overte/libraries/shared/src/DistanceConstraint.cpp
2014-07-24 09:50:16 -07:00

43 lines
1.5 KiB
C++

//
// DistanceConstraint.cpp
// libraries/shared/src
//
// Created by Andrew Meadows 2014.07.24
// Copyright 2014 High Fidelity, Inc.
//
// Distributed under the Apache License, Version 2.0.
// See the accompanying file LICENSE or http://www.apache.org/licenses/LICENSE-2.0.html
//
#include "DistanceConstraint.h"
#include "SharedUtil.h" // for EPSILON
#include "VerletPoint.h"
DistanceConstraint::DistanceConstraint(VerletPoint* startPoint, VerletPoint* endPoint) : _distance(-1.0f) {
_points[0] = startPoint;
_points[1] = endPoint;
_distance = glm::distance(_points[0]->_position, _points[1]->_position);
}
DistanceConstraint::DistanceConstraint(const DistanceConstraint& other) {
_distance = other._distance;
_points[0] = other._points[0];
_points[1] = other._points[1];
}
void DistanceConstraint::setDistance(float distance) {
_distance = fabsf(distance);
}
float DistanceConstraint::enforce() {
// TODO: use a fast distance approximation
float newDistance = glm::distance(_points[0]->_position, _points[1]->_position);
glm::vec3 direction(0.0f, 1.0f, 0.0f);
if (newDistance > EPSILON) {
direction = (_points[0]->_position - _points[1]->_position) / newDistance;
}
glm::vec3 center = 0.5f * (_points[0]->_position + _points[1]->_position);
_points[0]->_position = center + (0.5f * _distance) * direction;
_points[1]->_position = center - (0.5f * _distance) * direction;
return glm::abs(newDistance - _distance);
}