Re: [Mesa-dev] Improving precision of mod(x,y)

2015-01-16 Thread Chris Forbes
Using the GLSL spec's definition (or something with equivalent precision) is also required for ARB_shader_precision, which we'll have really soon, so +1 from me too. On Fri, Jan 16, 2015 at 8:01 PM, Iago Toral wrote: > Thanks Roland and everyone else for the input. Based on the feedback > I'll in

Re: [Mesa-dev] Improving precision of mod(x,y)

2015-01-15 Thread Iago Toral
Thanks Roland and everyone else for the input. Based on the feedback I'll include the fix in thew next round of deqp fixes. Iago On Thu, 2015-01-15 at 15:32 +0100, Roland Scheidegger wrote: > Am 15.01.2015 um 10:05 schrieb Iago Toral: > > Hi, > > > > We have 16 deqp tests that fail, at least on

Re: [Mesa-dev] Improving precision of mod(x,y)

2015-01-15 Thread Ian Romanick
On 01/15/2015 10:05 PM, Iago Toral wrote: > Hi, > > We have 16 deqp tests that fail, at least on i965, because of > insufficient precision of the mod GLSL function. > > Mesa lowers mod(x,y) to y * fract(x,y) so there can be some precision > lost due to fract operation. Since the result is multipl

Re: [Mesa-dev] Improving precision of mod(x,y)

2015-01-15 Thread Glenn Kennard
On Thu, 15 Jan 2015 15:32:59 +0100, Roland Scheidegger wrote: Am 15.01.2015 um 10:05 schrieb Iago Toral: Hi, We have 16 deqp tests that fail, at least on i965, because of insufficient precision of the mod GLSL function. Mesa lowers mod(x,y) to y * fract(x,y) so there can be some precision

Re: [Mesa-dev] Improving precision of mod(x,y)

2015-01-15 Thread Roland Scheidegger
Am 15.01.2015 um 10:05 schrieb Iago Toral: > Hi, > > We have 16 deqp tests that fail, at least on i965, because of > insufficient precision of the mod GLSL function. > > Mesa lowers mod(x,y) to y * fract(x,y) so there can be some precision > lost due to fract operation. Since the result is multip

[Mesa-dev] Improving precision of mod(x,y)

2015-01-15 Thread Iago Toral
Hi, We have 16 deqp tests that fail, at least on i965, because of insufficient precision of the mod GLSL function. Mesa lowers mod(x,y) to y * fract(x,y) so there can be some precision lost due to fract operation. Since the result is multiplied by y the total precision lost usually grows together