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

[Tuomas J. Lukka]

CVSROOT:        /cvsroot/gzz
Module name:    gzz
Changes by:     Tuomas J. Lukka <address@hidden>        02/11/15 06:01:04

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

Log message:
        sect

CVSWeb URLs:
http://savannah.gnu.org/cgi-bin/viewcvs/gzz/gzz/Documentation/Manuscripts/Paper/paper.tex.diff?tr1=1.23&tr2=1.24&r1=text&r2=text

Patches:
Index: gzz/Documentation/Manuscripts/Paper/paper.tex
diff -u gzz/Documentation/Manuscripts/Paper/paper.tex:1.23 
gzz/Documentation/Manuscripts/Paper/paper.tex:1.24
--- gzz/Documentation/Manuscripts/Paper/paper.tex:1.23  Fri Nov 15 05:49:17 2002
+++ gzz/Documentation/Manuscripts/Paper/paper.tex       Fri Nov 15 06:01:04 2002
@@ -176,12 +176,14 @@
 
 \subsection{Basis textures}
 
+We call the textures assigned to each OpenGL texture unit {\em basis textures}.
+
 In order to avoid shapes or features from the basis textures becoming 
 identifiable, the basis textures should be relatively uniform.
 We have obtained good results with a mix of
 small textures with uniformly random texels, 
 larger textures with noise or turbulence\cite{perlin-noise-intro}, 
-and simple geometric images (checkerboard, cone).
+and simple geometric images (e.g. checkerboard).
 
 As for selection of basis textures for each paper, the principle of ``saving 
bits'' applies:
 using hyperparameters for each paper to control the probabilities of
@@ -190,13 +192,27 @@
 
 \subsection{Texture coordinates}
 
-Basic choice: finite repeating unit or not?
-
-Absolute scale --- sharp/blur
-
-Repeating unit
-
-{\bf tjl}
+Texture coordinates define the mapping of the basis textures to the paper.
+Each basis texture is repeating, but by choosing the texture coordinates
+appropriately we can make the final paper 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.
+On the other hand, for user interfaces where zooming at widely different 
+scales is desirable, a non-repeating paper can be better. 
+
+In order to create more interesting textures, it can also be useful
+to use repeating units for non-repeating papers --- but use more than one,
+which are not rationally related.
+
+The choice of the repeating unit fixes an absolute scale to the paper.
+The repeating unit should be relatively isotropic to avoid 
+the degeneration of textures to diagonal lines.
+
+After a repeating unit is fixed, there is still 
+freedom in choosing
+textures coordinates for each texture
+unit: any mapping of the texture is fine, as long as it repeats
+with the selected repeating unit.
 
 \subsection{Register combiners}