Field of view (or fog of war)

[darkfrei]

Hi all!

There is my try to make the field-of view in Lua.
Issue: the diagonal walls are transparent.

Use WASD to move the green point.




If uses the diagonal marching, the worth points are on the crossings of line, between source and target midpoints and diagonals of every tile.
Exactly one point per tile and all tiles have a point (except 45 degree lines).

[darkfrei]

Second version:
fixed bugs, the diagonal wall is not more transparent;
the field of view is round;
the seen tiles have another color.

[paco72]

Very nice work!

[darkfrei]

Diagonal Marching

Code: Select all

-- License CC0 (Creative Commons license) (c) darkfrei, 2023
function getDiagonalMarch(angle)
    local dx, dy = math.cos(angle), math.sin(angle)
    local k = 1 / (math.abs(dx) + math.abs(dy))
    return dx * k, dy * k, k
end

2023-03-31.png (47.67 KiB) Viewed 1927 times

[GVovkiv]

link to video is probably broken

[darkfrei]

link to video is probably broken

Thanks, probably fixed.

Also, the math for factor k:
dx + dy is always 1;
atan2 (dy, dx) is always as given angle.
But normally the cos (angle) + sin (angle) cannot always give the 1, but the squared cos and sin functions.

So we are need to make the factor k, that will be used to make dx+dy=1 to be true.
It give us the dx and dy distances between diagonals. With this steps dx and dy you can march by all diagonals and step every tile just once, but every tile (it works 100% if you are in the diagonals crossings or on the diagonal that is more perpendicular to your movement).

https://www.desmos.com/calculator/0h3tavpxmw

2023-03-31T14_27_12-Desmos _ Grafik-Rechner.png (187.45 KiB) Viewed 1918 times

https://www.desmos.com/calculator/lu0axfvswn

2023-03-31T14_43_43-Desmos _ Grafik-Rechner.png (170.44 KiB) Viewed 1902 times

Code: Select all

function getDiagonalMarch(angle)
	local nx, ny = math.cos(angle), math.sin(angle)
	local k = 1 / (math.abs(nx) + math.abs(ny))
	return nx * k, ny * k, k
end