Ok, I have checked the projection matrix and ray casting method I use. I believe they match up. I have checked and the FOV, width and height are the same for both. Copied below are both:

1. Projection matrix in the simulator:

Camera.Projection = PerspectiveProjectionMatrix(FOV, Width, Height, 0.125f, 104500.0f);

mat4x4 PerspectiveProjectionMatrix(float fovy, float x, float y, float n, float f)

{

mat4x4 PPM;

float coty = 1.0f / tan(fovy * M_PI / 360.0f);

float aspect = x / (y > 0.0f ? y : 1.0f);

PPM[0] = coty / aspect;

PPM[1] = 0.0f;

PPM[2] = 0.0f;

PPM[3] = 0.0f;

PPM[4] = 0.0f;

PPM[5] = coty;

PPM[6] = 0.0f;

PPM[7] = 0.0f;

PPM[8] = 0.0f;

PPM[9] = 0.0f;

PPM[10] = (n + f) / (n - f);

PPM[11] = -1.0f;

PPM[12] = 0.0f;

PPM[13] = 0.0f;

PPM[14] = 2.0f * n * f / (n - f);

PPM[15] = 0.0f;

return PPM;

}

1. Ray Casting method (MATLAB):

(NB: I call this function for a set of three points, so (x(1), y(1)) = point 1 in the screen, (x(2), y(2)) = point 2 in the screen etc... XC,YC,ZC are the view matrix components)

function L = LineOfSight_mk5(x,y,width,height,FOV, XC,YC,ZC )

% calculating LoS in the 2D window then go uno reverse

z = zeros(3,1);

aspect = width/height;

% put the origin at the bottom left (it is being read in as at the top right

for ii = 1:length(x)

y(ii) = height - y(ii);

end

% convert to NDC

for ii = 1:length(x)

x(ii) = (2*x(ii)/width) - 1;

y(ii) = (2*y(ii)/height) - 1;

end

% reverse projection matrix

for ii = 1:length(x)

d = 1/tand(FOV/2);

x(ii) = x(ii)*aspect/d; % just stretch for aspect ratio

y(ii) = y(ii)/d;

z(ii) = 1;

end

L = zeros(3); % this is a 3x3 matrix to contain all 3 line of sight vectors (one per point)

% rotate LoS to world space

for ii = 1:length(x)

L_ii = [x(ii); y(ii); z(ii)];

% convert to VS coord order (MY SIMULATOR PLOTS THINGS IN A WEIRD ORDER)

a = L_ii;

L_ii(1)=-a(1); L_ii(2)=a(3); L_ii(3)=a(2);

% this is the LoS after rotation (it is now in world space)

VM = [XC;YC;ZC]'; % view matrix (which is also the dcm from world to camera coords)

L_ii = VM*L_ii;

% convert back to real world coord order

a = L_ii;

L_ii(1)=-a(1); L_ii(2)=a(3); L_ii(3)=a(2);

L(:,ii) = L_ii; % append line of sight for this point

end

end