element decides, which interface is supposed to be used for operating the 3D graphics. By setting its value to 1
the interface selected is given in the table below. After setting the value to 0
an automatically detected interface will be used. The interface selected is used to initialize the 3D mode by the 3D graphics window
command. If the 3D window is not active, or if the interface required has not been found, then the element will return 0. In the other cases the number of the active interface will be returned. The interface can be changed even after the 3D window has been activated. The interface can also be changed automatically after switching over the full screen mode or after changing the active Windows videomode.
1 OpenGL version 1.0
2 OpenGL version 1.1
4 DirectX version 3
5 DirectX version 5
6 DirectX version 6
7 DirectX version 7
8 DirectX version 8
The OpenGL interface is supported by all Windows version including the Windows NT (the OpenGL interface is a component of the system). The OpenGL interface does not support the multitexturing, only the texture stage 0 can be utilized, this being possible for several basic operations only (texture modulation). It does not enable to distinguish between a hardware and software variant; the non-supported videocard features are simulated by means of the software. The graphics speed is strongly dependent on the videocard driver. When the driver is supported (e.g. in the case of GeForce videocards), it can be slightly faster than the HAL DirectX driver in simple scenes. When the driver is not supported (e.g. in the case of ATI videocards), it is generally slightly faster than the RGB DirectX software driver. The OpenGL interface, version 1.0, uses a slower texture support. Therefore its speed gets lower rather quickly in more complex scene as compared with version 1.1. The OpenGL interface supports the videomode of 256 colors.
The DirectX interface is not supported in the Windows NT. In the Windows 2000 the DirectX, version 7, is a component of the system. A component of the Windows 98 system is the DirectX interface, version 6. A component of the Windows 95, 2nd edition, is the DirectX 5. The 1st edition does not contain the DirectX. The DirectX interface, version 6 through 8, support the multitexturing. The DirectX does not simulate the missing videocard function, therefore it can sometimes be more suitable to use a software driver. From among the software drivers only the reference driver is supported by the DirectX 8. The reference driver is, however, rather slow for normal use. The DirectX interface 4 through 6 support the videomode of 256 colors (generally only in connection with the RGB software driver). The Direct 5 and 4 support the Ramp driver without textures, which can be used as an lack driver when graphics speed problems occur.
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