多边形和顶点

Question

您好，我只是想在Matlab中编写一个背面剔除功能，因为我不确定如何最好地获取多边形列表，因此很难。

我希望能够从“顶点矩阵”和“面矩阵”开始，并以某种方式获得一种结构，在该结构中，我有一个对象之类的列表，其中包含可以迭代的多边形。下面是我对特定已知矩阵V和F非常幼稚的方法。

%Vertices Matrix
V = [0.5,-0.86,0.36,-0.5;
    -0.5,-0.36,0.86,0.05;
    10.71,9.65,9.65,10.71;];

% Faces Matrix
F = [1,2,3;
    2,4,3;
    3,4,1;
    1,4,2;];

% Camera Position
P = [1,1,2]';

% Getting Size of F to inform us of the number of polygons
% Currently useless as the program is very specific
[n,m] = size(F);

% Defining Polygons from Faces and vertices
Poly1 = [V(:,1),V(:,2),V(:,3)];
Poly2 = [V(:,2),V(:,4),V(:,3)];
Poly3 = [V(:,3),V(:,4),V(:,1)];
Poly4 = [V(:,1),V(:,4),V(:,2)];

% Trying to create some sort of polygon list not sure how to automate
% this from just V and F.
Polygons = [];
Polygons(:,:,1) = Poly1;
Polygons(:,:,2) = Poly2;
Polygons(:,:,3) = Poly3;
Polygons(:,:,4) = Poly4;

% Call Function
BackFaceCull(Polygons,P,n)




function F = BackFaceCull(Polygons,P,n)
    % Front Facing Polygons
    F = [];
    % So we can label Polygons A-Z (Though in practise we would not use
    % However for my use will be very simple set ups with less than 25
    % Objects
    k = 65;

    for i = 1:n
        % Create each point on polygon 
        Polygon = Polygons(:,:,i);
        P1 = Polygon(:,1);
        P2 = Polygon(:,2);
        P3 = Polygon(:,3);
        % Find the Normal for this polygon
        N = cross((P2 -P1),(P3-P2));
        % Find the centre of the polygon ( Triangle) What if it's not a
        % triangle?
        C = Centroid(P1,P2,P3);
        % Apply Test for if forward facing if so add associated polygon
        %letter to Front list
        if dot((C-P),N) < 0
            F = [F char(k)];
        end
        % update k
        k = k+1;
    end            
end


function C = Centroid(p1,p2,p3)
P1 = (p1(1)+p2(1)+p3(1))/3;
P2 = (p1(2)+p2(2)+p3(2))/3;
P3 = (p1(3)+p2(3)+p3(3))/3;

C = [P1,P2,P3]';
end

TLDR：我要如何在Matlab中实现背面剔除算法，前提是矩阵V包含所有顶点，矩阵F包含绘制顶点的顶点。