Re: [ft] anti-aliasing question

[Massimo DZ8]

Side note:
... taking the output of FreeType and putting it in a texture ... note 
the removal of "3d"
3D textures are volumes with stp texture coordinates, GL_TEXTURE_3D (not 
to be confused with cube textures, as in GL_TEXTURE_CUBE_MAP, also using 
stp coords).
for standard text, standard texturing with st texture coords is 
sufficient, to be drawn using GL_TEXTURE_2D.

*Yes, freetype allows to control antialiasing, there's an interactive 
demo about that;* however in a 3D pipeline you may have to take in 
consideration eventual non-standard blend modes and alpha test, which 
could shave off some pixels. Most GL applications will automatically 
linearly interpolate texels (as this is the default mode and most people 
don't mind setting GL_TEXTURE_NEAREST_MIPMAP_NEAREST as opposed to D3D9, 
where the default filtering is a NEAREST - blocky - one) and thus the 
effect of interpolating antialiased texture samples may result in overly 
blurry bounduaries: recall that 3d pipe texture samples are "points" as 
opposed to "pixels" as one (as the antialiaser) might expect/assume.

Embedding 2D text on 3D perspective-corrected surfaces? Then, you have 
nothing else to do than rely on texture interpolators, and just hope and 
pray everything is kept readable (all bets about constant sampling as 
intended by the antialiaser are off, as the texture domain is linearly 
deformed after AA operations). Don't worry, it's years texture 
interpolators are good enough to let you do this without much trouble.

Massimo


Dave Calkins ha scritto:
> Werner, the more I think about this, I believe FreeType provides 
> anti-aliased rendering doesn't it?  I think the GL component is simply 
> taking the output of FreeType and putting it in a 3D texture to be 
> drawn by GL.  But I think the anti-aliasing is something being done by 
> FreeType.
>
> Does FreeType allow you to control the degree of anti-aliasing?