On Thursday, March 31, 2016 12:37:31 AM PDT Jordan Justen wrote: > On 2016-03-30 02:03:29, Alejandro Piñeiro wrote: > > On 30/03/16 09:44, Alejandro Piñeiro wrote: > > > On 30/03/16 06:16, Kenneth Graunke wrote: > > > > >> I was just looking at that today...adding an ordinary global variable > > >> in builtin_variables.cpp seems really wrong. > > > I think that I don't follow. Why gl_GlobalInvocationID is an ordinary > > > global variable? It is a built-in variable, and I assumed that all > > > built-ins would be using the ir_var_system_value ir_variable_mode. As > > > far as I understand this is not happening here due the lowering. > > > > Ah ok, I think that I understand what you mean, now that I took a look > > to builtin_variables.cpp::1171. Yes gl_GlobalInvocationID and > > gl_LocalInvocationIndex are not added with add_system_value. As far as I > > see, it is because they are not included as system values at > > shader_enums.h:gl_system_value. I guess that because it is lowered as > > Illia mentioned. Jordan could you confirm the reason of adding those > > built-ins as regular variables? > > > > In v1, they were system values: > > http://thread.gmane.org/gmane.comp.video.mesa3d.devel/109477 > > I think based on Ilia's feedback: > > " have you considered just starting out *every* CS with the > instructions to compute them and then not having any lowering at > all? " > > I tried to handle the initialization of the variables differently. I > don't think Ilia's feedback really commented on if it was a system > value or not, so dropping the system value type was my idea/fault. > > In v2, instead having a lowering pass that replaces the system value, > I inserted some code into main to initialize the variable. > > http://thread.gmane.org/gmane.comp.video.mesa3d.devel/110920
Ahh. Thanks. That makes sense, it was just a bit surprising to see. It's probably best to leave this as is, and just add !is_gl_identifier() to Alejandro's warning code as Ilia suggested. That'll ensure every built-in value is skipped. --Ken
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