations are free to use glXGetCurrentContext() and
>  * glXGetCurrentDrawable() functions for internal purposes.
>  *
>  * @param[in]  dpy        the VA display
>  * @param[in]  gl_surface the VA surface
>  * @return VA_STATUS_SUCCESS if successful
>  */
> VAStatus vaSyncSurfaceGLX(
>     VADisplay dpy,
>     void     *gl_surface
> );
>
> /**
>  * Prepare VA/GLX surface for rendering
>  *
>  * This function performs an implicit vaSyncSurfaceGLX().
>  *
>  * Implementations using the GLX texture-from-pixmap extension will
>  * generally call glXBindTexImage() here.
>  *
>  * The application shall maintain the live GLX context itself.
>  * Implementations are free to use glXGetCurrentContext() and
>  * glXGetCurrentDrawable() functions for internal purposes.
>  *
>  * @param[in]  dpy        the VA display
>  * @param[in]  gl_surface the VA surface
>  * @return VA_STATUS_SUCCESS if successful
>  */
> VAStatus vaBeginRenderSurfaceGLX(
>     VADisplay dpy,
>     void     *gl_surface
> );
>
> /**
>  * Notify the server that the VA/GLX surface is no longer used for
>  * rendering
>  *
>  * Implementations using the GLX texture-from-pixmap extension will
>  * generally call glXReleaseTexImage() here.
>  *
>  * The application shall maintain the live GLX context itself.
>  * Implementations are free to use glXGetCurrentContext() and
>  * glXGetCurrentDrawable() functions for internal purposes.
>  *
>  * @param[in]  dpy        the VA display
>  * @param[in]  gl_surface the VA surface
>  * @return VA_STATUS_SUCCESS if successful
>  */
> VAStatus vaEndRenderSurfaceGLX(
>     VADisplay dpy,
>     void     *gl_surface
> );
>
> /**
>  * Copy a VA surface to a VA/GLX surface
>  *
>  * This function kills any association that was previously made with
>  * vaAssociateSurfaceGLX() and will not return until the copy is
>  * completed.
>  *
>  * Upon successful return, the underlying GL texture will contain the
>  * complete pixels and no call to vaBeginRenderSurfaceGLX() or
>  * vaEndRenderSurfaceGLX() is required.
>  *
>  * The application shall maintain the live GLX context itself.
>  * Implementations are free to use glXGetCurrentContext() and
>  * glXGetCurrentDrawable() functions for internal purposes.
>  *
>  * @param[in]  dpy        the VA display
>  * @param[in]  gl_surface the VA API surface
>  * @param[in]  surface    the VA API surface
>  * @param[in]  flags      the PutSurface flags
>  * @return VA_STATUS_SUCCESS if successful
>  */
> VAStatus vaCopySurfaceGLX(
>     VADisplay    dpy,
>     void        *gl_surface,
>     VASurfaceID  surface,
>     unsigned int flags
> );
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