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