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-- 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/>.

-- 16X50M Intersection Tests    

library ieee;

use ieee.std_logic_1164.all;

package powerGrid is

        -- A scan flip flop, aka selectable input ff.

        component scanFF

                generic (

                W       : integer := 8);

                port    (

                clk,rst,ena,sel         : in std_logic; -- The usual  control signals

                d0,d1   : in std_logic_vector (W-1 downto 0);    -- The two operands.

                q               : out std_logic_vector (W-1 downto 0)    -- The selected data.

                );

        end component;

        --A one stage pipe (1 Clk) a+b+c with w width bits in input as well as output.

        --As a fixed signed addtion we have:

        -- A(B,C) ====> B+C SIGNED BITS FORMAT : 1 bit for sign, B bits for integer part, C bits for decimal part. (FORMAT)

        -- A(15,20)*A(15,20) = A(15,20). (This component format)

        component p1ax

                generic (

                -- The width of the operands and result.

                W               : integer := 36 );

                port    (

                -- The usual control signals.

                clk             :        in std_logic;

                rst             :        in std_logic;

                enable  :        in std_logic;

                -- Operand A.

                dataa           :        in std_logic_vector(W-1 downto 0);

                -- Operand B.

                datab           :        in std_logic_vector(W-1 downto 0);

                -- Operand C

                datac           :        in std_logic_vector(W-1 downto 0);

                -- Result.

                result          :        out std_logic_vector(W-1 downto 0)

                );

        end component;

        -- A 1 stage pipe 18x18 multiplier. On Cycle III devices is a M-R (Multiplier, Register). (Should be generated using a synthesis tool....).

        -- As a fixed signed multiplication we have :

        -- A(B,C) ====> B+C SIGNED BITS FORMAT : 1 bit for sign, B bits for integer part, C bits for decimal part. (FORMAT)

        -- A(7,10)*A(7,10) = A(15,20). (This component format)

        component p1m18

                port    (

                -- Asynchronous clear signal.

                aclr            : in std_logic ;

                -- The usual control signals.

                clken           : in std_logic ;

                clock           : in std_logic ;

                -- Factor A.

                dataa           : in std_logic_vector (17 downto 0);

                -- Factor B.

                datab           : in std_logic_vector (17 downto 0);

                -- Product.

                result          : out std_logic_vector (35 downto 0)

                );

        end component;

        -- Signed "less than". dataa < datab

        component sl32

                port    (

                dataa   : in std_logic_vector (31 downto 0);

                datab   : in std_logic_vector (31 downto 0);

                AlB             : out std_logic

                );

                end component;

        -- Signed "greater than". dataa >= datab.

        component sge32

                port    (

                dataa   : in std_logic_vector (31 downto 0);

                datab   : in std_logic_vector (31 downto 0);

                AgeB    : out std_logic

                );

                end component;

        -- Dot Product Calculation Cell. 

        -- A 4 side cell along with an upper side. 

        -- V input flows through V output using a data flipflop, so turning V output in the next cell on the next row V Input. V input also flows upwards into the dotproduct 3 stage pipeline. 

        -- D input flows through D output using a data flipflop, so turning D output in the next column cell. D input also flows upwards into the dotproduct 3 stage. 

        component dotCell

                generic (

                -- Register V?, by default register the pass of V to the next grid. This should be NO when using a single grid cube or in the last grid of the grid array.

                RV      : string := "yes";

                -- Actual Level Width

                W0      : integer := 18;

                -- Next Level Width

                W1      : integer := 32);

                port    (

                --The usual control signals

                clk                     : in std_logic;

                rst                     : in std_logic;

                -- This bit controls when the sphere center goes to the next row.

                nxtSphere       : in std_logic;

                -- This bit controls when the ray goes to the next column.

                nxtRay          : in std_logic;

                -- First Side.

                vxInput         : in std_logic_vector(W0-1 downto 0);

                vyInput         : in std_logic_vector(W0-1 downto 0);

                vzInput         : in std_logic_vector(W0-1 downto 0);

                -- Second Side (Opposite to the first one)

                vxOutput        : out std_logic_vector(W0-1 downto 0);

                vyOutput        : out std_logic_vector(W0-1 downto 0);

                vzOutput        : out std_logic_vector(W0-1 downto 0);

                -- Third Side (Perpendicular to the first and second ones)

                dxInput         : in std_logic_vector(W0-1 downto 0);

                dyInput         : in std_logic_vector(W0-1 downto 0);

                dzInput         : in std_logic_vector(W0-1 downto 0);

                --Fourth Side (Opposite to the third one)

                dxOutput        : in std_logic_vector(W0-1 downto 0);

                dyOutput        : in std_logic_vector(W0-1 downto 0);

                dzOutput        : in std_logic_vector(W0-1 downto 0);

                --Fifth Side (Going to the floor right upstairs!)

                vdOutput        : out std_logic_vector(W1-1 downto 0) -- Dot product.

                );

        end component;

        -- K discriminant comparison.

        -- The vdinput value is the calculation of the ray and the column's sphere dot product. This value should be compared to a sphere constant in order to find out whether the ray intersects

        -- or not the sphere. If vdinput is grather or equal than kinput there's an intersection or else when vdinput is less than kinput. If there's an intersection the block sets vdinput at vdoutput,

        -- whenever there's no intersection the output is asserted with the maximum positive distance in 32 bits : 0x7fffffff.

        component kComparisonCell

                generic (

                RK      : string        := "yes";

                W1      : integer       := 32

                );

                port (

                clk,rst         : in std_logic;

                scanOut         : in std_logic; -- This signals overrides the 'signed greater or equal than' internal function and allows vdinput to flow upwards.

                nxtSphere       : in std_logic; -- Controls when the sphere goes to the next Row. 

                pipeOn          : in std_logic; -- Enables / Disable the upwarding flow.

                kinput          : in std_logic_vector (W1-1 downto 0);

                koutputhor      : out std_logic_vector (W1-1 downto 0);

                koutputver      : out std_logic_vector (W1-1 downto 0);  -- K input  flowing to the next floor upstairs (but waits one clock). 

                vdinput         : in std_logic_vector (W1-1 downto 0);   -- V.D input.

                vdoutput        : out std_logic_vector (W1-1 downto 0)   -- Selected dot product.

                );

        end component;

        -- Minimun distance Comparison.

        -- The reference value, refvd, is the ray minimal intersection distance calculated in the moment of the comparison. 

        -- The column value, colvd, is the column sphere and ray intersection distance (if any or else the maximum distance is asserted).

        component dComparisonCell

                generic (

                -- V.D, minDistance and selectD Width 

                W1              : integer := 32;

                -- Column Sphere ID width. 1 = 2 columns max, 2= 4 colums max... and so on.

                IDW     : integer := 2;

                -- Column Id

                idCol   : integer := 0

                );

                port    (

                -- The usual control signals.           

                clk, rst, pipeOn : in std_logic;

                intd    : in    std_logic;

                intq    : out   std_logic;

                -- This is the reference column identification input.

                cIdd    : in    std_logic_vector (IDW - 1 downto 0);

                -- This is the result column identification output.

                cIdq    : out   std_logic_vector (IDW - 1 downto 0);

                refk    : in    std_logic_vector (W1 - 1 downto 0); -- This is the columns sphere constant

                colk    : in    std_logic_vector (W1 - 1 downto 0); -- This is the reference sphere constant

                selk    : out   std_logic_vector (W1 - 1 downto 0); -- This is the selected sphere constant              

                -- This is the reference projection incoming from the previous cell.

                refvd   : in    std_logic_vector (W1 - 1 downto 0);

                -- This is the sphere position over the ray traced vector projection.

                colvd   : in    std_logic_vector (W1 - 1 downto 0);

                -- This is the smallest value between refvd and colvd.

                selvd   : out   std_logic_vector (W1 - 1 downto 0)

                );

        end component;

        component floor0Row

                generic (

                -- Floor Level Width (V.D width)

                W1 : integer := 32;

                -- Vector input Width           

                W0 : integer := 18;

                -- Number of Colums

                C       : integer := 4

        );

        port (

                -- The usual control signals. nxtRay should be 0 whenever I want to stop the entire machine.

                clk, rst, nxtRay : in std_logic;

                -- Clk, Rst, the usual control signals.

                -- enabled, the machine is running when this input is set.

                -- enabled, all the counters begin again.

                nxtSphere : in std_logic_vector (C-1 downto 0);

                -- Input Values. 

                -- The ray input vector.

                iRayx: in std_logic_vector (W0 - 1 downto 0);

                iRayy: in std_logic_vector (W0 - 1 downto 0);

                iRayz: in std_logic_vector (W0 - 1 downto 0);

                -- The spheres x position (sphere centers) input vectors.

                iSphrCenterx: in std_logic_vector (C*W0 - 1 downto 0);

                -- The spheres y position (sphere centers) input vectors.

                iSphrCentery: in std_logic_vector (C*W0 - 1 downto 0);

                -- The spheres z position (sphere centers) input vectors.

                iSphrCenterz: in std_logic_vector (C*W0 - 1 downto 0);

                -- The spheres x position (sphere centers) output vectors.

                oSphrCenterx: out std_logic_vector (C*W0 - 1 downto 0);

                -- The spheres y positions (sphere centes) output vectors.

                oSphrCentery: out std_logic_vector (C*W0 - 1 downto 0);

                -- The spheres z positions (sphere centers) output vectors.             

                oSphrCenterz: out std_logic_vector (C*W0 - 1 downto 0);

                -- Output Values

                -- The ray output vector.

                oRayx: out std_logic_vector (W0 - 1 downto 0);

                oRayy: out std_logic_vector (W0 - 1 downto 0);

                oRayz: out std_logic_vector (W0 - 1 downto 0);

                -- The dot product result from each dot prod cell.

                vdOutput : out std_logic_vector (W1*C - 1 downto 0)

                );

        end component;

        -- In this level the V.D results from floor 0 are compared whether they are greater or equal than column's sphere K constants, in order to find if there's an intersection per column or not.

        -- When any comparison is true, meaning VD value greater or equal than K, the outgoing value to floor2 level is the same VD, if not the outgoing value is 0x7fffffff (the maximum)

        -- distance value.

        component floor1Row

        generic (

                -- Vector input Width   

                W1 : integer := 32;

                -- Number of Colums

                C       : integer := 4

        );

        port (

                -- Input Control Signals, pipe on is one when raysr going on. 

                clk, rst        : in std_logic;

                pipeOn          : in std_logic;

                -- Clk, Rst, the usual control signals.

                nxtSphere       : in std_logic_vector (C-1 downto 0);

                -- VD Input / Output.

                vdInput : in std_logic_vector (W1*C-1 downto 0);

                vdOutput: out std_logic_vector (W1*C-1 downto 0);

                -- K Input / Output.

                kInput  : in std_logic_vector (W1*C - 1 downto 0);

                kOutput : out std_logic_vector (W1*C - 1 downto 0)

        );

        end component;

        -- This level takes the -on the moment smalles distance-- value per ray in the extreme left, and starts making comparisons from left to right, one comparison each clock and so on, searching for the smallest V.D value in the row incomung from the floor1 level. When the ray has finished crossing throguh all the spheres in the scene, the row extreme right value will be the smallest V.D found along with an ID of the sphere intersected. This is the goal of the intersection architecture : to find out which is the closest sphere intersected by a particular ray. 

        component floor2Row

        generic (

                -- Vector input Width

                W1 : integer := 32;

                -- ID Column width

                IDW : integer := 2;

                -- Number of Colums

                C       : integer := 4

        );

        port (

                -- Input Control Signal

                -- Clk, Rst, the usual control signals.

                clk, rst, pipeOn: in std_logic;

                -- Input Values

                -- Reference VD, the "at the moment" smallest VD sphere ray projection value.

                refvd   : in std_logic_vector (W1-1 downto 0);

                -- The smallest VD, value found.

                selvd   : out std_logic_vector (W1-1 downto 0);

                -- The column's sphere ray projection value.

                colvd   : in std_logic_vector (W1*C-1 downto 0);

                -- The smallest VD projection value column id.

                colid   : out std_logic_vector (IDW-1 downto 0);

                -- The intersection signal (1 on intersection else 0).

                inter   : out std_logic

        );

        end component;

        component rayxsphereGrid

        generic (

                -- Width of Column identificator.

                IDW     : integer := 2;

                -- Number of Columns.

                C       : integer := 4;

                -- Input rays width.

                W0      : integer := 18;

                -- Dot products and spheres constant width

                W1      : integer := 32

                );

        port (

                -- The usual control signals.

                clk,rst         : in std_logic;

                -- Grid, rays and sphere flow through control signals.

                pipeOn          : in std_logic;

                nxtSphere       : in std_logic_vector (C-1 downto 0);

                -- R-F0

                -- Input Values. 

                -- The ray input vector.

                iRayx: in std_logic_vector (W0 - 1 downto 0);

                iRayy: in std_logic_vector (W0 - 1 downto 0);

                iRayz: in std_logic_vector (W0 - 1 downto 0);

                -- The spheres x position (sphere centers) input vectors.

                iSphrCenterx: in std_logic_vector (C*W0 - 1 downto 0);

                -- The spheres y position (sphere centers) input vectors.

                iSphrCentery: in std_logic_vector (C*W0 - 1 downto 0);

                -- The spheres z position (sphere centers) input vectors.

                iSphrCenterz: in std_logic_vector (C*W0 - 1 downto 0);

                -- The spheres x position (sphere centers) output vectors.

                oSphrCenterx: out std_logic_vector (C*W0 - 1 downto 0);

                -- The spheres y positions (sphere centes) output vectors.

                oSphrCentery: out std_logic_vector (C*W0 - 1 downto 0);

                -- The spheres z positions (sphere centers) output vectors.             

                oSphrCenterz: out std_logic_vector (C*W0 - 1 downto 0);

                -- Output Values

                -- The ray output vector.

                oRayx: out std_logic_vector (W0 - 1 downto 0);

                oRayy: out std_logic_vector (W0 - 1 downto 0);

                oRayz: out std_logic_vector (W0 - 1 downto 0);

                -- R-F1

                -- K Input / Output.

                kInput  : in std_logic_vector (C*W1 - 1 downto 0);

                kOutput : out std_logic_vector (C*W1 - 1 downto 0);

                --R-F2

                -- Input Values

                refvd   : in std_logic_vector (W1-1 downto 0);

                selvd   : out std_logic_vector (W1-1 downto 0);

                colid   : out std_logic_vector (IDW-1 downto 0);

                inter   : out std_logic

                );

        end component;

        component gridCube

        generic (

                -- Depth

                D       : integer := 4;

                -- ID width.

                IDW     : integer := 2;

                -- Number of Columns.

                C       : integer := 4;

                -- Input rays width.

                W0      : integer := 18;

                -- Dot products and spheres constant width

                W1      : integer := 32

                );

        port (

                        -- The usual control signals.

                clk,rst : in std_logic;

                -- Grid, rays and sphere flow through control signals.

                pipeOn                  : in std_logic;

                -- The same column nxtSphere signal control..... regardless the Cube Depth.

                nxtSphere               : in std_logic_vector (C-1 downto 0);

                -- R-F0

                -- Input Values. 

                -- The ray input vector. 

                iRayx: in std_logic_vector (D*W0 - 1 downto 0);

                iRayy: in std_logic_vector (D*W0 - 1 downto 0);

                iRayz: in std_logic_vector (D*W0 - 1 downto 0);

                -- The spheres x position (sphere centers) input vectors.

                iSphrCenterx: in std_logic_vector (C*W0 - 1 downto 0);

                -- The spheres y position (sphere centers) input vectors.

                iSphrCentery: in std_logic_vector (C*W0 - 1 downto 0);

                -- The spheres z position (sphere centers) input vectors.

                iSphrCenterz: in std_logic_vector (C*W0 - 1 downto 0);

                -- The spheres x position (sphere centers) output vectors.

                oSphrCenterx: out std_logic_vector (C*W0 - 1 downto 0);

                -- The spheres y positions (sphere centes) output vectors.

                oSphrCentery: out std_logic_vector (C*W0 - 1 downto 0);

                -- The spheres z positions (sphere centers) output vectors.             

                oSphrCenterz: out std_logic_vector (C*W0 - 1 downto 0);

                -- Output Values

                -- The ray output vector.

                oRayx: out std_logic_vector (D*W0 - 1 downto 0);

                oRayy: out std_logic_vector (D*W0 - 1 downto 0);

                oRayz: out std_logic_vector (D*W0 - 1 downto 0);

                -- R-F1

                -- K Input / Output.

                kInput  : in std_logic_vector (C*W1 - 1 downto 0);

                kOutput : out std_logic_vector (C*W1 - 1 downto 0);

                --R-F2

                -- Input Values

                refvd   : in std_logic_vector (D*W1-1 downto 0);

                selvd   : out std_logic_vector (D*W1-1 downto 0);

                colid   : out std_logic_vector (D*IDW-1 downto 0);

                inter   : out std_logic_vector (D-1 downto 0)

                );

        end component;

end powerGrid;