688 |
entirely from a small set of {\em basis textures} |
entirely from a small set of {\em basis textures} |
689 |
Even though the basis |
Even though the basis |
690 |
textures are RGB textures, they contain no color information: |
textures are RGB textures, they contain no color information: |
691 |
they are simply treated as 3-vectors to be used in |
they are simply treated as 3- or 4-vectors to be used in |
692 |
various ways to create shapes, and color is added |
various ways to create shapes, and color is added |
693 |
by the register combiners. |
by the register combiners. |
694 |
|
|
860 |
|
|
861 |
\subsection{Multi-pass} |
\subsection{Multi-pass} |
862 |
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|
863 |
Because there are only a few register combiner computation |
Because there are only a two general register combiner |
864 |
stages on NV10, a single rendering pass cannot |
stages on the NV10 architecture, a single rendering pass cannot |
865 |
produce a satisfactory background. |
produce a satisfactory background texture. |
|
A simple way of increasing the visual features of the |
|
|
backgrounds is to use multiple passes. |
|
|
|
|
866 |
The register combiners can be used to compute an alpha |
The register combiners can be used to compute an alpha |
867 |
value in the same way as the color interpolation values |
value in the same way as the color interpolation values |
868 |
and use it for blending shapes over the background drawn in the first pass. |
and use it for blending over previous passes. |
|
This allows using features of different register combiner codes |
|
|
in one background. |
|
869 |
|
|
870 |
All the passes are assigned the same set of colors and |
All the passes are assigned the same set of colors and |
871 |
the same repeating unit(s) to make them blend into a |
the same repeating unit(s) to make them blend into a |