[Gzz-commits] gzz/Documentation/Manuscripts/Paper paper.tex

[Janne V. Kujala]

CVSROOT:        /cvsroot/gzz
Module name:    gzz
Changes by:     Janne V. Kujala <address@hidden>        02/11/25 15:00:48

Modified files:
        Documentation/Manuscripts/Paper: paper.tex 

Log message:
        point out problems in section 3

CVSWeb URLs:
http://savannah.gnu.org/cgi-bin/viewcvs/gzz/gzz/Documentation/Manuscripts/Paper/paper.tex.diff?tr1=1.70&tr2=1.71&r1=text&r2=text

Patches:
Index: gzz/Documentation/Manuscripts/Paper/paper.tex
diff -u gzz/Documentation/Manuscripts/Paper/paper.tex:1.70 
gzz/Documentation/Manuscripts/Paper/paper.tex:1.71
--- gzz/Documentation/Manuscripts/Paper/paper.tex:1.70  Mon Nov 25 14:51:45 2002
+++ gzz/Documentation/Manuscripts/Paper/paper.tex       Mon Nov 25 15:00:47 2002
@@ -538,6 +538,7 @@
 using hyperparameters for each paper to control the probabilities of
 different basis textures so that a paper will have mostly basis textures
 of one or two types will give a specific feel to the paper.
+% XXX: and how does that amount to maximising entropy?
 
 \begin{figure}
 \centering
@@ -557,9 +558,12 @@
 appropriately we can make the final background repeating or not.
 If the paper will be used only at relatively few magnifications, it is
 useful to use a repeating paper because of saving bits.
+% XXX: explain
 On the other hand, for user interfaces where zooming at widely different 
 scales is desirable, a non-repeating paper can be better. 
+% XXX: why is that?
 
+% XXX: define repeating unit
 In order to create more interesting backgrounds, it can also be useful
 to use repeating units for non-repeating backgrounds --- but use more than one,
 which are not rationally related.
@@ -573,6 +577,7 @@
 texture coordinates for each texture
 unit: any mapping of the texture is fine, as long as it repeats
 with the selected repeating unit.
+% this is unclear
 
 \subsection{Register combiners}
 
@@ -597,8 +602,9 @@
 Additionlly, we want to create more variation by varying
 the parameters of the combiner code based on the seed number.
 
-We use dot products between texture values and random constant vectors
+We use dot products of texture values and random constant vectors
 to extract features from the textures.
+% XXX: either (texture \cdot texture) or (texture \cdot constant)
 Because the numeric range of all register values is $[-1,1]$, 
 the complete shape of a basis texture may easily be carried on 
 to the output range, resulting in too little variation.
@@ -607,10 +613,11 @@
 the gradients and to diminish the area from which the features
 of a single basis texture are extracted.
 
-New shapes can be created by computing polynomials of the real values.
+New shapes can be created by computing polynomials of the real values
+extracted from the basis textures.
 For example, the zero value contour of a real value can be obtained
 by squaring the value, scaling up, and then clamping to $1$.
-This produces nice band-like shapes.
+This produces nice band-like shapes (see fig.~\ref{fig-regcomb}).
 
 Finally, the computed real values are used for interpolating between
 the colors chosen for the backround. Typically, because of the scaling
@@ -634,8 +641,12 @@
 
 \subsection{Multi-pass}
 
+Because there are only a few register combiner computation 
+stages on NV10, a single rendering pass cannot
+produce a very full background.
 A simple way of increasing the visual features of the
 backrounds is to use multiple passes. 
+
 The register combiners can be used to compute an alpha
 value in the same way as the color interpolation values
 and use it for blending shapes over the background drawn in the first pass.
@@ -643,7 +654,7 @@
 in one background. 
 
 All the passes are assigned the same set of colors and 
-the same base repeating unit to make them blend into a
+the same repeating unit(s) to make them blend into a
 single perceived layer.
 
 We use 3 passes on NV10 and 2 passes on NV20. 
@@ -652,7 +663,16 @@
 
 \subsection{Texture shading}
 
-Offset textures used for creating new shapes.
+On higher end hardware, the diversity of the shapes can be 
+increased with offset textures. 
+Another set of basis textures are randomly chosen for
+offsetting the texture coordinates of the first set of textures.
+To further increase variation, the offset values are multiplied
+by a random matrix.
+The textures used for offsetting are similar to the
+basic textures, but loaded as higher precision two-component HILO textures.
+
+%Offset textures used for creating new shapes.
 
 XXX