DriftEngineAnimation · function
solveTwoBone
Reach target with the chain root → mid → tip, writing the two rotations into pose.
Explained in Animation.
function solveTwoBone(skeleton: Skeleton, pose: Pose, root: number, mid: number, tip: number, target: ArrayLike<number>, poleHint: ArrayLike<number>): booleanimport { solveTwoBone } from '@driftengine/animation';Parameters
| Parameter | Type | Description |
|---|---|---|
skeleton | Skeleton | |
pose | Pose | |
root | number | |
mid | number | |
tip | number | |
target | ArrayLike<number> | |
poleHint | ArrayLike<number> |
In depth
Returns whether the target was reachable. An unreachable one straightens the chain toward it, which is the behaviour a limb should have: an arm reaching for something too far away extends, it does not give up or fold.
poleHint decides the one thing the target cannot — which way the joint bends. A world-space
point or direction the mid joint should lean toward; without it, a chain that is already
straight has no plane to bend in and the elbow would flip unpredictably as a character turned.
The skeleton's world matrices are refreshed as it goes, so they are current when this returns.