WIP ppu foreground sprite component

6 files changed, 241 insertions, 38 deletions

diff --git a/basys3/basys3.srcs/er_ram.vhd b/basys3/basys3.srcs/er_ram.vhd
index f106d4e..66f905b 100644
--- a/basys3/basys3.srcs/er_ram.vhd
+++ b/basys3/basys3.srcs/er_ram.vhd
@@ -21,8 +21,8 @@ end er_ram;
 architecture Behavioral of er_ram is
 	component er_ram_mod
 		generic(
-			W : natural := 1; -- module data width
-			ADDR_W : natural := 1; -- address width
+			W : natural := DATA_W; -- module data width
+			ADDR_W : natural := ADDR_W; -- address width
 			ADDR_M : std_logic_vector(ADDR_W-1 downto 0) := (others => '0')); -- address match
 		port(
 			CLK : in std_logic; -- clock
@@ -36,12 +36,12 @@ architecture Behavioral of er_ram is
 begin
 	REG <= INT_REG;
 
-	registers : for idx in ADDR_LOW to ADDR_LOW + ADDR_RANGE - 1 generate
+	registers : for idx in 0 to ADDR_RANGE - 1 generate
 		reg : component er_ram_mod
 			generic map(
 				W => DATA_W,
 				ADDR_W => ADDR_W,
-				ADDR_M => std_logic_vector(to_unsigned(idx, ADDR_W)))
+				ADDR_M => std_logic_vector(to_unsigned(ADDR_LOW + idx, ADDR_W)))
 			port map(
 				CLK => CLK,
 				RST => RST,
diff --git a/basys3/basys3.srcs/ppu.vhd b/basys3/basys3.srcs/ppu.vhd
index c798400..22ee210 100644
--- a/basys3/basys3.srcs/ppu.vhd
+++ b/basys3/basys3.srcs/ppu.vhd
@@ -18,6 +18,7 @@ entity ppu is port(
 end ppu;
 
 architecture Behavioral of ppu is
+	-- TODO: separate SPRITE_BG and SPRITE_FG lines (foreground_sprite only needs 2 clock cycles)
 	component ppu_pceg port( -- pipeline clock edge generator
 		CLK : in std_logic; -- system clock
 		RESET : in std_logic; -- async reset
@@ -98,27 +99,30 @@ architecture Behavioral of ppu is
 		-- outputs
 		CIDX : out std_logic_vector(PPU_PALETTE_CIDX_WIDTH-1 downto 0)); -- output color
 	end component;
-	component ppu_sprite_fg port( -- foreground sprite
-		-- inputs
-		CLK : in std_logic; -- pipeline clock
-		RESET : in std_logic; -- reset internal memory and clock counters
-		OE : in std_logic; -- output enable (of CIDX)
-		X : in std_logic_vector(PPU_POS_H_WIDTH-1 downto 0); -- current screen pixel x
-		Y : in std_logic_vector(PPU_POS_V_WIDTH-1 downto 0); -- current screen pixel y
-		FETCH : in std_logic; -- fetch sprite data from TMM (TODO : generic map, set foreground sprite component index)
+	component ppu_sprite_fg -- foreground sprite
+		generic (
+			IDX : natural := 0);
+		port(
+			-- inputs
+			CLK : in std_logic; -- pipeline clock
+			RESET : in std_logic; -- reset internal memory and clock counters
+			OE : in std_logic; -- output enable (of CIDX)
+			X : in std_logic_vector(PPU_POS_H_WIDTH-1 downto 0); -- current screen pixel x
+			Y : in std_logic_vector(PPU_POS_V_WIDTH-1 downto 0); -- current screen pixel y
+			FETCH : in std_logic; -- fetch sprite data from TMM (TODO : generic map, set foreground sprite component index)
 
-		-- internal memory block (FAM)
-		FAM_WEN : in std_logic; -- VRAM FAM write enable
-		FAM_ADDR : in std_logic_vector(PPU_FAM_ADDR_WIDTH-1 downto 0); -- VRAM fam address
-		FAM_DATA : in std_logic_vector(PPU_FAM_DATA_WIDTH-1 downto 0); -- VRAM fam data
+			-- internal memory block (FAM)
+			FAM_WEN : in std_logic; -- VRAM FAM write enable
+			FAM_ADDR : in std_logic_vector(PPU_FAM_ADDR_WIDTH-1 downto 0); -- VRAM fam address
+			FAM_DATA : in std_logic_vector(PPU_FAM_DATA_WIDTH-1 downto 0); -- VRAM fam data
 
-		-- used memory blocks
-		TMM_ADDR : out std_logic_vector(PPU_TMM_ADDR_WIDTH-1 downto 0);
-		TMM_DATA : in std_logic_vector(PPU_TMM_DATA_WIDTH-1 downto 0);
+			-- used memory blocks
+			TMM_ADDR : out std_logic_vector(PPU_TMM_ADDR_WIDTH-1 downto 0);
+			TMM_DATA : in std_logic_vector(PPU_TMM_DATA_WIDTH-1 downto 0);
 
-		-- outputs
-		CIDX : out std_logic_vector(PPU_PALETTE_CIDX_WIDTH-1 downto 0); -- output color
-		HIT : out std_logic); -- current pixel is not transparent
+			-- outputs
+			CIDX : out std_logic_vector(PPU_PALETTE_CIDX_WIDTH-1 downto 0); -- output color
+			HIT : out std_logic); -- current pixel is not transparent
 	end component;
 	component ppu_comp port( -- compositor
 		FG_HIT : in std_logic_vector(PPU_FG_SPRITE_COUNT-1 downto 0);
@@ -266,20 +270,22 @@ begin
 		CIDX => CIDX);
 
 	foreground_sprites : for FG_IDX in 0 to PPU_FG_SPRITE_COUNT-1 generate
-		foreground_sprite : component ppu_sprite_fg port map(
-			CLK => PL_SPRITE,
-			RESET => SYSRST,
-			OE => FG_EN(FG_IDX),
-			X => X,
-			Y => Y,
-			FETCH => FG_FETCH,
-			FAM_WEN => FAM_WEN,
-			FAM_ADDR => FAM_AO,
-			FAM_DATA => DATA(PPU_FAM_DATA_WIDTH-1 downto 0),
-			TMM_ADDR => TMM_AI,
-			TMM_DATA => TMM_DO,
-			CIDX => CIDX,
-			HIT => FG_HIT(FG_IDX));
+		foreground_sprite : component ppu_sprite_fg
+			generic map( IDX => FG_IDX )
+			port map(
+				CLK => PL_SPRITE,
+				RESET => SYSRST,
+				OE => FG_EN(FG_IDX),
+				X => X,
+				Y => Y,
+				FETCH => FG_FETCH,
+				FAM_WEN => FAM_WEN,
+				FAM_ADDR => FAM_AO,
+				FAM_DATA => DATA(PPU_FAM_DATA_WIDTH-1 downto 0),
+				TMM_ADDR => TMM_AI,
+				TMM_DATA => TMM_DO,
+				CIDX => CIDX,
+				HIT => FG_HIT(FG_IDX));
 	end generate;
 
 	compositor : component ppu_comp port map( -- compositor
diff --git a/basys3/basys3.srcs/ppu_sprite_fg.vhd b/basys3/basys3.srcs/ppu_sprite_fg.vhd
new file mode 100644
index 0000000..340104a
--- /dev/null
+++ b/basys3/basys3.srcs/ppu_sprite_fg.vhd
@@ -0,0 +1,164 @@
+library ieee;
+library work;
+
+use ieee.std_logic_1164.all;
+use ieee.std_logic_unsigned.all;
+use ieee.numeric_std.all;
+use work.ppu_consts.all;
+
+-- TODO: add input stable / output stable pipeline stages if this doesn't work with propagation delays
+entity ppu_sprite_fg is -- foreground sprite
+	generic (
+		IDX : natural := 0); -- sprite index number
+	port(
+		-- inputs
+		CLK : in std_logic; -- system clock
+		PL_CLK : in std_logic; -- pipeline clock
+		RESET : in std_logic; -- reset internal memory and clock counters
+		OE : in std_logic; -- output enable (of CIDX)
+		X : in std_logic_vector(PPU_POS_H_WIDTH-1 downto 0); -- current screen pixel x
+		Y : in std_logic_vector(PPU_POS_V_WIDTH-1 downto 0); -- current screen pixel y
+		FETCH : in std_logic; -- fetch sprite data from TMM
+
+		-- internal memory block (FAM)
+		FAM_WEN : in std_logic; -- VRAM FAM write enable
+		FAM_ADDR : in std_logic_vector(PPU_FAM_ADDR_WIDTH-1 downto 0); -- VRAM fam address
+		FAM_DATA : in std_logic_vector(PPU_FAM_DATA_WIDTH-1 downto 0); -- VRAM fam data
+
+		-- used memory blocks
+		TMM_ADDR : out std_logic_vector(PPU_TMM_ADDR_WIDTH-1 downto 0);
+		TMM_DATA : in std_logic_vector(PPU_TMM_DATA_WIDTH-1 downto 0);
+
+		-- outputs
+		CIDX : out std_logic_vector(PPU_PALETTE_CIDX_WIDTH-1 downto 0); -- output color
+		HIT : out std_logic); -- current pixel is not transparent
+end ppu_sprite_fg;
+
+architecture Behavioral of ppu_sprite_fg is
+	component ppu_sprite_transform port(
+		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;
+	component er_ram -- exposed register RAM
+		generic(
+			ADDR_W : natural := PPU_FAM_ADDR_WIDTH; -- ADDR line width
+			DATA_W : natural := PPU_FAM_DATA_WIDTH; -- DATA line width
+			ADDR_LOW : natural := IDX*2; -- starting address
+			ADDR_RANGE : natural := 2); -- amount of valid addresses after ADDR_LOW
+		port(
+			CLK : in std_logic; -- clock
+			RST : in std_logic; -- async memory clear
+			WEN : in std_logic; -- write enable
+			ADDR : in std_logic_vector(ADDR_W-1 downto 0); -- address line
+			DATA : in std_logic_vector(DATA_W-1 downto 0); -- data input
+			REG : out std_logic_vector((ADDR_RANGE*DATA_W)-1 downto 0)); -- exposed register output
+	end component;
+
+	-- FAM and TMM in/out temp + registers
+	signal T_TMM_ADDR, R_TMM_ADDR : std_logic_vector(PPU_TMM_ADDR_WIDTH-1 downto 0) := (others => '0');
+	signal T_TMM_DATA, R_TMM_DATA : std_logic_vector(PPU_TMM_DATA_WIDTH-1 downto 0) := (others => '0');
+
+	-- state machine for synchronizing pipeline stages
+	type states is (PL_TMM_ADDR, PL_TMM_DATA);
+	signal state : states := PL_TMM_ADDR;
+
+	-- auxiliary signals (temp variables)
+	signal T_CIDX : std_logic_vector(PPU_PALETTE_CIDX_WIDTH-1 downto 0) := (others => '0'); -- output color buffer/register
+	signal INT_FAM : std_logic_vector(31 downto 0);
+
+	-- FAM aliases (docs/architecture.md#foreground-attribute-memory)
+	alias FAM_REG_FLIP_H is INT_FAM(31); -- Flip horizontally
+	alias FAM_REG_FLIP_V is INT_FAM(30); -- Flip vertically
+	alias FAM_REG_POS_H is INT_FAM(29 downto 21); -- horizontal position (offset by -16)
+	alias FAM_REG_POS_V is INT_FAM(20 downto 13); -- vertical position (offset by -16)
+	alias FAM_REG_COL_IDX is INT_FAM(12 downto 10); -- Palette index for tile
+	alias FAM_REG_TILE_IDX is INT_FAM(9 downto 0); -- Tilemap index
+
+	-- signal PIXEL_ABS_X, PIXEL_ABS_Y : integer := 0; -- absolute pixel position (relative to FG canvas instead of viewport)
+	-- signal TILE_IDX_X, TILE_IDX_Y : integer := 0; -- background canvas tile grid xy
+	-- signal TILE_PIXEL_IDX_X, TILE_PIXEL_IDX_Y : integer := 0; -- xy position of pixel within tile (local tile coords)
+	-- signal TRANS_TILE_PIDX_X, TRANS_TILE_PIDX_Y : integer := 0; -- transformed xy position of pixel within tile
+	-- signal TRANS_TILE_PIXEL_IDX : integer := 0; -- index of pixel within tile (reading order)
+	-- signal TRANSFORM_XI, TRANSFORM_XO : std_logic_vector(PPU_SPRITE_POS_H_WIDTH-1 downto 0); -- transform inputs/outputs (x axis)
+	-- signal TRANSFORM_YI, TRANSFORM_YO : std_logic_vector(PPU_SPRITE_POS_V_WIDTH-1 downto 0); -- transform inputs/outputs (y axis)
+	-- signal TILEMAP_WORD_OFFSET : integer := 0; -- word offset from tile start address in TMM
+	-- signal PIXEL_BIT_OFFSET : integer := 0; -- pixel index within word of TMM
+	signal TMM_DATA_PAL_IDX : std_logic_vector(PPU_PALETTE_COLOR_WIDTH-1 downto 0); -- color of palette
+begin
+	-- output drivers
+	CIDX <= T_CIDX when OE = '1' else (others => 'Z');
+	TMM_ADDR <= R_TMM_ADDR;
+	T_TMM_DATA <= TMM_DATA;
+	-- CIDX combination
+	T_CIDX <= FAM_REG_COL_IDX & TMM_DATA_PAL_IDX;
+
+	-- FAM memory
+	FAM : component er_ram port map(
+		CLK => CLK,
+		RST => RESET,
+		WEN => FAM_WEN,
+		ADDR => FAM_ADDR,
+		DATA => FAM_DATA,
+		REG => INT_FAM);
+
+	-- -- -- FAM address calculations
+	-- -- PIXEL_ABS_X <= to_integer(unsigned(X)) + to_integer(unsigned(FG_SHIFT_X));
+	-- -- PIXEL_ABS_Y <= to_integer(unsigned(Y)) + to_integer(unsigned(FG_SHIFT_Y));
+	-- -- TILE_IDX_X <= PIXEL_ABS_X / 16;
+	-- -- TILE_IDX_Y <= PIXEL_ABS_Y / 16;
+	-- -- TILE_PIXEL_IDX_X <= PIXEL_ABS_X - TILE_IDX_X * 16;
+	-- -- TILE_PIXEL_IDX_Y <= PIXEL_ABS_Y - TILE_IDX_Y * 16;
+	-- -- T_FAM_ADDR <= std_logic_vector(to_unsigned((TILE_IDX_Y * integer(PPU_FG_CANVAS_TILES_H)) + TILE_IDX_X, PPU_FAM_ADDR_WIDTH));
+
+	-- -- -- FAM data dependant calculations
+	-- -- TRANSFORM_XI <= std_logic_vector(to_unsigned(TILE_PIXEL_IDX_X, PPU_SPRITE_POS_H_WIDTH));
+	-- -- TRANSFORM_YI <= std_logic_vector(to_unsigned(TILE_PIXEL_IDX_Y, PPU_SPRITE_POS_V_WIDTH));
+	-- -- transform: component ppu_sprite_transform port map(
+	-- -- 	XI => TRANSFORM_XI,
+	-- -- 	YI => TRANSFORM_YI,
+	-- -- 	FLIP_H => FAM_DATA_FLIP_H,
+	-- -- 	FLIP_V => FAM_DATA_FLIP_V,
+	-- -- 	XO => TRANSFORM_XO,
+	-- -- 	YO => TRANSFORM_YO);
+	-- -- TRANS_TILE_PIDX_X <= to_integer(unsigned(TRANSFORM_XO));
+	-- -- TRANS_TILE_PIDX_Y <= to_integer(unsigned(TRANSFORM_YO));
+
+	-- -- TRANS_TILE_PIXEL_IDX <= integer(PPU_SPRITE_WIDTH) * TRANS_TILE_PIDX_Y + TRANS_TILE_PIDX_X;
+	-- -- TILEMAP_WORD_OFFSET <= TRANS_TILE_PIXEL_IDX / PPU_PIXELS_PER_TILE_WORD;
+	-- -- PIXEL_BIT_OFFSET <= TRANS_TILE_PIXEL_IDX mod PPU_PIXELS_PER_TILE_WORD;
+
+	-- -- T_TMM_ADDR <= std_logic_vector(to_unsigned(PPU_SPRITE_PIXELS_PER_WORD * to_integer(unsigned(FAM_DATA_TILE_IDX)) + TILEMAP_WORD_OFFSET, PPU_TMM_ADDR_WIDTH));
+
+	-- -- -- TMM DATA
+	-- -- with PIXEL_BIT_OFFSET select
+	-- -- 	TMM_DATA_PAL_IDX <= R_TMM_DATA(2 downto 0) when 0,
+	-- -- 	                    R_TMM_DATA(5 downto 3) when 1,
+	-- -- 	                    R_TMM_DATA(8 downto 6) when 2,
+	-- -- 	                    R_TMM_DATA(11 downto 9) when 3,
+	-- -- 	                    R_TMM_DATA(14 downto 12) when 4,
+	-- -- 	                    (others => '0') when others;
+
+	-- state machine (pipeline stage counter) + sync r/w
+	process(CLK, RESET)
+	begin
+		if RESET = '1' then
+			-- reset state
+			state <= PL_TMM_ADDR;
+			-- reset internal pipeline registers
+			R_TMM_ADDR <= (others => '0');
+			R_TMM_DATA <= (others => '0');
+		elsif rising_edge(CLK) then
+			case state is
+				when PL_TMM_ADDR =>
+					state <= PL_TMM_DATA;
+					R_TMM_ADDR <= T_TMM_ADDR;
+				when PL_TMM_DATA =>
+					state <= PL_TMM_ADDR;
+					R_TMM_DATA <= T_TMM_DATA;
+			end case;
+		end if;
+	end process;
+end Behavioral;
diff --git a/basys3/basys3.srcs/ppu_sprite_fg_tb.vhd b/basys3/basys3.srcs/ppu_sprite_fg_tb.vhd
new file mode 100644
index 0000000..87c4f6e
--- /dev/null
+++ b/basys3/basys3.srcs/ppu_sprite_fg_tb.vhd
@@ -0,0 +1,15 @@
+library ieee;
+library work;
+library unisim;
+
+use ieee.std_logic_1164.all;
+use ieee.numeric_std.all;
+use unisim.vcomponents.all;
+use work.ppu_consts.all;
+
+entity ppu_sprite_fg_tb is
+end ppu_sprite_fg_tb;
+
+architecture Behavioral of ppu_sprite_fg_tb is
+begin
+end Behavioral;
diff --git a/basys3/basys3.xpr b/basys3/basys3.xpr
index af6fbe7..7bc2f3c 100644
--- a/basys3/basys3.xpr
+++ b/basys3/basys3.xpr
@@ -160,9 +160,15 @@
           <Attr Name="UsedIn" Val="simulation"/>
         </FileInfo>
       </File>
+      <File Path="$PSRCDIR/ppu_sprite_fg.vhd">
+        <FileInfo SFType="VHDL2008">
+          <Attr Name="UsedIn" Val="synthesis"/>
+          <Attr Name="UsedIn" Val="simulation"/>
+        </FileInfo>
+      </File>
       <Config>
         <Option Name="DesignMode" Val="RTL"/>
-        <Option Name="TopModule" Val="ppu_sprite_bg"/>
+        <Option Name="TopModule" Val="ppu"/>
         <Option Name="dataflowViewerSettings" Val="min_width=16"/>
       </Config>
     </FileSet>
@@ -223,9 +229,15 @@
           <Attr Name="UsedIn" Val="simulation"/>
         </FileInfo>
       </File>
+      <File Path="$PSRCDIR/ppu_sprite_fg_tb.vhd">
+        <FileInfo SFType="VHDL2008">
+          <Attr Name="UsedIn" Val="synthesis"/>
+          <Attr Name="UsedIn" Val="simulation"/>
+        </FileInfo>
+      </File>
       <Config>
         <Option Name="DesignMode" Val="RTL"/>
-        <Option Name="TopModule" Val="ppu_sprite_bg_tb"/>
+        <Option Name="TopModule" Val="ppu_sprite_fg_tb"/>
         <Option Name="TopLib" Val="xil_defaultlib"/>
         <Option Name="TransportPathDelay" Val="0"/>
         <Option Name="TransportIntDelay" Val="0"/>
diff --git a/docs/architecture.md b/docs/architecture.md
index 56bbb62..0c6fea7 100644
--- a/docs/architecture.md
+++ b/docs/architecture.md
@@ -134,6 +134,12 @@ Notable differences:
   
   Our game doesn't need this capability for any visual effects. Leaving this
   feature out will lead to a simpler hardware design
+- Sprites are positioned relative to the viewport, not the background layer
+  
+  This leads to a simpler hardware architecture for the foreground sprite
+  rendering component. Since the CPU is already likely to reposition all
+  foreground sprites on every frame, the position calculation is moved to
+  hardware to software.
 
 ## Hardware design schematics