On 12.04.2016 07:45, Marek Olšák wrote:
On Tue, Apr 12, 2016 at 1:53 AM, Marek Olšák <[email protected]> wrote:
On Mon, Apr 11, 2016 at 7:37 PM, Nicolai Hähnle <[email protected]> wrote:
On 10.04.2016 17:34, Marek Olšák wrote:
From: Marek Olšák <[email protected]>
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.
Started by Grigori Goronzy <[email protected]>.
---
src/gallium/drivers/radeonsi/si_state.c | 73
+++++++++++++++++++++++++++++++--
1 file changed, 69 insertions(+), 4 deletions(-)
diff --git a/src/gallium/drivers/radeonsi/si_state.c
b/src/gallium/drivers/radeonsi/si_state.c
index b5db456..bc04b46 100644
--- a/src/gallium/drivers/radeonsi/si_state.c
+++ b/src/gallium/drivers/radeonsi/si_state.c
@@ -887,6 +887,15 @@ static void si_clip_scissor(struct pipe_scissor_state
*out,
out->maxy = MIN2(out->maxy, clip->maxy);
}
+static void si_scissor_make_union(struct si_signed_scissor *out,
+ struct si_signed_scissor *in)
+{
+ out->minx = MIN2(out->minx, in->minx);
+ out->miny = MIN2(out->miny, in->miny);
+ out->maxx = MAX2(out->maxx, in->maxx);
+ out->maxy = MAX2(out->maxy, in->maxy);
+}
+
static void si_emit_one_scissor(struct radeon_winsys_cs *cs,
struct si_signed_scissor *vp_scissor,
struct pipe_scissor_state *scissor)
@@ -908,12 +917,64 @@ static void si_emit_one_scissor(struct
radeon_winsys_cs *cs,
S_028254_BR_Y(final.maxy));
}
+/* the range is [-MAX, MAX] */
+#define SI_MAX_VIEWPORT_RANGE 32768
+
+static void si_emit_guardband(struct si_context *sctx,
+ struct si_signed_scissor *vp_as_scissor)
+{
+ struct radeon_winsys_cs *cs = sctx->b.gfx.cs;
+ struct pipe_viewport_state vp;
+ float left, top, right, bottom, max_range, guardband_x,
guardband_y;
+
+ /* Reconstruct the viewport transformation from the scissor. */
+ vp.translate[0] = (vp_as_scissor->minx + vp_as_scissor->maxx) /
2.0;
+ vp.translate[1] = (vp_as_scissor->miny + vp_as_scissor->maxy) /
2.0;
+ vp.scale[0] = vp_as_scissor->maxx - vp.translate[0];
+ vp.scale[1] = vp_as_scissor->maxy - vp.translate[1];
+
+ /* Treat a 0x0 viewport as 1x1 to prevent division by zero. */
+ if (vp_as_scissor->minx == vp_as_scissor->maxx)
+ vp.scale[0] = 0.5;
+ if (vp_as_scissor->miny == vp_as_scissor->maxy)
+ vp.scale[1] = 0.5;
+
+ /* Find the biggest guard band that is inside the supported
viewport
+ * range. The guard band is specified as a horizontal and vertical
+ * distance from (0,0) in clip space.
+ *
+ * This is done by applying the inverse viewport transformation
+ * on the viewport limits to get those limits in clip space.
+ *
+ * Use a limit one pixel smaller to allow for some precision
error.
+ */
+ max_range = SI_MAX_VIEWPORT_RANGE - 1;
+ left = (-max_range - vp.translate[0]) / vp.scale[0];
+ right = ( max_range - vp.translate[0]) / vp.scale[0];
+ top = (-max_range - vp.translate[1]) / vp.scale[1];
+ bottom = ( max_range - vp.translate[1]) / vp.scale[1];
+
+ assert(left < 0 && top < 0 && right > 0 && bottom > 0);
The viewport transform is supplied directly by the user, isn't it? So if
they provide a crazy transform, this assert might trigger. On the other
hand, for reasonable viewport transforms, it should even be the case that
left <= -1.0, right >= 1.0, and so on, right? I guess what I'm saying is
that the spirit of the assert is good and could probably be even
strengthened, but in reality it probably needs to go away.
In a similar spirit, perhaps guardband_x/y should be bounded to be at least
1.0?
glViewport is clamped to ctx->Const.ViewportBounds.Min/Max. This
assures that all guard bands are >= 1. However, if we get invalid
coordinates from other sources, the guard band must prevent generating
That should be "if we get invalid viewport transform from other sources".
I think the assertion should stay and be strengthened to "x >= 1", because:
- we don't know how the discard guard band interacts with the clip guard band
- we should keep the assertion to prevent and detect possible
corruption caused by invalid viewport transformation
Does this sound good?
Yes, sounds good. With these changes, you can add my R-b to this patch
as well.
Cheers,
Nicolai
Marek
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