Subversion Repositories jart

-- Author : Julian Andres Guarin Reyes.

-- Project : JART, Just Another Ray Tracer.

-- email : jguarin2002 at gmail.com, j.guarin at javeriana.edu.co

-- This code was entirely written by Julian Andres Guarin Reyes.

-- The following code is licensed under GNU Public License

-- http://www.gnu.org/licenses/gpl-3.0.txt.

 -- This file is part of JART (Just Another Ray Tracer).

    -- JART (Just Another Ray Tracer) is free software: you can redistribute it and/or modify

    -- it under the terms of the GNU General Public License as published by

    -- the Free Software Foundation, either version 3 of the License, or

    -- (at your option) any later version.

    -- JART (Just Another Ray Tracer) is distributed in the hope that it will be useful,

    -- but WITHOUT ANY WARRANTY; without even the implied warranty of

    -- MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

    -- GNU General Public License for more details.

    -- You should have received a copy of the GNU General Public License

    -- along with JART (Just Another Ray Tracer).  If not, see <http://www.gnu.org/licenses/>.library ieee;

-- Ray Generator.....

-- The entity synthesizes 4 simmetrical rays each clock. The ena signal enables/disables the ray production.

-- The Ray Generator starts by generating after the first clock's rising edge with the ena signal set. 

-- The first four rays generated are the Rays passing through the center of the screen, in the 320x200 screen these rays are : (159,99)(160,99)(159,100)(160,100), after those rays the next four rays are (158,99)(161,99)(158,100)(161,100).

library ieee;

use ieee.std_logic_1164.all;

use ieee.std_logic_signed.all;

use work.powerGrid.all;

entity yu is

        generic (

                VALSTARTX : integer := 34;

                VALSTARTY : integer := 1023;

                VALSTARTZ : integer := 9;

                TOP : integer := 1024;                                                          -- Define the max counting number.. the number must be expressed as 2 power, cause the range of counting is going to be defined as TOP-1 downto TOP/2.

                                                                                                                        -- However this is going to be by now, cause in the future the ray generation will GO on for higher resolution images , and perhaps it would be required a more extended range for the yu component.

                SCREENW : integer := 320                        --  resolution width is 320 

        );

        port (

                clk,rst,ena             : in std_logic;

                lineDone                : out std_logic;                                        -- Finished image row. once a hundred and sixty times....

                ocntr                   : out integer range 0 to SCREENW/2;

                ypos                    : out integer range TOP/2 to TOP-1;

                zpos                    : out integer range -TOP to TOP-1;

                zneg                    : out integer range -TOP to TOP-1;

                xpos                    : out integer range -TOP to TOP-1;

                xneg                    : out integer range -TOP to TOP-1

        );

end entity;

architecture rtl of yu is

        -- 1x16384 bits, true dual port, ROM Memory declaration.

        -- This memory uses 2 cycles.. a memory fetch cycle and a data to q memory cycle.

        component yurom

        port

        (

                address_a       : in std_logic_vector (13 downto 0);

                address_b       : in std_logic_vector (13 downto 0);

                clock           : in std_logic ;

                q_a                     : out std_logic_vector (0 downto 0);

                q_b                     : out std_logic_vector (0 downto 0)

        );

        end component;

        constant linefeed : integer range 0 to (SCREENW/2) := (SCREENW/2)-4;

        -- Support signals.

        signal s1addf0  : std_logic_vector (13 downto 0);        -- The function 0 is the function of the y component derivative.

        signal s1addf1  : std_logic_vector (13 downto 0);        -- The function 1 is the function of the y component integration curve initial constant.

        signal sf0              : std_logic_vector (0 downto 0);  -- Derivative function

        signal sf1              : std_logic_vector (0 downto 0);  -- Derivative curve, initial constant derivative function.

        signal cc               : integer range 0 to SCREENW/2;

        signal fy : integer range TOP/2 to TOP-1;

        signal pivotCol,pivotRow        : std_logic;

        signal fz       : integer range  -TOP to TOP-1;

        signal fx       : integer range  -TOP to TOP-1;

begin

        -- Connect fy, to the output.

        ypos <= fy;

        xpos <= fx;

        xneg <= -fx;

        zpos <= fz;

        zneg <= -fz;

        ocntr<= cc;

        derivate : yurom

        port map (

                address_a       => s1addf0,

                address_b       => s1addf1,

                clock           => clk,

                q_a                     => sf0,

                q_b                     => sf1

        );

        integrationControl : process (clk,rst,ena)

                variable f1 : integer range TOP/2 to TOP-1;

        begin

                if rst='0' then

                        fy<=TOP/2;

                        f1:=VALSTARTY;

                        fz<=VALSTARTZ-2;

                        fx<=0;

                        pivotCol <= '0';

                        pivotRow <= '0';

                elsif rising_edge(clk) and ena='1' then

                        if cc=(SCREENW/2)-1 then

                                -- Y component

                                f1 := f1 - CONV_INTEGER('0'&sf1(0));

                                fy <= f1;

                                -- X component

                                fx <= VALSTARTX;

                                -- Z component

                                fz <= fz+2+CONV_INTEGER('0'&pivotRow); -- Beware of the sign!

                                pivotRow <= not (pivotRow);

                        else

                                -- Y Component

                                fy <= fy-CONV_INTEGER('0'&sf0(0));

                                -- X component

                                fx <= fx+2+CONV_INTEGER('0'&pivotCol); -- Beware of the sign!

                                pivotCol <= not(pivotCol);

                        end if;

                end if;

        end process;

        counterControl : process (clk,rst,ena)

        begin

                if rst='0' then

                        cc<=SCREENW/2-1;

                        lineDone<='0';

                elsif rising_edge(clk) and ena='1' then

                        if cc=(SCREENW/2)-1 then

                                lineDone<='1';

                                cc<=0;

                        else

                                lineDone<='0';

                                cc<=cc+1;

                        end if;

                end if;

        end process;

        addressControl : process (clk,rst,ena)

        begin

                if rst='0' then

                        -- Right from the start.

                        s1addf0 (13 downto 1) <= (others=>'0');          -- 00001.

                        s1addf0 (0) <= '1';

                        s1addf1 <= "11111010000000";    -- 3E80.        

                elsif rising_edge(clk) and ena='1' then

                        s1addf0 <= s1addf0+1;

                        -- Count f1 address (158)

                        if cc=linefeed then

                                s1addf1 <= s1addf1+1;

                        end if;

                end if;

        end process;

end rtl;