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.
v2: the rasterizer doesn't clamp coordinates, so use coordinates
before viewport clamping to determine guardband clipping.
---
So, how about this? I don't like the introduction of the new struct,
but this seems to be cleaner than v1 anyway.
src/gallium/drivers/radeonsi/si_state.c | 83 +++++++++++++++++++++++----------
src/gallium/drivers/radeonsi/si_state.h | 7 +++
2 files changed, 66 insertions(+), 24 deletions(-)
diff --git a/src/gallium/drivers/radeonsi/si_state.c
b/src/gallium/drivers/radeonsi/si_state.c
index 0bb41e5..a9a58e8 100644
--- a/src/gallium/drivers/radeonsi/si_state.c
+++ b/src/gallium/drivers/radeonsi/si_state.c
@@ -838,39 +838,53 @@ static void si_set_scissor_states(struct pipe_context
*ctx,
si_mark_atom_dirty(sctx, &sctx->scissors.atom);
}
+static void si_mix_scissor(struct si_viewport_scissor *out,
+ struct si_viewport_scissor *mix)
+{
+ out->minx = MIN2(out->minx, mix->minx);
+ out->miny = MIN2(out->miny, mix->miny);
+ out->maxx = MAX2(out->maxx, mix->maxx);
+ out->maxy = MAX2(out->maxy, mix->maxy);
+}
+
static void si_get_scissor_from_viewport(struct pipe_viewport_state *vp,
- struct pipe_scissor_state *scissor)
+ struct si_viewport_scissor *scissor)
{
int tmp;
/* Convert (-1, -1) and (1, 1) from clip space into window space. */
- int minx = (int)(-vp->scale[0] + vp->translate[0]);
- int miny = (int)(-vp->scale[1] + vp->translate[1]);
- int maxx = (int)(vp->scale[0] + vp->translate[0]);
- int maxy = (int)(vp->scale[1] + vp->translate[1]);
+ scissor->minx = (int)(-vp->scale[0] + vp->translate[0]);
+ scissor->miny = (int)(-vp->scale[1] + vp->translate[1]);
+ scissor->maxx = (int)(vp->scale[0] + vp->translate[0]);
+ scissor->maxy = (int)(vp->scale[1] + vp->translate[1]);
/* r600_draw_rectangle sets this. Disable the scissor. */
- if (minx == -1 && miny == -1 && maxx == 1 && maxy == 1) {
- minx = miny = 0;
- maxx = maxy = 16384;
+ if (scissor->minx == -1 && scissor->miny == -1 &&
+ scissor->maxx == 1 && scissor->maxy == 1) {
+ scissor->minx = scissor->miny = 0;
+ scissor->maxx = scissor->maxy = 16384;
}
/* Handle inverted viewports. */
- if (minx > maxx) {
- tmp = minx;
- minx = maxx;
- maxx = tmp;
+ if (scissor->minx > scissor->maxx) {
+ tmp = scissor->minx;
+ scissor->minx = scissor->maxx;
+ scissor->maxx = tmp;
}
- if (miny > maxy) {
- tmp = miny;
- miny = maxy;
- maxy = tmp;
+ if (scissor->miny > scissor->maxy) {
+ tmp = scissor->miny;
+ scissor->miny = scissor->maxy;
+ scissor->maxy = tmp;
}
+}
- scissor->minx = CLAMP(minx, 0, 16384);
- scissor->miny = CLAMP(miny, 0, 16384);
- scissor->maxx = CLAMP(maxx, 0, 16384);
- scissor->maxy = CLAMP(maxy, 0, 16384);
+static void si_clamp_scissor(struct pipe_scissor_state *out,
+ struct si_viewport_scissor *scissor)
+{
+ out->minx = CLAMP(scissor->minx, 0, 16384);
+ out->miny = CLAMP(scissor->miny, 0, 16384);
+ out->maxx = CLAMP(scissor->maxx, 0, 16384);
+ out->maxy = CLAMP(scissor->maxy, 0, 16384);
}
static void si_clip_scissor(struct pipe_scissor_state *out,
@@ -884,14 +898,18 @@ static void si_clip_scissor(struct pipe_scissor_state
*out,
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 si_viewport_scissor *mix)
{
+ struct si_viewport_scissor vp_scissor;
struct pipe_scissor_state final;
/* Since the guard band disables clipping, we have to clip per-pixel
* using a scissor.
*/
- si_get_scissor_from_viewport(vp, &final);
+ si_get_scissor_from_viewport(vp, &vp_scissor);
+ si_mix_scissor(mix, &vp_scissor);
+ si_clamp_scissor(&final, &vp_scissor);
if (scissor)
si_clip_scissor(&final, scissor);
@@ -903,19 +921,35 @@ 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 si_viewport_scissor *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 si_viewport_scissor max_clip = {32768, 32768, -32768, -32768};
/* 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 +963,10 @@ 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;
}
diff --git a/src/gallium/drivers/radeonsi/si_state.h
b/src/gallium/drivers/radeonsi/si_state.h
index 2a63279..d1b4c52 100644
--- a/src/gallium/drivers/radeonsi/si_state.h
+++ b/src/gallium/drivers/radeonsi/si_state.h
@@ -219,6 +219,13 @@ struct si_buffer_resources {
struct pipe_resource **buffers; /* this has num_buffers
elements */
};
+struct si_viewport_scissor {
+ int minx;
+ int miny;
+ int maxx;
+ int maxy;
+};
+
#define si_pm4_block_idx(member) \
(offsetof(union si_state, named.member) / sizeof(struct si_pm4_state *))
--
1.9.1
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