devtools/eigen
1
0
Fork 0
mirror of https://gitlab.com/libeigen/eigen.git synced 2026-04-10 11:34:33 +08:00
Code Issues Packages Projects Releases Wiki Activity

started a small OpenGL demo making use of Eigen's geometry features

Browse Source
This commit is contained in:
Gael Guennebaud
2008-09-07 23:15:11 +00:00
parent 12e9de4abb
commit 31c33b9ed4
11 changed files with 1410 additions and 0 deletions
Download Patch File Download Diff File Expand all files Collapse all files

72
demos/opengl/trackball.cpp Normal file
View File

@@ -0,0 +1,72 @@
// This file is part of Eigen, a lightweight C++ template library
// for linear algebra. Eigen itself is part of the KDE project.
//
// Copyright (C) 2008 Gael Guennebaud <g.gael@free.fr>
//
// Eigen 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.
//
// Alternatively, you can redistribute it and/or
// modify it under the terms of the GNU General Public License as
// published by the Free Software Foundation; either version 2 of
// the License, or (at your option) any later version.
//
// Eigen 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 or the
// GNU General Public License for more details.
//
// You should have received a copy of the GNU Lesser General Public
// License and a copy of the GNU General Public License along with
// Eigen. If not, see <http://www.gnu.org/licenses/>.
#include "trackball.h"
#include "camera.h"
using namespace Eigen;
void Trackball::track(const Vector2i& newPoint2D)
{
if (mpCamera==0)
return;
Vector3f newPoint3D;
bool newPointOk = mapToSphere(newPoint2D, newPoint3D);
if (mLastPointOk && newPointOk)
{
Vector3f axis = mLastPoint3D.cross(newPoint3D).normalized();
float cos_angle = mLastPoint3D.dot(newPoint3D);
if ( ei_abs(cos_angle) < 1.0 )
{
float angle = 2.0 * acos(cos_angle);
mpCamera->rotateAroundTarget(Quaternionf(AngleAxisf(angle, axis)));
}
}
mLastPoint2D = newPoint2D;
mLastPoint3D = newPoint3D;
mLastPointOk = newPointOk;
}
bool Trackball::mapToSphere(const Vector2i& p2, Vector3f& v3)
{
if ((p2.x() >= 0) && (p2.x() <= int(mpCamera->vpWidth())) &&
(p2.y() >= 0) && (p2.y() <= int(mpCamera->vpHeight())) )
{
double x = (double)(p2.x() - 0.5*mpCamera->vpWidth()) / (double)mpCamera->vpWidth();
double y = (double)(0.5*mpCamera->vpHeight() - p2.y()) / (double)mpCamera->vpHeight();
double sinx = sin(M_PI * x * 0.5);
double siny = sin(M_PI * y * 0.5);
double sinx2siny2 = sinx * sinx + siny * siny;
v3.x() = sinx;
v3.y() = siny;
v3.z() = sinx2siny2 < 1.0 ? sqrt(1.0 - sinx2siny2) : 0.0;
return true;
}
else
return false;
}