ELSA GLADIAC 511, Руководство пользователя

Страница: 20 / 46

Graphics know-how
|
| ELSA GLADIAC 5II |
20
EN
4.2 3D interfaces
Software interfaces, including 3D interfaces, are known as APIs (Application
Programming Interface). The question is what these interfaces are used for
and how they work.
In simple terms: They make developers' work easier. In the past it was
necessary to address the various hardware components directly in
programming if you wanted to exploit their capabilities to the full. The APIs
are a kind of translator operating between the hardware and the software.
The specification of standard definitions was the precondition for the proper
function of these translation routines. These definitions are implemented by
the hardware manufacturers during development and optimized for the
hardware concerned. Developers can implement complex procedures
relatively easily by using these definitions. They can use a uniform command
set when programming and do not need to know the characteristics specific
to the hardware.
4.2.1 What APIs are available?
There are a good dozen more or less commonly found 3D APIs. However, in
recent years, two formats have established themselves as the favorites:
Direct3D and OpenGL. ELSA graphics boards support these commonly found
3D interfaces. The functional differences between the interfaces are slight.
Your
ELSA GLADIAC 511 supports the following APIs.
4.2.2 Direct 3D
As a development of Mode X and DirectDraw under Windows 3.1x, Direct 3D
is a branch of the DirectX multimedia family which was developed directly for
Windows 95 to accelerate the slow 3D display characteristics of the
operating system. Direct 3D cooperates with Direct Draw in two-dimen-
sional display. A typical situation would be, for instance, rendering a 3D
object while Direct Draw is placing a two-dimensional background bitmap.
Immediate mode and retained mode
As can be assumed from the two terms, immediate mode is a programming
mode that is close to the hardware. Retained mode, on the other hand, is a
programming mode that is largely predefined through an API interface. What
does this mean in detail? Looking at the two systems hierarchically, the
immediate mode is also known as the low-level mode. The programming