Ubuntu Manpage: icetDrawFrame -- renders and composites a frame

Provided by: paraview_5.11.2+dfsg-6build5_amd64

NAME

       icetDrawFrame -- renders and composites a frame

Synopsis

       #include <IceT.h>

       IceTImage icetDrawFrame(
                                  const IceTDouble *   projection_matrix,
                                  const IceTDouble *   modelview_matrix,
                                  const IceTFloat *    background_color  );

Description

Initiates a frame draw using the given transformation matrices (modelview and projection). If you are
using OpenGL ,you should probably use the icetGLDrawFrame function and associated icetGLDrawCallback.

Before IceT may render an image, the tiled display needs to be defined (using icetAddTile), the drawing
function needs to be set (using icetDrawCallback), and composite strategy must be set (using
icetStrategy). The single image sub-strategy may also optionally be set (using icetSingleImageStrategy).

All processes in the current IceT context must call icetDrawFrame for it to complete.

During compositing, IceT uses the given projection_matrix and modelview_matrix, as well as the bounds
given in the last call to icetBoundingBox or icetBoundingVertices, to determine onto which pixels the
local geometry projects. If the given matrices are not the same used in the rendering or the given bounds
do not contain the geometry, IceT may clip the geometry in surprising ways. Furthermore, IceT will modify
the projection_matrix for the drawing callback to change the projection onto (or in between) tiles. Thus,
you should pass the desired projection_matrix to icetDrawFrame and then use the version passed to the
drawing callback.

The background_color argument specifies the desired background color for the image. It is given as an
array of 4 floating point values specifying, in order, the red, green, blue, and alpha channels of the
color in the range from 0.0 to 1.0.

When rendering using a depth buffer, the background color is used to fill in empty regions of images.
When rendering using color blending, the background color is changed to transparent black during
rendering to prevent the background from being blended multiple times from different renderings. If the
ICET_CORRECT_COLORED_BACKGROUND feature is enabled, this background color is blended back into the final
composited image.

Return Value

       On  each  .igdisplay  processdisplay process (as defined by icetAddTile), icetDrawFrame returns the fully
       composited image in an IceTImage object. The contents of the image  are  undefined  for  any  non-display
       process.

       If  the  ICET_COMPOSITE_ONE_BUFFER  option  is  on  and  both  a color and depth buffer is specified with
       icetSetColorFormatand icetSetDepthFormat,then the returned image might be missing the depth  buffer.  The
       rational  behind  this  option  is  that  often  both the color and depth buffer is necessary in order to
       composite the color buffer, but the composited depth buffer is not needed. In this case, the  compositing
       might save some time by not transferring depth information at the latter stage of compositing.

       The  returned image uses memory buffers that will be reclaimed the next time IceT renders or composites a
       frame. Do not use this image after the next call to icetDrawFrame  (unless  you  have  changed  the  IceT
       context).

Errors

       ICET_INVALID_OPERATION
               Raised  if  the  drawing callback has not been set. Also can be raised if icetDrawFrame is called
              recursively, probably from within the drawing callback.

       ICET_OUT_OF_MEMORY
               Not enough memory left to hold intermittent frame buffers and other temporary data.

       icetDrawFrame may also indirectly raise an error if there is an issue with the strategy or callback.

Warnings

       None.

Bugs

       If compositing with color blending on, the image returned may have a  black  background  instead  of  the
       background_color  requested.  This  can  be  corrected  by  blending  the returned image over the desired
       background. This will be done for you if the ICET_CORRECT_COLORED_BACKGROUND feature is enabled.

Copyright

       Copyright (C)2003 Sandia Corporation

       Under the terms of Contract DE-AC04-94AL85000  with  Sandia  Corporation,  the  U.S.  Government  retains
       certain rights in this software.

       This source code is released under the New BSD License.