[Mesa-dev] [PATCH 5/8] radeonsi: don't interpolate colors if flatshading is enabled

[Marek Olšák]

From: Marek Olšák <marek.olsak at amd.com>

use v_interp_mov for those
---
 src/gallium/drivers/radeonsi/si_shader.c        | 13 ++++++++++++-
 src/gallium/drivers/radeonsi/si_shader.h        |  2 +-
 src/gallium/drivers/radeonsi/si_state_shaders.c |  1 +
 3 files changed, 14 insertions(+), 2 deletions(-)

diff --git a/src/gallium/drivers/radeonsi/si_shader.c b/src/gallium/drivers/radeonsi/si_shader.c
index 10dd12a..a408dee 100644
--- a/src/gallium/drivers/radeonsi/si_shader.c
+++ b/src/gallium/drivers/radeonsi/si_shader.c
@@ -1528,6 +1528,11 @@ static void declare_input_fs(
 		interp_param = get_interp_param(ctx, interp_param_idx);
 	}
 
+	if (decl->Semantic.Name == TGSI_SEMANTIC_COLOR &&
+	    decl->Interp.Interpolate == TGSI_INTERPOLATE_COLOR &&
+	    ctx->shader->key.ps.prolog.flatshade_colors)
+		interp_param = NULL; /* load the constant color */
+
 	interp_fs_input(ctx, input_index, decl->Semantic.Name,
 			decl->Semantic.Index, shader->selector->info.num_inputs,
 			shader->selector->info.colors_read, interp_param,
@@ -6455,6 +6460,7 @@ void si_dump_shader_key(unsigned shader, union si_shader_key *key, FILE *f)
 
 	case PIPE_SHADER_FRAGMENT:
 		fprintf(f, "  prolog.color_two_side = %u\n", key->ps.prolog.color_two_side);
+		fprintf(f, "  prolog.flatshade_colors = %u\n", key->ps.prolog.flatshade_colors);
 		fprintf(f, "  prolog.poly_stipple = %u\n", key->ps.prolog.poly_stipple);
 		fprintf(f, "  prolog.force_persp_sample_interp = %u\n", key->ps.prolog.force_persp_sample_interp);
 		fprintf(f, "  prolog.force_linear_sample_interp = %u\n", key->ps.prolog.force_linear_sample_interp);
@@ -7597,6 +7603,7 @@ static bool si_shader_select_ps_parts(struct si_screen *sscreen,
 		}
 
 		for (i = 0; i < 2; i++) {
+			unsigned interp = info->input_interpolate[color[i]];
 			unsigned location = info->input_interpolate_loc[color[i]];
 
 			if (!(info->colors_read & (0xf << i*4)))
@@ -7604,7 +7611,11 @@ static bool si_shader_select_ps_parts(struct si_screen *sscreen,
 
 			prolog_key.ps_prolog.color_attr_index[i] = color[i];
 
-			switch (info->input_interpolate[color[i]]) {
+			if (shader->key.ps.prolog.flatshade_colors &&
+			    interp == TGSI_INTERPOLATE_COLOR)
+				interp = TGSI_INTERPOLATE_CONSTANT;
+
+			switch (interp) {
 			case TGSI_INTERPOLATE_CONSTANT:
 				prolog_key.ps_prolog.color_interp_vgpr_index[i] = -1;
 				break;
diff --git a/src/gallium/drivers/radeonsi/si_shader.h b/src/gallium/drivers/radeonsi/si_shader.h
index 3b7b3e1..14ef4e7 100644
--- a/src/gallium/drivers/radeonsi/si_shader.h
+++ b/src/gallium/drivers/radeonsi/si_shader.h
@@ -311,7 +311,7 @@ struct si_tcs_epilog_bits {
 /* Common PS bits between the shader key and the prolog key. */
 struct si_ps_prolog_bits {
 	unsigned	color_two_side:1;
-	/* TODO: add a flatshade bit that skips interpolation for colors */
+	unsigned	flatshade_colors:1;
 	unsigned	poly_stipple:1;
 	unsigned	force_persp_sample_interp:1;
 	unsigned	force_linear_sample_interp:1;
diff --git a/src/gallium/drivers/radeonsi/si_state_shaders.c b/src/gallium/drivers/radeonsi/si_state_shaders.c
index 42ebf69..766ef2c 100644
--- a/src/gallium/drivers/radeonsi/si_state_shaders.c
+++ b/src/gallium/drivers/radeonsi/si_state_shaders.c
@@ -924,6 +924,7 @@ static inline void si_shader_selector_key(struct pipe_context *ctx,
 			bool is_line = !is_poly && sctx->current_rast_prim != PIPE_PRIM_POINTS;
 
 			key->ps.prolog.color_two_side = rs->two_side && sel->info.colors_read;
+			key->ps.prolog.flatshade_colors = rs->flatshade && sel->info.colors_read;
 
 			if (sctx->queued.named.blend) {
 				key->ps.epilog.alpha_to_one = sctx->queued.named.blend->alpha_to_one &&
-- 
2.7.4