%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% 
% function ColorPerVertex() : Creates an RGB color matrix based on height 
%			      values. 
%			      
%			      
% INPUT : m x n matrix, name of file to write to,'filename'.
% OUTPUT: m x 3n matrix of RGB colors, also writes as text to 'filename'.
% 
% MODIFY: level height values, # of levels, colors, & # of colors to fit
%	  your problem. If you change the number of levels don't forget to
%      	  add or remove if/elseif statements below.
%
% Author: Jason Tate June 10, 1998
%         tate@edcenter.sdsu.edu
%
% Educational Center for Computational Science & Engineering
% http://www.edcenter.sdsu.edu
%
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

function [ColorMatrix] = ColorPerVertex(ElevationMatrix,filename)

 % DEFINE COLOR HEIGHT BOUNDARIES 
		  %less than 732
   level_1 = 732; % 732 to 785
   level_2 = 785; % 785 to 840
   level_3 = 840; % 840 to 910
   level_4 = 910; % 910 or greater
		  
 % INITIALIZE RGB COLORS
   color_0 = [0.1 0.3 0.9];    % Blue
   color_1 = [0.2 0.8 0.2];    % Green
   color_2 = [0.4 0.6 0.5];    % Darker Green
   color_3 = [0.75 0.75 0.75]; % Gray
   color_4 = [1.0 1.0 1.0];    % White
   
   % INITIALIZE COLORS FOR TEXT OUTPUT TO FILE
   color_0_string = '0.1 0.3 0.9';
   color_1_string = '0.2 0.8 0.2,';
   color_2_string = '0.4 0.6 0.5,';
   color_3_string = '0.75 0.75 0.75,';
   color_4_string = '1.0 1.0 1.0,';

 % CHECK # OF ARGUMENTS
        if nargin > 2 
		error('too many arguments')
 	end;

	if nargin < 2 
		error('too few arguments')
	end; 
 
 % DETERMINE DIMENSIONS OF MATRIX
	Dimensions =  size(ElevationMatrix);
	numRows = Dimensions(1);
	numColumns = Dimensions(2);

 % INITIALIZE COLORMATRIX
	ColorMatrix = ones(numRows,3 * numColumns);

 % OPEN FILE TO WRITE MATRIX TO
   fp = fopen(filename,'w');
	
 for i = 1:numRows
	for j = 1:numColumns
		if ElevationMatrix(i,j) >= level_4 
			% SAVE TO MATRIX FOR FURTHER PROCESSING
			ColorMatrix(i,j*3-2) = color_4(1);
			ColorMatrix(i,j*3-1) = color_4(2);
			ColorMatrix(i,j*3)   = color_4(3);
			% WRITE TO FILE FORMATTED FOR VRML COLOR NODE
		        fprintf(fp,'%s',color_4_string);	
		elseif ElevationMatrix(i,j) >= level_3
			% SAVE TO MATRIX FOR FURTHER PROCESSING
			ColorMatrix(i,j*3-2) = color_3(1);
                        ColorMatrix(i,j*3-1) = color_3(2);
                        ColorMatrix(i,j*3)   = color_3(3);
			% WRITE TO FILE FORMATTED FOR VRML COLOR NODE
                        fprintf(fp,'%s',color_3_string);
		elseif ElevationMatrix(i,j) >= level_2 
			% SAVE TO MATRIX FOR FURTHER PROCESSING
			ColorMatrix(i,j*3-2) = color_2(1);
                        ColorMatrix(i,j*3-1) = color_2(2);
                        ColorMatrix(i,j*3)   = color_2(3);
		        % WRITE TO FILE FORMATTED FOR VRML COLOR NODE
                        fprintf(fp,'%s',color_2_string);
		elseif ElevationMatrix(i,j) >= level_1
			% SAVE TO MATRIX FOR FURTHER PROCESSING
			ColorMatrix(i,j*3-2) = color_1(1);
                        ColorMatrix(i,j*3-1) = color_1(2);
                        ColorMatrix(i,j*3)   = color_1(3);
			% WRITE TO FILE FORMATTED FOR VRML COLOR NODE
                        fprintf(fp,'%s',color_1_string);
		else	
			% SAVE TO MATRIX FOR FURTHER PROCESSING
			ColorMatrix(i,j*3-2) = color_0(1);
                        ColorMatrix(i,j*3-1) = color_0(2);
                        ColorMatrix(i,j*3)   = color_0(3);
			% WRITE TO FILE FORMATTED FOR VRML COLOR NODE
                        fprintf(fp,'%s',color_0_string);
		end;
	end
	fprintf(fp,'\n');
	
 end
 fclose(fp);