1 /////////////////////////////////////////////////////////////////////////////////////////////////// 2 // OpenGL Mathematics Copyright (c) 2005 - 2014 G-Truc Creation (www.g-truc.net) 3 /////////////////////////////////////////////////////////////////////////////////////////////////// 4 // Created : 2006-01-04 5 // Updated : 2011-10-14 6 // Licence : This source is under MIT License 7 // File : glm/gtx/fast_square_root.inl 8 /////////////////////////////////////////////////////////////////////////////////////////////////// 9 10 namespace glm 11 { 12 // fastSqrt 13 template <typename genType> 14 GLM_FUNC_QUALIFIER genType fastSqrt 15 ( 16 genType const & x 17 ) 18 { 19 GLM_STATIC_ASSERT(std::numeric_limits<genType>::is_iec559, "'fastSqrt' only accept floating-point input"); 20 21 return genType(1) / fastInverseSqrt(x); 22 } 23 24 VECTORIZE_VEC(fastSqrt) 25 26 // fastInversesqrt 27 template <> 28 GLM_FUNC_QUALIFIER float fastInverseSqrt<float>(float const & x) 29 { 30 # ifdef __CUDACC__ // Wordaround for a CUDA compiler bug up to CUDA6 31 detail::tvec1<T, P> tmp(detail::compute_inversesqrt<detail::tvec1, float, lowp>::call(detail::tvec1<float, lowp>(x))); 32 return tmp.x; 33 # else 34 return detail::compute_inversesqrt<detail::tvec1, float, lowp>::call(detail::tvec1<float, lowp>(x)).x; 35 # endif 36 } 37 38 template <> 39 GLM_FUNC_QUALIFIER double fastInverseSqrt<double>(double const & x) 40 { 41 # ifdef __CUDACC__ // Wordaround for a CUDA compiler bug up to CUDA6 42 detail::tvec1<T, P> tmp(detail::compute_inversesqrt<detail::tvec1, double, lowp>::call(detail::tvec1<double, lowp>(x))); 43 return tmp.x; 44 # else 45 return detail::compute_inversesqrt<detail::tvec1, double, lowp>::call(detail::tvec1<double, lowp>(x)).x; 46 # endif 47 } 48 49 template <template <class, precision> class vecType, typename T, precision P> 50 GLM_FUNC_QUALIFIER vecType<T, P> fastInverseSqrt 51 ( 52 vecType<T, P> const & x 53 ) 54 { 55 return detail::compute_inversesqrt<vecType, T, P>::call(x); 56 } 57 58 VECTORIZE_VEC(fastInverseSqrt) 59 60 // fastLength 61 template <typename genType> 62 GLM_FUNC_QUALIFIER genType fastLength 63 ( 64 genType const & x 65 ) 66 { 67 return abs(x); 68 } 69 70 template <typename valType, precision P> 71 GLM_FUNC_QUALIFIER valType fastLength 72 ( 73 detail::tvec2<valType, P> const & x 74 ) 75 { 76 valType sqr = x.x * x.x + x.y * x.y; 77 return fastSqrt(sqr); 78 } 79 80 template <typename valType, precision P> 81 GLM_FUNC_QUALIFIER valType fastLength 82 ( 83 detail::tvec3<valType, P> const & x 84 ) 85 { 86 valType sqr = x.x * x.x + x.y * x.y + x.z * x.z; 87 return fastSqrt(sqr); 88 } 89 90 template <typename valType, precision P> 91 GLM_FUNC_QUALIFIER valType fastLength 92 ( 93 detail::tvec4<valType, P> const & x 94 ) 95 { 96 valType sqr = x.x * x.x + x.y * x.y + x.z * x.z + x.w * x.w; 97 return fastSqrt(sqr); 98 } 99 100 // fastDistance 101 template <typename genType> 102 GLM_FUNC_QUALIFIER genType fastDistance 103 ( 104 genType const & x, 105 genType const & y 106 ) 107 { 108 return fastLength(y - x); 109 } 110 111 // fastNormalize 112 template <typename genType> 113 GLM_FUNC_QUALIFIER genType fastNormalize 114 ( 115 genType const & x 116 ) 117 { 118 return x > genType(0) ? genType(1) : -genType(1); 119 } 120 121 template <typename valType, precision P> 122 GLM_FUNC_QUALIFIER detail::tvec2<valType, P> fastNormalize 123 ( 124 detail::tvec2<valType, P> const & x 125 ) 126 { 127 valType sqr = x.x * x.x + x.y * x.y; 128 return x * fastInverseSqrt(sqr); 129 } 130 131 template <typename valType, precision P> 132 GLM_FUNC_QUALIFIER detail::tvec3<valType, P> fastNormalize 133 ( 134 detail::tvec3<valType, P> const & x 135 ) 136 { 137 valType sqr = x.x * x.x + x.y * x.y + x.z * x.z; 138 return x * fastInverseSqrt(sqr); 139 } 140 141 template <typename valType, precision P> 142 GLM_FUNC_QUALIFIER detail::tvec4<valType, P> fastNormalize 143 ( 144 detail::tvec4<valType, P> const & x 145 ) 146 { 147 valType sqr = x.x * x.x + x.y * x.y + x.z * x.z + x.w * x.w; 148 return x * fastInverseSqrt(sqr); 149 } 150 }//namespace glm 151
