2 files changed, 68 insertions, 2 deletions

diff --git a/basys3/basys3.srcs/ppu_sprite_transform.vhd b/basys3/basys3.srcs/ppu_sprite_transform.vhd
index d1b1a23..fa10b9b 100644
--- a/basys3/basys3.srcs/ppu_sprite_transform.vhd
+++ b/basys3/basys3.srcs/ppu_sprite_transform.vhd
@@ -19,6 +19,6 @@ begin
 	FLIPPED_X <= std_logic_vector(to_unsigned(PPU_SPRITE_WIDTH-1 - to_integer(unsigned(XI)), PPU_SPRITE_POS_H_WIDTH));
 	FLIPPED_Y <= std_logic_vector(to_unsigned(PPU_SPRITE_HEIGHT-1 - to_integer(unsigned(YI)), PPU_SPRITE_POS_V_WIDTH));
 
-	XO <= FLIPPED_X when FLIP_H = '1' else XI;
-	YO <= FLIPPED_Y when FLIP_V = '1' else YI;
+	XO <= FLIPPED_X when FLIP_V = '1' else XI;
+	YO <= FLIPPED_Y when FLIP_H = '1' else YI;
 end Behavioral;
diff --git a/basys3/basys3.srcs/ppu_sprite_transform_tb.vhd b/basys3/basys3.srcs/ppu_sprite_transform_tb.vhd
new file mode 100644
index 0000000..cec8c20
--- /dev/null
+++ b/basys3/basys3.srcs/ppu_sprite_transform_tb.vhd
@@ -0,0 +1,66 @@
+library ieee;
+library unisim;
+library work;
+
+use ieee.std_logic_1164.all;
+use ieee.numeric_std.all;
+use unisim.vcomponents.all;
+use work.ppu_consts.all;
+
+entity ppu_sprite_transform_tb is
+end ppu_sprite_transform_tb;
+
+architecture behavioral of ppu_sprite_transform_tb is
+	component ppu_sprite_transform port( -- flip sprites
+		XI : in std_logic_vector(PPU_SPRITE_POS_H_WIDTH-1 downto 0); -- pixel position relative to tile
+		YI : in std_logic_vector(PPU_SPRITE_POS_V_WIDTH-1 downto 0); -- pixel position relative to tile
+		FLIP_H, FLIP_V : in std_logic; -- flip sprite
+		XO : out std_logic_vector(PPU_SPRITE_POS_H_WIDTH-1 downto 0); -- new pixel position relative to tile
+		YO : out std_logic_vector(PPU_SPRITE_POS_V_WIDTH-1 downto 0)); -- new pixel position relative to tile
+	end component;
+
+	signal XI : std_logic_vector(PPU_SPRITE_POS_H_WIDTH-1 downto 0);
+	signal YI : std_logic_vector(PPU_SPRITE_POS_V_WIDTH-1 downto 0);
+	signal FLIP_H, FLIP_V : std_logic := '0';
+	signal XO : std_logic_vector(PPU_SPRITE_POS_H_WIDTH-1 downto 0);
+	signal YO : std_logic_vector(PPU_SPRITE_POS_V_WIDTH-1 downto 0);
+begin
+	uut : component ppu_sprite_transform
+		port map(
+			XI => XI,
+			YI => YI,
+			FLIP_H => FLIP_H,
+			FLIP_V => FLIP_V,
+			XO => XO,
+			YO => YO);
+
+	tb : process
+	begin
+		XI <= std_logic_vector(to_unsigned(4, PPU_SPRITE_POS_H_WIDTH));
+		YI <= std_logic_vector(to_unsigned(6, PPU_SPRITE_POS_V_WIDTH));
+		wait for 5 ns;
+
+		XI <= std_logic_vector(to_unsigned(2, PPU_SPRITE_POS_H_WIDTH));
+		YI <= std_logic_vector(to_unsigned(14, PPU_SPRITE_POS_V_WIDTH));
+		wait for 5 ns;
+
+		FLIP_H <= '1';
+		wait for 5 ns;
+
+		FLIP_V <= '1';
+		wait for 5 ns;
+
+		XI <= std_logic_vector(to_unsigned(6, PPU_SPRITE_POS_H_WIDTH));
+		YI <= std_logic_vector(to_unsigned(8, PPU_SPRITE_POS_V_WIDTH));
+		wait for 5 ns;
+
+		FLIP_H <= '0';
+		wait for 5 ns;
+
+		XI <= std_logic_vector(to_unsigned(2, PPU_SPRITE_POS_H_WIDTH));
+		YI <= std_logic_vector(to_unsigned(14, PPU_SPRITE_POS_V_WIDTH));
+		wait for 5 ns;
+
+		wait; -- stop for simulator
+	end process;
+end;