function XYsIn3D = CalcXYsIn3D( frameNum, SeqTemplate, numDigs, iFirsts, iLasts, DataBlock )

%%
%%  LARGLY  from inside MotBoostEvalOneFrame    MOSTLY
%%


numLasts = size(iLasts(:),1);
iLast = iLasts( numLasts );
if( frameNum > iLast )
    fprintf( 1, 'Error: Wanted Eval frame %d but batches only reach %d\n', frameNum, iLast );
elseif( frameNum > iLast -25 )
    iBatch = numLasts;
else
    iBatch = find( iLasts - 25 > frameNum, 1 ); % The (...,1) says: give me at most 1 index.
end;


if( numDigs == 4 )
    % These two have been precomputed already!
    %banFileName = sprintf( '%s%.4d_%.4d.ban', SeqTemplate, iFirsts(iBatch), iLasts(iBatch) );
    %txt2DfileName = sprintf( '%s%.4d_%.4d_2D.txt', SeqTemplate, iFirsts(iBatch), iLasts(iBatch) );
    matFileName = sprintf( '%s%.4d_%.4d.mat', SeqTemplate, iFirsts(iBatch), iLasts(iBatch) );
    %matTriFileName = sprintf( '%s%.4d_%.4d_TriVIds.mat', SeqTemplate, iFirsts(iBatch), iLasts(iBatch) );
elseif( numDigs == 5 )
    % These two have been precomputed already!
    %banFileName = sprintf( '%s%.5d_%.5d.ban', SeqTemplate, iFirsts(iBatch), iLasts(iBatch) );
    %txt2DfileName = sprintf( '%s%.5d_%.5d_2D.txt', SeqTemplate, iFirsts(iBatch), iLasts(iBatch) );
    matFileName = sprintf( '%s%.5d_%.5d.mat', SeqTemplate, iFirsts(iBatch), iLasts(iBatch) );
    %matTriFileName = sprintf( '%s%.5d_%.5d_TriVIds.mat', SeqTemplate, iFirsts(iBatch), iLasts(iBatch) );
elseif( numDigs == 6 )
    % These two have been precomputed already!
    %banFileName = sprintf( '%s%.5d_%.5d.ban', SeqTemplate, iFirsts(iBatch), iLasts(iBatch) );
    %txt2DfileName = sprintf( '%s%.5d_%.5d_2D.txt', SeqTemplate, iFirsts(iBatch), iLasts(iBatch) );
    matFileName = sprintf( '%s%.6d_%.6d.mat', SeqTemplate, iFirsts(iBatch), iLasts(iBatch) );
    %matTriFileName = sprintf( '%s%.6d_%.6d_TriVIds.mat', SeqTemplate, iFirsts(iBatch), iLasts(iBatch) );
end;

%Using pad-by-6 for all TriFiles!!
%matTriFileName = sprintf( '%s%.6d_%.6d_TriVIds.mat', SeqTemplate, iFirsts(iBatch), iLasts(iBatch) );


% Now load up the 2D traj file and 3D camera calibs
load( matFileName );

%load( matTriFileName );


if( DataBlock == 1 )
    % Restore! After ICCV deadline.
    %debugImgName = sprintf( 'G:\\MotBoostData01\\StillsRaw_full\\Test\\Seq05VD_f%.5d.png', frameNum );

    debugImgName = sprintf( 'G:\\MotBoostData01\\701_StillsRaw_full\\Seq05VD_f%.5d.png', frameNum );
elseif( DataBlock == 2 )
    debugImgName = sprintf( 'G:\\MotBoostData01\\701_StillsRaw_full\\0016E5_%.5d.png', frameNum );
elseif( DataBlock ==3 )
    debugImgName = sprintf( 'G:\\MotBoostData01\\701_StillsRaw_full\\0006R0_f%.5d.png', frameNum );
elseif( DataBlock ==4 )
    debugImgName = sprintf( 'G:\\MotBoostData01\\701_StillsRaw_full\\0001TP_%.6d.png', frameNum );
end;
% debugImgName =
% 'G:\\MotBoostData01\\StillsRaw_full\\blankWhite320x240.png';
% debugImgName =
% 'G:\\MotBoostData01\\StillsRaw_full\\blankWhite960x720.png';


%       find( TrajTable(:, 1) == 7074 );    % Find indexes to all frames with this Traj#
%       find( TrajTable(:, 2) == 1502 );    % Find indexes to all Traj's with this Frame#



isOfTrajsExistingNow = find( TrajTable(:, 2) == frameNum );     % Look through column 2 of TrajTable, return indexes.
XYs = TrajTable( isOfTrajsExistingNow, 3:4 );




%%
%% Accum 3D camera center for the frames in this batch:
%%
numXYs = size(XYs,1);
offsetForFrameNums = iFirsts(iBatch) -1;
Cs = zeros( iLasts(iBatch) - iFirsts(iBatch) + 1,   3);
j=1;
for( iFrameC = iFirsts(iBatch):iLasts(iBatch) )
    iInBig = iFrameC - offsetForFrameNums;
    %                      Long way, if we only have P...
    %P = Kbig(:,:, iInBig ) * Rbig(:,:, iInBig ) * [eye(3) -Tbig(:,:, iInBig )];
    %p1 = P(:,1); p2 = P(:,2); P(:,3); p3 = P(:,3); p4 = P(:,4);
    %C = [det([p2 p3 p4])  -det([p1 p3 p4])  det([p1 p2 p4])   -det([p1 p2 p3]) ];
    %Rbig(:,:, iInBig ) * [eye(3) -Tbig(:,:, iInBig )]
    %C = C(1:3) / C(4);
    %Cs(j, 1:3) = C;
    Cs(j, 1:3) = [Tbig(:,:, iInBig )]';     % ...vs short way if we have T
    j = j+1;
end;
% curC = Cs( frameNum-offsetForFrameNums,    1:3);  % Unused?



XYsIn3D = zeros( numXYs, 3 );
for( iTraj = 1:numXYs )
    %fprintf(1, 'iTraj #%d\n', iTraj);
    trajNum = TrajTable(isOfTrajsExistingNow(iTraj), 1);

    rowsTrajWasTracked = find( TrajTable(:, 1) == trajNum );
    %rowsTrajWasTracked = find( (TrajTable(:, 1) <= trajNum+0.001) && (TrajTable(:, 1) >= trajNum-0.001) );

    %% Weird hacks, attempting to circumvent Matlab bug that would crash
    %% here... Still breaks!
    %%
    %TrajByFrame = sortrows( TrajTable(rowsTrajWasTracked, 2:4), 1);
    rowsTrajWasTracked2 = find( TrajTable(:, 1) == trajNum );
    while( (size(rowsTrajWasTracked,1) ~= size(rowsTrajWasTracked2,1))  ||  sum(rowsTrajWasTracked == rowsTrajWasTracked2) ~= size(rowsTrajWasTracked,1) )
        fprintf(1, ',');
        rowsTrajWasTracked = find( TrajTable(:, 1) == trajNum );
        rowsTrajWasTracked2 = find( TrajTable(:, 1) == trajNum );
    end;
    TrajByFrame = TrajTable(round(rowsTrajWasTracked), 2:4);
    if( size( TrajByFrame, 1 ) < 3 )
        continue;   % No point in processing too short a track.
    end;

    %[VarianceIn3D Res] = VarOfBackProjectTraj( TrajByFrame, offsetForFrameNums, Kbig, Rbig, Tbig );
    XYsIn3D(iTraj, 1:3) = BackProject2DTrajTo3D( TrajByFrame, offsetForFrameNums, Kbig, Rbig, Tbig );
    fprintf(1, '.');
end;
fprintf(1, '\n');