There is one small issue with this. It uses viewport extents clamped to [0, 16384], but it should use unclamped signed coordinates of the viewport. The hw clipper doesn't do any clamping, so it's easy to generate window coordinates outside of [-32768, 32768] if the viewport covers [-32768, 1] in one dimension and the guard band is > 1 in that dimension.
Marek On Wed, Apr 6, 2016 at 10:15 PM, Grigori Goronzy <g...@chown.ath.cx> wrote: > With the previous changes to handling of viewport clipping, it is > almost trivial to add proper support for guard band clipping. Select a > suitable integer clipping value to keep inside the rasterizer's guard > band range of [-32768, 32767] and program the hardware to use guard > band clipping. > > Guard band clipping speeds up rasterization for primitives that are > partially off-screen. This change in particular results in small > framerate improvements in a wide range of games. > --- > src/gallium/drivers/radeonsi/si_state.c | 34 > ++++++++++++++++++++++++++++++--- > 1 file changed, 31 insertions(+), 3 deletions(-) > > diff --git a/src/gallium/drivers/radeonsi/si_state.c > b/src/gallium/drivers/radeonsi/si_state.c > index 0bb41e5..013fcf1 100644 > --- a/src/gallium/drivers/radeonsi/si_state.c > +++ b/src/gallium/drivers/radeonsi/si_state.c > @@ -882,9 +882,19 @@ static void si_clip_scissor(struct pipe_scissor_state > *out, > out->maxy = MIN2(out->maxy, clip->maxy); > } > > +static void si_mix_scissor(struct pipe_scissor_state *out, > + struct pipe_scissor_state *clip) > +{ > + out->minx = MIN2(out->minx, clip->minx); > + out->miny = MIN2(out->miny, clip->miny); > + out->maxx = MAX2(out->maxx, clip->maxx); > + out->maxy = MAX2(out->maxy, clip->maxy); > +} > + > static void si_emit_one_scissor(struct radeon_winsys_cs *cs, > struct pipe_viewport_state *vp, > - struct pipe_scissor_state *scissor) > + struct pipe_scissor_state *scissor, > + struct pipe_scissor_state *mix) > { > struct pipe_scissor_state final; > > @@ -895,6 +905,7 @@ static void si_emit_one_scissor(struct radeon_winsys_cs > *cs, > > if (scissor) > si_clip_scissor(&final, scissor); > + si_mix_scissor(mix, &final); > > radeon_emit(cs, S_028250_TL_X(final.minx) | > S_028250_TL_Y(final.miny) | > @@ -903,19 +914,35 @@ static void si_emit_one_scissor(struct radeon_winsys_cs > *cs, > S_028254_BR_Y(final.maxy)); > } > > +static void si_emit_guardband(struct si_context *sctx, > + struct pipe_scissor_state *scissor) > +{ > + struct radeon_winsys_cs *cs = sctx->b.gfx.cs; > + > + int width = scissor->maxx - scissor->minx; > + int height = scissor->maxy - scissor->miny; > + float guardband_x = width ? (32768 / width) : 1.0; > + float guardband_y = height ? (32768 / height) : 1.0; > + > + radeon_set_context_reg(cs, R_028BF0_PA_CL_GB_HORZ_CLIP_ADJ, > fui(guardband_x)); > + radeon_set_context_reg(cs, R_028BE8_PA_CL_GB_VERT_CLIP_ADJ, > fui(guardband_y)); > +} > + > static void si_emit_scissors(struct si_context *sctx, struct r600_atom *atom) > { > struct radeon_winsys_cs *cs = sctx->b.gfx.cs; > struct pipe_scissor_state *states = sctx->scissors.states; > unsigned mask = sctx->scissors.dirty_mask; > bool scissor_enable = sctx->queued.named.rasterizer->scissor_enable; > + struct pipe_scissor_state max_clip = {0}; > > /* The simple case: Only 1 viewport is active. */ > if (mask & 1 && > !si_get_vs_info(sctx)->writes_viewport_index) { > radeon_set_context_reg_seq(cs, > R_028250_PA_SC_VPORT_SCISSOR_0_TL, 2); > si_emit_one_scissor(cs, &sctx->viewports.states[0], > - scissor_enable ? &states[0] : NULL); > + scissor_enable ? &states[0] : NULL, > &max_clip); > + si_emit_guardband(sctx, &max_clip); > sctx->scissors.dirty_mask &= ~1; /* clear one bit */ > return; > } > @@ -929,9 +956,10 @@ static void si_emit_scissors(struct si_context *sctx, > struct r600_atom *atom) > start * 4 * 2, count * 2); > for (i = start; i < start+count; i++) { > si_emit_one_scissor(cs, &sctx->viewports.states[i], > - scissor_enable ? &states[i] : > NULL); > + scissor_enable ? &states[i] : > NULL, &max_clip); > } > } > + si_emit_guardband(sctx, &max_clip); > sctx->scissors.dirty_mask = 0; > } > > -- > 1.9.1 > > _______________________________________________ > 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