--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/OrthancStone/Sources/Toolbox/GeometryToolbox.h	Tue Jul 07 16:21:02 2020 +0200
@@ -0,0 +1,177 @@
+/**
+ * Stone of Orthanc
+ * Copyright (C) 2012-2016 Sebastien Jodogne, Medical Physics
+ * Department, University Hospital of Liege, Belgium
+ * Copyright (C) 2017-2020 Osimis S.A., Belgium
+ *
+ * This program is free software: you can redistribute it and/or
+ * modify it under the terms of the GNU Affero 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
+ * Affero General Public License for more details.
+ * 
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program. If not, see <http://www.gnu.org/licenses/>.
+ **/
+
+
+#pragma once
+
+#include "LinearAlgebra.h"
+
+namespace OrthancStone
+{
+  namespace GeometryToolbox
+  {
+    void ProjectPointOntoPlane(Vector& result,
+                               const Vector& point,
+                               const Vector& planeNormal,
+                               const Vector& planeOrigin);
+
+    /*
+    Alternated faster implementation (untested yet)
+    */
+    void ProjectPointOntoPlane2(double& resultX,
+                                double& resultY,
+                                double& resultZ,
+                                const Vector& point,
+                                const Vector& planeNormal,
+                                const Vector& planeOrigin);
+
+    bool IsParallel(const Vector& u,
+                    const Vector& v);
+
+    bool IsParallelOrOpposite(bool& isOpposite,
+                              const Vector& u,
+                              const Vector& v);
+
+    bool IntersectTwoPlanes(Vector& p,
+                            Vector& direction,
+                            const Vector& origin1,
+                            const Vector& normal1,
+                            const Vector& origin2,
+                            const Vector& normal2);
+
+    bool ClipLineToRectangle(double& x1,  // Coordinates of the clipped line (out)
+                             double& y1,
+                             double& x2,
+                             double& y2,
+                             const double ax,  // Two points defining the line (in)
+                             const double ay,
+                             const double bx,
+                             const double by,
+                             const double& xmin,   // Coordinates of the rectangle (in)
+                             const double& ymin,
+                             const double& xmax,
+                             const double& ymax);
+
+    void GetPixelSpacing(double& spacingX, 
+                         double& spacingY,
+                         const Orthanc::DicomMap& dicom);
+
+    inline double ProjectAlongNormal(const Vector& point,
+                                     const Vector& normal)
+    {
+      return boost::numeric::ublas::inner_prod(point, normal);
+    }
+
+    Matrix CreateRotationMatrixAlongX(double a);
+
+    Matrix CreateRotationMatrixAlongY(double a);
+
+    Matrix CreateRotationMatrixAlongZ(double a);
+
+    Matrix CreateTranslationMatrix(double dx,
+                                   double dy,
+                                   double dz);
+
+    Matrix CreateScalingMatrix(double sx,
+                               double sy,
+                               double sz);
+    
+    bool IntersectPlaneAndSegment(Vector& p,
+                                  const Vector& normal,
+                                  double d,
+                                  const Vector& edgeFrom,
+                                  const Vector& edgeTo);
+
+    bool IntersectPlaneAndLine(Vector& p,
+                               const Vector& normal,
+                               double d,
+                               const Vector& origin,
+                               const Vector& direction);
+
+    void AlignVectorsWithRotation(Matrix& r,
+                                  const Vector& a,
+                                  const Vector& b);
+
+    void ComputeNormalFromCosines(Vector& normal,
+                                  const Vector& cosines);
+
+    bool ComputeNormal(Vector& normal,
+                       const Orthanc::DicomMap& dicom);
+
+    inline float ComputeBilinearInterpolationUnitSquare(float x,
+                                                        float y,
+                                                        float f00,    // source(0, 0)
+                                                        float f01,    // source(1, 0)
+                                                        float f10,    // source(0, 1)
+                                                        float f11);   // source(1, 1)
+
+    inline float ComputeTrilinearInterpolationUnitSquare(float x,
+                                                         float y,
+                                                         float z,
+                                                         float f000,   // source(0, 0, 0)
+                                                         float f001,   // source(1, 0, 0)
+                                                         float f010,   // source(0, 1, 0)
+                                                         float f011,   // source(1, 1, 0)
+                                                         float f100,   // source(0, 0, 1)
+                                                         float f101,   // source(1, 0, 1)
+                                                         float f110,   // source(0, 1, 1)
+                                                         float f111);  // source(1, 1, 1)
+  };
+}
+
+
+float OrthancStone::GeometryToolbox::ComputeBilinearInterpolationUnitSquare(float x,
+                                                                            float y,
+                                                                            float f00,
+                                                                            float f01,
+                                                                            float f10,
+                                                                            float f11)
+{
+  // This function only works within the unit square
+  assert(x >= 0 && y >= 0 && x <= 1 && y <= 1);
+
+  // https://en.wikipedia.org/wiki/Bilinear_interpolation#Unit_square
+  return (f00 * (1.0f - x) * (1.0f - y) +
+          f01 * x * (1.0f - y) +
+          f10 * (1.0f - x) * y +
+          f11 * x * y);
+}
+
+
+float OrthancStone::GeometryToolbox::ComputeTrilinearInterpolationUnitSquare(float x,
+                                                                             float y,
+                                                                             float z,
+                                                                             float f000,
+                                                                             float f001,
+                                                                             float f010,
+                                                                             float f011,
+                                                                             float f100,
+                                                                             float f101,
+                                                                             float f110,
+                                                                             float f111)
+{
+  // "In practice, a trilinear interpolation is identical to two
+  // bilinear interpolation combined with a linear interpolation"
+  // https://en.wikipedia.org/wiki/Trilinear_interpolation#Method
+  float a = ComputeBilinearInterpolationUnitSquare(x, y, f000, f001, f010, f011);
+  float b = ComputeBilinearInterpolationUnitSquare(x, y, f100, f101, f110, f111);
+
+  return (1.0f - z) * a + z * b;
+}