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

[Tuomas J. Lukka]

CVSROOT:        /cvsroot/gzz
Module name:    gzz
Changes by:     Tuomas J. Lukka <address@hidden>        02/11/29 04:49:26

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

Log message:
        More pseudofinal

CVSWeb URLs:
http://savannah.gnu.org/cgi-bin/viewcvs/gzz/gzz/Documentation/Manuscripts/Paper/paper.tex.diff?tr1=1.91&tr2=1.92&r1=text&r2=text

Patches:
Index: gzz/Documentation/Manuscripts/Paper/paper.tex
diff -u gzz/Documentation/Manuscripts/Paper/paper.tex:1.91 
gzz/Documentation/Manuscripts/Paper/paper.tex:1.92
--- gzz/Documentation/Manuscripts/Paper/paper.tex:1.91  Fri Nov 29 04:21:54 2002
+++ gzz/Documentation/Manuscripts/Paper/paper.tex       Fri Nov 29 04:49:26 2002
@@ -337,7 +337,7 @@
 fashion\cite{widrow60adaptive,rosenblatt62neurodynamics}.
 
 From this picture, we can formulate the following points:
-To be distinguishable,
+To be distinguishable, \label{secfeaturevec}
 \begin{itemize}
 \item A feature vector for a given texture should be always the
     same, and not a smudged distribution; 
@@ -449,29 +449,47 @@
 
 In this section, we discuss our hardware-accelerated implementation
 of unique backgrounds .
-Our main platforms are NV10, i.e. OpenGL 1.3 + GL\_NV\_register\_combiners,
-and NV25, i.e. NV10 + GL\_NV\_texture\_shader2.
+Our main platforms are NV10, i.e. OpenGL 1.3 + 
+\url{GL\_\hyp NV\_\hyp register\_\hyp combiners},
+and NV25, i.e. NV10 + \url{GL\_\hyp NV\_\hyp texture\_\hyp shader2}.
 
 One important goal for the implementation is that it should be easily 
 applicable in a variety of situations. 
 For example, mapping between paper and screen can be complicated,
 e.g.~fisheye. 
 Because of this, we have 
-adapted the OpenGL model: the background ``texture coordinate'' is set
-and then a vertex is rendered using glvertex. If a vertex program
-extension is available, it is used to allow the use of vertex and texture
+adapted the OpenGL model: 
+the background ``texture coordinate'' is set
+and then a vertex is rendered using glvertex. 
+If a vertex program
+extension is available, 
+it is used to allow the use of vertex and texture
 coordinate arrays.
+To achieve this, all processing to obtain shapes on the paper 
+must be done after the texture accesses, i.e. we cannot use
+procedural geometry.
 % XXX 
 
-This enables the use of distortion inside the nodes.
+
+%Performance: zoomability, memory, speed
 
 \subsection{Resource usage}
 
-In hardware rendering, the use of resources is critical
+In hardware rendering, the use of resources is critical.
 The two relevant types of resources here are texture memory
 and rendering time.
 
-Performance: zoomability, memory, speed
+We have two rendering modes which make different
+tradeoffs between these goals: direct, where
+the same small basis textures are used, which takes 2-3 passes
+with all texture units enabled, and
+pre-rendered, where the repeating unit of the texture
+is pre-rendered into a larger texture of its own, where rendering
+takes 1 pass with one texture unit.
+To achieve a satisfactory image quality in zooming
+with the latter approach,
+a relatively large texture has to be used.
+
 
 \subsection{Colors}
 
@@ -479,20 +497,27 @@
 Therefore, it is essential that the overall colors of the
 backgrounds are maximally diverse with respect to color perception.
 
+However, we come again to the entropy arguments 
+in Section~\ref{secfeaturevec}:
+too many different colors in one background are perceived just 
+as a mix of many colors, making all such backgrounds look the same.
+The backgrounds of random texels discussed earlier are an
+extreme example of this.
+
 %In addition to choosing perceptually diverse colors, 
 %there is the the question of how many colors to use.
 %
-Using multiple different colors in a background allows 
-a multitude of different combinations 
-but too many different colors in one background are perceived just 
-as a mix of many colors, making all such backgrounds look the same.
-As an extreme case, consider the example of random texels discussed earlier.
+% Using multiple different colors in a background allows 
+% a multitude of different combinations 
 
 To maintain color balance,
-we use a small palette of carefully chosen colors for each background,
-independent of the basis textures producing the shapes of the background. 
-Register combiners are used to combine the shape with the colors 
-as explained in the following sections.
+we use a small palette 
+of carefully chosen colors for each background,
+
+% independent of the basis textures producing 
+% the shapes of the background. 
+% Register combiners are used to combine the shape with the colors 
+% as explained in the following sections.
 
 %The most important constraint for the colors is readability:
 %% XXX This is our CHOICE for a goal, not an absolute one.