Well, nvidia hw (pre-GM204; it seems like it's supported there now) doesn't support setting gl_Layer from VS, so it's just not an option there. However I do believe that the HW has enough support to handle color masking as well as scissors, so I might try to add a PIPE_CAP which indicates that pipe->clear can do it all. [First I'd have to double-check that the nvidia hw really can support all this stuff properly.]
On the subject of strings -- yeah, parameterizing strings is annoying. When parameters are involved, using ureg_* seems like the better way to go. However for static shaders like this, it'll be hard to beat the readability of a plain string. Either way, I was just copying the way that the existing (gl_Layer-using) vertex shader was implemented. Perhaps the decision of whether to do it one way or another can be arrived at separately from this change? -ilia On Mon, Nov 17, 2014 at 8:20 AM, Jose Fonseca <jfons...@vmware.com> wrote: > Hi Marek, > >> First of all, sorry for breaking Draw yesterday. > > No problem. draw_llvm.c was really obfuscating the fact that it relied on the > layout of the pipe_viewport_state. > >> There's also the OpenGL extension AMD_vertex_shader_layer which is >> supported by all GS-capable Mesa drivers except for nouveau and >> llvmpipe I think. > > I see. It sounds we should try to support these things from vs then. > >> tgsi_parse is something else. Did you mean tgsi_text_translate? > > Yes, I meant tgsi_text_translate. > >> I >> don't like using ureg for helper shaders unless I have to. Shaders >> written with ureg are harder to read and the code is longer. I've been >> thinking of rewriting all simple shaders to text. > > I don't think that's a good idea. > > Besides all the reasons I said before, string constants are not convenient to > parameterize. One needs to have multiple versions of the text file, or use > snprintf. either way quite ugly. > > Regarding readability, if one has a comment before the code is just as > readable. This is not what's done in u_simple_shaders.c, but we use this > approach elsewhere and it works quite nicely: > > [...] > > /* DP3 TEMP.w, SRC, SRC */ > ureg_DP3(tbi->prog, temp_dst_w, src, src); > > /* RSQ TEMP.w, TEMP.w */ > ureg_RSQ(tbi->prog, temp_dst_w, temp_src_w); > > [...] > > > If people feel strongly about writing helper TGSI shaders in plain text, then > we should create a simple off-line compilation tool that compiles the TGSI > and creates *.h files (similar like DirectX HLSL tools). > > > Jose > > PS: Apologies for quoting only parts of the email. I'm sort of limited to > using Outlook Web Access for email when working from home, and need to > manually quote... > > ________________________________________ > From: Marek Olšák <mar...@gmail.com> > Sent: 16 November 2014 15:51 > To: Jose Fonseca > Cc: Ilia Mirkin; mesa-dev@lists.freedesktop.org; 10.3 10.4 > Subject: Re: [Mesa-dev] [PATCH] st/mesa: add a fallback for clear_with_quad > when no vs_layer > > Hi Jose, > > First of all, sorry for breaking Draw yesterday. > > On Sun, Nov 16, 2014 at 2:57 PM, Jose Fonseca <jfons...@vmware.com> wrote: >>> Fun fact -- llvmpipe also needs this. >> >> I think this is because this functionality was developed with D3D10 in mind, >> and >> >> https://urldefense.proofpoint.com/v2/url?u=http-3A__msdn.microsoft.com_en-2Dgb_library_windows_desktop_bb509647.aspx&d=AAIBaQ&c=Sqcl0Ez6M0X8aeM67LKIiDJAXVeAw-YihVMNtXt-uEs&r=zfmBZnnVGHeYde45pMKNnVyzeaZbdIqVLprmZCM2zzE&m=W_WiVknXaiEWMUhwH9NoKnxZ7SZQGp1B1VyLSBhv0rU&s=hwsRL-R8OHz5lpkwIvnmSRlHe-ijQAReKLFMkeVDWHM&e= >> >> states that SV_RenderTargetArrayIndex "an be written from the geometry >> shader and read by the pixel shader." > > There's also the OpenGL extension AMD_vertex_shader_layer which is > supported by all GS-capable Mesa drivers except for nouveau and > llvmpipe I think. > >> >> >> BTW, coding these helper shaders as text is not a great idea IMO: >> >> - The tgsi_parse thing was written for debugging purposes mainly. >> >> - Whenever there are TGSI interface changes, any breakage with ureg will >> cause compile errors, where as it will only be detected at runtime with TGSI >> >> - ureg module makes it really easy to write shaders. It's not really much >> more work. > > tgsi_parse is something else. Did you mean tgsi_text_translate? I > don't like using ureg for helper shaders unless I have to. Shaders > written with ureg are harder to read and the code is longer. I've been > thinking of rewriting all simple shaders to text. > > Marek _______________________________________________ mesa-dev mailing list mesa-dev@lists.freedesktop.org http://lists.freedesktop.org/mailman/listinfo/mesa-dev
