icetcreatecontext(3) [debian man page]
icetCreateContext(3) IceT Reference icetCreateContext(3) NAME
icetCreateContext -- creates a new context. Synopsis #include <IceT.h> IceTContext icetCreateContext( IceTCommunicator comm ); Description The icetCreateContext function creates a new .igcontext!IceT IceT context, makes it current, and returns a handle to the new context. The handle returned is of type IceTContext. This is an opaque type that should not be handled directly, but rather simply passed to other IceT functions. Like OpenGL ,the IceT engine behaves like a large state machine. The parameters for engine operation is held in the current state. The entire state is encapsulated in a context. Each new context contains its own state. It is therefore possible to change the entire current state of IceT by simply switching contexts. Switching contexts is much faster, and often more convenient, than trying to change many state parameters. Errors None. Warnings None. Bugs It may be tempting to use contexts to run different IceT operations on separate program threads. Although certainly possible, great care must be taken. First of all, all threads will share the same context. Second of all, IceT is not thread safe. Therefore, a multi-threaded program would have to run all IceT commands in `critical sections' to ensure that the correct context is being used, and the methods exe- cute safely in general. Notes icetCreateContext duplicates the communicator comm. Thus, to avoid deadlocks on certain implementations (such as MPI), the user level pro- gram should call icetCreateContext on all processes with the same comm object at about the same time. 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 icetDestroyContext(3), icetGetContext(3), icetSetContext(3), icetCopyState(3), icetGet(3) IceT Reference August 9, 2010 icetCreateContext(3)
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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)