Text properties and FTGL

Michael Goffioul michael.goffioul at gmail.com
Sat Nov 1 09:26:31 CDT 2008


On Sat, Nov 1, 2008 at 1:18 PM, John Swensen <jpswensen at comcast.net> wrote:
> I now have an OpenGL question about textures.  Poppler converts the PDF into
> a buffer of the form numpixels * (RGBA), where the PDF has been scaled and
> the DPI chosen before this conversion to pixels takes place, so things are
> anti-aliased and everything is beautiful.  My problem is that it renders a
> white background and that keeps showing up when I render the texture to
> opengl with glBegin(GL_QUADS);...glEnd();.  With other programs I have used
> before, I should either be able to (1) just set the color I want to be the
> alpha color or (2) go through and set the value in the alpha channel for
> each of the pixels where I want it to be transparent to 1 (or 255).  I don't
> know how to do (1) with OpenGL and when I try to do (2) nothing happens.

Did you enable alpha blending in the OpenGL context?

When you create you texture for the text, do you resize it to 2^n x 2^m
or do you use rectangular texture?

Note: starting from next week, I should be able to help again on the
graphics side.

Michael.


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