source: projectionDesigner/tag/ProjectionDesigner_1.1.5/projdesigner/include/gmtl/VecExprMeta.h @ 2

Last change on this file since 2 was 2, checked in by Torben Dannhauer, 10 years ago
File size: 5.8 KB
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1/************************************************************** ggt-head beg
2 *
3 * GGT: Generic Graphics Toolkit
4 *
5 * Original Authors:
6 *   Allen Bierbaum
7 *
8 * -----------------------------------------------------------------
9 * File:          VecExprMeta.h,v
10 * Date modified: 2004/11/11 21:34:33
11 * Version:       1.3
12 * -----------------------------------------------------------------
13 *
14 *********************************************************** ggt-head end */
15/*************************************************************** ggt-cpr beg
16*
17* GGT: The Generic Graphics Toolkit
18* Copyright (C) 2001,2002 Allen Bierbaum
19*
20* This library is free software; you can redistribute it and/or
21* modify it under the terms of the GNU Lesser General Public
22* License as published by the Free Software Foundation; either
23* version 2.1 of the License, or (at your option) any later version.
24*
25* This library is distributed in the hope that it will be useful,
26* but WITHOUT ANY WARRANTY; without even the implied warranty of
27* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
28* Lesser General Public License for more details.
29*
30* You should have received a copy of the GNU Lesser General Public
31* License along with this library; if not, write to the Free Software
32* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
33*
34 ************************************************************ ggt-cpr end */
35#ifndef _GMTL_VEC_EXPR_META_H
36#define _GMTL_VEC_EXPR_META_H
37
38#include <gmtl/Util/Meta.h>
39#include <gmtl/VecOpsMeta.h>
40#include <gmtl/VecBase.h>
41
42/** Expression template classes for vec operations
43 */
44namespace gmtl
45{
46namespace meta
47{
48/** @ingroup VecExprMeta */
49//@{
50
51
52// ------------ Expression templates primitives ----------- //
53// Expression templates for vectors
54//
55// NOTE: These could probably be optimized more in the future
56
57// Concepts:
58//
59// VectorExpression:
60//    types:
61//    interface:
62//       TYPE eval(unsigned i):  Returns evaluation of expression at elt i
63
64
65/** template to hold a scalar argument. */
66template <typename T>
67struct ScalarArg
68{
69   typedef T DataType;
70
71   const T mScalar;
72
73   inline ScalarArg(const T scalar) : mScalar(scalar) {}
74   inline T operator[](const unsigned) const
75   { return mScalar; }
76};
77
78template <typename T>
79inline ScalarArg<T> makeScalarArg(T val)
80{ return ScalarArg<T>(val); }
81
82// --- TRAITS --- //
83/** Traits class for expression template parameters.
84* NOTE: These types are VERY important to the performance of the code.
85*    They allow the compiler to optimize (ie. eliminate) much code.
86*/
87template<typename T>
88struct ExprTraits
89{
90   typedef const T ExprRef;     // Refer using a constant reference
91};
92
93template<typename T, unsigned SIZE>
94struct ExprTraits< VecBase<T, SIZE, ScalarArg<T> > >
95{
96   typedef const VecBase<T,SIZE,ScalarArg<T> > ExprRef;
97};
98
99template<typename T, unsigned SIZE>
100struct ExprTraits< VecBase<T, SIZE, DefaultVecTag> >
101{
102   typedef const VecBase<T,SIZE,DefaultVecTag>& ExprRef;
103};
104
105
106// -- Expressions -- //
107/** Binary vector expression.
108*
109* Stores the two vector expressions to process.
110*/
111template <typename EXP1_T, typename EXP2_T, typename OP>
112struct VecBinaryExpr
113{
114   typedef typename EXP1_T::DataType DataType;
115
116   typename ExprTraits<EXP1_T>::ExprRef Exp1;
117   typename ExprTraits<EXP2_T>::ExprRef Exp2;
118
119   inline VecBinaryExpr(const EXP1_T& e1, const EXP2_T& e2) : Exp1(e1), Exp2(e2) {;}
120   inline DataType operator[](const unsigned i) const
121   { return OP::eval(Exp1[i], Exp2[i]); }
122};
123
124/** Unary vector expression.
125* Holds the vector expression and unary operation to apply to it.
126*/
127template <typename EXP1_T, typename OP>
128struct VecUnaryExpr
129{
130   typedef typename EXP1_T::DataType DataType;
131
132   typename ExprTraits<EXP1_T>::ExprRef Exp1;
133
134   inline VecUnaryExpr(const EXP1_T& e1) : Exp1(e1) {;}
135   inline DataType operator[](const unsigned i) const
136   { return OP::eval(Exp1[i]); }
137};
138
139// --- Operations --- //
140/* Binary operations to add two vector expressions. */
141struct VecPlusBinary
142{
143   template <typename T>
144   static inline T eval(const T a1, const T a2)
145   { return a1+a2; }
146};
147
148/* Binary operations to subtract two vector expressions. */
149struct VecMinusBinary
150{
151   template <typename T>
152   static inline T eval(const T a1, const T a2)
153   { return a1-a2; }
154};
155
156struct VecMultBinary
157{
158   template<typename T>
159   static inline T eval(const T a1, const T a2)
160   { return a1 * a2; }
161};
162
163struct VecDivBinary
164{
165   template<typename T>
166   static inline T eval(const T a1, const T a2)
167   { return a1/a2; }
168};
169
170/** Negation of the values. */
171struct VecNegUnary
172{
173   template <typename T>
174   static inline T eval(const T a1)
175   { return -a1; }
176};
177
178
179/*
180template<typename T, unsigned SIZE, typename R1, typename R2>
181inline VecBase<T,SIZE, VecBinaryExpr<VecBase<T,SIZE,R1>, VecBase<T,SIZE,R2>, VecPlusBinary> >
182sum(const VecBase<T,SIZE,R1>& v1, const VecBase<T,SIZE,R2>& v2)
183{
184   return VecBase<T,SIZE,
185               VecBinaryExpr<VecBase<T,SIZE,R1>,
186                             VecBase<T,SIZE,R2>,
187                             VecPlusBinary> >( VecBinaryExpr<VecBase<T,SIZE,R1>,
188                                                             VecBase<T,SIZE,R2>,
189                                                             VecPlusBinary>(v1,v2) );
190}
191
192
193template<typename T, unsigned SIZE, typename R1>
194inline VecBase<T,SIZE, VecBinaryExpr<VecBase<T,SIZE,R1>, VecBase<T,SIZE,ScalarArg<T> >, VecPlusBinary> >
195sum(const VecBase<T,SIZE,R1>& v1, const T& arg)
196{
197   return VecBase<T,SIZE,
198               VecBinaryExpr<VecBase<T,SIZE,R1>,
199                             VecBase<T,SIZE,ScalarArg<T> >,
200                             VecPlusBinary> >( VecBinaryExpr<VecBase<T,SIZE,R1>,
201                                                             VecBase<T,SIZE,ScalarArg<T> >,
202                                                             VecPlusBinary>(v1,ScalarArg<T>(arg)) );
203}
204*/
205
206//@}
207
208
209} // namespace meta
210} // end namespace
211
212
213#endif
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