On 30 September 2011 10:04, Eric Anholt <<a href="mailto:eric@anholt.net">eric@anholt.net</a>> wrote: <div class="gmail_quote"><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex;"> On Fri, 30 Sep 2011 01:09:32 -0700, Paul Berry <<a href="mailto:stereotype441@gmail.com">stereotype441@gmail.com</a>> wrote: Non-text part: multipart/mixed Non-text part: multipart/alternative <div class="im">> On 29 September 2011 23:16, Kenneth Graunke <<a href="mailto:kenneth@whitecape.org">kenneth@whitecape.org</a>> wrote: > > > On 09/27/2011 11:05 AM, Paul Berry wrote: </div><div class="im">> > So, we trade support for fixed function clipping for gl_ClipVertex > > clipping? That seems really unfortunate. I know we don't use the new > > VS backend for fixed function today, but we will. > > > > My intention was never to give up support for fixed function clipping. I > just don't know how to tell, from within the vertex shader backend, whether > the shader we're compiling is an application-defined GLSL shader or Mesa's > built-in fixed function vertex shader. Since at the moment we use the old > VS backend for fixed function, and the new VS backend for > application-defined GLSL shaders, I figured I could dodge the question for > now by putting the fixed-function logic in the old VS backend and the > non-fixed-function logic in the new VS backend. Unfortunately your eyes > were too sharp for me to get away with that dodge :) </div>ctx->Shader.CurrentVertexProgram is the vertex shader, if enabled. If not, ctx->VertexProgram._Enabled tells us if a vertex program is in use, and ctx->VertexProgram.Current is that program. Otherwise, you're in fixed function. ctx->VertexProgram._Current points at one of those three. </blockquote></div> Ok, thanks. I'll send out a v2 patch that is more future proof.