-- ========================================================================
-- Renderer  (scrolling world)
-- world_col = pixel_column + cam_x
-- world_row = pixel_row    + cam_y
-- All comparisons in world-space (11-bit).
-- Obstacles imported from level package (use work.level.all).
--
-- Color priority:
--   Arrow = White (111)  >  Char = Red (100)  >  Obs = Yellow (110)
--   >  Ground/Ceil/Walls = Green (010)  >  Trail = Magenta (101)  >  Sky = Black (000)
-- ========================================================================

library IEEE;
use IEEE.STD_LOGIC_1164.all;
use IEEE.STD_LOGIC_ARITH.all;
use IEEE.STD_LOGIC_UNSIGNED.all;
use work.level.all;

entity renderer is
    port(
        pixel_row    : in  std_logic_vector(9 downto 0);
        pixel_column : in  std_logic_vector(9 downto 0);
        char_x       : in  std_logic_vector(10 downto 0);
        char_y       : in  std_logic_vector(10 downto 0);
        char_width   : in  std_logic_vector(9 downto 0);
        char_height  : in  std_logic_vector(9 downto 0);
        cam_x        : in  std_logic_vector(10 downto 0);
        cam_y        : in  std_logic_vector(10 downto 0);
        trail_on_in  : in  std_logic;
        red          : out std_logic;
        green        : out std_logic;
        blue         : out std_logic
    );
end renderer;

architecture behavior of renderer is

    -- World boundaries (11-bit)
    constant GROUND_TOP : std_logic_vector(10 downto 0) := CONV_STD_LOGIC_VECTOR(1488, 11);
    constant CEIL_BOT   : std_logic_vector(10 downto 0) := CONV_STD_LOGIC_VECTOR(8,    11);
    constant LEFT_WALL  : std_logic_vector(10 downto 0) := CONV_STD_LOGIC_VECTOR(8,    11);
    constant RIGHT_WALL : std_logic_vector(10 downto 0) := CONV_STD_LOGIC_VECTOR(1492, 11);

    -- World-space pixel coordinates (shared between processes)
    signal wc : std_logic_vector(10 downto 0);
    signal wr : std_logic_vector(10 downto 0);

    signal char_on, ground_on, wall_on, ceiling_on, obs_on : std_logic;

begin

    -- Convert screen coordinates to world coordinates
    wc <= ('0' & pixel_column) + cam_x;
    wr <= ('0' & pixel_row)    + cam_y;

    -- ----------------------------------------------------------------
    -- Scene geometry: character, world edges, obstacles
    -- ----------------------------------------------------------------
    render : process(wc, wr, char_x, char_y, char_width, char_height)
    begin
        char_on    <= '0';
        ground_on  <= '0';
        wall_on    <= '0';
        ceiling_on <= '0';
        obs_on     <= '0';

        -- Character
        if wc >= char_x - ('0' & char_width)  and
           wc <= char_x + ('0' & char_width)  and
           wr >= char_y - ('0' & char_height) and
           wr <= char_y + ('0' & char_height) then
            char_on <= '1';
        end if;

        -- World edges
        if wr >= GROUND_TOP then ground_on  <= '1'; end if;
        if wr <= CEIL_BOT   then ceiling_on <= '1'; end if;
        if wc < LEFT_WALL or wc > RIGHT_WALL then wall_on <= '1'; end if;

        -- Obstacles (loop over level_pkg arrays)
        for obs_i in 0 to OBS_COUNT-1 loop
            if wc >= OBS_L(obs_i) and wc <= OBS_R(obs_i) and
               wr >= OBS_T(obs_i) and wr <= OBS_B(obs_i) then
                obs_on <= '1';
            end if;
        end loop;

    end process render;

    -- ----------------------------------------------------------------
    -- Color output with priority
    -- ----------------------------------------------------------------
    color : process(char_on, ground_on, wall_on, ceiling_on, obs_on, trail_on_in)
    begin
        if    char_on = '1' then
            red <= '1'; green <= '0'; blue <= '0';  -- Red
        elsif obs_on = '1' then
            red <= '1'; green <= '1'; blue <= '0';  -- Yellow
        elsif ground_on = '1' or ceiling_on = '1' then
            red <= '0'; green <= '1'; blue <= '0';  -- Green
        elsif wall_on = '1' then
            red <= '0'; green <= '1'; blue <= '0';  -- Green
        elsif trail_on_in = '1' then
            red <= '1'; green <= '0'; blue <= '1';  -- Magenta
        else
            red <= '0'; green <= '0'; blue <= '0';  -- Black (sky)
        end if;
    end process color;

end behavior;