Re: [PyOpenGL-Users] Texture mapped font. Improve antialiasing

[Black <py...@bl...>]

As a side note, this probably has little to do with PyOpenGL and you  
might get more responses form a list more dedicated to OpenGL  
debugging....

That said, it is not clear what you mean by "not looking as smooth as  
it has to" and you don't include anything about what the texture looks  
like, where it came from or how you are using it, so it is hard to  
know what you are doing "wrong". It is slightly suspicious to me that  
you are using an RGBA texture for fonts, but maybe that is just me.

The one generic piece of advice I can give you about choppy looking  
texture mapped fonts is that I found that on some systems I had  
problems if the quads I was mapping the texture to weren't pixel  
aligned to the display (i.e., placed in such a way that the vertices  
of the quad didn't correspond to actual pixels).


On Jul 11, 2008, at 12:14 PM, Prashant Saxena wrote:

> Hi,
>
> I am using texture mapped polygon technique to display strings on  
> canvas. The texture is in 'tiff' format with alpha channel. Problem  
> is that the font
> is not looking as smooth as it has to.
>
> This is my 'init' function:
>     def InitGL(self):
>         self.size = self.GetClientSize()
>         glEnable(GL_BLEND)
>         glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA)
>         glEnable(GL_TEXTURE_2D)
>         glEnable(GL_LINE_SMOOTH)
>         glHint(GL_LINE_SMOOTH_HINT, GL_NICEST)
>         glClearColor(0.5, 0.5, 0.5, 0.0)
>         glDisable(GL_DEPTH_TEST)
>         glShadeModel(GL_SMOOTH)
>         glMatrixMode(GL_PROJECTION)
>         glLoadIdentity()
>         glOrtho( 0.0, self.size.width, self.size.height, 0.0, -1.0,  
> 1.0 )
>         glMatrixMode(GL_MODELVIEW)
>
> This is my font texture file loader:
>
>     textureSurface = Image.open(textureFile)
>     textureData = textureSurface.convert( "RGBA").tostring()
>     width, height = textureSurface.size[0], textureSurface.size[1]
>
>     #Bind it to a texture
>     textureId = glGenTextures(1)
>     fontTexture[0] = textureId
>
>     glBindTexture(GL_TEXTURE_2D, textureId)
>
>     glTexImage2D( GL_TEXTURE_2D, 0, GL_RGBA, width, height, 0,
>                   GL_RGBA, GL_UNSIGNED_BYTE, textureData )
>
>     glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR)
>     glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR)
>
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