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ofer_bz
03-15-2001, 12:31 AM
I am having problems coloring concave forms (a star for example) with transparent colors.
The regular color functions do not apply to concave forms when trying to use transparent colors.

Any suggestions ?

Thanks,

Ofer

Deiussum
03-15-2001, 05:58 AM
I'm not sure I understand what you mean by concave forms. Do you mean concave polygons? Concave polygons aren't guaranteed to be rendered correctly. You should break them up into convex polygons, or better yet, triangles.

So far as transparent colors, do you mean alpha blending? OpenGL doesn't specify a particular color as a "transparency color" the same way something like a GIF file does. You have to use an alpha component and enable blending by doing something like so...

glEnable(GL_BLEND);
glBlendFunc(GL_SRC_ALPHA, GL_SRC_ONE_MINUS_ALPHA);

(Edit note: oops... forgot to write the doesn't above http://www.opengl.org/discussion_boards/ubb/smile.gif)



[This message has been edited by Deiussum (edited 03-15-2001).]