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Godot 3.x backport: Fix for SkeletonIK not working correctly with 0 interpolation and incorrectly rotating with animation. Now the root bone rotates differently to ensure it always rotates correctly and works with BoneAttachment nodes.

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This commit is contained in:
TwistedTwigleg 2021-04-08 18:45:54 -04:00
parent e3c59bf0ff
commit 9c33f091cd
2 changed files with 71 additions and 17 deletions
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86
scene/animation/skeleton_ik.cpp
View file

@ -267,6 +267,18 @@ void FabrikInverseKinematic::make_goal(Task *p_task, const Transform &p_inverse_
void FabrikInverseKinematic::solve(Task *p_task, real_t blending_delta, bool override_tip_basis, bool p_use_magnet, const Vector3 &p_magnet_position) {
if (blending_delta <= 0.01f) {
// Before skipping, make sure we undo the global pose overrides
ChainItem *ci(&p_task->chain.chain_root);
while (ci) {
p_task->skeleton->set_bone_global_pose_override(ci->bone, ci->initial_transform, 0.0, false);
if (!ci->children.empty()) {
ci = &ci->children.write[0];
} else {
ci = nullptr;
}
}
return; // Skip solving
}
@ -281,8 +293,8 @@ void FabrikInverseKinematic::solve(Task *p_task, real_t blending_delta, bool ove
}
// Update the initial root transform
p_task->chain.chain_root.initial_transform = p_task->skeleton->get_bone_global_pose(p_task->chain.chain_root.bone);
p_task->chain.chain_root.current_pos = p_task->chain.chain_root.initial_transform.origin;
// (Needed to sync IK with animation)
_update_chain(p_task->skeleton, &p_task->chain.chain_root);
make_goal(p_task, p_task->skeleton->get_global_transform().affine_inverse(), blending_delta);
@ -298,23 +310,49 @@ void FabrikInverseKinematic::solve(Task *p_task, real_t blending_delta, bool ove
Transform new_bone_pose(ci->initial_transform);
new_bone_pose.origin = ci->current_pos;
if (!ci->children.empty()) {
/// Rotate basis
const Vector3 initial_ori((ci->children[0].initial_transform.origin - ci->initial_transform.origin).normalized());
const Vector3 rot_axis(initial_ori.cross(ci->current_ori).normalized());
if (rot_axis[0] != 0 && rot_axis[1] != 0 && rot_axis[2] != 0) {
const real_t rot_angle(Math::acos(CLAMP(initial_ori.dot(ci->current_ori), -1, 1)));
new_bone_pose.basis.rotate(rot_axis, rot_angle);
// The root bone needs to be rotated differently so it isn't frozen in place
if (ci == &p_task->chain.chain_root && !ci->children.empty()) {
new_bone_pose = new_bone_pose.looking_at(ci->children[0].current_pos, Vector3(0, 1, 0));
const Vector3 bone_rest_dir = p_task->skeleton->get_bone_rest(ci->children[0].bone).origin.normalized().abs();
const Vector3 bone_rest_dir_abs = bone_rest_dir.abs();
if (bone_rest_dir_abs.x > bone_rest_dir_abs.y && bone_rest_dir_abs.x > bone_rest_dir_abs.z) {
if (bone_rest_dir.x < 0) {
new_bone_pose.basis.rotate_local(Vector3(0, 1, 0), -Math_PI / 2.0f);
} else {
new_bone_pose.basis.rotate_local(Vector3(0, 1, 0), Math_PI / 2.0f);
}
} else if (bone_rest_dir_abs.y > bone_rest_dir_abs.x && bone_rest_dir_abs.y > bone_rest_dir_abs.z) {
if (bone_rest_dir.y < 0) {
new_bone_pose.basis.rotate_local(Vector3(1, 0, 0), Math_PI / 2.0f);
} else {
new_bone_pose.basis.rotate_local(Vector3(1, 0, 0), -Math_PI / 2.0f);
}
} else {
if (bone_rest_dir.z < 0) {
// Do nothing!
} else {
new_bone_pose.basis.rotate_local(Vector3(0, 0, 1), Math_PI);
}
}
} else {
// Set target orientation to tip
if (override_tip_basis)
new_bone_pose.basis = p_task->chain.tips[0].end_effector->goal_transform.basis;
else
new_bone_pose.basis = new_bone_pose.basis * p_task->chain.tips[0].end_effector->goal_transform.basis;
if (!ci->children.empty()) {
/// Rotate basis
const Vector3 initial_ori((ci->children[0].initial_transform.origin - ci->initial_transform.origin).normalized());
const Vector3 rot_axis(initial_ori.cross(ci->current_ori).normalized());
if (rot_axis[0] != 0 && rot_axis[1] != 0 && rot_axis[2] != 0) {
const real_t rot_angle(Math::acos(CLAMP(initial_ori.dot(ci->current_ori), -1, 1)));
new_bone_pose.basis.rotate(rot_axis, rot_angle);
}
} else {
// Set target orientation to tip
if (override_tip_basis)
new_bone_pose.basis = p_task->chain.tips[0].end_effector->goal_transform.basis;
else
new_bone_pose.basis = new_bone_pose.basis * p_task->chain.tips[0].end_effector->goal_transform.basis;
}
}
// IK should not affect scale, so undo any scaling
@ -330,6 +368,20 @@ void FabrikInverseKinematic::solve(Task *p_task, real_t blending_delta, bool ove
}
}
void FabrikInverseKinematic::_update_chain(const Skeleton *p_sk, ChainItem *p_chain_item) {
if (!p_chain_item) {
return;
}
p_chain_item->initial_transform = p_sk->get_bone_global_pose(p_chain_item->bone);
p_chain_item->current_pos = p_chain_item->initial_transform.origin;
ChainItem *items = p_chain_item->children.ptrw();
for (int i = 0; i < p_chain_item->children.size(); i += 1) {
_update_chain(p_sk, items + i);
}
}
void SkeletonIK::_validate_property(PropertyInfo &property) const {
if (property.name == "root_bone" || property.name == "tip_bone") {

2
scene/animation/skeleton_ik.h
View file

@ -131,6 +131,8 @@ public:
static void set_goal(Task *p_task, const Transform &p_goal);
static void make_goal(Task *p_task, const Transform &p_inverse_transf, real_t blending_delta);
static void solve(Task *p_task, real_t blending_delta, bool override_tip_basis, bool p_use_magnet, const Vector3 &p_magnet_position);
static void _update_chain(const Skeleton *p_skeleton, ChainItem *p_chain_item);
};
class SkeletonIK : public Node {