Again, the point of this example is to load the system
in various ways and move the performance bottleneck around so that you can
get a feel for how to manage vertex submission in your own applications.
Ef?¬?cient Handling of Texture Data
Many applications are far more texture intensive than vertex intensive these
days. Here are some things to keep in mind when you are handling large quantities
of texture data.
Formats and Types
The number of pixel types and formats in OpenGL has been on the rise since
its inception. This increase has been driven, to a large extent, by scienti?¬?c and
entertainment visualization work in which the data is acquired from a device
Ef?¬?cient Handling of Texture Data 221
Figure 11-1 Vertex Submission Example Application
that works natively with the pixel format. The video acquisition of YCBCRformatted
data is a good example. Another is high-?¬?delity single-component
pixel data used for medical imaging. In Mac OS X, there are about two dozen
pixel types; more than a dozen pixel formats can be speci?¬?ed for OpenGL.
Consider the architecture of OpenGL on the Mac OS with regard to handling
pixel data: The Mac OS implementation provides an abstraction layer over multiple
types of graphics hardware, each with its own capacity for handling various
types of pixel data. If an application requests a pixel format/type pairing
that cannot be handled natively by the graphics hardware, the hardware driver
will make a request of the Mac OS OpenGL layer to convert the pixel data from
the requested format into the hardware??™s native format.
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