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/*
* Collision.cpp
*
* Copyright (C) 2009 Matthias Schiffer <matthias@gamezock.de>
*
* This program is free software: you can redistribute it and/or modify it
* under the terms of the GNU Lesser General Public License as published by the
* Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
* See the GNU Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public License along
* with this program. If not, see <http://www.gnu.org/licenses/>.
*/
#include "Collision.h"
#include <cmath>
#include <limits>
namespace Zoom {
bool Collision::test(const Triangle &t, const MathUtil::Ray &ray, float *distance) {
vmml::vec3f edge1 = t.getVertex(1) - t.getVertex(0);
vmml::vec3f edge2 = t.getVertex(2) - t.getVertex(0);
vmml::vec3f pvec = ray.getDirection().cross(edge2);
float det = vmml::dot(edge1, pvec);
if(det < MathUtil::EPSILON)
return false;
vmml::vec3f tvec = ray.getVertex() - t.getVertex(0);
float u = vmml::dot(pvec, tvec);
if(u < 0 || u > det)
return false;
vmml::vec3f qvec = tvec.cross(edge1);
float v = vmml::dot(ray.getDirection(), qvec);
if(v < 0 || u+v > det)
return false;
if(distance)
*distance = vmml::dot(edge2, qvec) / det;
return true;
}
vmml::vec3f Collision::projectToEdge(const vmml::vec3f& p, const vmml::vec3f& v1, const vmml::vec3f& v2) {
vmml::vec3f pVec = p - v1;
vmml::vec3f edge = v2 - v1;
float lengthSq = edge.squared_length();
float edgeProj = vmml::dot(edge, pVec);
if(edgeProj < 0) return v1;
if(edgeProj > lengthSq) return v2;
return v1 + (edgeProj/lengthSq)*edge;
}
bool Collision::testEdge(const vmml::vec3f &v1, const vmml::vec3f &v2, const vmml::vec3f &m, float r, const vmml::vec3f &move, float *distance) {
vmml::vec3f edge = v2 - v1;
vmml::vec3f avec = vmml::dot(edge, move)*edge / edge.squared_length() - move;
vmml::vec3f cvec = v1 + vmml::dot(edge, m-v1)*edge / edge.squared_length() - m;
float a = avec.squared_length();
float b_2 = vmml::dot(avec, cvec);
float c = cvec.squared_length() - r*r;
float rootSq = b_2*b_2 - a*c;
if(rootSq < 0)
return false;
float minRoot = -a - b_2;
float maxRoot = a*MathUtil::EPSILON - b_2;
if(minRoot < 0)
minRoot = 0;
if(maxRoot < 0)
return false;
if(rootSq < minRoot*minRoot || rootSq >= maxRoot*maxRoot)
return false;
minRoot = a*(edge.dot(m - v1) - edge.squared_length())/edge.dot(move) - b_2;
maxRoot = a*edge.dot(m - v1)/edge.dot(move) - b_2;
if(minRoot < 0)
minRoot = 0;
if(maxRoot < 0)
return false;
if(rootSq < minRoot*minRoot || rootSq > maxRoot*maxRoot)
return false;
*distance = -(b_2 + std::sqrt(rootSq))/a;
return true;
}
bool Collision::testVertex(const vmml::vec3f &v, const vmml::vec3f &m, float r, const vmml::vec3f &move, float *distance) {
float a = move.squared_length();
float b_2 = vmml::dot(m-v, move);
float c = (m-v).squared_length() - r*r;
float rootSq = b_2*b_2 - a*c;
if(rootSq < 0)
return false;
float minRoot = -a - b_2;
float maxRoot = a*MathUtil::EPSILON - b_2;
if(minRoot < 0)
minRoot = 0;
if(maxRoot < 0)
return false;
if(rootSq <= minRoot*minRoot || rootSq >= maxRoot*maxRoot)
return false;
*distance = -(b_2 + std::sqrt(rootSq))/a;
return true;
}
bool Collision::test(const Triangle &t, const vmml::vec3f &m, float r, const vmml::vec3f &move, float *distance, vmml::vec3f *normal) {
if(move.squared_length() == 0)
return false;
float d;
vmml::vec3f triangleNormal = t.getNormal();
if(test(t, MathUtil::Ray(m - r*triangleNormal, move), &d) && d > -MathUtil::EPSILON) {
if(d < 1) {
if(distance)
*distance = d;
if(normal)
*normal = triangleNormal;
return true;
}
else {
return false;
}
}
bool collision = false;
float minDistance;
for(int i = 0; i < 3; ++i) {
if(testEdge(t.getVertex(i), t.getVertex((i+1)%3), m, r, move, &d)) {
if(!collision || d < minDistance) {
collision = true;
minDistance = d;
if(normal) {
vmml::vec3f p = m + move*d;
*normal = (p - projectToEdge(p, t.getVertex(i), t.getVertex((i+1)%3)))/r;
}
}
}
}
if(collision) {
if(distance)
*distance = minDistance;
return true;
}
collision = false;
for(int i = 0; i < 3; ++i) {
if(testVertex(t.getVertex(i), m, r, move, &d)) {
if(!collision || d < minDistance) {
collision = true;
minDistance = d;
}
if(normal) {
vmml::vec3f p = m + move*d;
*normal = (p - t.getVertex(i))/r;
}
}
}
if(collision) {
if(distance)
*distance = minDistance;
return true;
}
else {
return false;
}
}
}
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