Hmmmm, if you convert to float you have a real problem: floats only have 23 bits of mantissa, so if bit 31 or 32 is set bits 0-7 will be lost. Converting directly won't change a thing there. Initing to 255 is definitively better it seems.
W.r.t clamping, in computer graphics clamping a value to an interval mean setting the value to the nearest boundary if it was outside of the interval. Clamping can never change a value to something *inside* the interval, which masking does. OG. On Thu, Dec 18, 2014 at 12:08 PM, Eduardo Lima Mitev <el...@igalia.com> wrote: > On 12/18/2014 10:28 AM, Eduardo Lima Mitev wrote: >> On 12/18/2014 09:55 AM, Olivier Galibert wrote: >>> Something is not clear to me: In which way -1 is incorrect? >>> >> >> Hi Olivier, >> >> The values being queried are the front and back stencil masks. Masks are >> (conceptually?) an unsigned integer, AFAIU. > > Well, more accurately, just a string of bits, so -1 (or any other value) > is probably fine. Problem is when the signed integer value is further > converted to float, which is the case for these failing tests. (Note > that only the test cases that query the mask as a float value are the > ones failing). > > Giving a bit more of thought to this, and assuming the test is fine > querying for a mask value using the glGetFloat API, the problem is Mesa > converting from unsigned int (the mask) to signed int, then to float; > instead of converting to float directly. I don't have a say on why it > does that intermediate conversion to int, though. > > So my original solution was wrong from different angles, and the final > solution is probably not the best one either, since we are "avoiding" > the type conversion problem rather than fixing it. > > Thanks for rising these points. > > Eduardo > _______________________________________________ > mesa-dev mailing list > mesa-dev@lists.freedesktop.org > http://lists.freedesktop.org/mailman/listinfo/mesa-dev _______________________________________________ mesa-dev mailing list mesa-dev@lists.freedesktop.org http://lists.freedesktop.org/mailman/listinfo/mesa-dev
