1 // Copyright 2009-2021 Intel Corporation
2 // SPDX-License-Identifier: Apache-2.0
3 
4 #pragma once
5 
6 #include "../common/geometry.h"
7 
8 namespace embree
9 {
10   static const size_t MAX_PATCH_VALENCE = 16;         //!< maximum number of vertices of a patch
11   static const size_t MAX_RING_FACE_VALENCE = 64;     //!< maximum number of faces per ring
12   static const size_t MAX_RING_EDGE_VALENCE = 2*64;   //!< maximum number of edges per ring
13 
14   class CatmullClarkPrecomputedCoefficients
15   {
16   private:
17 
18     float table_cos_2PI_div_n[MAX_RING_FACE_VALENCE+1];
19 
20     float* table_limittangent_a[MAX_RING_FACE_VALENCE+1];
21     float* table_limittangent_b[MAX_RING_FACE_VALENCE+1];
22     float table_limittangent_c[MAX_RING_FACE_VALENCE+1];
23 
set_cos_2PI_div_n(const size_t n)24     __forceinline float set_cos_2PI_div_n(const size_t n) {
25       if (unlikely(n == 0)) return 1.0f;
26       return cosf(2.0f*float(pi)/(float)n);
27     }
28 
set_limittangent_a(const size_t i,const size_t n)29     __forceinline float set_limittangent_a(const size_t i, const size_t n)
30     {
31       if (unlikely(n == 0)) return 1.0f;
32       const float c0 = 1.0f/(float)n * 1.0f / sqrtf(4.0f + cosf(float(pi)/(float)n)*cosf(float(pi)/(float)n));
33       const float c1 = (1.0f/(float)n + cosf(float(pi)/(float)n) * c0);
34       return cosf(2.0f*float(pi)*(float)i/(float)n) * c1;
35     }
36 
set_limittangent_b(const size_t i,const size_t n)37     __forceinline float set_limittangent_b(const size_t i, const size_t n)
38     {
39       if (unlikely(n == 0)) return 1.0f;
40       const float c0 = 1.0f/(float)n * 1.0f / sqrtf(4.0f + cosf(float(pi)/(float)n)*cosf(float(pi)/(float)n));
41       return cosf((2.0f*float(pi)*i+float(pi))/(float)n) * c0;
42     }
43 
set_limittangent_c(const size_t n)44     __forceinline float set_limittangent_c(const size_t n)
45     {
46       if (unlikely(n == 0)) return 1.0f;
47       return 2.0f/16.0f * (5.0f + cosf(2.0f*float(pi)/(float)n) + cosf(float(pi)/(float)n) * sqrtf(18.0f+2.0f*cosf(2.0f*float(pi)/(float)n)));
48     }
49 
50   public:
51 
cos_2PI_div_n(const size_t n)52     __forceinline float cos_2PI_div_n(const size_t n)
53     {
54       if (likely(n <= MAX_RING_FACE_VALENCE))
55         return table_cos_2PI_div_n[n];
56       else
57         return set_cos_2PI_div_n(n);
58     }
59 
limittangent_a(const size_t i,const size_t n)60     __forceinline float limittangent_a(const size_t i, const size_t n)
61     {
62       assert(n <= MAX_RING_FACE_VALENCE);
63       assert(i < n);
64       return table_limittangent_a[n][i];
65     }
66 
limittangent_b(const size_t i,const size_t n)67     __forceinline float limittangent_b(const size_t i, const size_t n)
68     {
69       assert(n <= MAX_RING_FACE_VALENCE);
70       assert(i < n);
71       return table_limittangent_b[n][i];
72     }
73 
limittangent_c(const size_t n)74     __forceinline float limittangent_c(const size_t n)
75     {
76       assert(n <= MAX_RING_FACE_VALENCE);
77       return table_limittangent_c[n];
78     }
79 
80     static CatmullClarkPrecomputedCoefficients table;
81 
82     CatmullClarkPrecomputedCoefficients();
83     ~CatmullClarkPrecomputedCoefficients();
84   };
85 }
86