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GLX_SGIX_video_resize


Name


    SGIX_video_resize

Name Strings


    GLX_SGIX_video_resize

Version


    $Date: 1999/12/28 01:40:36 $ $Revision: 1.5 $

Number


    83

Dependencies


    None

Overview


    This extension provides a means for doing swap or frame synchronous 
resizing/panning of the area
that is to be magnified (or passed through) to the output
video resolution. The purpose of this functionality is to provide a
means of allowing an application to draw into a smaller viewport to
reduce the time spent doing pixel fill. This reduced size viewport
is then magnified up to the video output resolution using the
SGIX_video_resize extension. This extension differs from SGIX_framezoom
(number 57) in that it is post framebuffer resizing. Over rendering
at swap rates and panning at frame rates is possible using frame synchronous
update instead of swap synchronous update used for the fill reduction case.

Issues


    This extension currently only works on an InfiniteReality and later 
high end machines.

New Procedures and Functions


    int glXBindChannelToWindowSGIX( Display *display,
int screen,
int channel,
Window window )

int glXChannelRectSGIX( Display *display,
int screen,
int channel,
int x,
int y,
int w,
int h )

int glXQueryChannelRectSGIX( Display *display,
int screen,
int channel,
int *dx,
int *dy,
int *dw,
int *dh )

int glXQueryChannelDeltasSGIX( Display *display,
int screen,
int channel,
int *x,
int *y,
int *w,
int *h )


int glXChannelRectSyncSGIX( Display *display,
int screen,
int channel,
GLenum synctype)


New Tokens


    Accepted by the <synctype> parameter of glXChannelRectSyncSGIX.

GLX_SYNC_FRAME_SGIX 0x00000000
GLX_SYNC_SWAP_SGIX 0x00000001

Additions to Chapter 2 of the 1.0 Specification (OpenGL Operation)


    None

Additions to Chapter 3 of the 1.0 Specification (Rasterization)


    None

Additions to Chapter 4 of the 1.0 Specification (Per-Fragment Operations and the Framebuffer)


    None

Additions to Chapter 5 of the 1.0 Specification (Special Functions)


    None

Additions to Chapter 6 of the 1.0 Specification (State and State Requests)


    None

Additions to the GLX Specification


    glXBindChannelToWindowSGIX associates a channel with an X window id
so that when the Xwid is destroyed, the channel input area care
revert back to the area before the bind took place. The other reason
for this binding is that the bound channel only updates when a swap
takes place on the associated Xwid (assuming swap sync updates)

glXChannelRectSGIX sets the input video rectangle that will take
effect the next swap on the bound did or next frame (based on
glXChannelRectSyncSGIX setting.)

glXQueryChannelRectSGIX returns the actual input area that took
effect given any hardware constraints on input area placement/size.

glXQueryChannelDeltasSGIX returns the resolution at which one can
place and size a video input area.

glXChannelRectSyncSGIX configures the system to update video input
areas on complete swap buffers of bound xwids, or on frame boundries.

Errors


    all SGIX_video_resize commands mentioned here return GLX_BAD_CONTEXT 
if there is no current GLXContext.

glXChannelRectSGIX returns GLX_BAD_CONTEXT if the current context is
not direct, or if there is no current context.

glXChannelRectSGIX returns GLX_BAD_VALUE if the x,y,w,h rectangle specified
does not fit within the channel's rectangle that was current at the time of the
glXBindChannelToWindowSGIX call.

glXBindChannelToWindowSGIX returns GLX_BAD_VALUE if window passed to it
is invalid.

all SGIX_video_resize commands mentioned here return GLX_BAD_VALUE
if the specified channel is invalid or inactive.

New State


    Get Value                   Get Command             Type    Initial Value
--------- ----------- ---- -------------
[deltas] glXQueryChannelDeltasSGIX Z+ dx=4,dy=1,dw=4,dh=1
[resize rect] glXQueryChannelRectSGIX Z+ current pan/zoom rect


New Implementation Dependent State


    Get Value                   Get Command             Type    Initial Value
--------- ----------- ---- -------------
[bound] B false

Implementation Support


   List of OpenGL implementations supporting the GLX_SGIX_video_resize extension

Original File


   Original text file for the GLX_SGIX_video_resize extension


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