FPS_Sample

How to create FPS by MATLAB

If you want to change the wall, you can change pos_wall parameter.

function test_FPS
clear,clc,close all;
m=200;

% Wall Samples
% pos_wall = [50 50; 100 300; 250 200; 50 50]+100;
p = nsidedpoly(50, 'Center', [200 200], 'Radius', 100);
pos_wall = [p.Vertices;p.Vertices(1,:)];

% Player 1st position
player.pos   = [10,10];
player.angle = 45;
Angle = 30;
dAngle = 10;
n = 21;

% Generate an arc and line segments
th = deg2rad(linspace(player.angle - Angle,player.angle + Angle,n))';
r = 100;
v = r.*[cos(th),sin(th)];
p2 = v + player.pos;

% Intersection calculation(1st step)
% Mapping Toolbox --> polyxpoly
% Free： https://jp.mathworks.com/matlabcentral/fileexchange/22441-curve-intersections
x = reshape(([repelem(player.pos(1),height(p2))',p2(:,1),nan(height(p2),1) ])',[],1);
y = reshape(([repelem(player.pos(2),height(p2))',p2(:,2),nan(height(p2),1) ])',[],1);
[xi,yi,kk] = polyxpoly(x,y,pos_wall(:,1),pos_wall(:,2));

% Wall for Bird's eye view
Wallx = (1:height(p2))';

% Calculate only in front
dummy = Wallx.*(4-1) + 1;
dummy = [1 ; dummy(1:end-1)];
Wally = nan(height(p2),1);
th2 = -deg2rad(linspace(-Angle,Angle,n))';

K = 3; % Fix parameter: 4-1


%% Plot
%% 1. Bird's eye view
f = figure('Color','#AAAAAA');
ax = axes('Color','#AAAAAA');
ax.Title.String = "Bird's eye view";

text(350,350,["r:ClockWise";"e:CounterClockWise";"a:ZoomIn";"s:ZoomOut"]);
axis off
hold on

% Wall
wall = fill(ax,pos_wall(:,1),pos_wall(:,2),'k',LineStyle='none');
axis equal
ax.XLim = [0 400];
ax.YLim = [0 400];

% Player1: Position
pl = plot(ax,player.pos(1), player.pos(2),'o', ...
    MarkerFaceColor='y',MarkerEdgeColor='none',...
    MarkerSize=5);

% Player2: Arc
pl1 = plot(ax,p2(:,1),p2(:,2),'LineStyle','-', ...
    'LineWidth',1,'Color','y');

% Player3: Line segments
for ii = 1:height(p2)
    pl2(ii) = plot(ax,[player.pos(1);p2(ii,1)],...
        [player.pos(2); p2(ii,2)],'LineStyle','--', ...
        'LineWidth',1,'Color','y');
end
tmp1 = [xi;nan(height(p2)-length(xi),1)]';
tmp2 = [yi;nan(height(p2)-length(yi),1)]';

% Collision detection
pl3 =  plot(ax,tmp1,tmp2,'o', ...
    LineStyle='none', ...
    MarkerFaceColor='r',MarkerEdgeColor='none',...
    MarkerSize=5);
hold off


%% 2. First person perspective
f_FPS   = figure('Color','#AAAAAA');
ax_FPS  = axes('Color','#AAAAAA');
ax_FPS.Title.String = "First person perspective";
hold on

pl_FPS_p  = stem(ax_FPS,-Wallx,Wally./2,'Marker','none','LineWidth',round(m/n),'Color','w');
pl_FPS_n  = stem(ax_FPS,-Wallx,-Wally./2,'Marker','none','LineWidth',round(m/n),'Color','w');
ax_FPS.XLim = [-(height(Wallx)+1) 0];

% Wall Max Height
ax_FPS.YLim = [-1 1].*K*2;

% Visualise
ax_FPS.XTick = [];
ax_FPS.YTick = [];
ax_FPS.XAxis.Color = 'none';
ax_FPS.YAxis.Color = 'none';
hold off


%% Trigger
f.WindowButtonDownFcn   = @motion;
f.WindowButtonUpFcn     = @motion;
f.KeyPressFcn           = @rotation;



%% Nested function
%% Rotation
    function rotation(src,data,eventdata)
        if strcmp(data.Key,'r')
            th = th + deg2rad(dAngle);
        elseif strcmp(data.Key,'e')
            th = th - deg2rad(dAngle);
        end

        if strcmp(data.Key,'a')
            r = r + 10;
        elseif strcmp(data.Key,'s')
            r = r - 10;
        end

        v = r*[cos(th),sin(th)];
        movepoint;
    end
%% Mouse Click
    function motion(src,data,eventdata)
        if strcmp(data.EventName,'WindowMousePress')
            f.WindowButtonMotionFcn = @movepoint;
        else
            f.WindowButtonMotionFcn = '';
        end
    end

%% Position update
    function movepoint(src,data)
        pos = get(gca,'CurrentPoint');
        pl.XData        = pos(1,1);
        pl.YData        = pos(1,2);
        pl1.XData       = v(:,1) + pl.XData;
        pl1.YData       = v(:,2) + pl.YData;

        player.pos      = pos(1,1:2);
        p2              = [pl1.XData; pl1.YData]';
        Cross;
        
        for ii = 1:length(pl2)
            pl2(ii).XData   = [0, v(ii,1)] + pl.XData;
            pl2(ii).YData   = [0, v(ii,2)] + pl.YData;
        end
    end

%% Collision detection
    function Cross
        x = reshape(([repelem(player.pos(1),height(p2))',p2(:,1),nan(height(p2),1) ])',[],1);
        y = reshape(([repelem(player.pos(2),height(p2))',p2(:,2),nan(height(p2),1) ])',[],1);
        [xi,yi,kk] = polyxpoly(x,y,pos_wall(:,1),pos_wall(:,2));

        % Vector from plyer to cross point
        tmp = [xi,yi] - player.pos;

        % extract more closer point when line segment has 2 cross points
        tmp = [xi, yi, (tmp(:,1).^2+tmp(:,2).^2), kk(:,1), false(length(xi),1)];
        t1 = unique(tmp(:,4));
        for jj = 1:length(t1)
            MIN_tmp  = min(tmp(tmp(:,4) == t1(jj),3));
            tmp( (tmp(:,4)==t1(jj)) & (tmp(:,3)==MIN_tmp) ,end) = true;
        end

        % point y
        idx = tmp(:,end)==true;

        % extract xi and yi
        tmp = tmp(idx,[1:4]);
        [~,I] = sort(tmp(:,4));

        tmp = tmp(I,:);
        xi = tmp(:,1);
        yi = tmp(:,2);

        idx2 = ismember(dummy,tmp(:,4));

        Wallx = (1:height(p2))';
        Wally = nan(height(p2),1);
        Wally(find(idx2)) = sqrt(tmp(:,3)./r.^2); %norm length
        Wally = Wally.*cos(th2);

        pl_FPS_p.YData = K./Wally./2;
        pl_FPS_n.YData = -K./Wally./2;

        pl3.XData = [xi;nan(height(p2)-length(xi),1)]';
        pl3.YData = [yi;nan(height(p2)-length(yi),1)]';
    end
end