// Persistence of Vision Ray Tracer Scene Description File
// File: mesh_tool.inc
// Vers: 3.5
// Desc: 
// Date: 04/11/2003
// Auth: Jean-Charles Marteau
//

#declare _Mem_Alloc_Base = 100;

// --------------------------------------------------------------------------------
// Constants

// Object types
#declare _Vert = 0;
#declare _Face = 1;
#declare _Norm = 2;
#declare _VrtF = 3;
#declare _Trgl = 4;

// Special 'object type' containing the number of objects of each type.
#declare _Nb = 3;

// --------------------------------------------------------------------------------
// Object creation methods
// Can be implemented in a general purpose object_mgr.inc package

// Creates a new mesh and returns it.
#macro New_Mesh ()
  // - Array of vertices
  #local _Vertices = array [_Mem_Alloc_Base];
  // - Array of faces
  #local _Faces = array [_Mem_Alloc_Base];
  // - Array of vertices normals
  #local _Normals = array [_Mem_Alloc_Base];
  // - Array giving the Faces that use the corresponding vertice.
  // We use this to inverse the indexes and find which face uses which vertice
  // We'll define it later.
  // - Nb_of_elements
  //     - Vertices
  //     - Faces
  #local _Nb_Elem = array [5] { 0, 0, 0, 0, 0 };

  #local _Mesh = array [4];
  #local _Mesh [_Vert] = _Vertices;
  #local _Mesh [_Norm] = _Normals;
  #local _Mesh [_Face] = _Faces;
  #local _Mesh [_Nb]   = _Nb_Elem;
  _Mesh
#end

#macro Add_Object (_Mesh, Obj, Obj_Type)
  // Checking if the array is big enough
  #if (_Mesh [_Nb][Obj_Type] >= dimension_size (_Mesh[Obj_Type],1))
    // We allocate a bigger one
    #local _New_Objects = array [dimension_size (_Mesh[Obj_Type],1)*2];
    // Copy the old one in the new one
    #local i = 0;
    #while (i < _Mesh [_Nb][Obj_Type])
      #local _New_Objects [i] = _Mesh[Obj_Type][i];
      #local i = i + 1;
    #end
    // Undef the old one
    #undef _Mesh[Obj_Type]
    // And affect the new one.
    #declare _Mesh[Obj_Type] = _New_Objects;
  #end
  // Setting the new object.
  #declare _Mesh[Obj_Type][_Mesh [_Nb][Obj_Type]] = Obj;
  #local res_index = _Mesh [_Nb][Obj_Type];
  #declare _Mesh [_Nb][Obj_Type] = _Mesh [_Nb][Obj_Type] + 1;
  res_index
#end

// Add a vertice to the mesh.
#macro Add_Vertice (_Mesh, P)
  Add_Object (_Mesh, P, _Vert)
#end

// Add a polygon to the mesh.
#macro Add_Polygon (_Mesh, _Vert_Indexes_Array)
  Add_Object (_Mesh, _Vert_Indexes_Array, _Face)
#end

// Add a triangle to the mesh.
#macro Add_Triangle (_Mesh, Pi1, Pi2, Pi3)
  #declare _Mesh[_Nb][_Trgl] = _Mesh[_Nb][_Trgl] + 1;
  Add_Polygon (_Mesh, array [3] { Pi1, Pi2, Pi3 })
#end

// Add a rectangle to the mesh.
#macro Add_Rectangle (_Mesh, Pi1, Pi2, Pi3, Pi4)
  #declare _Mesh[_Nb][_Trgl] = _Mesh[_Nb][_Trgl] + 2;
  Add_Polygon (_Mesh, array [4] { Pi1, Pi2, Pi3, Pi4 })
#end

// --------------------------------------------------------------------------------
// Object accessors

// --------------------------------------------------------------------------------
// 'High level' mesh manipulation methods

#macro Generate_Mesh (_Mesh, Smooth_Max_Angle)
// {
  // We create the array giving the faces that a vertice uses.
  // This will ease up normals calcultation.
  /*
  #local _Vertices_Faces = array [dimension_size (_Mesh[_Vert], 1)];
  #local i = 0;
  #while (i < _Mesh[_Nb][_Face])
    #local j = 0;
    #while (j < dimension_size (_Mesh[_Face][i], 1))
      // Adding face i to the list of faces of vertice number _Mesh[_Face][i][j]
      #local vert_index = _Mesh[_Face][i][j];
      #ifndef _Vertices_Faces [vert_index]
	_Vertices_Faces [vert_index]
      #end
      #local j = j + 1;
    #end
  #end
  */
  
  mesh2 {
    vertex_vectors {
      _Mesh[_Nb][_Vert],
      #local i = 0;
      #while (i < _Mesh[_Nb][_Vert])
	_Mesh[_Vert][i],
	#local i = i + 1;
      #end
    }
    face_indices {
      _Mesh[_Nb][_Trgl],
      #local i = 0;
      #while (i < _Mesh[_Nb][_Face])
	#switch (dimension_size (_Mesh[_Face][i], 1))

	  #case (3)
	    <_Mesh[_Face][i][0], _Mesh[_Face][i][1], _Mesh[_Face][i][2]>,
	  #break
	  
	  #case (4)
	    <_Mesh[_Face][i][0], _Mesh[_Face][i][1], _Mesh[_Face][i][2]>,
	    <_Mesh[_Face][i][0], _Mesh[_Face][i][2], _Mesh[_Face][i][3]>,
	  #break
	  
	#else
	  #error "Only Triangle and Rectangle faces supported for now !\n"
	#end
	
	#local i = i + 1;
      #end
    }
  }
#end

// Saves the mesh as an array for later use by this package
#macro Save_Mesh_Data (_Mesh, filename)
#end

// Saves the mesh as a mesh
#macro Save_Mesh (_Mesh, filename, Smooth_Max_Angle)
#end