world angle of bone?

[davoodice2]

hi?
how can i achieve that?

[hayasidist]

2d case : i.e. no rotation about x/y

for a root bone (i.e. one without a parent) bone.fAngle is absolute; for a child bone bone.fAngle is relative to its parent so (e.g.) two bones - one root, one child - pointing down will have angles 270 and 0 respectively.

those are relative to the layer; so if (e.g.) the layer is rotated in z by (say) 90 then bone.fAngle is unchanged, but the bone will be pointing to the right - i.e. world 90+270 (or that mod 360 = 0)

[davoodice2]

2d case : i.e. no rotation about x/y

for a root bone (i.e. one without a parent) bone.fAngle is absolute; for a child bone bone.fAngle is relative to its parent so (e.g.) two bones - one root, one child - pointing down will have angles 270 and 0 respectively.

those are relative to the layer; so if (e.g.) the layer is rotated in z by (say) 90 then bone.fAngle is unchanged, but the bone will be pointing to the right - i.e. world 90+270 (or that mod 360 = 0)

that means I must calculate sum of all rotations ?
is there shortway? or function?
and how to define a vector that doesn't start from 0,0

[hayasidist]

depends what you're trying to do ... you might find that a bone transform matrix (fRest or fMoved) will do what you want -- or you might find it makes sense to use a Matrix to accumulate the rotations and translations.

as for vectors that don't start from {0,0} ... well at the risk of totally misunderstanding what you're thinking here ... an LM_Vector2 has an x value and y value, so if you want your vector to start at {X0, Y0} and go to {X1, Y1} you can store those two vectors exactly like that - or if you have a vector that is {dX, dY} wrt {0,0} then X1=X0+dX, Y1=Y0+dY - either store dX,dY and remember to add - or add and store the result

[davoodice2]

depends what you're trying to do ... you might find that a bone transform matrix (fRest or fMoved) will do what you want -- or you might find it makes sense to use a Matrix to accumulate the rotations and translations.

as for vectors that don't start from {0,0} ... well at the risk of totally misunderstanding what you're thinking here ... an LM_Vector2 has an x value and y value, so if you want your vector to start at {X0, Y0} and go to {X1, Y1} you can store those two vectors exactly like that - or if you have a vector that is {dX, dY} wrt {0,0} then X1=X0+dX, Y1=Y0+dY - either store dX,dY and remember to add - or add and store the result

thanks. i will some test . i'll come back with more questions