4 function vector.new(a, b, c)
5 if type(a) == "table" then
6 assert(a.x and a.y and a.z, "Invalid vector passed to vector.new()")
7 return {x=a.x, y=a.y, z=a.z}
9 assert(b and c, "Invalid arguments for vector.new()")
10 return {x=a, y=b, z=c}
12 return {x=0, y=0, z=0}
15 function vector.equals(a, b)
21 function vector.length(v)
22 return math.hypot(v.x, math.hypot(v.y, v.z))
25 function vector.normalize(v)
26 local len = vector.length(v)
28 return {x=0, y=0, z=0}
30 return vector.divide(v, len)
34 function vector.floor(v)
42 function vector.round(v)
44 x = math.floor(v.x + 0.5),
45 y = math.floor(v.y + 0.5),
46 z = math.floor(v.z + 0.5)
50 function vector.apply(v, func)
58 function vector.distance(a, b)
62 return math.hypot(x, math.hypot(y, z))
65 function vector.direction(pos1, pos2)
66 return vector.normalize({
73 function vector.angle(a, b)
74 local dotp = vector.dot(a, b)
75 local cp = vector.cross(a, b)
76 local crossplen = vector.length(cp)
77 return math.atan2(crossplen, dotp)
80 function vector.dot(a, b)
81 return a.x * b.x + a.y * b.y + a.z * b.z
84 function vector.cross(a, b)
86 x = a.y * b.z - a.z * b.y,
87 y = a.z * b.x - a.x * b.z,
88 z = a.x * b.y - a.y * b.x
92 function vector.add(a, b)
93 if type(b) == "table" then
94 return {x = a.x + b.x,
104 function vector.subtract(a, b)
105 if type(b) == "table" then
106 return {x = a.x - b.x,
116 function vector.multiply(a, b)
117 if type(b) == "table" then
118 return {x = a.x * b.x,
128 function vector.divide(a, b)
129 if type(b) == "table" then
130 return {x = a.x / b.x,
140 function vector.offset(v, x, y, z)
146 function vector.sort(a, b)
147 return {x = math.min(a.x, b.x), y = math.min(a.y, b.y), z = math.min(a.z, b.z)},
148 {x = math.max(a.x, b.x), y = math.max(a.y, b.y), z = math.max(a.z, b.z)}
151 local function sin(x)
152 if x % math.pi == 0 then
159 local function cos(x)
160 if x % math.pi == math.pi / 2 then
167 function vector.rotate_around_axis(v, axis, angle)
168 local cosangle = cos(angle)
169 local sinangle = sin(angle)
170 axis = vector.normalize(axis)
171 -- https://en.wikipedia.org/wiki/Rodrigues%27_rotation_formula
172 local dot_axis = vector.multiply(axis, vector.dot(axis, v))
173 local cross = vector.cross(v, axis)
175 cross.x * sinangle + (v.x - dot_axis.x) * cosangle + dot_axis.x,
176 cross.y * sinangle + (v.y - dot_axis.y) * cosangle + dot_axis.y,
177 cross.z * sinangle + (v.z - dot_axis.z) * cosangle + dot_axis.z
181 function vector.rotate(v, rot)
182 local sinpitch = sin(-rot.x)
183 local sinyaw = sin(-rot.y)
184 local sinroll = sin(-rot.z)
185 local cospitch = cos(rot.x)
186 local cosyaw = cos(rot.y)
187 local cosroll = math.cos(rot.z)
188 -- Rotation matrix that applies yaw, pitch and roll
191 sinyaw * sinpitch * sinroll + cosyaw * cosroll,
192 sinyaw * sinpitch * cosroll - cosyaw * sinroll,
201 cosyaw * sinpitch * sinroll - sinyaw * cosroll,
202 cosyaw * sinpitch * cosroll + sinyaw * sinroll,
206 -- Compute matrix multiplication: `matrix` * `v`
208 matrix[1][1] * v.x + matrix[1][2] * v.y + matrix[1][3] * v.z,
209 matrix[2][1] * v.x + matrix[2][2] * v.y + matrix[2][3] * v.z,
210 matrix[3][1] * v.x + matrix[3][2] * v.y + matrix[3][3] * v.z
214 function vector.dir_to_rotation(forward, up)
215 forward = vector.normalize(forward)
216 local rot = {x = math.asin(forward.y), y = -math.atan2(forward.x, forward.z), z = 0}
220 assert(vector.dot(forward, up) < 0.000001,
221 "Invalid vectors passed to vector.dir_to_rotation().")
222 up = vector.normalize(up)
223 -- Calculate vector pointing up with roll = 0, just based on forward vector.
224 local forwup = vector.rotate({x = 0, y = 1, z = 0}, rot)
225 -- 'forwup' and 'up' are now in a plane with 'forward' as normal.
226 -- The angle between them is the absolute of the roll value we're looking for.
227 rot.z = vector.angle(forwup, up)
229 -- Since vector.angle never returns a negative value or a value greater
230 -- than math.pi, rot.z has to be inverted sometimes.
231 -- To determine wether this is the case, we rotate the up vector back around
232 -- the forward vector and check if it worked out.
233 local back = vector.rotate_around_axis(up, forward, -rot.z)
235 -- We don't use vector.equals for this because of floating point imprecision.
236 if (back.x - forwup.x) * (back.x - forwup.x) +
237 (back.y - forwup.y) * (back.y - forwup.y) +
238 (back.z - forwup.z) * (back.z - forwup.z) > 0.0000001 then