icetDrawFrame(3) IceT Reference icetDrawFrame(3)
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 icetBound-
ingBox 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 pro-
jection_matrix to icetDrawFrame and then use the version passed to the drawing callback.
Return Value
On each .igdisplay processdisplay process (as defined by icetAddTile, icetDrawFrame returns an image of the fully composited image. 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 icetSetDepthFor-
mat,then the returned image might be missing the depth buffer. The rational behind this option is that often both the color and depth buf-
fer 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 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 icetGLInitialize has not been called or 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
is on.
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.
See Also
icetAddTile(3), icetBoundingBox(3), icetBoundingVertices(3), icetDrawCallback(3), icetGLDrawFrame(3), icetSingleImageStrategy(3),
icetStrategy(3)
IceT Reference August 9, 2010 icetDrawFrame(3)