Libs/MaterialSystem/Common/DepRelMatrix.hpp

   1 /*
   2 Cafu Engine, http://www.cafu.de/
   3 Copyright (c) Carsten Fuchs and other contributors.
   4 This project is licensed under the terms of the MIT license.
   5 */
   6
   7 /****************************************/
   8 /*** Dependency Relationship Matrices ***/
   9 /****************************************/
  10
  11 #ifndef CAFU_DEP_REL_MATRIX_HPP_INCLUDED
  12 #define CAFU_DEP_REL_MATRIX_HPP_INCLUDED
  13
  14 #include "Math3D/Matrix.hpp"
  15
  16
  17 /// A matrix class with which dependencies among matrices can be handled.
  18 /// In order to model a specific dependency relationship, child classes should be derived from this class,
  19 /// see InverseMatrixT and ProductMatrixT for examples.
  20 /// Note that also the roots/parents/sources of the dep. relationships should (or at least: can) be matrix objects
  21 /// of the DepRelMatrixT class, because that helps to avoid unecessary updates of the dependents.
  22 class DepRelMatrixT
  23 {
  24     public:
  25
  26     DepRelMatrixT();
  27     DepRelMatrixT(const DepRelMatrixT& Other);
  28     virtual ~DepRelMatrixT() { }
  29
  30     /// This method updates this matrix from the matrices it depends on (the source matrices).
  31     /// Derived classes are expected to overwrite this method in order to provide the desired behaviour.
  32     /// Their code should make good use of the Age member in order to minimize update efforts.
  33     /// User code should call this method before accessing the Matrix (or Age) member whenever
  34     /// there is a chance that the source matrices changed since the last call to Update().
  35     virtual void Update()
  36     {
  37     }
  38
  39     MatrixT             Matrix;     ///< The matrix.
  40     unsigned long       Age;        ///< The "age" or change-count of this matrix. How old the source matrix was when we were last updated.
  41     const unsigned long ID;         ///< The unique ID of this matrix. Useful for unambiguous identification.
  42
  43
  44     private:
  45
  46     static unsigned long GlobalIDCount;
  47 };
  48
  49
  50 /// This class models the relationship with which a inverse matrix depends on its original matrix.
  51 class InverseMatrixT : public DepRelMatrixT
  52 {
  53     public:
  54
  55     InverseMatrixT(DepRelMatrixT* Source=NULL);
  56
  57     /// Sets the source matrix. Useful if InverseMatrixTs are stored in an array.
  58     void SetSourceMatrix(DepRelMatrixT* Source);
  59
  60     /// Overwrite the base class method.
  61     virtual void Update();
  62
  63
  64     private:
  65
  66     DepRelMatrixT* m_Source;
  67 };
  68
  69
  70 /// This class models the relationship with which a product matrix A*B depends on its components A and B
  71 /// (e.g.\ how a model-to-view matrix depends on the model-to-world and world-to-view matrices).
  72 ///
  73 /// Note that \code ProductMatrixT ModelView(WorldToView, ModelToWorld); \endcode would be the correct statement
  74 /// for a model-to-view matrix, whereas the opposite component order
  75 /// \code ProductMatrixT ModelView(ModelToWorld, WorldToView); \endcode is wrong.
  76 class ProductMatrixT : public DepRelMatrixT
  77 {
  78     public:
  79
  80     ProductMatrixT(DepRelMatrixT& A, DepRelMatrixT& B);
  81
  82     /// Overwrite the base class method.
  83     virtual void Update();
  84
  85
  86     private:
  87
  88     DepRelMatrixT& m_A;
  89     DepRelMatrixT& m_B;
  90 };
  91
  92 #endif