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++ // Copyright 2009-2021 Intel Corporation
++ // SPDX-License-Identifier: Apache-2.0
++
++ #pragma once
++
++ #include "../common/geometry.h"
++
++ namespace embree
++ {
++ static const size_t MAX_PATCH_VALENCE = 16; //!< maximum number of vertices of a patch
++ static const size_t MAX_RING_FACE_VALENCE = 64; //!< maximum number of faces per ring
++ static const size_t MAX_RING_EDGE_VALENCE = 2*64; //!< maximum number of edges per ring
++
++ class CatmullClarkPrecomputedCoefficients
++ {
++ private:
++
++ float table_cos_2PI_div_n[MAX_RING_FACE_VALENCE+1];
++
++ float* table_limittangent_a[MAX_RING_FACE_VALENCE+1];
++ float* table_limittangent_b[MAX_RING_FACE_VALENCE+1];
++ float table_limittangent_c[MAX_RING_FACE_VALENCE+1];
++
++ __forceinline float set_cos_2PI_div_n(const size_t n) {
++ if (unlikely(n == 0)) return 1.0f;
++ return cosf(2.0f*float(pi)/(float)n);
++ }
++
++ __forceinline float set_limittangent_a(const size_t i, const size_t n)
++ {
++ if (unlikely(n == 0)) return 1.0f;
++ const float c0 = 1.0f/(float)n * 1.0f / sqrtf(4.0f + cosf(float(pi)/(float)n)*cosf(float(pi)/(float)n));
++ const float c1 = (1.0f/(float)n + cosf(float(pi)/(float)n) * c0);
++ return cosf(2.0f*float(pi)*(float)i/(float)n) * c1;
++ }
++
++ __forceinline float set_limittangent_b(const size_t i, const size_t n)
++ {
++ if (unlikely(n == 0)) return 1.0f;
++ const float c0 = 1.0f/(float)n * 1.0f / sqrtf(4.0f + cosf(float(pi)/(float)n)*cosf(float(pi)/(float)n));
++ return cosf((2.0f*float(pi)*i+float(pi))/(float)n) * c0;
++ }
++
++ __forceinline float set_limittangent_c(const size_t n)
++ {
++ if (unlikely(n == 0)) return 1.0f;
++ 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)));
++ }
++
++ public:
++
++ __forceinline float cos_2PI_div_n(const size_t n)
++ {
++ if (likely(n <= MAX_RING_FACE_VALENCE))
++ return table_cos_2PI_div_n[n];
++ else
++ return set_cos_2PI_div_n(n);
++ }
++
++ __forceinline float limittangent_a(const size_t i, const size_t n)
++ {
++ assert(n <= MAX_RING_FACE_VALENCE);
++ assert(i < n);
++ return table_limittangent_a[n][i];
++ }
++
++ __forceinline float limittangent_b(const size_t i, const size_t n)
++ {
++ assert(n <= MAX_RING_FACE_VALENCE);
++ assert(i < n);
++ return table_limittangent_b[n][i];
++ }
++
++ __forceinline float limittangent_c(const size_t n)
++ {
++ assert(n <= MAX_RING_FACE_VALENCE);
++ return table_limittangent_c[n];
++ }
++
++ static CatmullClarkPrecomputedCoefficients table;
++
++ CatmullClarkPrecomputedCoefficients();
++ ~CatmullClarkPrecomputedCoefficients();
++ };
++ }