%
% nimOut = Edge_contrast_circle_animation( flRadius, imDim, flAngle, flPhaseStart, flPxShiftMax, flDuration )
% -------------------------------------------------------------------------
%
%   Creates a set of circle with center-surround frames of a movie for 
%   a "directional edge contrast motion" illusion.
%
% USAGE:    nimOut = Edge_contrast_circle_animation( 25, 100, 45, 90, 36, 1.0 );
%
% INPUT:
%
%   flRadius        - Circle radius, in pixels.
%   imDim           - One dimension of the resulting square image, in
%                     pixels, unless this dimension will clip the circle image.
%   nAngle          - Direction of apparent motion, in degrees.
%   nPhaseStart     - First frame phase, in degrees.
%   flPxShiftMax    - Proportional to maximum edge shift. Edge speed 
%                     is flPxShiftMax*nFrameRate/24(see hardcoded nFrameRate). 
%   flDuration      - Approximate duration of one cycle of the animation, 
%                     in pixels/second. This will be rounded to the nearest 
%                     increment of the frame duration (see hardcoded nFrameRate).
%
% HARDCODED (immediately below function declaration):
%
%   strFilestem       - File stem naming of output file.
%   strFileFmt        - File extension that specifies the image format,
%                       e.g.'.png', '.tif', '.jpg', etc.
%   nOverSample       - [1, 16] Flat aperture oversampling rate.
%   nFrameRate        - Expected animation frame rate.
%
%   bShowResult       - [0, 1] Display final image (only last frame).
%   bWriteResult      - [0, 1] Write image to file.
%
% RETURN VALUES:
%
%   nimOut     - Grayscale [ imDim x imDim ] image array of 8-bit integers
%                (uint8).
%
% OUTPUT:
%
%	If bWriteResult == 1, writes grayscale image to current directory.
%
% FUNCTION CALLS and DEPENDENCIES: 
%
%	Edge_contrast_circle.m
%   write_Space_volume.m
%
%
% Mark Dow,             May 5, 2008
% Mark Dow, modified    May 6, 2008 (added phase and maximum shift)
%
%
%   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 nimOut = Edge_contrast_circle_animation( flRadius, imDim, nAngle, nPhaseStart, flPxShiftMax, flDuration )

flAngle      = nAngle*pi/180;
flPhaseStart = nPhaseStart*pi/180;

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

strFilestem   = [ 'Circle-' num2str(flRadius) '_' num2str(imDim) '_' num2str(nAngle) '_' num2str(nPhaseStart) '_' num2str(flPxShiftMax) '_' num2str(flDuration) ];
strFileFormat = '.png';
nOverSample   = 5;
nFrameRate    = 24;

bShowResult           = 0;   % [0,1]
bWriteEachFrame       = 0;   % [0,1]
bWriteSpaceVolume     = 0;   % [0,1]


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

flShiftMax = 24*flPxShiftMax/nFrameRate;    % maximum shift, in pixels

%   nFramesPerCycle = (flDuration*nFrameRate)
%   nDegreesPerFrame = 360(degrees/cycle)/nFramesPerCycle
nDegreesPerFrame = round( 360/(flDuration*nFrameRate) );
nDegreesPhaseStart = flPhaseStart*180/pi;

i = 0;
for ndegPhase = nDegreesPhaseStart : nDegreesPerFrame : 360 + nDegreesPhaseStart - nDegreesPerFrame
    
    i = i + 1;
    
    nimOut(:,:,i) = Edge_contrast_circle( flRadius, imDim, flAngle, ndegPhase, flShiftMax );

    if bWriteEachFrame 

        imwrite( nimOut(:,:,1), [ strFilestem '_' num2str(ndegPhase) strFileFormat ] );
    end
end

nimOut = permute( nimOut, [ 1 3 2 ] );

if bWriteSpaceVolume
    
    write_Space_volume( nimOut, [ strFilestem ] );
end

if bShowResult

    imshow( nimOut(:,:,1) )
end