% Transverse Electromagnetic Wave
% Greg Galloway
%
% This file demonstrates visually the fields involved with
% a transverse electromagnetic wave.

clc;clear;clf
%Values
repetitions = 5;                    %Number of times to repeat
x_range = 14;
x_start = -7;
tsteps = .01;
time = 0:tsteps:x_range;
step_cnt = floor(x_range/tsteps);       %Total number of steps
bars = 40;                           %delay between bars
magnitude = 6;                       %Magnitude of waves
x_modulo = 14;                       %Loop size
% x_start = -x_modulo/2;                        %X start location
filler = zeros(size(mod(time,x_modulo)));    %Zero vector filler

% BALL COLORS
colr = [1 0 0;0 1 0;0 0 1];

% DIMENSIONS OF BOX: Width:X, Length:Y, Height:Z
width = 15;height = 15;length=15;
center=[0,0,0];
% Graph dimensions
dimensions = [-width/2+center(1) width/2+center(1) -length/2+center(2) ...
    length/2+center(2) -height/2+center(3) height/2+center(3)];


for j = 1:1:3   %This initializes the 'ball' values
handle(j) = line(0,0,0,'linestyle','none','marker','o','markersize',10,'erasemode','normal','markeredgecolor','k','markerfacecolor',colr(j,:));
end
handle(4) = line([0,0],[0,0],[0,0]);

%This initializes the paths the balls will travel along

pos_1 = [time+x_start; filler; filler];            %Axis of propogation
pos_2 = [time+x_start; magnitude.*sin(time); filler];            
pos_3 = [time+x_start; filler; magnitude.*sin(time)];

pos = cat(3,pos_1,pos_2,pos_3);
%This begins the plotting portion
axis(dimensions);
title('Transverse Electromagnetic Wave Demonstration')
for x = 1:1:repetitions;
    for i = 1:1:step_cnt;
        for k = 1:1:3
            set(handle(k),'xdata',pos(1,i,k),'ydata',pos(2,i,k),'zdata',pos(3,i,k),'erasemode','normal');
        end
         for k = 2:1:3
             if floor(i/bars) == ceil(i/bars)
             handle(4)=line([pos(1,i,k),pos(1,i,k)],[0,pos(2,i,k)],[0,pos(3,i,k)],'color',colr(k,:));
             end
         end
         if pos(1,i,2) ==x_start
             clf;
             for j = 1:1:3   %This redisplays the balls
                handle(j) = line(0,0,0,'linestyle','none','marker','o','markersize',10,'erasemode','normal','markeredgecolor','k','markerfacecolor',colr(j,:));
                axis(dimensions);
                title('Transverse Electromagnetic Wave Demonstration')
             end
         end
         
    drawnow;
    end
end