[PyOpenGL-Users] blend and depth problem

[altern <en...@al...>]

hi

i am doing a 2D engine with ortographic proyection. I need to implement 
alpha blend and also depth, so that the shapes can be drawn at different 
z depths but also that the ones on front get blended against the ones 
behind. I am getting problems to achive this as either they wont blend 
or they wont get drawn on the depth they should.

After checking out for the whole day and read the redbook and some 
online examples ... as far as i understand  i need to play around with 
these parameters

glEnable(GL_BLEND)
glDepthMask (GL_FALSE)
glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA)

#before i draw the alpha shapes, and this:

glDepthMask (GL_TRUE)
glDisable (GL_BLEND)

#before the shapes with no alpha

But still i doesnt work properly. Maybe i need to switch alpha on before 
drawing alpha shapes and as soon as they are drawn switch it  off. i am 
not sure, i have done hundreds of tests today and i am really confused.

can anyone point into some example or solution?

thanks



-- 
enrike