function [ angle tf vp R] = look_down( phi, f, sz, hallpts )
%UNTITLED2 Summary of this function goes here
%   Detailed explanation goes here

theta = phi*pi/180;
vi = [1 0 0];
vk = [0 sin(theta) cos(theta)];
% vi = [0 0 -1];
% vk = [-1 0 0];
vj = cross(vk,vi);

A1 = [ 1 0 -sz(2)/2; 0 1 -sz(1)/2; 0 0 -f];
R = [vi; vj; vk];

T1 = R*A1;

newcp = [0 0]';

% First entry is -600 for script 8, but +600 for earlier scripts.
% Maybe the rotation matrix above is not defined quite right
M = [ 600 0 0; 0 -600 0; 0 0 1]*[eye(2,2) -newcp ;  0 0 1];
T = M*T1;

tf = maketform('projective',T');

pts = tformfwd(tf,hallpts(:,1),hallpts(:,2));


angle = cross2d(pts(1:2,:),pts(3:4,:));

vp = intersect(pts(1:2,:),pts(3:4,:));


end

Published with MATLAB® 7.14