Module vec2
Represents a 2D vector in Lua.
This module allows you to manipulate 2D vectors. Usage is generally as follows:
my_vec = vec2.new( 3, 2 ) -- my_vec is now (3,2) my_vec:add( 5, 3 ) -- my_vec is now (8,5) my_vec = my_vec * 3 -- my_vec is now (24,15) your_vec = vec2.new( 5, 2 ) -- your_vec is now (5,2) my_vec = my_vec - your_vec -- my_vec is now (19,13)
To call members of the metatable always use:
vector:function( param )
Functions
| new ([x=0[, y=x]]) | Creates a new vector. |
| newP ([m=0[, a=0]]) | Creates a new vector using polar coordinates. |
| copy (v) | Copies a vector. |
| __tostring (v) | Converts a vector to a string. |
| add (v, x, y) | Adds two vectors or a vector and some cartesian coordinates. |
| sub (v, x, y) | Subtracts two vectors or a vector and some cartesian coordinates. |
| mul (v, mod) | Multiplies a vector by a number. |
| div (v, mod) | Divides a vector by a number. |
| dot (a, b) | Dot product of two vectors. |
| cross (a, b) | Cross product of two vectors. |
| get (v) | Gets the cartesian positions of the vector. |
| polar (v) | Gets polar coordinates of a vector. |
| set (v, x, y) | Sets the vector by cartesian coordinates. |
| setP (v, m, a) | Sets the vector by polar coordinates. |
| dist (v[, v2=vec2.new()]) | Gets the distance from the Vec2. |
| dist2 (v[, v2=vec2.new()]) | Gets the squared distance from the Vec2 (saves a sqrt()) |
| mod (v) | Gets the modulus of the vector. |
| angle (v) | Gets the angle of the vector. |
| normalize (v[, n=1]) | Normalizes a vector. |
| collideLineLine (s1, e1, s2, e2) | Sees if two line segments collide. |
| collideCircleLine (center, radius, p1, p2) | Computes the intersection of a line segment and a circle. |
Functions
- new ([x=0[, y=x]])
-
Creates a new vector.
Parameters:
- x number If set, the X value for the new vector. (default 0)
- y number If set, the Y value for the new vector. (default x)
Returns:
-
Vec2
The new vector.
Usage:
vec2.new( 5, 3 ) -- creates a vector at (5,3)
vec2.new() -- creates a vector at (0,0)
- newP ([m=0[, a=0]])
-
Creates a new vector using polar coordinates.
Parameters:
- m number If set, the modulus for the new vector. (default 0)
- a number If set, the angle for the new vector, in radians. (default 0)
Returns:
-
Vec2
The new vector.
Usage:
vec2.newP( 1000, 90 ) -- creates a vector at (0,1000)
vec2.newP() -- creates a vector at (0,0)
- copy (v)
-
Copies a vector.
Parameters:
- v Vec2 Vector to copy.
Returns:
-
Vec2
A copy of v.
- __tostring (v)
-
Converts a vector to a string.
Parameters:
- v Vector Vector to convert to as string.
Returns:
-
string
String version of v.
- add (v, x, y)
-
Adds two vectors or a vector and some cartesian coordinates.
If x is a vector it adds both vectors, otherwise it adds cartesian coordinates to the vector.
Parameters:
- v Vector Vector getting stuff added to.
- x number or Vec2 X coordinate or vector to add to.
- y number or nil Y coordinate or nil to add to.
Returns:
-
Vec2
The result of the vector operation.
Usage:
my_vec = my_vec + your_vec
my_vec:add( your_vec )
my_vec:add( 5, 3 )
- sub (v, x, y)
-
Subtracts two vectors or a vector and some cartesian coordinates.
If x is a vector it subtracts both vectors, otherwise it subtracts cartesian coordinates to the vector.
Parameters:
- v Vec2 Vector getting stuff subtracted from.
- x number or Vec2 X coordinate or vector to subtract.
- y number or nil Y coordinate or nil to subtract.
Returns:
-
Vec2
The result of the vector operation.
Usage:
my_vec = my_vec - your_vec
my_vec:sub( your_vec )
my_vec:sub( 5, 3 )
- mul (v, mod)
-
Multiplies a vector by a number.
Parameters:
- v Vec2 Vector to multiply.
- mod number Amount to multiply by.
Returns:
-
Vec2
The result of the vector operation.
Usage:
my_vec = my_vec * 3
my_vec:mul( 3 )
- div (v, mod)
-
Divides a vector by a number.
Parameters:
- v Vec2 Vector to divide.
- mod number Amount to divide by.
Returns:
-
Vec2
The result of the vector operation.
Usage:
my_vec = my_vec / 3
my_vec:div(3)
- dot (a, b)
-
Dot product of two vectors.
Parameters:
- a Vec2 First vector.
- b Vec2 Second vector.
Returns:
-
number
The dot product.
- cross (a, b)
-
Cross product of two vectors.
Parameters:
- a Vec2 First vector.
- b Vec2 Second vector.
Returns:
-
number
The cross product.
- get (v)
-
Gets the cartesian positions of the vector.
Parameters:
- v Vec2 Vector to get position of.
Returns:
- number X position of the vector.
- number Y position of the vector.
Usage:
x,y = my_vec:get()
- polar (v)
-
Gets polar coordinates of a vector.
The angle is in radians.
Parameters:
- v Vec2 Vector to get polar coordinates of.
Returns:
- number The modulus of the vector.
- number The angle of the vector.
Usage:
modulus, angle = my_vec:polar()
- set (v, x, y)
-
Sets the vector by cartesian coordinates.
Parameters:
- v Vec2 Vector to set coordinates of.
- x number X coordinate to set.
- y number Y coordinate to set.
Usage:
my_vec:set(5, 3) -- my_vec is now (5,3)
- setP (v, m, a)
-
Sets the vector by polar coordinates.
Parameters:
- v Vec2 Vector to set coordinates of.
- m number Modulus to set.
- a number Angle to set, in radians.
Usage:
my_vec:setP( 1, 90 ) -- my_vec is now (0,1)
- dist (v[, v2=vec2.new()])
-
Gets the distance from the Vec2.
Parameters:
- v Vec2 Vector to act as origin.
- v2 Vec2 Vector to get distance from, uses origin (0,0) if not set. (default vec2.new())
Returns:
-
number
The distance calculated.
Usage:
my_vec:dist() -- Gets length of the vector (distance from origin).
my_vec:dist( your_vec ) -- Gets distance from both vectors (your_vec - my_vec).
- dist2 (v[, v2=vec2.new()])
-
Gets the squared distance from the Vec2 (saves a sqrt())
Parameters:
- v Vec2 Vector to act as origin.
- v2 Vec2 Vector to get squared distance from, uses origin (0,0) if not set. (default vec2.new())
Returns:
-
number
The distance calculated.
Usage:
my_vec:dist2() -- Gets squared length of the vector (distance squared from origin).
my_vec:dist2( your_vec ) -- Gets squared distance from both vectors (your_vec - my_vec)^2.
- mod (v)
-
Gets the modulus of the vector.
Parameters:
- v Vec2 Vector to get modulus of.
Returns:
-
number
The modulus of the vector.
- angle (v)
-
Gets the angle of the vector.
Parameters:
- v Vec2 Vector to get angle of.
Returns:
-
number
The angle of the vector.
- normalize (v[, n=1])
-
Normalizes a vector.
Parameters:
- v Vec2 Vector to normalize.
- n number Length to normalize the vector to. (default 1)
Returns:
-
Vec2
Normalized vector.
- collideLineLine (s1, e1, s2, e2)
-
Sees if two line segments collide.
Parameters:
- s1 Vec2 Start point of the first segment.
- e1 Vec2 End point of the first segment.
- s2 Vec2 Start point of the second segment.
- e2 Vec2 End point of the second segment.
Returns:
-
integer
0 if they don't collide, 1 if they collide on a point,
2 if they are parallel, and 3 if they are coincident.
- collideCircleLine (center, radius, p1, p2)
-
Computes the intersection of a line segment and a circle.
Parameters:
- center Vector Center of the circle.
- radius number Radius of the circle.
- p1 Vector First point of the line segment.
- p2 Vector Second point of the line segment.
Returns:
- Vector or nil First point of collision or nil if no collision.
- Vector or nil Second point of collision or nil if single-point collision.