On 13 May 2016 at 18:34, Juan A. Suarez Romero <jasua...@igalia.com> wrote: > On Fri, 2016-05-13 at 05:34 +1000, Dave Airlie wrote: >> On 13 May 2016 4:28 AM, "Antia Puentes" <apuen...@igalia.com> wrote: >> > >> > >> > From: "Juan A. Suarez Romero" <jasua...@igalia.com> >> > >> > From the GL 4.5 core spec, section 11.1.1 (Vertex Attributes): >> > >> > "A program with more than the value of MAX_VERTEX_ATTRIBS >> > active attribute variables may fail to link, unless >> > device-dependent optimizations are able to make the program >> > fit within available hardware resources. For the purposes >> > of this test, attribute variables of the type dvec3, dvec4, >> > dmat2x3, dmat2x4, dmat3, dmat3x4, dmat4x3, and dmat4 may >> > count as consuming twice as many attributes as equivalent >> > single-precision types. While these types use the same number >> > of generic attributes as their single-precision equivalents, >> > implementations are permitted to consume two single-precision >> > vectors of internal storage for each three- or four-component >> > double-precision vector." >> > >> > This commits adds a flag that allows driver to specify if dvec3, >> > dvec4, >> > dmat2x3, dmat2x4, dmat3, dmat3x4, dmat4x3 and dmat4 count as >> > consuming >> > twice as many attributes as equivalent single-precision types >> > (default >> > value being false). >> Doesn't this patch break all the drivers currently implementing this >> extension? >> >> If I read it correctly, it creates the new Const, and then turns off >> the feature. >> > > > Right. That const defines if those doubles consume two locations (flag > as true) or just one (flag as false), for the purposes of checking if > it reaches the MAX_VERTEX_ATTRIBS. > > And the default value is to count as one (flag as false). The reason is > that this is what is happening right now in that function, except when > we use explicit location. > > When you added the code to count doubles as consuming two locations, > you only did it if the locations were explicit. But in other case, > double attributes as counted as consuming one attribute. > > I don't know if you only added it with explicit location for a good > reason, or just forgot to add in the general case. > > So I took the general case as the default one. > > If actually the general case should count the doubles as consuming two > (as in the case of explicit), when either we can swap the flag set it > to true as default, or directly remove the flag and force all drivers > to count doubles as consuming two attributes.
For MAX_VERTEX_ATTRIBS I think we always want to count as 2. It's was an oversight on my part I think if I missed that. But yes be careful with locations as it consumes two attributes, but not two locations. so location 3 dvec3 location 4 dvec3 is valid, but they consume 4 attributes. Dave. _______________________________________________ mesa-dev mailing list mesa-dev@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/mesa-dev
