On Wed, Aug 24, 2016 at 2:46 PM, Ian Romanick <i...@freedesktop.org> wrote: > From: Ian Romanick <ian.d.roman...@intel.com> > > Fixes long standing bug on NV10 and NV20 where using a non-1x RGB or A > post-scale with GL_DOT3_RGB or GL_DOT3_RGBA texture environment would > not work. > > The old combiner math uses HALF_BIAS_NORMAL and HALF_BIAS_NEGATE. The > GL_NV_register_combiners defines these as > > HALF_BIAS_NORMAL_NV max(0.0, e) - 0.5 > HALF_BIAS_NEGATE_NV -max(0.0, e) + 0.5 > > In order to get the correct result from the dot-product, the > intermediate dot-product must be multiplied by 4. This is a literal > implementation of the GL_ARB_texture_env_dot3 spec. It also requires > using the register combiner post-scale. As a result, the post-scale > cannot be used for the post-scale set by the application. > > The new combiner math uses EXPAND_NORMAL and EXPAND_NEGATE. The > GL_NV_register_combiners defines these as > > EXPAND_NORMAL_NV 2.0 * max(0.0, e) - 1.0 > EXPAND_NEGATE_NV -2.0 * max(0.0, e) + 1.0 > > Since this fully expands the value to [-1, 1] range, the intermediate > dot-product result is the desired value. This leaves the register > combiner post-scale available for application use. > > NOTE: I have not actually tested this.
I can confirm that this is what the GL_NV_register_combiners specs say, but I have no clue if this is 1:1 with how the hw works (seems quite likely though). Is there a piglit test that you're aware of that would be sensitive to this? If so, I may test it out. In the meanwhile, have a Acked-by: Ilia Mirkin <imir...@alum.mit.edu> > > Signed-off-by: Ian Romanick <ian.d.roman...@intel.com> > --- > src/mesa/drivers/dri/nouveau/nv10_state_frag.c | 18 ++++++++---------- > 1 file changed, 8 insertions(+), 10 deletions(-) > > diff --git a/src/mesa/drivers/dri/nouveau/nv10_state_frag.c > b/src/mesa/drivers/dri/nouveau/nv10_state_frag.c > index c007c6c..e78eac3 100644 > --- a/src/mesa/drivers/dri/nouveau/nv10_state_frag.c > +++ b/src/mesa/drivers/dri/nouveau/nv10_state_frag.c > @@ -135,7 +135,7 @@ get_input_source(struct combiner_state *rc, int source) > /* Get the RC input mapping for the specified texture_env_combine > * operand, possibly inverted or biased. */ > #define INVERT 0x1 > -#define HALF_BIAS 0x2 > +#define NORMALIZE 0x2 > > static uint32_t > get_input_mapping(struct combiner_state *rc, int operand, int flags) > @@ -148,12 +148,12 @@ get_input_mapping(struct combiner_state *rc, int > operand, int flags) > map |= RC_IN_USAGE(ALPHA); > > if (is_negative_operand(operand) == !(flags & INVERT)) > - map |= flags & HALF_BIAS ? > - RC_IN_MAPPING(HALF_BIAS_NEGATE) : > + map |= flags & NORMALIZE ? > + RC_IN_MAPPING(EXPAND_NEGATE) : > RC_IN_MAPPING(UNSIGNED_INVERT); > else > - map |= flags & HALF_BIAS ? > - RC_IN_MAPPING(HALF_BIAS_NORMAL) : > + map |= flags & NORMALIZE ? > + RC_IN_MAPPING(EXPAND_NORMAL) : > RC_IN_MAPPING(UNSIGNED_IDENTITY); > > return map; > @@ -270,12 +270,10 @@ setup_combiner(struct combiner_state *rc) > > case GL_DOT3_RGB: > case GL_DOT3_RGBA: > - INPUT_ARG(rc, A, 0, HALF_BIAS); > - INPUT_ARG(rc, B, 1, HALF_BIAS); > + INPUT_ARG(rc, A, 0, NORMALIZE); > + INPUT_ARG(rc, B, 1, NORMALIZE); > > - rc->out = RC_OUT_DOT_AB | RC_OUT_SCALE_4; > - > - assert(!rc->logscale); > + rc->out = RC_OUT_DOT_AB; > break; > > default: > -- > 2.5.5 > > _______________________________________________ > 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
