initial implementation of projection matrix, 3D to window coordinates, window coordinates to 3D ray (not yet tested)

modules/viz/include/opencv2/viz/types.hpp

@@ -110,6 +110,8 @@ namespace cv
             inline const Vec2f & getFov() const { return fov_; }
             inline void setFov(const Vec2f & fov) { fov_ = fov; }
             
+            void computeProjectionMatrix(Matx44f &proj) const;
+            
         private:
             Vec2d clip_;
             Vec2f fov_;

modules/viz/include/opencv2/viz/viz3d.hpp

@@ -42,6 +42,9 @@ namespace cv
             void setCamera(const Camera2 &camera);
             Affine3f getViewerPose();
             void setViewerPose(const Affine3f &pose);
+            
+            void convertToWindowCoordinates(const Point3f &pt, Point3f &window_coord);
+            void converTo3DRay(const Point3f &window_coord, Point3f &origin, Vec3f &direction);
 
             void spin();
             void spinOnce(int time = 1, bool force_redraw = false);