Christoph, Luca, Twoside lighting has is a bit of a special case GL-ism. On a lot of hardware we end up implementing it by passing both front and back colors to the fragment shader and selecting between them using the FACE variable. If we removed the implicit fixed-function support for two-side lighting in the rasterizer, it would solve the issue of how this is represented in any routing table.
How does that sit with your drivers? Keith ________________________________________ From: luca.barbi...@gmail.com [luca.barbi...@gmail.com] On Behalf Of Luca Barbieri [l...@luca-barbieri.com] Sent: Monday, February 01, 2010 7:29 AM To: Christoph Bumiller Cc: Keith Whitwell; mesa3d-dev@lists.sourceforge.net Subject: Re: [Mesa3d-dev] [PATCH] glsl: put varyings in texcoord slots > I can't really use a routing table state to produce a cso, because the hw > routing table I generate depends on rasterizer state, e.g. I must not > put in back face colour (we have a 2 to 1 mapping here) if twoside > is disabled. > > Also, I'm routing based on the scalar *components* the FP reads, > not whole TGSI pseudo vec4 registers (NUM_INTERPOLATORS will > thus be inaccurate) - set_routing_table will have to pass me the > respective programs too. > Well, I can still use the cso and insert it into the rest of the routing > table that still need to be assembled on the fly, I did that before the > 1:1 mapping between FP and VP regs was removed. You are right, the routing table CSO needs to contain the fragment and vertex shader handles, and ideally light_twoside should be moved to the vertex->fragment routing table since it is really an attribute of that and not polygon rasterization/setup. You can then just look at your internal data structure and construct a scalar routing table from the vec4 one provided by Gallium. We could also, as a further extension, support scalar routing tables directly in Gallium. Note however that radeon hardware presumably only supports vector ones, so we would need all 3 options with caps. A further intermediate step could be vector routing tables with swizzling. ------------------------------------------------------------------------------ The Planet: dedicated and managed hosting, cloud storage, colocation Stay online with enterprise data centers and the best network in the business Choose flexible plans and management services without long-term contracts Personal 24x7 support from experience hosting pros just a phone call away. http://p.sf.net/sfu/theplanet-com _______________________________________________ Mesa3d-dev mailing list Mesa3d-dev@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/mesa3d-dev
