mirror of
https://github.com/appgurueu/modlib.git
synced 2024-08-19 21:04:13 +02:00
147 lines
3.8 KiB
Lua
147 lines
3.8 KiB
Lua
-- Localize globals
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local math, modlib, pairs, unpack, vector = math, modlib, pairs, unpack, vector
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-- Set environment
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local _ENV = {}
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setfenv(1, _ENV)
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-- TODO OOP, extend vector
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function from_euler_rotation(rotation)
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rotation = vector.divide(rotation, 2)
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local cos = vector.apply(rotation, math.cos)
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local sin = vector.apply(rotation, math.sin)
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return {
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sin.z * cos.x * cos.y - cos.z * sin.x * sin.y,
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cos.z * sin.x * cos.y + sin.z * cos.x * sin.y,
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cos.z * cos.x * sin.y - sin.z * sin.x * cos.y,
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cos.z * cos.x * cos.y + sin.z * sin.x * sin.y
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}
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end
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function multiply(self, other)
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return {
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other[1] * self[1] - other[2] * self[2] - other[3] * self[3] - other[4] * self[4],
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other[1] * self[2] + other[2] * self[1] - other[3] * self[4] + other[4] * self[3],
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other[1] * self[3] + other[2] * self[4] + other[3] * self[1] - other[4] * self[2],
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other[1] * self[4] - other[2] * self[3] + other[3] * self[2] + other[4] * self[1]
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}
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end
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function normalize(self)
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local len = math.sqrt(self[1] ^ 2 + self[2] ^ 2 + self[3] ^ 2 + (self[4] ^ 4))
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local res = {}
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for key, value in pairs(self) do
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res[key] = value / len
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end
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return res
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end
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function conjugate(self)
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return {
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-self[1],
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-self[2],
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-self[3],
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self[4]
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}
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end
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function inverse(self)
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return modlib.vector.divide_scalar(conjugate(self), self[1] ^ 2 + self[2] ^ 2 + self[3] ^ 2 + self[4] ^ 2)
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end
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function negate(self)
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for key, value in pairs(self) do
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self[key] = -value
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end
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end
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function dot(self, other)
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return self[1] * other[1] + self[2] * other[2] + self[3] * other[3] + self[4] * other[4]
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end
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--: self normalized quaternion
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--: other normalized quaternion
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function slerp(self, other, ratio)
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local d = dot(self, other)
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if d < 0 then
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d = -d
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negate(other)
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end
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-- Threshold beyond which linear interpolation is used
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if d > 1 - 1e-10 then
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return modlib.vector.interpolate(self, other, ratio)
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end
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local theta_0 = math.acos(d)
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local theta = theta_0 * ratio
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local sin_theta = math.sin(theta)
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local sin_theta_0 = math.sin(theta_0)
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local s_1 = sin_theta / sin_theta_0
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local s_0 = math.cos(theta) - d * s_1
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return modlib.vector.add(modlib.vector.multiply_scalar(self, s_0), modlib.vector.multiply_scalar(other, s_1))
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end
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--> axis, angle
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function to_axis_angle(self)
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local axis = modlib.vector.new{self[1], self[2], self[3]}
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local len = axis:length()
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-- HACK invert axis for correct rotation in Minetest
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return len == 0 and axis or axis:divide_scalar(-len), 2 * math.atan2(len, self[4])
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end
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--> {x = pitch, y = yaw, z = roll} euler rotation in degrees
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function to_euler_rotation(self)
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local rotation = {}
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local sinr_cosp = 2 * (self[4] * self[1] + self[2] * self[3])
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local cosr_cosp = 1 - 2 * (self[1] ^ 2 + self[2] ^ 2)
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rotation.x = math.atan2(sinr_cosp, cosr_cosp)
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local sinp = 2 * (self[4] * self[2] - self[3] * self[1])
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if sinp <= -1 then
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rotation.y = -math.pi/2
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elseif sinp >= 1 then
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rotation.y = math.pi/2
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else
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rotation.y = math.asin(sinp)
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end
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local siny_cosp = 2 * (self[4] * self[3] + self[1] * self[2])
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local cosy_cosp = 1 - 2 * (self[2] ^ 2 + self[3] ^ 2)
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rotation.z = math.atan2(siny_cosp, cosy_cosp)
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return vector.apply(rotation, math.deg)
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end
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-- See https://github.com/zaki/irrlicht/blob/master/include/quaternion.h#L652
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function to_euler_rotation_irrlicht(self)
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local x, y, z, w = unpack(self)
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local test = 2 * (y * w - x * z)
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local function _calc()
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if math.abs(test - 1) <= 1e-6 then
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return {
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z = -2 * math.atan2(x, w),
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x = 0,
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y = math.pi/2
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}
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end
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if math.abs(test + 1) <= 1e-6 then
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return {
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z = 2 * math.atan2(x, w),
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x = 0,
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y = math.pi/-2
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}
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end
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return {
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z = math.atan2(2 * (x * y + z * w), x ^ 2 - y ^ 2 - z ^ 2 + w ^ 2),
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x = math.atan2(2 * (y * z + x * w), -x ^ 2 - y ^ 2 + z ^ 2 + w ^ 2),
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y = math.asin(math.min(math.max(test, -1), 1))
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}
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end
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return vector.apply(_calc(), math.deg)
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end
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-- Export environment
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return _ENV |