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
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