function to discretize a line between two points

following are the two questions I have to do.

I did the first one and it does not look right. following is the code

function [points] = discretizeLine(p1, p2, stepsize) 

dt = stepsize;

theta = atan2(p2(1,2)-p1(1,2),p2(1,1)-p1(1,1));
i_comp = dt * cos(theta);
j_comp = dt * sin(theta);

i=0;
    while(1)
        points(i+1,1) = p1(1,1) + i_comp * i;
        points(i+1,2) = p1(1,2) + j_comp * i;
        i = i+1;
            if((abs(p1(1,1) + i_comp * i-p2(1,1)) < abs(i_comp))||(abs(p1(1,2)+j_comp*i-p2(1,2))<abs(j_comp)))
            break;
            end
    end
end

please help me with these two questions thanks!

Answer 1

[Victor Parry]

just took me a few hours to answer this 5 yo question, but at least it works now.

function [points] = discretizeLine(p1, p2, stepsize) 
dt = stepsize;
theta = atan2(p2(1,2)-p1(1,2),p2(1,1)-p1(1,1));
i_comp = dt * cos(theta);
j_comp = dt * sin(theta);
deltadist = [i_comp,j_comp];
i=0;
    while(1)
        points(i+1,1) = p1(1,1) + i_comp * i;
        points(i+1,2) = p1(1,2) + j_comp * i;
        i = i+1;
            if(abs(p1+i*deltadist-p2)<=abs(deltadist)) %((abs(p1(1,1) + i_comp * i-p2(1,1)) < abs(i_comp))||(abs(p1(1,2)+j_comp*i-p2(1,2))<abs(j_comp)))
            break;
            end
    end
end

[Russell Niven]

This is great! However, it breaks when you have a perfectly horizontal line, assuming since arctan(90)= undefined)

[Torsten]

p0 = [0,0];
p1 = [1,1];
stepsize = 0.1;
t = (0:stepsize:1).';
points = [(1-t)*p0(1) + t*p1(1),(1-t)*p0(2) + t*p1(2)]

points = 11×2

0 0 0.1000 0.1000 0.2000 0.2000 0.3000 0.3000 0.4000 0.4000 0.5000 0.5000 0.6000 0.6000 0.7000 0.7000 0.8000 0.8000 0.9000 0.9000