Moho curvature to bezier handles conversion

Bezier handles is not the way Moho stores keys for curvature. Handles can be obtained by M_Curve:GetControlHandle or M_Curve:GetControlPoints, but these values are not directly from channels with keys. These values may also include deformations made by smartbones.
Clean keys are stored in curvature, weight and offset subchannels of the "Point Curvature" channel, so "Point Curvature" channel has M_Curve:CountPoints * 5 subchannels, five for each point: smoothness (curvature itself), weight_in, weight_out, offset_in and offset_out.

Here is the way to convert these three values to XY coordinates of a handle.

function GetBezierHandle(curve, pointID, frame, prePoint)

    local curvature = curve:GetCurvature(pointID, frame)

    local weight = curve:GetWeight(pointID, frame, prePoint)

    local offset = curve:GetOffset(pointID, frame, prePoint)

    local pointToRange = function(p)

      if curve.fClosed then

         if p < 0 then p = curve:CountPoints()-1 end

         if p >= curve:CountPoints() then p = 0  end

      else

         if p < 0 then p = 0 end

         if p >= curve:CountPoints() then p = curve:CountPoints()-1 end    

      end

      return p    

    end

    local postPointID = pointToRange(pointID + 1)

    local prePointID = pointToRange(pointID - 1)

    local secondPointID = postPointID

    if prePoint then secondPointID = prePointID end

    if secondPointID == pointID then 

        return curve:Point(pointID).fAnimPos:GetValue(frame)

    end

    local N = curve:Point(postPointID).fAnimPos:GetValue(frame) - curve:Point(prePointID).fAnimPos:GetValue(frame)

    N:NormMe()

    if prePoint then N = N*-1 end

    local L = (curve:Point(secondPointID).fAnimPos:GetValue(frame) - curve:Point(pointID).fAnimPos:GetValue(frame)):Mag()

    L = L * curvature * weight

    local vec = N * L

    vec:Rotate(offset)

    return curve:Point(pointID).fAnimPos:GetValue(frame) + vec

end

Tags: Curvature Handles