[Gzz-commits] manuscripts/AGPU fonts.txt

[Tuomas J. Lukka]

CVSROOT:        /cvsroot/gzz
Module name:    manuscripts
Changes by:     Tuomas J. Lukka <address@hidden>        03/04/12 07:40:59

Modified files:
        AGPU           : fonts.txt 

Log message:
        Edit - remove fragment-based text: no experiences yet

CVSWeb URLs:
http://savannah.gnu.org/cgi-bin/viewcvs/gzz/manuscripts/AGPU/fonts.txt.diff?tr1=1.8&tr2=1.9&r1=text&r2=text

Patches:
Index: manuscripts/AGPU/fonts.txt
diff -u manuscripts/AGPU/fonts.txt:1.8 manuscripts/AGPU/fonts.txt:1.9
--- manuscripts/AGPU/fonts.txt:1.8      Sat Apr 12 07:33:46 2003
+++ manuscripts/AGPU/fonts.txt  Sat Apr 12 07:40:59 2003
@@ -1,6 +1,5 @@
-ISSUES:
-- how much should we discuss the texel-character stuff?
-- what should we say about proportional fonts?
+This proposal is a bit long - feel free to take just the parts
+you're interested in.
 
 Legible text using the flexibility of modern GPUs
 =================================================
@@ -32,6 +31,14 @@
 can be implemented optimally with a fragment program, and, with less
 quality, with a combination of register combiners and LOD-biasing.
 
+The second approach is to change the filtering paradigm entirely.
+This is possible because of the flexibility of e.g. the NV30.  We have
+had some encouraging results from using NEAREST-filtering in OpenGL,
+but where at each texel, the *texel distance* between the texel and the
+font outline is stored. This allows the filtering to be based more on
+the font outline and less the pixellated representation, approximating
+a real font rasterer on the GPU. 
+
 2. Subpixel rendering
 ---------------------
 
@@ -43,7 +50,7 @@
 
 We show how a fragment program can be used to implement the sub-pixel
 filtering by using the DDX, DDY and TXD instructions to access the
-texture several times, for the ctriangular sampling filter commonly
+texture several times, for the tri-triangular sampling filter commonly
 used in subpixel rendering.
 
 A lesser-quality approximation can be obtained on NV2X with three
@@ -52,17 +59,9 @@
 for discussing the inverting of the homogeneous coordinate transformations
 in the vertex programs to shift the texture coordinates in screen space.
 
-[ there are also some practical aspects related to rendering of mosaiced
-fonts such as borders &c which we *can* discuss here if you feel like it
-]
-
-3. Fragment-based text
-----------------------
-The rendering of text strings from texture uses offset texturing: each
-texel in the text texture stores the offset to the correct glyph in a
-font texture. The rendering time depends only on the rendered size of
-the text fragment and not on the number of individual characters.
 
+Figures
+-------
 
 FIGS!!!
 - sharpening