-- File:	Voxel_CollisionDetection.cdl
-- Created:	Mon Jul 14 13:18:04 2008
-- Author:	Vladislav ROMASHKO
--		<vladislav.romashko@opencascade.com>
---Copyright:	 Open CASCADE S.A.

class CollisionDetection from Voxel

    ---Purpose: Detects collisions between shapes.

uses

    Shape from TopoDS,
    ListOfShape from TopTools,
    BoolDS from Voxel,
    Box from Bnd
    
is

    Create
    ---Purpose: An empty constructor.
    returns CollisionDetection from Voxel;


    ---Category: Initialization
    --           ==============
    
    Create(deflection : Real from Standard;
    	   nbx : Integer from Standard;
    	   nby : Integer from Standard;
    	   nbz : Integer from Standard)
    ---Purpose: A constructor.
    --          It defines deflection of triangulation for the shapes.
    --          As lower the deflection is, as proper the triangulation is generated.
    --          Also, it defines number of splits along X, Y and Z axes for generation of voxels.
    --          As greater the numbers are, as greater number of voxels is used for detection of collision.
    returns CollisionDetection from Voxel;
    
    AddShape(me : in out;
    	     shape : Shape from TopoDS)
    ---Purpose: Adds a shape.
    --          Returns an index of the shape.
    returns Integer from Standard;

    ReplaceShape(me : in out;
    	    	 ishape : Integer from Standard;
    	    	 shape : Shape from TopoDS)
    ---Purpose: Replaces a shape by another one.
    --          <ishape> is an index of the shape.
    --          This method is useful for moving shape, for example.
    returns Boolean from Standard;

    SetDeflection(me : in out;
    	    	  deflection : Real from Standard);
    ---Purpose: Defines the deflection of triangulation of shapes.

    SetNbVoxels(me : in out;
    	    	nbx : Integer from Standard;
    	    	nby : Integer from Standard;
    	    	nbz : Integer from Standard);
    ---Purpose: Defines the number of voxels along X, Y and Z axes.

    SetBoundaryBox(me : in out;
    	    	   box: Box from Bnd);
    ---Purpose: Defines a user-defined boundary box for generation of voxels.
    --          If this method is not called, the algorithm calculates the boundary box itself.

    SetUsageOfVolume(me : in out;
    	    	     usage : Boolean from Standard);
    ---Purpose: Defines usage of volume of shapes in collision detection algorithm.
    --          Beware, usage of volume a little bit decreases the speed of algorithm.

    KeepCollisions(me : in out;
    	    	   keep : Boolean from Standard);
    ---Purpose: Doesn't clean the collision points on new call to the method Compute().
    --          It allows to see the collisions for a moving shape.


    ---Category: Computation
    --           ===========

    -- Call the method in the following order:
    -- Voxelize(); 
    -- Compute();

    Voxelize(me : in out;
    	     ishape : Integer from Standard = -1)
    ---Purpose: Prepares data for computation of collisions.
    --          It checks the inner parameters (number of voxels along X, Y and Z axes) and 
    --          voxelizes the shapes.
    --          If the shape is not changed since the last call to this method,
    --          this method may be not called for this shape.
    --          <ishape> - is the index of the shape for processing by this method.
    --          If it is equal to -1, all shapes will be processed.
    returns Boolean from Standard;

    Compute(me : in out)
    ---Purpose: Computes the collisions.
    --          This method may be called many times if, for example, the shapes are being moved.
    returns Boolean from Standard;
    
    
    ---Category: Result (collisions)
    --           ===================

    HasCollisions(me)
    ---Purpose: Returns true if a collision is detected.
    returns Boolean from Standard;
    
    GetCollisions(me)
    ---C++: return const &
    ---Purpose: Returns the collided voxels.
    returns BoolDS from Voxel;
    

    ---Category: Some internal methods
    --           =====================

    Destroy(me : in out);
    ---C++: alias ~
    ---Purpose: A destructor.

    Clear(me : in out)
    ---Purpose: An internal method for cleaning the intermediate data.
    is private;

    CheckVoxels(me;
    	    	voxels : BoolDS from Voxel)
    ---Purpose: An internal method, which checks correspondance 
    --          of voxels to the parameters defined by user.
    returns Boolean from Standard
    is private;


fields

    -- Initial data.
    myShapes : ListOfShape from TopTools;
    myDeflection : Real from Standard;
    myNbX : Integer from Standard;
    myNbY : Integer from Standard;
    myNbZ : Integer from Standard;
    myUsageOfVolume : Boolean from Standard;
    myKeepCollisions : Boolean from Standard;

    -- User-defined boundary box of shapes.
    myX : Real from Standard;
    myY : Real from Standard;
    myZ : Real from Standard;
    myXLen : Real from Standard;
    myYLen : Real from Standard;
    myZLen : Real from Standard;

    -- An array of voxels of all shapes.
    myVoxels : Address from Standard;

    -- The result.
    myCollisions : BoolDS from Voxel;
    myHasCollisions : Boolean from Standard;


end CollisionDetection;