%
% replace_block_matrix( mtxLS0, mtxRT0, mtxMR0, arrayRules, arrayRotes, arrayMirrs )
%
%   Applys a block replacement transform to a matrix, including n*pi/2 rotations and mirroring.
%   
%	Written as a utility for L_system_tiling.m. This function does no 
%   sanity checks on dimensions, bounds, or number of arguments. 
%   See L_system tiling for examples of bounds checking.
%
%   USAGE:  % arrayRules( 1:2, 1:2, 1 ) = [1 0; 0 1];
%             arrayRules( 1:2, 1:2, 2 ) = [1 1; 0 0];
%             arrayRotes = arrayRules;
%             arrayMirrs = arrayRules;
%             [arrayNext arrayNextRotes arrayNextMirrs] =
%             replace_block_matrix( [1; 0], [0; 1], [0; 0], arrayRules, arrayRotes, arrayMirrs );
%
%   ARGUMENTS:
%
%       mtxLS0:         L-system initial 2-D matrix, which follows the same
%                           coding conventions as the replacement rules.
%       mtxRT0:         Rotation codes.
%       mtxRT0:         Mirror codes.
%
%
%       arrayRules:     A set of L-system block replacement rules, n x m x nRules. .
%       arrayRotes:     Rotation codes.
%       arrayMirrs:     Mirror codes.
%
%   RETURN VALUES:
%
%       mtxOut:         Matrix of integers of the output pattern.
%       mtxRT:          Matrix of integers of the output rotations.
%       mtxMR:          Matrix of integers of the output mirrors.
%
%   HARDCODED:  (see below 'function' statement)
%
%       bShow:  Show details for debugging, and show output matrix in a
%               figure window.
%
%
% Mark Dow,     August 25, 2009
%


function [mtxOut mtxRT mtxMR] = replace_block_matrix( mtxLS0, mtxRT0, mtxMR0, arrayRules, arrayRotes, arrayMirrs )

%%%%%%%%%%%%%%%%%%%%%%%%
% Hardcoded information:

bShow = false;
%
%%%%%%%%%%%%%%%%%%%%%%%%

% To Do: 2-argument version, no mirrors or rotations.

% mtxLS0
% mtxRT0
% mtxMR0
% 
% arrayRules
% arrayRotes
% arrayMirrs

szRules = size( arrayRules );


% To Do: If non-square system and rotations (and mirrors?) are non-zero, it
% will fail. Insert reality check and abort with message.


% Initialize matrices.
szLS0 = size(mtxLS0);
mtxOut( 1:szLS0(1)*szRules(1), 1:szLS0(2)*szRules(2) ) = 0;
mtxRT(  1:szLS0(1)*szRules(1), 1:szLS0(2)*szRules(2) ) = 0;
mtxMR(  1:szLS0(1)*szRules(1), 1:szLS0(2)*szRules(2) ) = 0;

% Construct the next generation of the pattern.
for j = 1 : szLS0(1)
for k = 1 : szLS0(2)

    y1 = (j-1)*szRules(1) + 1 : j*szRules(1);
    x1 = (k-1)*szRules(2) + 1 : k*szRules(2);

    % Insert rotated replacement pattern.
    mtxOut( y1, x1 ) = rot90( arrayRules( 1:szRules(1), 1:szRules(2), mtxLS0( j, k ) + 1 ), ...
                             -mtxRT0( j, k ) );
    % Mirror replaced pattern.
    if mod( mtxMR0( j, k ), 2 ) == 1
        mtxOut( y1, x1 ) = fliplr( mtxOut( y1, x1 ) );
    end
    
    % Copy rotate and mirror rules.
    mtxRT( y1, x1 ) =   mtxRT0( j, k );
    mtxMR( y1, x1 ) =   mtxMR0( j, k );
    % Rotate rotate and mirror rules.
    mtxRT( y1, x1 ) =   mtxRT( y1, x1 ) ...
                      + rot90( arrayRotes( 1:szRules(1), 1:szRules(2), mtxLS0( j, k ) + 1 ), ...
                               -mtxRT0( j, k ) );
    % Mirror rotate and mirror rules.
    if mod( mtxMR0( j, k ), 2 ) == 1
        mtxMR( y1, x1 ) =   mtxMR( y1, x1 ) ...
                          + fliplr( arrayMirrs( 1:szRules(1), 1:szRules(2), mtxLS0( j, k ) + 1 ) );
    else
        mtxMR( y1, x1 ) =   mtxMR( y1, x1 ) ...
                         + arrayMirrs( 1:szRules(1), 1:szRules(2), mtxLS0( j, k ) + 1 );
    end

end
end

mtxRT = mod( mtxRT, 4 );
mtxMR = mod( mtxMR, 2 );

if bShow
    
    figure; imshow( mtxOut )
end