   Darn Alpha!
  Ok, so you have 2 triangles. One is red, the other is blue and each are transparent. if you render rTri before bTri, then rTri gets occluded by bTri. This works vice versa also. However when you add the depth buffer you can render in any order, and the triangle closest to the camera gets rendered on top of the one behind it. This is always good.Here is the problem. It's transparency related.Say I render rTri, and then bTri. bTri is in front of rTri because of the depth test. The overlapping areas become purplish. But if I render bTri and THEN rTri, bTri is still in front of rTri but there is no purplish area. this is bad.I assume this is because the red color is not already on the back buffer when the blue color gets rendered. Is there any way around this?Please let me know if my post is scatterbrained, and I'll reword it, or give a differant example. - Thanks in advance - Chris   
  Someone call me?   ;  umm... unintentionaly. Sorry... lol   ;  I'm no graphics expert (frankly i know nothing), but can't you determine depth value by what triangle is in closest to the camera?   ;  right... but I don't understand how that applies to what I'm asking   ;  Generally when rendering polygons with translucency you first render all non-transparent polygons with the depth buffer and then you sort the transparent polygons by depth and render those back to front.   ;  Curse you, Fixed Function Pipeline... Guess I'll have to sort my sprites :(   ;  More geared toward OpenGL, but relevent to DirectX also.Alpha-blending and the Z-bufferSorting isn't too bad, even if sorting in the thousands, just choose the correct sorting algorithm.   ;  Ok, so I've been thinking, and I believe its the renderers fault that we can't do transparency the way we should be able to. Would it be THAT much more difficult for the computer to test weither or not the value in the depth buffer is a transparent value, and then render the new pixel behind it according to that alpha value? This seems reasonably simple, but I wouldn't know how to go about doing it. Then again, it would get a little messy when you render the closest value, then the furthest, then the mid. hmm... anyways. Thanks for the help guys!   ;Quote:Original post by Christopher HarrisWould it be THAT much more difficult for the computer to test weither or not the value in the depth buffer is a transparent value, and then render the new pixel behind it according to that alpha value? Yes. Yes, it would.