mirror of
https://github.com/appgurueu/modlib.git
synced 2024-07-07 08:35:15 +02:00
72 lines
2.1 KiB
Lua
72 lines
2.1 KiB
Lua
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 + (q[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 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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--> {x, y, z} 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] * self[1] + self[2] * self[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] * self[2] + self[3] * self[3])
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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 |