source: pacpussensors/trunk/Vislab/lib3dv-1.2.0/lib3dv/eigen/demos/opengl/trackball.cpp

Last change on this file was 136, checked in by ldecherf, 8 years ago

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1// This file is part of Eigen, a lightweight C++ template library
2// for linear algebra.
3//
4// Copyright (C) 2008 Gael Guennebaud <gael.guennebaud@inria.fr>
5//
6// This Source Code Form is subject to the terms of the Mozilla
7// Public License v. 2.0. If a copy of the MPL was not distributed
8// with this file, You can obtain one at http://mozilla.org/MPL/2.0/.
9
10#include "trackball.h"
11#include "camera.h"
12
13using namespace Eigen;
14
15void Trackball::track(const Vector2i& point2D)
16{
17 if (mpCamera==0)
18 return;
19 Vector3f newPoint3D;
20 bool newPointOk = mapToSphere(point2D, newPoint3D);
21
22 if (mLastPointOk && newPointOk)
23 {
24 Vector3f axis = mLastPoint3D.cross(newPoint3D).normalized();
25 float cos_angle = mLastPoint3D.dot(newPoint3D);
26 if ( internal::abs(cos_angle) < 1.0 )
27 {
28 float angle = 2. * acos(cos_angle);
29 if (mMode==Around)
30 mpCamera->rotateAroundTarget(Quaternionf(AngleAxisf(angle, axis)));
31 else
32 mpCamera->localRotate(Quaternionf(AngleAxisf(-angle, axis)));
33 }
34 }
35
36 mLastPoint3D = newPoint3D;
37 mLastPointOk = newPointOk;
38}
39
40bool Trackball::mapToSphere(const Vector2i& p2, Vector3f& v3)
41{
42 if ((p2.x() >= 0) && (p2.x() <= int(mpCamera->vpWidth())) &&
43 (p2.y() >= 0) && (p2.y() <= int(mpCamera->vpHeight())) )
44 {
45 double x = (double)(p2.x() - 0.5*mpCamera->vpWidth()) / (double)mpCamera->vpWidth();
46 double y = (double)(0.5*mpCamera->vpHeight() - p2.y()) / (double)mpCamera->vpHeight();
47 double sinx = sin(M_PI * x * 0.5);
48 double siny = sin(M_PI * y * 0.5);
49 double sinx2siny2 = sinx * sinx + siny * siny;
50
51 v3.x() = sinx;
52 v3.y() = siny;
53 v3.z() = sinx2siny2 < 1.0 ? sqrt(1.0 - sinx2siny2) : 0.0;
54
55 return true;
56 }
57 else
58 return false;
59}
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