only make some faces transparend

OpenGL OpenGL: Advanced Coding
1

hi
does one of you know, how i can make opengl to use alpha blending only for some of my GL_QUADS?
thx in advance
Harry

2

Hi, if u know which of ur quads must be blended, u should group them like this:

glBegin(GL_QUADS);
//**** the quads blended
glEnable(GL_BLEND);
glBlendFunc(Ur_blend_func);
draw_the_blended_quads;
glDisable(GL_BLEND);
draw_the_other_quads;
glEnd();

I don’t if it works but u can try it

3

Thank you, i always used the
glEnable(blending****)
command
before calling
glBegin(GL_QUADS)
thank you

4

I just tries to use your version.
but it does not work
do you (or someone else) know a working sollution?
this would be very nice of you
cu

5

ok, now i found the sollution.
i have to draw the transparent objects after drawing all the others.
ok thanx
bye

6

Keep in mind that depending on the effect you are trying to achieve, you will either have to draw the transparent objects in order from furthest to nearest, -or- make the depth buffer read-only before drawing your unordered transparent quads. If you don’t make the depth buffer read-only, any transparent quad which is directly behind another transparent quad won’t get drawn if the nearer quad is rendered first.

Good Luck!

MikeM

[This message has been edited by MikeM (edited 08-11-2000).]