%
% flVct = Edge_contrast_1D( flHalfWidth, ndegPhase )
% -------------------------------------------------------------------------
%
%   Creates vector with a center-surround aura and edge at a given angle. 
%   This vector is used as a member of a sequence.
%
% USAGE:    flVct = Edge_contrast_1D( 13.3, 20 );
%
% INPUT:
%
%   flHalfWidth     - 
%   ndegPhase       - Phase angle, in degrees
%
% HARDCODED (immediately below function declaration):
%
%   nOverSample     - [1, 16] Flat aperture oversampling rate.
%   bShowResult     - [0, 1] Show progress, display final image.
%
% RETURN VALUES:
%
%   flVct = range [0,1], length 2*ceil( flHalfWidth )
%
% FUNCTION CALLS and DEPENDENCIES: 
%
%       None.
%
% Mark Dow,           November 11, 2008
% Mark Dow, modified             , 2008 ()
%
%
%   TERMS FOR USE: There are no restrictions on the use of this code, 
%                  auxilliary code and other required resources. Claiming 
%                  to be the originator, explicitly or implicitly, is bad  
%                  karma. A link (if appropriate), a note to dow[at]uoregon.edu, 
%                  and credit are appreciated but not required.
%

function flVct = Edge_contrast_1D( flHalfWidth, ndegPhase )

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% hardcoded parameters

nOverSample = 16;   % Approximate flat aperture sampling 
                    % with high integer oversampling.
bTilingEdge = true;

bShowResult         = false;    % [0,1]

ndegPhase = ndegPhase + 280; % I don't know why.
ndegPhase = mod( ndegPhase, 360 );

% hardcoded parameters
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

    % Initialize gray
    nWOS = nOverSample*2*ceil( flHalfWidth );
%     flVct  ( 1 : 2*ceil( flHalfWidth ) ) = -.5;
%     flVctOS( 1 : nWOS ) = -.5;
    flVct  ( 1 : 2*ceil( flHalfWidth ) ) = 0;
    flVctOS( 1 : nWOS ) = 0;

    flInterval = .5/(flHalfWidth*nOverSample);

    % Background profile:
    % Triangular peak [ 0, .5 ]:
%    ramp = .5: -flInterval : flInterval;
    ramp = 1 : -flInterval : flInterval + .5;
%    ramp = flInterval : flInterval : .5;
    % Zero fill right end.
    lRamp = length(ramp);
    nZeroEnds = nWOS/2 - lRamp;
    if nZeroEnds > 0
        ramp( lRamp + 1 : nWOS/2 ) = 0;
    end
    
    rampUp = fliplr( ramp );
     flVctOS(          1 : nWOS/2 ) = flVctOS(          1 : nWOS/2 ) + rampUp;
%     flVctOS(          1 : nWOS/2 ) = flVctOS(          1 : nWOS/2 ) - .5;

    rampDn = ramp;
     flVctOS( nWOS/2 + 1 : nWOS   ) = flVctOS( nWOS/2 + 1 : nWOS   ) + rampDn;
%     flVctOS( nWOS/2 + 1 : nWOS   ) = flVctOS( nWOS/2 + 1 : nWOS   ) - .5;
    
    
    % Peridic fence:
    flFenceOS( 1 : nWOS ) = 1;
%     flFenceOS( 1*nWOS/2 + 1 : 2*nWOS/2 )  = -1;
%     flFenceOS( 3*nWOS/2 + 1 : 4*nWOS/2 )  = -1;
%     flFenceOS( nZeroEnds + round( 1*lRamp/2 ) + 1 : nZeroEnds + round( 2*lRamp/2 ) )  = -1;
%     flFenceOS( nZeroEnds + round( 3*lRamp/2 ) + 1 : nZeroEnds + round( 4*lRamp/2 ) )  = -1;
    flFenceOS( nZeroEnds + round( 1*lRamp/2 ) + 1 : nZeroEnds + round( 2*lRamp/2 ) )  = 0;
    flFenceOS( nZeroEnds + round( 3*lRamp/2 ) + 1 : nZeroEnds + round( 4*lRamp/2 ) )  = 0;
    
    % Cycle fence:
    nCycle = round( nOverSample*2*flHalfWidth*ndegPhase/360 + 0 );
    if nCycle > 0
        
        flFenceTemp( nZeroEnds + ( 2*lRamp - nCycle ) + 1 : nZeroEnds + 2*lRamp ) = flFenceOS( nZeroEnds + 1 : nZeroEnds + nCycle );
        flFenceTemp( nZeroEnds + 1 : nZeroEnds + 2*lRamp - nCycle ) = flFenceOS( nZeroEnds + nCycle + 1 : nZeroEnds + 2*lRamp );
        
        % Zero fill right end.
        if nZeroEnds > 0
            flFenceTemp( nZeroEnds + 2*lRamp + 1 : nWOS ) = 0;
        end
        
        flFenceOS = flFenceTemp;
    end
    
    % Convolve background with fence:
    flVctOS = flVctOS .* flFenceOS;
    
%    flVctOS = flVctOS + .5;
    flVctOS = flVctOS + 0;
    
    % Flat aperture block undersample:
    for iOS = 1:2*ceil( flHalfWidth )
        
        if bTilingEdge

            wrapI = nZeroEnds - ( 0 + (iOS-1)*nOverSample ) + 0;
            wrapF = iOS*nOverSample - ( nWOS - nZeroEnds ) + 0;
            if wrapI > 0

                flVct( iOS ) = (  sum( flVctOS( 1 + (iOS-1)*nOverSample + wrapI : iOS*nOverSample ) ) ...
                                    + sum( flVctOS( ( nWOS - nZeroEnds ) - wrapI : ( nWOS - nZeroEnds ) - 1 ) ) )/nOverSample;
            else
                if wrapF > 0
                    
                    flVct( iOS ) = (  sum( flVctOS( 1 + (iOS-1)*nOverSample : iOS*nOverSample - wrapF ) ) ...
                                    + sum( flVctOS( 1 + nZeroEnds : nZeroEnds + wrapF ) ) )/nOverSample;
                else
                    
                    flVct( iOS ) = sum( flVctOS( 1 + (iOS-1)*nOverSample : iOS*nOverSample ) )/nOverSample;
                end
            end
        else
            flVct( iOS ) = sum( flVctOS( 1 + (iOS-1)*nOverSample : iOS*nOverSample ) )/nOverSample;
        end
        
%         if    ( 1 + (iOS-1)*nOverSample ) < nZeroEnds ...
%            && iOS*nOverSample > nZeroEnds ...
%            && sum( flVctOS( 1 + (iOS)*nOverSample : (iOS+1)*nOverSample ) )/nOverSample < 0.01
%             flVct( iOS ) = 0;
%         end
%         if     ( 1 + (iOS-1)*nOverSample ) < nZeroEnds + 2*lRamp  ...
%             && iOS*nOverSample > nZeroEnds + 2*lRamp ...
%             && flVct( iOS - 1 ) < 0.01
%                
%             flVct( iOS ) = 0;
%         end
    end
        
    
    if bShowResult
        
        nim = zeros( 2*ceil( flHalfWidth ), 2*ceil( flHalfWidth ) );
        
        for i = 1 : 2*ceil( flHalfWidth )
            nim( i, : ) = flVct;
        end
        
    	figure
        imshow( nim );
        colormap( gray )
    end