60 lines
1.7 KiB
C++
60 lines
1.7 KiB
C++
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// This file is part of Eigen, a lightweight C++ template library
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// for linear algebra.
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//
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// Copyright (C) 2008 Gael Guennebaud <gael.guennebaud@inria.fr>
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//
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// This Source Code Form is subject to the terms of the Mozilla
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// Public License v. 2.0. If a copy of the MPL was not distributed
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// with this file, You can obtain one at http://mozilla.org/MPL/2.0/.
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#include "trackball.h"
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#include "camera.h"
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using namespace Eigen;
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void Trackball::track(const Vector2i& point2D)
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{
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if (mpCamera==0)
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return;
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Vector3f newPoint3D;
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bool newPointOk = mapToSphere(point2D, newPoint3D);
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if (mLastPointOk && newPointOk)
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{
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Vector3f axis = mLastPoint3D.cross(newPoint3D).normalized();
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float cos_angle = mLastPoint3D.dot(newPoint3D);
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if ( std::abs(cos_angle) < 1.0 )
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{
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float angle = 2. * acos(cos_angle);
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if (mMode==Around)
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mpCamera->rotateAroundTarget(Quaternionf(AngleAxisf(angle, axis)));
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else
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mpCamera->localRotate(Quaternionf(AngleAxisf(-angle, axis)));
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}
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}
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mLastPoint3D = newPoint3D;
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mLastPointOk = newPointOk;
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}
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bool Trackball::mapToSphere(const Vector2i& p2, Vector3f& v3)
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{
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if ((p2.x() >= 0) && (p2.x() <= int(mpCamera->vpWidth())) &&
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(p2.y() >= 0) && (p2.y() <= int(mpCamera->vpHeight())) )
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{
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double x = (double)(p2.x() - 0.5*mpCamera->vpWidth()) / (double)mpCamera->vpWidth();
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double y = (double)(0.5*mpCamera->vpHeight() - p2.y()) / (double)mpCamera->vpHeight();
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double sinx = sin(M_PI * x * 0.5);
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double siny = sin(M_PI * y * 0.5);
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double sinx2siny2 = sinx * sinx + siny * siny;
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v3.x() = sinx;
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v3.y() = siny;
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v3.z() = sinx2siny2 < 1.0 ? sqrt(1.0 - sinx2siny2) : 0.0;
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return true;
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}
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else
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return false;
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}
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