Hi everyone, Long time listener, first-time caller. I''m trying to get a quadric object (gluDisk) to show its alpha channel. What do I need to do except setting the color with an alpha and drawing the object? Lame question, I know. Please help. Thanks

awesome... welcome! I don''t know if you can specify the alpha channel of each vertice of a quadric, but I know you can generate the quadrics with texture coordinates... so perhaps you can apply a texture with an alpha channel. Even if the texture is just all white with special alpha values that you desire. Or I can provided you with an algorithm to generate the vertices of any size disc at any resolution if you really want... its simple trig

1. Enable blending during INITIALISATION

glEnable (GL_BLEND);

2. Disable depth writes when RENDERING the transparent object

glDepthMask (GL_FALSE);

3. Render the transparent object

4. Re-enable depth writes after drawing the transparent object

glDepthMask (GL_TRUE);


If you don't disable depth buffer writes, sometimes the pixels won't blend into ones further away.

Hope it helps

-MENTAL