1 /*
2  * Copyright (C) 2011 The Android Open Source Project
3  *
4  * Licensed under the Apache License, Version 2.0 (the "License");
5  * you may not use this file except in compliance with the License.
6  * You may obtain a copy of the License at
7  *
8  *      http://www.apache.org/licenses/LICENSE-2.0
9  *
10  * Unless required by applicable law or agreed to in writing, software
11  * distributed under the License is distributed on an "AS IS" BASIS,
12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13  * See the License for the specific language governing permissions and
14  * limitations under the License.
15  */
16 
17 #ifndef ANDROID_VEC_H
18 #define ANDROID_VEC_H
19 
20 #include <math.h>
21 
22 #include <stdint.h>
23 #include <stddef.h>
24 
25 #include "traits.h"
26 
27 // -----------------------------------------------------------------------
28 
29 #define PURE __attribute__((pure))
30 
31 namespace android {
32 
33 // -----------------------------------------------------------------------
34 // non-inline helpers
35 
36 template <typename TYPE, size_t SIZE>
37 class vec;
38 
39 template <typename TYPE, size_t SIZE>
40 struct vbase;
41 
42 namespace helpers {
43 
min(T a,T b)44 template <typename T> inline T min(T a, T b) { return a<b ? a : b; }
max(T a,T b)45 template <typename T> inline T max(T a, T b) { return a>b ? a : b; }
46 
47 template < template<typename T, size_t S> class VEC,
48     typename TYPE, size_t SIZE, size_t S>
doAssign(vec<TYPE,SIZE> & lhs,const VEC<TYPE,S> & rhs)49 vec<TYPE, SIZE>& doAssign(
50         vec<TYPE, SIZE>& lhs, const VEC<TYPE, S>& rhs) {
51     const size_t minSize = min(SIZE, S);
52     const size_t maxSize = max(SIZE, S);
53     for (size_t i=0 ; i<minSize ; i++)
54         lhs[i] = rhs[i];
55     for (size_t i=minSize ; i<maxSize ; i++)
56         lhs[i] = 0;
57     return lhs;
58 }
59 
60 
61 template <
62     template<typename T, size_t S> class VLHS,
63     template<typename T, size_t S> class VRHS,
64     typename TYPE,
65     size_t SIZE
66 >
doAdd(const VLHS<TYPE,SIZE> & lhs,const VRHS<TYPE,SIZE> & rhs)67 VLHS<TYPE, SIZE> PURE doAdd(
68         const VLHS<TYPE, SIZE>& lhs,
69         const VRHS<TYPE, SIZE>& rhs) {
70     VLHS<TYPE, SIZE> r;
71     for (size_t i=0 ; i<SIZE ; i++)
72         r[i] = lhs[i] + rhs[i];
73     return r;
74 }
75 
76 template <
77     template<typename T, size_t S> class VLHS,
78     template<typename T, size_t S> class VRHS,
79     typename TYPE,
80     size_t SIZE
81 >
doSub(const VLHS<TYPE,SIZE> & lhs,const VRHS<TYPE,SIZE> & rhs)82 VLHS<TYPE, SIZE> PURE doSub(
83         const VLHS<TYPE, SIZE>& lhs,
84         const VRHS<TYPE, SIZE>& rhs) {
85     VLHS<TYPE, SIZE> r;
86     for (size_t i=0 ; i<SIZE ; i++)
87         r[i] = lhs[i] - rhs[i];
88     return r;
89 }
90 
91 template <
92     template<typename T, size_t S> class VEC,
93     typename TYPE,
94     size_t SIZE
95 >
doMulScalar(const VEC<TYPE,SIZE> & lhs,typename TypeTraits<TYPE>::ParameterType rhs)96 VEC<TYPE, SIZE> PURE doMulScalar(
97         const VEC<TYPE, SIZE>& lhs,
98         typename TypeTraits<TYPE>::ParameterType rhs) {
99     VEC<TYPE, SIZE> r;
100     for (size_t i=0 ; i<SIZE ; i++)
101         r[i] = lhs[i] * rhs;
102     return r;
103 }
104 
105 template <
106     template<typename T, size_t S> class VEC,
107     typename TYPE,
108     size_t SIZE
109 >
doScalarMul(typename TypeTraits<TYPE>::ParameterType lhs,const VEC<TYPE,SIZE> & rhs)110 VEC<TYPE, SIZE> PURE doScalarMul(
111         typename TypeTraits<TYPE>::ParameterType lhs,
112         const VEC<TYPE, SIZE>& rhs) {
113     VEC<TYPE, SIZE> r;
114     for (size_t i=0 ; i<SIZE ; i++)
115         r[i] = lhs * rhs[i];
116     return r;
117 }
118 
119 }; // namespace helpers
120 
121 // -----------------------------------------------------------------------
122 // Below we define the mathematical operators for vectors.
123 // We use template template arguments so we can generically
124 // handle the case where the right-hand-size and left-hand-side are
125 // different vector types (but with same value_type and size).
126 // This is needed for performance when using ".xy{z}" element access
127 // on vec<>. Without this, an extra conversion to vec<> would be needed.
128 //
129 // example:
130 //      vec4_t a;
131 //      vec3_t b;
132 //      vec3_t c = a.xyz + b;
133 //
134 //  "a.xyz + b" is a mixed-operation between a vbase<> and a vec<>, requiring
135 //  a conversion of vbase<> to vec<>. The template gunk below avoids this,
136 // by allowing the addition on these different vector types directly
137 //
138 
139 template <
140     template<typename T, size_t S> class VLHS,
141     template<typename T, size_t S> class VRHS,
142     typename TYPE,
143     size_t SIZE
144 >
145 inline VLHS<TYPE, SIZE> PURE operator + (
146         const VLHS<TYPE, SIZE>& lhs,
147         const VRHS<TYPE, SIZE>& rhs) {
148     return helpers::doAdd(lhs, rhs);
149 }
150 
151 template <
152     template<typename T, size_t S> class VLHS,
153     template<typename T, size_t S> class VRHS,
154     typename TYPE,
155     size_t SIZE
156 >
157 inline VLHS<TYPE, SIZE> PURE operator - (
158         const VLHS<TYPE, SIZE>& lhs,
159         const VRHS<TYPE, SIZE>& rhs) {
160     return helpers::doSub(lhs, rhs);
161 }
162 
163 template <
164     template<typename T, size_t S> class VEC,
165     typename TYPE,
166     size_t SIZE
167 >
168 inline VEC<TYPE, SIZE> PURE operator * (
169         const VEC<TYPE, SIZE>& lhs,
170         typename TypeTraits<TYPE>::ParameterType rhs) {
171     return helpers::doMulScalar(lhs, rhs);
172 }
173 
174 template <
175     template<typename T, size_t S> class VEC,
176     typename TYPE,
177     size_t SIZE
178 >
179 inline VEC<TYPE, SIZE> PURE operator * (
180         typename TypeTraits<TYPE>::ParameterType lhs,
181         const VEC<TYPE, SIZE>& rhs) {
182     return helpers::doScalarMul(lhs, rhs);
183 }
184 
185 
186 template <
187     template<typename T, size_t S> class VLHS,
188     template<typename T, size_t S> class VRHS,
189     typename TYPE,
190     size_t SIZE
191 >
dot_product(const VLHS<TYPE,SIZE> & lhs,const VRHS<TYPE,SIZE> & rhs)192 TYPE PURE dot_product(
193         const VLHS<TYPE, SIZE>& lhs,
194         const VRHS<TYPE, SIZE>& rhs) {
195     TYPE r(0);
196     for (size_t i=0 ; i<SIZE ; i++)
197         r += lhs[i] * rhs[i];
198     return r;
199 }
200 
201 template <
202     template<typename T, size_t S> class V,
203     typename TYPE,
204     size_t SIZE
205 >
length(const V<TYPE,SIZE> & v)206 TYPE PURE length(const V<TYPE, SIZE>& v) {
207     return sqrt(dot_product(v, v));
208 }
209 
210 template <
211     template<typename T, size_t S> class V,
212     typename TYPE,
213     size_t SIZE
214 >
length_squared(const V<TYPE,SIZE> & v)215 TYPE PURE length_squared(const V<TYPE, SIZE>& v) {
216     return dot_product(v, v);
217 }
218 
219 template <
220     template<typename T, size_t S> class V,
221     typename TYPE,
222     size_t SIZE
223 >
normalize(const V<TYPE,SIZE> & v)224 V<TYPE, SIZE> PURE normalize(const V<TYPE, SIZE>& v) {
225     return v * (1/length(v));
226 }
227 
228 template <
229     template<typename T, size_t S> class VLHS,
230     template<typename T, size_t S> class VRHS,
231     typename TYPE
232 >
cross_product(const VLHS<TYPE,3> & u,const VRHS<TYPE,3> & v)233 VLHS<TYPE, 3> PURE cross_product(
234         const VLHS<TYPE, 3>& u,
235         const VRHS<TYPE, 3>& v) {
236     VLHS<TYPE, 3> r;
237     r.x = u.y*v.z - u.z*v.y;
238     r.y = u.z*v.x - u.x*v.z;
239     r.z = u.x*v.y - u.y*v.x;
240     return r;
241 }
242 
243 
244 template <typename TYPE, size_t SIZE>
245 vec<TYPE, SIZE> PURE operator - (const vec<TYPE, SIZE>& lhs) {
246     vec<TYPE, SIZE> r;
247     for (size_t i=0 ; i<SIZE ; i++)
248         r[i] = -lhs[i];
249     return r;
250 }
251 
252 // -----------------------------------------------------------------------
253 
254 // This our basic vector type, it just implements the data storage
255 // and accessors.
256 
257 template <typename TYPE, size_t SIZE>
258 struct vbase {
259     TYPE v[SIZE];
260     inline const TYPE& operator[](size_t i) const { return v[i]; }
261     inline       TYPE& operator[](size_t i)       { return v[i]; }
262 };
263 template<> struct vbase<float, 2> {
264     union {
265         float v[2];
266         struct { float x, y; };
267         struct { float s, t; };
268     };
269     inline const float& operator[](size_t i) const { return v[i]; }
270     inline       float& operator[](size_t i)       { return v[i]; }
271 };
272 template<> struct vbase<float, 3> {
273     union {
274         float v[3];
275         struct { float x, y, z; };
276         struct { float s, t, r; };
277         vbase<float, 2> xy;
278         vbase<float, 2> st;
279     };
280     inline const float& operator[](size_t i) const { return v[i]; }
281     inline       float& operator[](size_t i)       { return v[i]; }
282 };
283 template<> struct vbase<float, 4> {
284     union {
285         float v[4];
286         struct { float x, y, z, w; };
287         struct { float s, t, r, q; };
288         vbase<float, 3> xyz;
289         vbase<float, 3> str;
290         vbase<float, 2> xy;
291         vbase<float, 2> st;
292     };
293     inline const float& operator[](size_t i) const { return v[i]; }
294     inline       float& operator[](size_t i)       { return v[i]; }
295 };
296 
297 // -----------------------------------------------------------------------
298 
299 template <typename TYPE, size_t SIZE>
300 class vec : public vbase<TYPE, SIZE>
301 {
302     typedef typename TypeTraits<TYPE>::ParameterType pTYPE;
303     typedef vbase<TYPE, SIZE> base;
304 
305 public:
306     // STL-like interface.
307     typedef TYPE value_type;
308     typedef TYPE& reference;
309     typedef TYPE const& const_reference;
310     typedef size_t size_type;
311 
312     typedef TYPE* iterator;
313     typedef TYPE const* const_iterator;
314     iterator begin() { return base::v; }
315     iterator end() { return base::v + SIZE; }
316     const_iterator begin() const { return base::v; }
317     const_iterator end() const { return base::v + SIZE; }
318     size_type size() const { return SIZE; }
319 
320     // -----------------------------------------------------------------------
321     // default constructors
322 
323     vec() { }
324     vec(const vec& rhs)  : base(rhs) { }
325     vec(const base& rhs) : base(rhs) { }
326 
327     // -----------------------------------------------------------------------
328     // conversion constructors
329 
330     vec(pTYPE rhs) {
331         for (size_t i=0 ; i<SIZE ; i++)
332             base::operator[](i) = rhs;
333     }
334 
335     template < template<typename T, size_t S> class VEC, size_t S>
336     explicit vec(const VEC<TYPE, S>& rhs) {
337         helpers::doAssign(*this, rhs);
338     }
339 
340     explicit vec(TYPE const* array) {
341         for (size_t i=0 ; i<SIZE ; i++)
342             base::operator[](i) = array[i];
343     }
344 
345     // -----------------------------------------------------------------------
346     // Assignment
347 
348     vec& operator = (const vec& rhs) {
349         base::operator=(rhs);
350         return *this;
351     }
352 
353     vec& operator = (const base& rhs) {
354         base::operator=(rhs);
355         return *this;
356     }
357 
358     vec& operator = (pTYPE rhs) {
359         for (size_t i=0 ; i<SIZE ; i++)
360             base::operator[](i) = rhs;
361         return *this;
362     }
363 
364     template < template<typename T, size_t S> class VEC, size_t S>
365     vec& operator = (const VEC<TYPE, S>& rhs) {
366         return helpers::doAssign(*this, rhs);
367     }
368 
369     // -----------------------------------------------------------------------
370     // operation-assignment
371 
372     vec& operator += (const vec& rhs);
373     vec& operator -= (const vec& rhs);
374     vec& operator *= (pTYPE rhs);
375 
376     // -----------------------------------------------------------------------
377     // non-member function declaration and definition
378     // NOTE: we declare the non-member function as friend inside the class
379     // so that they are known to the compiler when the class is instantiated.
380     // This helps the compiler doing template argument deduction when the
381     // passed types are not identical. Essentially this helps with
382     // type conversion so that you can multiply a vec<float> by an scalar int
383     // (for instance).
384 
385     friend inline vec PURE operator + (const vec& lhs, const vec& rhs) {
386         return helpers::doAdd(lhs, rhs);
387     }
388     friend inline vec PURE operator - (const vec& lhs, const vec& rhs) {
389         return helpers::doSub(lhs, rhs);
390     }
391     friend inline vec PURE operator * (const vec& lhs, pTYPE v) {
392         return helpers::doMulScalar(lhs, v);
393     }
394     friend inline vec PURE operator * (pTYPE v, const vec& rhs) {
395         return helpers::doScalarMul(v, rhs);
396     }
397     friend inline TYPE PURE dot_product(const vec& lhs, const vec& rhs) {
398         return android::dot_product(lhs, rhs);
399     }
400 };
401 
402 // -----------------------------------------------------------------------
403 
404 template <typename TYPE, size_t SIZE>
405 vec<TYPE, SIZE>& vec<TYPE, SIZE>::operator += (const vec<TYPE, SIZE>& rhs) {
406     vec<TYPE, SIZE>& lhs(*this);
407     for (size_t i=0 ; i<SIZE ; i++)
408         lhs[i] += rhs[i];
409     return lhs;
410 }
411 
412 template <typename TYPE, size_t SIZE>
413 vec<TYPE, SIZE>& vec<TYPE, SIZE>::operator -= (const vec<TYPE, SIZE>& rhs) {
414     vec<TYPE, SIZE>& lhs(*this);
415     for (size_t i=0 ; i<SIZE ; i++)
416         lhs[i] -= rhs[i];
417     return lhs;
418 }
419 
420 template <typename TYPE, size_t SIZE>
421 vec<TYPE, SIZE>& vec<TYPE, SIZE>::operator *= (vec<TYPE, SIZE>::pTYPE rhs) {
422     vec<TYPE, SIZE>& lhs(*this);
423     for (size_t i=0 ; i<SIZE ; i++)
424         lhs[i] *= rhs;
425     return lhs;
426 }
427 
428 // -----------------------------------------------------------------------
429 
430 typedef vec<float, 2> vec2_t;
431 typedef vec<float, 3> vec3_t;
432 typedef vec<float, 4> vec4_t;
433 
434 // -----------------------------------------------------------------------
435 
436 }; // namespace android
437 
438 #endif /* ANDROID_VEC_H */
439