On Fri, 13 May 2011 15:56:28 -0700, Kenneth Graunke <kenn...@whitecape.org> wrote: > On 05/12/2011 09:05 PM, Eric Anholt wrote: > > Fixes glean pointAtten. > > --- > > src/mesa/drivers/dri/i965/gen6_sf_state.c | 9 +++++++-- > > 1 files changed, 7 insertions(+), 2 deletions(-) > > > > diff --git a/src/mesa/drivers/dri/i965/gen6_sf_state.c > > b/src/mesa/drivers/dri/i965/gen6_sf_state.c > > index 50a5ad3..f96cfe5 100644 > > --- a/src/mesa/drivers/dri/i965/gen6_sf_state.c > > +++ b/src/mesa/drivers/dri/i965/gen6_sf_state.c > > @@ -103,6 +103,7 @@ upload_sf_state(struct brw_context *brw) > > int attr = 0; > > int urb_start; > > int two_side_color = (ctx->Light.Enabled&& ctx->Light.Model.TwoSide); > > + float point_size; > > > > /* _NEW_TRANSFORM */ > > if (ctx->Transform.ClipPlanesEnabled) > > @@ -209,8 +210,12 @@ upload_sf_state(struct brw_context *brw) > > ctx->Point._Attenuated)) > > dw4 |= GEN6_SF_USE_STATE_POINT_WIDTH; > > > > - dw4 |= U_FIXED(CLAMP(ctx->Point.Size, 0.125, 255.875), 3)<< > > - GEN6_SF_POINT_WIDTH_SHIFT; > > + /* Clamp to ARB_point_parameters user limits */ > > + point_size = CLAMP(ctx->Point.Size, ctx->Point.MinSize, > > ctx->Point.MaxSize); > > + > > + /* Clamp to the hardware limits, in fixed point */ > > + dw4 |= CLAMP(U_FIXED(point_size, 3), 1, 0x7ff); > > + > > if (ctx->Point.SpriteOrigin == GL_LOWER_LEFT) > > dw1 |= GEN6_SF_POINT_SPRITE_LOWERLEFT; > > Why the change to clamp in fixed point? Unless it's necessary for > correctness, I'd prefer to stick with 0.125 and 255.875, since those are > directly readable/searchable in the hardware documentation, while 0x7ff > is not.
My concern was justifying to myself that 0.125 and 255.875 would produce exactly 1 and 0x7ff after U_FIXED. Since they do actually produce the correct numbers, I went with your change.
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