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Merge pull request #5798 from AndrewMeadows/minor-ik-tuning

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minor tuning of IK behavior
This commit is contained in:
Brad Davis 2015-09-14 18:55:31 -07:00
commit 7a843b3610
1 changed files with 7 additions and 27 deletions
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34
libraries/animation/src/AnimInverseKinematics.cpp
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@ -149,28 +149,6 @@ const AnimPoseVec& AnimInverseKinematics::evaluate(const AnimVariantMap& animVar
glm::vec3 tip = absolutePoses[tipIndex].trans; glm::vec3 tip = absolutePoses[tipIndex].trans;
float error = glm::length(targetPose.trans - tip); float error = glm::length(targetPose.trans - tip);
if (error < ACCEPTABLE_RELATIVE_ERROR) {
if (largestError < error) {
largestError = error;
}
// this targetPose has been met
// finally set the relative rotation of the tip to agree with absolute target rotation
int parentIndex = _skeleton->getParentIndex(tipIndex);
if (parentIndex != -1) {
// compute tip's new parent-relative rotation
// Q = Qp * q --> q' = Qp^ * Q
glm::quat newRelativeRotation = glm::inverse(absolutePoses[parentIndex].rot) * targetPose.rot;
RotationConstraint* constraint = getConstraint(tipIndex);
if (constraint) {
constraint->apply(newRelativeRotation);
// TODO: ATM the final rotation target may fails but we need to provide
// feedback to the IK system so that it can adjust the bones up the skeleton
// to help this rotation target get met.
}
_relativePoses[tipIndex].rot = newRelativeRotation;
}
break;
}
// descend toward root, rotating each joint to get tip closer to target // descend toward root, rotating each joint to get tip closer to target
int index = _skeleton->getParentIndex(tipIndex); int index = _skeleton->getParentIndex(tipIndex);
@ -191,6 +169,8 @@ const AnimPoseVec& AnimInverseKinematics::evaluate(const AnimVariantMap& animVar
// NOTE: even when axisLength is not zero (e.g. lever-arm and pivot-arm are not quite aligned) it is // NOTE: even when axisLength is not zero (e.g. lever-arm and pivot-arm are not quite aligned) it is
// still possible for the angle to be zero so we also check that to avoid unnecessary calculations. // still possible for the angle to be zero so we also check that to avoid unnecessary calculations.
if (angle > EPSILON) { if (angle > EPSILON) {
// reduce angle by half: slows convergence but adds stability to IK solution
angle = 0.5f * angle;
glm::quat deltaRotation = glm::angleAxis(angle, axis); glm::quat deltaRotation = glm::angleAxis(angle, axis);
int parentIndex = _skeleton->getParentIndex(index); int parentIndex = _skeleton->getParentIndex(index);
@ -268,7 +248,7 @@ const AnimPoseVec& AnimInverseKinematics::overlay(const AnimVariantMap& animVars
loadPoses(underPoses); loadPoses(underPoses);
} else { } else {
// relax toward underpose // relax toward underpose
const float RELAXATION_TIMESCALE = 0.25f; const float RELAXATION_TIMESCALE = 0.125f;
const float alpha = glm::clamp(dt / RELAXATION_TIMESCALE, 0.0f, 1.0f); const float alpha = glm::clamp(dt / RELAXATION_TIMESCALE, 0.0f, 1.0f);
int numJoints = (int)_relativePoses.size(); int numJoints = (int)_relativePoses.size();
for (int i = 0; i < numJoints; ++i) { for (int i = 0; i < numJoints; ++i) {
@ -342,7 +322,7 @@ void AnimInverseKinematics::initConstraints() {
// compute corresponding absolute poses // compute corresponding absolute poses
int numJoints = (int)_defaultRelativePoses.size(); int numJoints = (int)_defaultRelativePoses.size();
AnimPoseVec absolutePoses; AnimPoseVec absolutePoses;
absolutePoses.reserve(numJoints); absolutePoses.resize(numJoints);
for (int i = 0; i < numJoints; ++i) { for (int i = 0; i < numJoints; ++i) {
int parentIndex = _skeleton->getParentIndex(i); int parentIndex = _skeleton->getParentIndex(i);
if (parentIndex < 0) { if (parentIndex < 0) {
@ -467,11 +447,11 @@ void AnimInverseKinematics::initConstraints() {
} else if (baseName.startsWith("Shoulder", Qt::CaseInsensitive)) { } else if (baseName.startsWith("Shoulder", Qt::CaseInsensitive)) {
SwingTwistConstraint* stConstraint = new SwingTwistConstraint(); SwingTwistConstraint* stConstraint = new SwingTwistConstraint();
stConstraint->setReferenceRotation(_defaultRelativePoses[i].rot); stConstraint->setReferenceRotation(_defaultRelativePoses[i].rot);
const float MAX_SHOULDER_TWIST = PI / 8.0f; const float MAX_SHOULDER_TWIST = PI / 20.0f;
stConstraint->setTwistLimits(-MAX_SHOULDER_TWIST, MAX_SHOULDER_TWIST); stConstraint->setTwistLimits(-MAX_SHOULDER_TWIST, MAX_SHOULDER_TWIST);
std::vector<float> minDots; std::vector<float> minDots;
const float MAX_SHOULDER_SWING = PI / 14.0f; const float MAX_SHOULDER_SWING = PI / 20.0f;
minDots.push_back(cosf(MAX_SHOULDER_SWING)); minDots.push_back(cosf(MAX_SHOULDER_SWING));
stConstraint->setSwingLimits(minDots); stConstraint->setSwingLimits(minDots);
@ -509,7 +489,7 @@ void AnimInverseKinematics::initConstraints() {
// we determine the max/min angles by rotating the swing limit lines from parent- to child-frame // we determine the max/min angles by rotating the swing limit lines from parent- to child-frame
// then measure the angles to swing the yAxis into alignment // then measure the angles to swing the yAxis into alignment
glm::vec3 hingeAxis = - mirror * zAxis; glm::vec3 hingeAxis = - mirror * zAxis;
const float MIN_ELBOW_ANGLE = 0.0f; const float MIN_ELBOW_ANGLE = 0.05f;
const float MAX_ELBOW_ANGLE = 11.0f * PI / 12.0f; const float MAX_ELBOW_ANGLE = 11.0f * PI / 12.0f;
glm::quat invReferenceRotation = glm::inverse(referenceRotation); glm::quat invReferenceRotation = glm::inverse(referenceRotation);
glm::vec3 minSwingAxis = invReferenceRotation * glm::angleAxis(MIN_ELBOW_ANGLE, hingeAxis) * yAxis; glm::vec3 minSwingAxis = invReferenceRotation * glm::angleAxis(MIN_ELBOW_ANGLE, hingeAxis) * yAxis;