317 lines
7.9 KiB
Lua
317 lines
7.9 KiB
Lua
--- A 3 component vector.
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-- @module vec3
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local sqrt = math.sqrt
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local vec3 = {}
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-- Private constructor.
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local function new(x, y, z)
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local v = {}
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v.x, v.y, v.z = x, y, z
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return setmetatable(v, vec3_mt)
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end
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-- Do the check to see if JIT is enabled. If so use the optimized FFI structs.
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local status, ffi
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if type(jit) == "table" and jit.status() then
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status, ffi = pcall(require, "ffi")
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if status then
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ffi.cdef "typedef struct { double x, y, z;} cpml_vec3;"
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new = ffi.typeof("cpml_vec3")
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end
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end
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-- Statically allocate a temporary variable used in some of our functions.
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local tmp = new(0, 0, 0)
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--- The public constructor.
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-- @param x Can be of three types: </br>
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-- number x component
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-- table {x, y, z} or {x = x, y = y, z = z}
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-- scalar to fill the vector eg. {x, x, x}
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-- @tparam number y y component
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-- @tparam number z z component
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function vec3.new(x, y, z)
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-- number, number, number
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if x and y and z then
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assert(type(x) == "number", "new: Wrong argument type for x (<number> expected)")
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assert(type(y) == "number", "new: Wrong argument type for y (<number> expected)")
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assert(type(z) == "number", "new: Wrong argument type for z (<number> expected)")
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return new(x, y, z)
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-- {x=x, y=y, z=z} or {x, y, z}
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elseif type(x) == "table" then
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local x, y, z = x.x or x[1], x.y or x[2], x.z or x[3]
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assert(type(x) == "number", "new: Wrong argument type for x (<number> expected)")
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assert(type(y) == "number", "new: Wrong argument type for y (<number> expected)")
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assert(type(z) == "number", "new: Wrong argument type for z (<number> expected)")
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return new(x, y, z)
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-- {x, x, x} eh. {0, 0, 0}, {3, 3, 3}
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elseif type(x) == "number" then
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return new(x, x, x)
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else
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return new(0, 0, 0)
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end
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end
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--- Clone a vector.
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-- @tparam vec3 a vector to be cloned
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-- @treturn vec3
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function vec3.clone(a)
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return new(a.x, a.y, a.z)
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end
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--- Add two vectors.
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-- @tparam vec3 out vector to store the result
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-- @tparam vec3 a Left hand operant
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-- @tparam vec3 b Right hand operant
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function vec3.add(out, a, b)
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out.x = a.x + b.x
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out.y = a.y + b.y
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out.z = a.z + b.z
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return out
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end
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--- Subtract one vector from another.
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-- @tparam vec3 out vector to store the result
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-- @tparam vec3 a Left hand operant
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-- @tparam vec3 b Right hand operant
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function vec3.sub(out, a, b)
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out.x = a.x - b.x
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out.y = a.y - b.y
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out.z = a.z - b.z
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return out
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end
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--- Multiply a vector by a scalar.
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-- @tparam vec3 out vector to store the result
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-- @tparam vec3 a Left hand operant
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-- @tparam number b Right hand operant
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function vec3.mul(out, a, b)
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out.x = a.x * b
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out.y = a.y * b
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out.z = a.z * b
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return out
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end
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--- Divide a vector by a scakar.
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-- @tparam vec3 out vector to store the result
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-- @tparam vec3 a Left hand operant
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-- @tparam number b Right hand operant
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function vec3.div(out, a, b)
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out.x = a.x / b
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out.y = a.y / b
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out.z = a.z / b
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return out
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end
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--- Get the normal of a vector.
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-- @tparam vec3 out vector to store the result
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-- @tparam vec3 a vector to normalize
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function vec3.normalize(out, a)
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local l = vec3.len(a)
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out.x = a.x / l
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out.y = a.y / l
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out.z = a.z / l
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return out
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end
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--- Trim a vector to a given length
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-- @tparam vec3 out vector to store the result
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-- @tparam vec3 a vector to be trimmed
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-- @tparam number len the length to trim the vector to
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function vec3.trim(out, a, len)
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len = math.min(vec3.len(a), len)
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vec3.normalize(out, a)
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vec3.mul(out, out, len)
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return out
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end
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--- Get the cross product of two vectors.
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-- @tparam vec3 out vector to store the result
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-- @tparam vec3 a Left hand operant
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-- @tparam vec3 b Right hand operant
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function vec3.cross(out, a, b)
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out.x = a.y * b.z - a.z * b.y
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out.y = a.z * b.x - a.x * b.z
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out.z = a.x * b.y - a.y * b.x
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return out
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end
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--- Get the dot product of two vectors.
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-- @tparam vec3 a Left hand operant
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-- @tparam vec3 b Right hand operant
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-- @treturn number
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function vec3.dot(a, b)
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return a.x * b.x + a.y * b.y + a.z * b.z
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end
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--- Get the length of a vector.
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-- @tparam vec3 a vector to get the length of
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-- @treturn number
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function vec3.len(a)
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return sqrt(a.x * a.x + a.y * a.y + a.z * a.z)
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end
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--- Get the squared length of a vector.
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-- @tparam vec3 a vector to get the squared length of
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-- @treturn number
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function vec3.len2(a)
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return a.x * a.x + a.y * a.y + a.z * a.z
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end
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--- Get the distance between two vectors.
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-- @tparam vec3 a first vector
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-- @tparam vec3 b second vector
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-- @treturn number
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function vec3.dist(a, b)
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local dx = a.x - b.x
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local dy = a.y - b.y
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local dz = a.z - b.z
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return sqrt(dx * dx + dy * dy + dz * dz)
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end
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--- Get the squared distance between two vectors.
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-- @tparam vec3 a first vector
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-- @tparam vec3 b second vector
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-- @treturn number
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function vec3.dist2(a, b)
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local dx = a.x - b.x
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local dy = a.y - b.y
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local dz = a.z - b.z
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return dx * dx + dy * dy + dz * dz
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end
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--- Lerp between two vectors.
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-- @tparam vec3 out vector for result to be stored in
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-- @tparam vec3 a first vector
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-- @tparam vec3 b second vector
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-- @tparam number s step value
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-- @treturn vec3
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function vec3.lerp(out, a, b, s)
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vec3.sub(out, b, a)
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vec3.mul(out, out, s)
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vec3.add(out, out, a)
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return out
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end
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--- Unpack a vector into form x,y,z
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-- @tparam vec3 a first vector
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-- @treturn number x component
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-- @treturn number y component
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-- @treturn number z component
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function vec3.unpack(a)
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return a.x, a.y, a.z
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end
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--- Return a string formatted "{x, y, z}"
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-- @tparam vec3 a the vector to be turned into a string
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-- @treturn string
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function vec3.tostring(a)
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return string.format("(%+0.3f,%+0.3f,%+0.3f)", a.x, a.y, a.z)
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end
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--- Return a boolean showing if a table is or is not a vec3
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-- @param v the object to be tested
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-- @treturn boolean
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function vec3.isvec3(v)
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return
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(
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type(v) == "table" or
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type(v) == "cdata"
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) and
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type(v.x) == "number" and
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type(v.y) == "number" and
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type(v.z) == "number"
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end
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function vec3.reflect(out, i, n)
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vec3.mul(out, n, 2.0 * vec3.dot(n, i))
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vec3.sub(out, i, out)
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return out
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end
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function vec3.refract(out, i, n, ior)
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local d = vec3.dot(n, i)
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local k = 1.0 - ior * ior * (1.0 - d * d)
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if k >= 0.0 then
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vec3.mul(out, i, ior)
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vec3.mul(tmp, n, ior * d + sqrt(k))
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vec3.sub(out, out, tmp)
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end
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return out
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end
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local vec3_mt = {}
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vec3_mt.__index = vec3
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vec3_mt.__tostring = vec3.tostring
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function vec3_mt.__call(self, x, y, z)
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return vec3.new(x, y, z)
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end
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function vec3_mt.__tostring(a)
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return vec3.tostring(a)
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end
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function vec3_mt.__unm(a)
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return vec3.new(-a.x, -a.y, -a.z)
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end
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function vec3_mt.__eq(a,b)
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assert(vec3.isvec3(a), "__eq: Wrong argument type for left hand operant. (<cpml.vec3> expected)")
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assert(vec3.isvec3(b), "__eq: Wrong argument type for right hand operant. (<cpml.vec3> expected)")
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return a.x == b.x and a.y == b.y and a.z == b.z
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end
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function vec3_mt.__add(a, b)
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assert(vec3.isvec3(a), "__add: Wrong argument type for left hand operant. (<cpml.vec3> expected)")
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assert(vec3.isvec3(b), "__add: Wrong argument type for right hand operant. (<cpml.vec3> expected)")
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return vec3.add(new(), a, b)
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end
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function vec3_mt.__sub(a, b)
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assert(vec3.isvec3(a), "__sub: Wrong argument type for left hand operant. (<cpml.vec3> expected)")
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assert(vec3.isvec3(b), "__sub: Wrong argument type for right hand operant. (<cpml.vec3> expected)")
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return vec3.sub(new(), a, b)
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end
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function vec3_mt.__mul(a, b)
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local isvecb = vec3.isvec3(b)
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a, b = isvecb and b or a, isvecb and a or b
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assert(vec3.isvec3(a), "__mul: Wrong argument type for left hand operant. (<cpml.vec3> expected)")
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assert(type(b) == "number", "__mul: Wrong argument type for right hand operant. (<number> expected)")
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return vec3.mul(new(), a, b)
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end
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function vec3_mt.__div(a, b)
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local isvecb = vec3.isvec3(b)
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a, b = isvecb and b or a, isvecb and a or b
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assert(vec3.isvec3(a), "__div: Wrong argument type for left hand operant. (<cpml.vec3> expected)")
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assert(type(b) == "number", "__div: Wrong argument type for right hand operant. (<number> expected)")
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return vec3.div(new(), a, b)
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end
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vec3.unit_x = new(1, 0, 0)
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vec3.unit_y = new(0, 1, 0)
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vec3.unit_z = new(0, 0, 1)
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if status then
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ffi.metatype(new, vec3_mt)
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end
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return setmetatable({}, vec3_mt)
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