+ fix cutting or selecting mesh in perspective projection mode

src/Base/ViewProj.cpp

@@ -0,0 +1,126 @@
+/***************************************************************************
+ *   Copyright (c) 2005 Imetric 3D GmbH                                    *
+ *                                                                         *
+ *   This file is part of the FreeCAD CAx development system.              *
+ *                                                                         *
+ *   This library is free software; you can redistribute it and/or         *
+ *   modify it under the terms of the GNU Library General Public           *
+ *   License as published by the Free Software Foundation; either          *
+ *   version 2 of the License, or (at your option) any later version.      *
+ *                                                                         *
+ *   This library  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 Library General Public License for more details.                  *
+ *                                                                         *
+ *   You should have received a copy of the GNU Library General Public     *
+ *   License along with this library; see the file COPYING.LIB. If not,    *
+ *   write to the Free Software Foundation, Inc., 59 Temple Place,         *
+ *   Suite 330, Boston, MA  02111-1307, USA                                *
+ *                                                                         *
+ ***************************************************************************/
+
+
+#include "PreCompiled.h"
+#include "ViewProj.h"
+
+using namespace Base;
+
+ViewProjMatrix::ViewProjMatrix (const Matrix4D &rclMtx)
+  : _clMtx(rclMtx)
+{
+    double m30 = _clMtx[3][0];
+    double m31 = _clMtx[3][1];
+    double m32 = _clMtx[3][2];
+    double m33 = _clMtx[3][3];
+    isOrthographic = (m30 == 0 && m31 == 0 && m32 == 0 && m33 == 1);
+
+    // Only for orthographic projection mode we can compute a single
+    // matrix performing all steps.
+    // For perspective projection the scaling and translation must
+    // be done afterwards because it depends on the input point.
+    if (isOrthographic) {
+        // Scale from [-1,1] to [0,1]
+        // As done in OpenInventor sources (see SbDPViewVolume::projectToScreen)
+        _clMtx.scale(0.5, 0.5, 0.5);
+        _clMtx.move(0.5, 0.5, 0.5);
+    }
+
+    _clMtxInv = _clMtx;
+    _clMtxInv.inverseGauss();
+}
+
+ViewProjMatrix::~ViewProjMatrix()
+{
+}
+
+template<typename Vec>
+void perspectiveTransform(const Base::Matrix4D& mat, Vec& pnt)
+{
+    double m30 = mat[3][0];
+    double m31 = mat[3][1];
+    double m32 = mat[3][2];
+    double m33 = mat[3][3];
+    double w = (pnt.x * m30 + pnt.y * m31 + pnt.z * m32 + m33);
+
+    mat.multVec(pnt, pnt);
+    pnt /= w;
+}
+
+Vector3f ViewProjMatrix::operator()(const Vector3f& src) const
+{
+    Vector3f dst;
+    if (!isOrthographic) {
+        dst = src;
+        perspectiveTransform<Vector3f>(_clMtx, dst);
+        dst.Set(0.5*dst.x+0.5, 0.5*dst.y+0.5, 0.5*dst.z+0.5);
+    }
+    else {
+        _clMtx.multVec(src, dst);
+    }
+
+    return dst;
+}
+
+Vector3d ViewProjMatrix::operator()(const Vector3d& src) const
+{
+    Vector3d dst;
+    if (!isOrthographic) {
+        dst = src;
+        perspectiveTransform<Vector3d>(_clMtx, dst);
+        dst.Set(0.5*dst.x+0.5, 0.5*dst.y+0.5, 0.5*dst.z+0.5);
+    }
+    else {
+        _clMtx.multVec(src, dst);
+    }
+
+    return dst;
+}
+
+Vector3f ViewProjMatrix::inverse (const Vector3f& src) const
+{
+    Vector3f dst;
+    if (!isOrthographic) {
+        dst.Set(2.0*src.x-1.0, 2.0*src.y-1.0, 2.0*src.z-1.0);
+        perspectiveTransform<Vector3f>(_clMtxInv, dst);
+    }
+    else {
+        _clMtxInv.multVec(src, dst);
+    }
+
+    return dst;
+}
+
+Vector3d ViewProjMatrix::inverse (const Vector3d& src) const
+{
+    Vector3d dst;
+    if (!isOrthographic) {
+        dst.Set(2.0*src.x-1.0, 2.0*src.y-1.0, 2.0*src.z-1.0);
+        perspectiveTransform<Vector3d>(_clMtxInv, dst);
+    }
+    else {
+        _clMtxInv.multVec(src, dst);
+    }
+
+    return dst;
+}