rtl/gfx: pass barycentric coords from fine raster to fragment shading

7 files changed, 47 insertions, 15 deletions

diff --git a/rtl/gfx/gfx.sv b/rtl/gfx/gfx.sv
index bd797df..8e6d20f 100644
--- a/rtl/gfx/gfx.sv
+++ b/rtl/gfx/gfx.sv
@@ -43,6 +43,7 @@ module gfx
 	);
 
 	logic raster_ready;
+	bary_lanes barys;
 	paint_lanes raster_valid;
 	frag_xy_lanes fragments;
 
diff --git a/rtl/gfx/gfx_defs.sv b/rtl/gfx/gfx_defs.sv
index 7da259a..f7c874c 100644
--- a/rtl/gfx/gfx_defs.sv
+++ b/rtl/gfx/gfx_defs.sv
@@ -127,9 +127,10 @@ typedef struct packed
 	xy_coord x, y;
 } frag_xy;
 
-typedef frag_xy[`GFX_FINE_LANES - 1:0] frag_xy_lanes;
-typedef logic[`GFX_FINE_LANES - 1:0]   paint_lanes;
-typedef fixed[`COLOR_CHANNELS - 1:0]   color_lerp_lanes;
+typedef frag_xy[`GFX_FINE_LANES - 1:0]   frag_xy_lanes;
+typedef logic[`GFX_FINE_LANES - 1:0]     paint_lanes;
+typedef fixed[`COLOR_CHANNELS - 1:0]     color_lerp_lanes;
+typedef fixed_tri[`GFX_FINE_LANES - 1:0] bary_lanes;
 
 typedef struct packed
 {
diff --git a/rtl/gfx/gfx_frag.sv b/rtl/gfx/gfx_frag.sv
index 79fb2b4..d4b2495 100644
--- a/rtl/gfx/gfx_frag.sv
+++ b/rtl/gfx/gfx_frag.sv
@@ -6,6 +6,7 @@ module gfx_frag
 	                     rst_n,
 
 	input  frag_xy_lanes fragments,
+	input  bary_lanes    barys,
 	input  paint_lanes   in_valid,
 	output logic         in_ready,
 
@@ -16,6 +17,7 @@ module gfx_frag
 
 	logic funnel_valid;
 	frag_xy funnel_frag;
+	fixed_tri bary;
 
 	gfx_frag_funnel funnel
 	(
@@ -58,10 +60,9 @@ module gfx_frag
 
 	fixed b1, b2;
 
-	gfx_frag_bary bary
+	gfx_frag_bary frag_bary
 	(
 		.ws(),
-		.edges(),
 		.stall(frag_stall),
 		.*
 	);
diff --git a/rtl/gfx/gfx_frag_bary.sv b/rtl/gfx/gfx_frag_bary.sv
index 5004866..4f4f452 100644
--- a/rtl/gfx/gfx_frag_bary.sv
+++ b/rtl/gfx/gfx_frag_bary.sv
@@ -4,7 +4,7 @@ module gfx_frag_bary
 (
 	input  logic     clk,
 
-	input  fixed_tri edges,
+	input  fixed_tri bary,
 	                 ws,
 	input  logic     stall,
 
@@ -19,9 +19,9 @@ module gfx_frag_bary
 	assign b1_w1 = bs_ws[1];
 	assign b2_w2 = bs_ws[2];
 
-	assign orthographic_bs[0] = edges[`EDGE_P1_TO_P2];
-	assign orthographic_bs[1] = edges[`EDGE_P2_TO_P0];
-	assign orthographic_bs[2] = edges[`EDGE_P0_TO_P1];
+	assign orthographic_bs[0] = bary[`EDGE_P1_TO_P2];
+	assign orthographic_bs[1] = bary[`EDGE_P2_TO_P0];
+	assign orthographic_bs[2] = bary[`EDGE_P0_TO_P1];
 
 	genvar i;
 	generate
diff --git a/rtl/gfx/gfx_frag_funnel.sv b/rtl/gfx/gfx_frag_funnel.sv
index f3458b4..943f582 100644
--- a/rtl/gfx/gfx_frag_funnel.sv
+++ b/rtl/gfx/gfx_frag_funnel.sv
@@ -6,29 +6,40 @@ module gfx_frag_funnel
 	                     rst_n,
 
 	input  frag_xy_lanes fragments,
+	input  bary_lanes    barys,
 	input  paint_lanes   in_valid,
 	output logic         in_ready,
 
 	input  logic         out_ready,
 	output logic         out_valid,
-	output frag_xy       frag
+	output frag_xy       frag,
+	output fixed_tri     bary
 );
 
 	logic skid_ready, stall, ready, valid;
-	frag_xy next_frag, out;
+	frag_xy next_frag, out_frag;
+	fixed_tri next_bary, out_bary;
+	bary_lanes barys_hold;
 	paint_lanes current, next;
 	frag_xy_lanes fragments_hold;
 
 	assign ready = !(|next);
 	assign in_ready = skid_ready && ready;
 
-	gfx_skid_buf #(.WIDTH($bits(frag))) skid
+	gfx_skid_buf #(.WIDTH($bits(frag))) skid_frag
 	(
-		.in(out),
+		.in(out_frag),
 		.out(frag),
 		.*
 	);
 
+	gfx_skid_buf #(.WIDTH($bits(bary))) skid_bary
+	(
+		.in(out_bary),
+		.out(bary),
+		.*
+	);
+
 	gfx_skid_flow skid_flow
 	(
 		.in_ready(skid_ready),
@@ -38,6 +49,7 @@ module gfx_frag_funnel
 
 	always_comb begin
 		next = 0;
+		next_bary = {($bits(next_bary)){1'bx}};
 		next_frag = {($bits(next_frag)){1'bx}};
 
 		for (integer i = 0; i < `GFX_FINE_LANES; ++i)
@@ -45,6 +57,7 @@ module gfx_frag_funnel
 				next = current;
 				next[i] = 0;
 
+				next_bary = barys_hold[i];
 				next_frag = fragments_hold[i];
 			end
 	end
@@ -60,10 +73,13 @@ module gfx_frag_funnel
 
 	always_ff @(posedge clk)
 		if (!stall) begin
-			if (ready)
+			if (ready) begin
+				barys_hold <= barys;
 				fragments_hold <= fragments;
+			end
 
-			out <= next_frag;
+			out_bary <= next_bary;
+			out_frag <= next_frag;
 		end
 
 endmodule
diff --git a/rtl/gfx/gfx_raster.sv b/rtl/gfx/gfx_raster.sv
index a51c4bb..ab282e7 100644
--- a/rtl/gfx/gfx_raster.sv
+++ b/rtl/gfx/gfx_raster.sv
@@ -12,6 +12,7 @@ module gfx_raster
 	output logic         in_ready,
 
 	output frag_xy_lanes fragments,
+	output bary_lanes    barys,
 	input  logic         out_ready,
 	output paint_lanes   out_valid
 );
@@ -69,6 +70,7 @@ module gfx_raster
 	);
 
 	frag_xy fragment_ij[`GFX_RASTER_SIZE][`GFX_RASTER_SIZE];
+	fixed_tri barys_ij[`GFX_RASTER_SIZE][`GFX_RASTER_SIZE];
 	logic[`GFX_FINE_LANES - 1:0] paint_ij, skid_paint_ij;
 
 	gfx_skid_buf #(.WIDTH(`GFX_FINE_LANES)) skid_paint
@@ -90,6 +92,7 @@ module gfx_raster
 					.pos(coarse_pos),
 					.corners(coarse_corners),
 
+					.barys(barys_ij[i][j]),
 					.paint(paint_ij[j * `GFX_RASTER_SIZE + i]),
 					.fragment(fragment_ij[i][j]),
 					.*
@@ -102,6 +105,14 @@ module gfx_raster
 					.stall(fine_stall),
 					.*
 				);
+
+				gfx_skid_buf #(.WIDTH($bits(fixed_tri))) skid_barys
+				(
+					.in(barys_ij[i][j]),
+					.out(barys[j * `GFX_RASTER_SIZE + i]),
+					.stall(fine_stall),
+					.*
+				);
 			end
 		end
 	endgenerate
diff --git a/rtl/gfx/gfx_raster_fine.sv b/rtl/gfx/gfx_raster_fine.sv
index 2cb9c6a..05d3b0d 100644
--- a/rtl/gfx/gfx_raster_fine.sv
+++ b/rtl/gfx/gfx_raster_fine.sv
@@ -11,6 +11,7 @@ module gfx_raster_fine
 	input  logic              stall,
 
 	output frag_xy            fragment,
+	output fixed_tri          barys,
 	output logic              paint
 );
 
@@ -34,6 +35,7 @@ module gfx_raster_fine
 
 	always_ff @(posedge clk)
 		if (!stall) begin
+			barys <= edges;
 			paint <= signs == 0;
 	
 			fragment <= fragment_hold;