On Sat, Sep 26, 2015 at 6:12 PM, Albert Freeman <albertwdfree...@gmail.com> wrote: > On 26 September 2015 at 03:32, Ilia Mirkin <imir...@alum.mit.edu> wrote: >> Hi Ian (and other spec experts), >> >> The ARB_ssbo spec mentions the following: >> >> OpenGL 4.0 (either core or compatibility profile) is required. >> >> ... >> >> Additionally, the shading language provides the memoryBarrier() function >> to control the relative order of memory accesses within individual shader >> invocations and provides various memory qualifiers controlling how the >> memory corresponding to individual variables is accessed. >> >> However the memoryBarrier() function only becomes available in GLSL >> 4.20 [along with the glMemoryBarrier() function that the spec also >> refers to] or with ARB_shader_image_load_store. >> >> Is the implication that such functionality should be auto-exposed in >> image-less drivers that support ssbo? Or that this functionality >> should just not exist unless images are supported? >> >> This is relevant to me as I plan on adding ssbo support to gallium >> before images. Also, is there really anything in there that would >> prevent this from being exposed on a GL 3.1 driver (I'm thinking of >> freedreno which doesn't support GS yet and is my initial target for >> this, since I can make atomics actually work on there, unlike NVIDIA >> where the damn things just won't budge without some magic >> yet-to-be-found make-it-work bit). >> >> Cheers, >> >> -ilia > > I think that is an error in the ARB_ssbo spec (as that spec also > mentions: "This extension is written against the OpenGL 4.2 > (Compatibility Profile) Specification."). I believe this occurred as > ARB_ssbo was adapted from NV_ssbo; NV_ssbo does not mention > MemoryBarrier (i.e. someone forgot to update the version when NV_ssbo > was enhanced for ARB).
Many extension specs are like this though... written as a diff against OpenGL version X, but require OpenGL version Y, s.t. Y < X. What are you saying is the spec error, by the way? The minimum version requirement? Or the fact that the interaction isn't listed? -ilia _______________________________________________ mesa-dev mailing list mesa-dev@lists.freedesktop.org http://lists.freedesktop.org/mailman/listinfo/mesa-dev
