I’m in the process of reading up on shadow maps before I try implementing them. While I’ve found quite a lot of docs (nvidia, google etc) none of them quite seem to cover all the finer points. Theory is well discussed, but implementations seem to use a variety of different extensions which have mostly been superceded. While some have been replaced by practically identical ARB versions it does muddy the water slightly. The best paper so far seems to be ‘Shadow mapping with Today’s OpenGL Hardware’ from CEDEC 2001. Has anyone got links for good articles along similar lines? Had a search through the board archives and found a few things that could be helpful yet (although there are discussions that could be ever so slightly useful once I get round to coding something).
I’m also looking up on this topic as shadowmaps seem to be a better technique to implement RT shadows.
I’ve downloaded quite a lot of demos from nVidia, SGI, etc. All of them however require extensions.
And I’ve not managed to get any to work as one extension was missing from my card…
SGIX_shadow_ambient or ARB_shadow_ambient
I’ve got SGIX_shadow/ARB_shadow as well as SGIX_depth_texture/ARB_depth_texture but not the one above. I’m using a GeForce3Ti200.
I’ve also tried on a GeForce4 MX420, it’s worse, I do not have any extensions
Both cards are using the latest nVidia drivers and the GL version on both cards are 1.4.0
Stupid me, I just found a demo on nVidia site using SGIX_shadow and SGIX_depth_teture.
And, instead of using, SGIX_shadow_ambient, they use NV_register_combiners instead.
Hardware shadows are running and the demo looks pretty cool!
You could try this demo: http://developer.nvidia.com/view.asp?IO=ogl_rtt_shadow
It doesn’t use the shadow_ambient extension, but does use a number of others including the shadow extensions, wgl_pbuffer pixel_format render_to_texture and nv_render_to_depth texture (extension names not necessarily accurate). Its a relatively old demo and should work on a GF3.
Trying to avoid WGL,
The demo that I’m using now is:
http://developer.nvidia.com/view.asp?IO=Shadow_Map
pretty old too, last updated 30 Nov 2001