Re: [ft] anti-aliasing question

[Massimo DZ8]

Dave Calkins ha scritto:
> I downloaded the demo file, however, I'm building on Windows with VC++ 
> 2005, so its not gonna be easy to build and run the demo.  Can you 
> point me to where in the source to find the anti-aliasing control?
ftview.c
I have to correct myself however, the degree of control is nowhere as I 
recalled; it seems to be related to LCD filtering more than anything 
else, but description strings are
"use normal anti-aliased rendering"
and
"use light anti-aliased rendering"
probably not the best description strings around...

See what happens when hitting 'L' (not 'l').

ftdiff.c seems to do the same thing hitting 'l' (not 'L').

> I just have noticed that when comparing GL text rendering to GDI, the 
> GL anti-aliasing seems much more aggressive. 
Probably because of the previously mentioned linear interpolation, or 
maybe you're messing up the alpha channel in some way. You may want to 
try out a NEAREST texture filter and a REPLACE texture operation (or 
just switch to shaders and let the fixed function pipe rot in its grave).
Clearly, GL AA cannot be "more aggressive" by some means as by default, 
textures are not AA'ed - it is easy to confuse filtering with some basic 
form of AA (to a certain degree, it is) but do not let your eyes fool you.

Some experimentation with The GIMP or the image editor of your choice 
will be able to visually demonstrate you the effect of linear interpolation.

> So from my perspective, I'm loading a font, sizing it, and then 
> rendering to GL. 
Probably not: unless you're using PBOs I hardly believe you're rendering 
directly to GL; you are probably just sending a void* down TexImage. As 
such, I believe you're dealing with a standard GL texture. You may want 
to check your assumptions and your understanding of what FTGL is doing 
for you.


Massimo