rtl/gfx: implement perspective correction

1 files changed, 52 insertions, 0 deletions

diff --git a/rtl/gfx/gfx_persp_vertex.sv b/rtl/gfx/gfx_persp_vertex.sv
new file mode 100644
index 0000000..f7434f0
--- /dev/null
+++ b/rtl/gfx/gfx_persp_vertex.sv
@@ -0,0 +1,52 @@
+`include "gfx/gfx_defs.sv"
+
+module gfx_persp_vertex
+(
+	input  logic       clk,
+
+	input  raster_xyzw in_vertex,
+	input  logic       stall,
+
+	output raster_xyzw out_vertex
+);
+
+	raster_xyzw skid_vertex;
+
+	gfx_fixed_div x_div
+	(
+		.z(in_vertex.xy.x),
+		.d(in_vertex.zw.w),
+		.q(skid_vertex.xy.x),
+		.*
+	);
+
+	gfx_fixed_div y_div
+	(
+		.z(in_vertex.xy.y),
+		.d(in_vertex.zw.w),
+		.q(skid_vertex.xy.y),
+		.*
+	);
+
+	gfx_pipes #(.WIDTH($bits(fixed)), .DEPTH(`FIXED_DIV_STAGES)) z_pipes
+	(
+		.in(in_vertex.zw.z),
+		.out(skid_vertex.zw.z),
+		.*
+	);
+
+	gfx_pipes #(.WIDTH($bits(fixed)), .DEPTH(`FIXED_DIV_STAGES)) w_pipes
+	(
+		.in(in_vertex.zw.w),
+		.out(skid_vertex.zw.w),
+		.*
+	);
+
+	gfx_skid_buf #(.WIDTH($bits(out_vertex))) vertex_skid
+	(
+		.in(skid_vertex),
+		.out(out_vertex),
+		.*
+	);
+
+endmodule