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Graphics know-how
21
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ELSA GLADIAC 5II
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EN
interface level is close to the hardware level and permits the programmer
direct access to special functions in the hardware component concerned. The
retained mode (high-level mode) makes it possible, for example, to load a
defined 3D object with textures into a Windows application. Here it can be
manipulated and moved using simple API commands. Translation takes place
in real time, without the need to know the technical structure of the object.
For further information see the Internet site
www.microsoft.com/directx
.
4.2.3
OpenGL API
Since the OpenGL API was introduced in 1992, it has grown into the industry's
leading cross-platform 2D and 3D graphics API and its presence continues to
grow every day.
OpenGL is platform-independent and makes a distinction between immediate
and display list modes. A display list stores specific sequences that can be
recalled again later. The object descriptions can then be taken directly from
the list, resulting in very high performance. However, if objects need to be
manipulated frequently, the display list will have to be generated again from
new. The OpenGL API provides a wide range of graphics features, from
rendering a simple geometric point, line, or filled polygon, to the most
sophisticated representations of curved surfaces with lighting and texture
mapping. The some 330 routines of OpenGL provide software developers
access to these graphics capabilities:
For further information see the Internet site
www.sgi.com/software/opengl
.