Mesa (master): radeonsi: don't discard points and lines

[Nicolai Hähnle]

Module: Mesa
Branch: master
Commit: 4d74432dd3b64814aca7d31fa133d5ee8bce9026
URL:    http://cgit.freedesktop.org/mesa/mesa/commit/?id=4d74432dd3b64814aca7d31fa133d5ee8bce9026

Author: Nicolai Hähnle <nicolai.haehnle at amd.com>
Date:   Sun Sep 17 11:26:53 2017 +0200

radeonsi: don't discard points and lines

This is a bit conservative, but a more precise solution requires access
to the rasterizer state. This is something to tackle after the fork between
r600 and radeonsi.

Cc: mesa-stable at lists.freedesktop.org
Reviewed-by: Marek Olšák <marek.olsak at amd.com>

---

 src/gallium/drivers/radeon/r600_viewport.c   | 21 +++++++++++++++++++--
 src/gallium/drivers/radeonsi/si_state_draw.c |  7 +++++++
 2 files changed, 26 insertions(+), 2 deletions(-)

diff --git a/src/gallium/drivers/radeon/r600_viewport.c b/src/gallium/drivers/radeon/r600_viewport.c
index cf6d5f28ac..6e4fc9d751 100644
--- a/src/gallium/drivers/radeon/r600_viewport.c
+++ b/src/gallium/drivers/radeon/r600_viewport.c
@@ -165,6 +165,7 @@ static void r600_emit_guardband(struct r600_common_context *rctx,
 	struct radeon_winsys_cs *cs = rctx->gfx.cs;
 	struct pipe_viewport_state vp;
 	float left, top, right, bottom, max_range, guardband_x, guardband_y;
+	float discard_x, discard_y;
 
 	/* Reconstruct the viewport transformation from the scissor. */
 	vp.translate[0] = (vp_as_scissor->minx + vp_as_scissor->maxx) / 2.0;
@@ -198,6 +199,22 @@ static void r600_emit_guardband(struct r600_common_context *rctx,
 	guardband_x = MIN2(-left, right);
 	guardband_y = MIN2(-top, bottom);
 
+	discard_x = 1.0;
+	discard_y = 1.0;
+
+	if (rctx->current_rast_prim < PIPE_PRIM_TRIANGLES) {
+		/* When rendering wide points or lines, we need to be more
+		 * conservative about when to discard them entirely. Since
+		 * point size can be determined by the VS output, we basically
+		 * disable discard completely completely here.
+		 *
+		 * TODO: This can hurt performance when rendering lines and
+		 * points with fixed size, and could be improved.
+		 */
+		discard_x = guardband_x;
+		discard_y = guardband_y;
+	}
+
 	/* If any of the GB registers is updated, all of them must be updated. */
 	if (rctx->chip_class >= CAYMAN)
 		radeon_set_context_reg_seq(cs, CM_R_028BE8_PA_CL_GB_VERT_CLIP_ADJ, 4);
@@ -205,9 +222,9 @@ static void r600_emit_guardband(struct r600_common_context *rctx,
 		radeon_set_context_reg_seq(cs, R600_R_028C0C_PA_CL_GB_VERT_CLIP_ADJ, 4);
 
 	radeon_emit(cs, fui(guardband_y)); /* R_028BE8_PA_CL_GB_VERT_CLIP_ADJ */
-	radeon_emit(cs, fui(1.0));         /* R_028BEC_PA_CL_GB_VERT_DISC_ADJ */
+	radeon_emit(cs, fui(discard_y));   /* R_028BEC_PA_CL_GB_VERT_DISC_ADJ */
 	radeon_emit(cs, fui(guardband_x)); /* R_028BF0_PA_CL_GB_HORZ_CLIP_ADJ */
-	radeon_emit(cs, fui(1.0));         /* R_028BF4_PA_CL_GB_HORZ_DISC_ADJ */
+	radeon_emit(cs, fui(discard_x));   /* R_028BF4_PA_CL_GB_HORZ_DISC_ADJ */
 }
 
 static void r600_emit_scissors(struct r600_common_context *rctx, struct r600_atom *atom)
diff --git a/src/gallium/drivers/radeonsi/si_state_draw.c b/src/gallium/drivers/radeonsi/si_state_draw.c
index e4f592c384..fb91d936c9 100644
--- a/src/gallium/drivers/radeonsi/si_state_draw.c
+++ b/src/gallium/drivers/radeonsi/si_state_draw.c
@@ -1255,6 +1255,13 @@ void si_draw_vbo(struct pipe_context *ctx, const struct pipe_draw_info *info)
 		rast_prim = info->mode;
 
 	if (rast_prim != sctx->b.current_rast_prim) {
+		bool old_is_poly = sctx->b.current_rast_prim >= PIPE_PRIM_TRIANGLES;
+		bool new_is_poly = rast_prim >= PIPE_PRIM_TRIANGLES;
+		if (old_is_poly != new_is_poly) {
+			sctx->b.scissors.dirty_mask = (1 << R600_MAX_VIEWPORTS) - 1;
+			si_set_atom_dirty(sctx, &sctx->b.scissors.atom, true);
+		}
+
 		sctx->b.current_rast_prim = rast_prim;
 		sctx->do_update_shaders = true;
 	}