Re: [Mesa-dev] [PATCH 08/29] nir/format_convert: Add linear <-> sRGB helpers
On Tue, Mar 06, 2018 at 09:53:03AM -0800, Jason Ekstrand wrote: > On Sat, Mar 3, 2018 at 11:57 PM, Pohjolainen, Topi < > topi.pohjolai...@gmail.com> wrote: > > > On Fri, Jan 26, 2018 at 05:59:37PM -0800, Jason Ekstrand wrote: > > > --- > > > src/compiler/nir/nir_format_convert.h | 26 ++ > > > 1 file changed, 26 insertions(+) > > > > I don't what is the official reference for the formulas and I just took > > what > > google gave me first. There was discussion about the cutoff point between > > linear and curved. I got the impression that what you chose below > > (open-ended: 0 <= linear < 0.0031308f and 0 <= linear < 0.04045f instead of > > close-ended) was more "correct". Just thought I check that anyway (that you > > chose that on purpose). > > > > I did some digging. Everyone agrees that it's supposed to be <= 0.04045 > for sRGB -> linear. For linear -> sRGB, it's a bit more confused. OpenGL > 4.5, OpenGL ES 3.2, and the WSI chapter of Vulkan 1.0 all say < 0.0031308 > but the Khronos data format spec, the W3C spec it references, and Wikipedia > all say <= 0.0031308. I've sent an e-mail off to Andrew Garrard, the > author of the data format spec, to see if he can shed some light on it. In > any case, no 8-bit UNORM value will ever hit this corner case, so I don't > think it matters in practice. In the mean time, I've adjusted the NIR > helpers to match the OpenGL [ES] convention for both formulas. Great, thanks for checking it! > > > > Reviewed-by: Topi Pohjolainen > > > > > > > > diff --git a/src/compiler/nir/nir_format_convert.h > > b/src/compiler/nir/nir_format_convert.h > > > index e09c955..07618dc 100644 > > > --- a/src/compiler/nir/nir_format_convert.h > > > +++ b/src/compiler/nir/nir_format_convert.h > > > @@ -104,3 +104,29 @@ nir_format_pack_uint(nir_builder *b, nir_ssa_def > > *color, > > > return nir_format_pack_uint_unmasked(b, nir_iand(b, color, > > mask_imm), > > > bits, num_components); > > > } > > > + > > > +static inline nir_ssa_def * > > > +nir_format_linear_to_srgb(nir_builder *b, nir_ssa_def *c) > > > +{ > > > + nir_ssa_def *linear = nir_fmul(b, c, nir_imm_float(b, 12.92f)); > > > + nir_ssa_def *curved = > > > + nir_fsub(b, nir_fmul(b, nir_imm_float(b, 1.055f), > > > + nir_fpow(b, c, nir_imm_float(b, 1.0 / > > 2.4))), > > > + nir_imm_float(b, 0.055f)); > > > + > > > + return nir_fsat(b, nir_bcsel(b, nir_flt(b, c, nir_imm_float(b, > > 0.0031308f)), > > > + linear, curved)); > > > +} > > > + > > > +static inline nir_ssa_def * > > > +nir_format_srgb_to_linear(nir_builder *b, nir_ssa_def *c) > > > +{ > > > + nir_ssa_def *linear = nir_fdiv(b, c, nir_imm_float(b, 12.92f)); > > > + nir_ssa_def *curved = > > > + nir_fpow(b, nir_fdiv(b, nir_fadd(b, c, nir_imm_float(b, 0.055f)), > > > + nir_imm_float(b, 1.055f)), > > > + nir_imm_float(b, 2.4f)); > > > + > > > + return nir_fsat(b, nir_bcsel(b, nir_flt(b, c, nir_imm_float(b, > > 0.04045f)), > > > + linear, curved)); > > > +} > > > -- > > > 2.5.0.400.gff86faf > > > > > > ___ > > > mesa-dev mailing list > > > mesa-dev@lists.freedesktop.org > > > https://lists.freedesktop.org/mailman/listinfo/mesa-dev > > ___ mesa-dev mailing list mesa-dev@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/mesa-dev
Re: [Mesa-dev] [PATCH 08/29] nir/format_convert: Add linear <-> sRGB helpers
On Sat, Mar 3, 2018 at 11:57 PM, Pohjolainen, Topi < topi.pohjolai...@gmail.com> wrote: > On Fri, Jan 26, 2018 at 05:59:37PM -0800, Jason Ekstrand wrote: > > --- > > src/compiler/nir/nir_format_convert.h | 26 ++ > > 1 file changed, 26 insertions(+) > > I don't what is the official reference for the formulas and I just took > what > google gave me first. There was discussion about the cutoff point between > linear and curved. I got the impression that what you chose below > (open-ended: 0 <= linear < 0.0031308f and 0 <= linear < 0.04045f instead of > close-ended) was more "correct". Just thought I check that anyway (that you > chose that on purpose). > I did some digging. Everyone agrees that it's supposed to be <= 0.04045 for sRGB -> linear. For linear -> sRGB, it's a bit more confused. OpenGL 4.5, OpenGL ES 3.2, and the WSI chapter of Vulkan 1.0 all say < 0.0031308 but the Khronos data format spec, the W3C spec it references, and Wikipedia all say <= 0.0031308. I've sent an e-mail off to Andrew Garrard, the author of the data format spec, to see if he can shed some light on it. In any case, no 8-bit UNORM value will ever hit this corner case, so I don't think it matters in practice. In the mean time, I've adjusted the NIR helpers to match the OpenGL [ES] convention for both formulas. > Reviewed-by: Topi Pohjolainen > > > > > diff --git a/src/compiler/nir/nir_format_convert.h > b/src/compiler/nir/nir_format_convert.h > > index e09c955..07618dc 100644 > > --- a/src/compiler/nir/nir_format_convert.h > > +++ b/src/compiler/nir/nir_format_convert.h > > @@ -104,3 +104,29 @@ nir_format_pack_uint(nir_builder *b, nir_ssa_def > *color, > > return nir_format_pack_uint_unmasked(b, nir_iand(b, color, > mask_imm), > > bits, num_components); > > } > > + > > +static inline nir_ssa_def * > > +nir_format_linear_to_srgb(nir_builder *b, nir_ssa_def *c) > > +{ > > + nir_ssa_def *linear = nir_fmul(b, c, nir_imm_float(b, 12.92f)); > > + nir_ssa_def *curved = > > + nir_fsub(b, nir_fmul(b, nir_imm_float(b, 1.055f), > > + nir_fpow(b, c, nir_imm_float(b, 1.0 / > 2.4))), > > + nir_imm_float(b, 0.055f)); > > + > > + return nir_fsat(b, nir_bcsel(b, nir_flt(b, c, nir_imm_float(b, > 0.0031308f)), > > + linear, curved)); > > +} > > + > > +static inline nir_ssa_def * > > +nir_format_srgb_to_linear(nir_builder *b, nir_ssa_def *c) > > +{ > > + nir_ssa_def *linear = nir_fdiv(b, c, nir_imm_float(b, 12.92f)); > > + nir_ssa_def *curved = > > + nir_fpow(b, nir_fdiv(b, nir_fadd(b, c, nir_imm_float(b, 0.055f)), > > + nir_imm_float(b, 1.055f)), > > + nir_imm_float(b, 2.4f)); > > + > > + return nir_fsat(b, nir_bcsel(b, nir_flt(b, c, nir_imm_float(b, > 0.04045f)), > > + linear, curved)); > > +} > > -- > > 2.5.0.400.gff86faf > > > > ___ > > mesa-dev mailing list > > mesa-dev@lists.freedesktop.org > > https://lists.freedesktop.org/mailman/listinfo/mesa-dev > ___ mesa-dev mailing list mesa-dev@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/mesa-dev
Re: [Mesa-dev] [PATCH 08/29] nir/format_convert: Add linear <-> sRGB helpers
On March 4, 2018 01:57:33 "Pohjolainen, Topi" wrote: On Fri, Jan 26, 2018 at 05:59:37PM -0800, Jason Ekstrand wrote: --- src/compiler/nir/nir_format_convert.h | 26 ++ 1 file changed, 26 insertions(+) I don't what is the official reference for the formulas and I just took what google gave me first. There was discussion about the cutoff point between linear and curved. I got the impression that what you chose below (open-ended: 0 <= linear < 0.0031308f and 0 <= linear < 0.04045f instead of close-ended) was more "correct". Just thought I check that anyway (that you chose that on purpose). I have no recollection whatsoever why I chose that one. Reviewed-by: Topi Pohjolainen diff --git a/src/compiler/nir/nir_format_convert.h b/src/compiler/nir/nir_format_convert.h index e09c955..07618dc 100644 --- a/src/compiler/nir/nir_format_convert.h +++ b/src/compiler/nir/nir_format_convert.h @@ -104,3 +104,29 @@ nir_format_pack_uint(nir_builder *b, nir_ssa_def *color, return nir_format_pack_uint_unmasked(b, nir_iand(b, color, mask_imm), bits, num_components); } + +static inline nir_ssa_def * +nir_format_linear_to_srgb(nir_builder *b, nir_ssa_def *c) +{ + nir_ssa_def *linear = nir_fmul(b, c, nir_imm_float(b, 12.92f)); + nir_ssa_def *curved = + nir_fsub(b, nir_fmul(b, nir_imm_float(b, 1.055f), + nir_fpow(b, c, nir_imm_float(b, 1.0 / 2.4))), + nir_imm_float(b, 0.055f)); + + return nir_fsat(b, nir_bcsel(b, nir_flt(b, c, nir_imm_float(b, 0.0031308f)), + linear, curved)); +} + +static inline nir_ssa_def * +nir_format_srgb_to_linear(nir_builder *b, nir_ssa_def *c) +{ + nir_ssa_def *linear = nir_fdiv(b, c, nir_imm_float(b, 12.92f)); + nir_ssa_def *curved = + nir_fpow(b, nir_fdiv(b, nir_fadd(b, c, nir_imm_float(b, 0.055f)), + nir_imm_float(b, 1.055f)), + nir_imm_float(b, 2.4f)); + + return nir_fsat(b, nir_bcsel(b, nir_flt(b, c, nir_imm_float(b, 0.04045f)), + linear, curved)); +} -- 2.5.0.400.gff86faf ___ mesa-dev mailing list mesa-dev@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/mesa-dev ___ mesa-dev mailing list mesa-dev@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/mesa-dev
Re: [Mesa-dev] [PATCH 08/29] nir/format_convert: Add linear <-> sRGB helpers
On Fri, Jan 26, 2018 at 05:59:37PM -0800, Jason Ekstrand wrote: > --- > src/compiler/nir/nir_format_convert.h | 26 ++ > 1 file changed, 26 insertions(+) I don't what is the official reference for the formulas and I just took what google gave me first. There was discussion about the cutoff point between linear and curved. I got the impression that what you chose below (open-ended: 0 <= linear < 0.0031308f and 0 <= linear < 0.04045f instead of close-ended) was more "correct". Just thought I check that anyway (that you chose that on purpose). Reviewed-by: Topi Pohjolainen > > diff --git a/src/compiler/nir/nir_format_convert.h > b/src/compiler/nir/nir_format_convert.h > index e09c955..07618dc 100644 > --- a/src/compiler/nir/nir_format_convert.h > +++ b/src/compiler/nir/nir_format_convert.h > @@ -104,3 +104,29 @@ nir_format_pack_uint(nir_builder *b, nir_ssa_def *color, > return nir_format_pack_uint_unmasked(b, nir_iand(b, color, mask_imm), > bits, num_components); > } > + > +static inline nir_ssa_def * > +nir_format_linear_to_srgb(nir_builder *b, nir_ssa_def *c) > +{ > + nir_ssa_def *linear = nir_fmul(b, c, nir_imm_float(b, 12.92f)); > + nir_ssa_def *curved = > + nir_fsub(b, nir_fmul(b, nir_imm_float(b, 1.055f), > + nir_fpow(b, c, nir_imm_float(b, 1.0 / 2.4))), > + nir_imm_float(b, 0.055f)); > + > + return nir_fsat(b, nir_bcsel(b, nir_flt(b, c, nir_imm_float(b, > 0.0031308f)), > + linear, curved)); > +} > + > +static inline nir_ssa_def * > +nir_format_srgb_to_linear(nir_builder *b, nir_ssa_def *c) > +{ > + nir_ssa_def *linear = nir_fdiv(b, c, nir_imm_float(b, 12.92f)); > + nir_ssa_def *curved = > + nir_fpow(b, nir_fdiv(b, nir_fadd(b, c, nir_imm_float(b, 0.055f)), > + nir_imm_float(b, 1.055f)), > + nir_imm_float(b, 2.4f)); > + > + return nir_fsat(b, nir_bcsel(b, nir_flt(b, c, nir_imm_float(b, 0.04045f)), > + linear, curved)); > +} > -- > 2.5.0.400.gff86faf > > ___ > mesa-dev mailing list > mesa-dev@lists.freedesktop.org > https://lists.freedesktop.org/mailman/listinfo/mesa-dev ___ mesa-dev mailing list mesa-dev@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/mesa-dev