HP SVA V2.0 Parallel Compositing Reference Guide

Table 2-10 Pixel Compositing Table
MeaningCompositing Algorithms (Pixel Operator)
The color of the pixel is a blending of the colors of the two
pixels. The blending is dictated by the transparency (alpha
value) of the two pixels.
PC_COMP_ALPHA_SORT
The color of the pixel closest to the eye masks a more
distant pixel.
PC_COMP_DEPTH
2.6 Summary of Frame Functions
This section summarizes context functions (there are no properties). Detailed syntax for the
functions is in “Frame Functions” (page 57).
Table 2-11 lists and briefly describes the frame functions.
Table 2-11 Frame Functions
DescriptionFunction
Add a framelet to the frame.
pcFrameAddFramelet
Supplies the pixels for a framelet.
pcFrameAddGLFrameletEXT
1
Begin a new frame.
pcFrameBegin
Finished adding framelets to the frame.
pcFrameEnd
Retrieves a channel of a result (for example, pixel color
data) for a frame.
pcFrameResultChannel
Queries if a result within a frame is available.
pcFrameResultQuery
Retrieves output pixels of the frame.
pcFrameWaitOutputHP
2
Returns a channel that describes one of the
two-dimensional arrays associated with the parameter
result.
pcResultGetChannelHP
2
Resets a PCresult so it no longer references a result.pcResultDestroyHP
2
1 Available from more than one vendor's library, including HP.
2 Available only from HP Library.
2.6.1 Data Structures used by Frames
The properties of a frame are shared among all hosts within a context. These include a width
and height of the frame and the type of pixels generated to fill the frame. These properties are
stored in the context.
Framelets are represented in the Library by one or more two-dimensional arrays of pixel values.
The actual number of arrays varies based on the operator used to composite the pixels
(PC_COMPOSITE_TYPE). Each array is described in the Library as a channel. Table 2-12 lists the
channels needed for each operator.
Table 2-12 Channels Needed by Pixel Operators
Channels Needed by the OperatorOperators
PC_CHANNEL_COLORPC_COMP_ALPHA_SORT
PC_CHANNEL_COLOR
PC_CHANNEL_DEPTH
PC_COMP_DEPTH
An output is also represented by the same two-dimensional arrays. The PC_CHANNEL_COLOR
is always created. PC_CHANNEL_DEPTH is only created if needed by the operator and the program
36 Overview of Functions and Properties