0024623: Visualization - improve selection mechanism

[occt.git] / src / SelectMgr / SelectMgr_Frustum.hxx

diff --git a/src/SelectMgr/SelectMgr_Frustum.hxx b/src/SelectMgr/SelectMgr_Frustum.hxx
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+// Created on: 2015-03-16
+// Created by: Varvara POSKONINA
+// Copyright (c) 2005-2014 OPEN CASCADE SAS
+//
+// This file is part of Open CASCADE Technology software library.
+//
+// This library is free software; you can redistribute it and/or modify it under
+// the terms of the GNU Lesser General Public License version 2.1 as published
+// by the Free Software Foundation, with special exception defined in the file
+// OCCT_LGPL_EXCEPTION.txt. Consult the file LICENSE_LGPL_21.txt included in OCCT
+// distribution for complete text of the license and disclaimer of any warranty.
+//
+// Alternatively, this file may be used under the terms of Open CASCADE
+// commercial license or contractual agreement.
+
+#ifndef _SelectMgr_Frustum_HeaderFile
+#define _SelectMgr_Frustum_HeaderFile
+
+#include <BVH_Box.hxx>
+#include <gp_Pnt.hxx>
+#include <SelectMgr_BaseFrustum.hxx>
+#include <SelectMgr_FrustumBuilder.hxx>
+#include <TColgp_HArray1OfPnt.hxx>
+#include <TColgp_Array1OfPnt2d.hxx>
+
+//! This is an internal class containing representation of rectangular selecting frustum, created in case
+//! of point and box selection, and algorithms for overlap detection between selecting
+//! frustum and sensitive entities. The principle of frustum calculation:
+//! - for point selection: on a near view frustum plane rectangular neighborhood of
+//!                        user-picked point is created according to the pixel tolerance
+//!                        given and then this rectangle is projected onto far view frustum
+//!                        plane. This rectangles define the parallel bases of selecting frustum;
+//! - for box selection: box points are projected onto near and far view frustum planes.
+//!                      These 2 projected rectangles define parallel bases of selecting frustum.
+//! Overlap detection tests are implemented according to the terms of separating axis
+//! theorem (SAT).
+//! Vertex order:
+//! - for triangular frustum: V0_Near, V1_Near, V2_Near,
+//!                           V0_Far, V1_Far, V2_Far;
+//! - for rectangular frustum: LeftTopNear, LeftTopFar,
+//!                            LeftBottomNear,LeftBottomFar,
+//!                            RightTopNear, RightTopFar,
+//!                            RightBottomNear, RightBottomFar.
+//! Plane order in array:
+//! - for triangular frustum: V0V1, V1V2, V0V2, Near, Far;
+//! - for rectangular frustum: Top, Bottom, Left, Right, Near, Far.
+//! Uncollinear edge directions order:
+//! - for rectangular frustum: Horizontal, Vertical,
+//!                            LeftLower, RightLower,
+//!                            LeftUpper, RightUpper;
+//! - for triangular frustum: V0_Near - V0_Far, V1_Near - V1_Far, V2_Near - V2_Far,
+//!                           V1_Near - V0_Near, V2_Near - V1_Near, V2_Near - V0_Near.
+template <int N>
+class SelectMgr_Frustum : public SelectMgr_BaseFrustum
+{
+public:
+
+  SelectMgr_Frustum() : SelectMgr_BaseFrustum() {};
+
+protected:
+
+  // SAT Tests for different objects
+
+  //! Returns true if selecting volume is overlapped by axis-aligned bounding box
+  //! with minimum corner at point theMinPt and maximum at point theMaxPt
+  const Standard_Boolean hasOverlap (const SelectMgr_Vec3& theMinPnt,
+                                     const SelectMgr_Vec3& theMaxPnt);
+
+  //! SAT intersection test between defined volume and given point
+  const Standard_Boolean hasOverlap (const gp_Pnt& thePnt);
+
+  //! SAT intersection test between defined volume and given segment
+  const Standard_Boolean hasOverlap (const gp_Pnt& thePnt1,
+                                     const gp_Pnt& thePnt2);
+
+  //! SAT intersection test between frustum given and planar convex polygon represented as ordered point set
+  const Standard_Boolean hasOverlap (const Handle(TColgp_HArray1OfPnt)& theArrayOfPnts,
+                                     SelectMgr_Vec3& theNormal);
+
+  //! SAT intersection test between defined volume and given triangle
+  const Standard_Boolean hasOverlap (const gp_Pnt& thePnt1,
+                                     const gp_Pnt& thePnt2,
+                                     const gp_Pnt& thePnt3,
+                                     SelectMgr_Vec3& theNormal);
+
+private:
+
+  //! Checks if AABB and frustum are separated along the given axis
+  Standard_Boolean isSeparated (const SelectMgr_Vec3& theBoxMin,
+                                const SelectMgr_Vec3& theBoxMax,
+                                const SelectMgr_Vec3& theAxis) const;
+
+  //! Checks if triangle and frustum are separated along the given axis
+  Standard_Boolean isSeparated (const gp_Pnt& thePnt1,
+                                const gp_Pnt& thePnt2,
+                                const gp_Pnt& thePnt3,
+                                const SelectMgr_Vec3& theAxis) const;
+
+protected:
+
+  SelectMgr_Vec3 myPlanes[N + 2];        //!< Plane equations
+  SelectMgr_Vec3 myVertices[N * 2];      //!< Vertices coordinates
+
+  Standard_Real myMaxVertsProjections[N + 2];      //!< Cached projections of vertices onto frustum plane directions
+  Standard_Real myMinVertsProjections[N + 2];      //!< Cached projections of vertices onto frustum plane directions
+  Standard_Real myMaxOrthoVertsProjections[3];     //!< Cached projections of vertices onto directions of ortho unit vectors
+  Standard_Real myMinOrthoVertsProjections[3];     //!< Cached projections of vertices onto directions of ortho unit vectors
+
+  SelectMgr_Vec3 myEdgeDirs[6];                    //!< Cached edge directions
+};
+
+#include <SelectMgr_Frustum.lxx>
+
+#endif // _SelectMgr_Frustum_HeaderFile