I've added translucent texture mapping with alpha blending to the
OpenGL hardware back end, except for the sorting. For those that know how
the DX rendering back-end work, I'd appreciate your advice and eyes on this
to see if my proposed solution is reasonable.
For objects with alpha textures to render and blend correctly
(ignoring cylical overlap...), opaque objs need to be rendered first, then
alpha objs in back-to-front order.
(Refer to the DX call tree below) From browsing the source it appears
that the alpha sorting for translucent objs is already there for objects
with "opacities" components (found and depth sorted in eye space in
_dxf_gather(), and rendered in the DrawTransparent() back-end specific
function).
So my question is, would adding objects with alpha textures into the
translucent sortList (along with those having "opacities" components), and
moving the alpha texturing support to the OpenGL DrawTransparent back-end
function be the best approach to this problem?
Is there any reason why these alpha textured objs should go in a
separate sort list and rendered after opaque objs and before "opacities"
objs?
Thanks,
Randy
==============================================================================
CALL TREE:
_dxfDraw
_dxfDrawMono/_dxfDrawStereo
_dxf_gather
_dxf_DrawEither
_dxf_paint
_paintRecurse
_dxf_DRAW_OPAQUE (HW backend-specific)
_dxf_DRAW_TRANSPARENT (HW backend-specific)
==============================================================================
--
Randall Hopper (mailto:[EMAIL PROTECTED])
Lockheed Martin Operation Support
EPA Scientific Visualization Center
US EPA MD/24 ERC-1A; RTP, NC 27711
