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3D voxel raycasting example
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raycast3D = function(pos, dir, callback) | |
local base = {x=math.floor(pos.x), y=math.floor(pos.y), z=math.floor(pos.z)} | |
local stepx, stepy, stepz = 0, 0, 0 | |
local componentx, componenty, componentz = 0, 0, 0 | |
local intersectx, intersecty, intersectz = 0, 0, 0 | |
if dir.x == 0 then | |
intersectx = math.huge | |
elseif dir.x > 0 then | |
stepx = 1 | |
componentx = 1 / dir.x | |
intersectx = ((base.x - pos.x) + 1) * componentx | |
else | |
stepx = -1 | |
componentx = 1 / -dir.x | |
intersectx = (pos.x - base.x) * componentx | |
end | |
if dir.y == 0 then | |
intersecty = math.huge | |
elseif dir.y > 0 then | |
stepy = 1 | |
componenty = 1 / dir.y | |
intersecty = ((base.y - pos.y) + 1) * componenty | |
else | |
stepy = -1 | |
componenty = 1 / -dir.y | |
intersecty = (pos.y - base.y) * componenty | |
end | |
if dir.z == 0 then | |
intersectz = math.huge | |
elseif dir.z > 0 then | |
stepz = 1 | |
componentz = 1 / dir.z | |
intersectz = ((base.z - pos.z) + 1) * componentz | |
else | |
stepz = -1 | |
componentz = 1 / -dir.z | |
intersectz = (pos.z - base.z) * componentz | |
end | |
local distance = 0 | |
local nearest = {x=base.x, y=base.y, z=base.z} | |
while true do | |
local values = {callback(base, nearest, distance)} | |
if #values > 0 then | |
return unpack(values) | |
end | |
nearest.x, nearest.y, nearest.z = base.x, base.y, base.z | |
if intersectx < intersecty then | |
if intersectx < intersectz then | |
base.x = base.x + stepx | |
distance = intersectx | |
intersectx = intersectx + componentx | |
else | |
base.z = base.z + stepz | |
distance = intersectz | |
intersectz = intersectz + componentz | |
end | |
elseif intersecty < intersectz then | |
base.y = base.y + stepy | |
distance = intersecty | |
intersecty = intersecty + componenty | |
else | |
base.z = base.z + stepz | |
distance = intersectz | |
intersectz = intersectz + componentz | |
end | |
end | |
end |
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