diff options
Diffstat (limited to 'inc/glm/gtx/fast_exponential.inl')
| -rw-r--r-- | inc/glm/gtx/fast_exponential.inl | 166 |
1 files changed, 166 insertions, 0 deletions
diff --git a/inc/glm/gtx/fast_exponential.inl b/inc/glm/gtx/fast_exponential.inl new file mode 100644 index 0000000..54e1d00 --- /dev/null +++ b/inc/glm/gtx/fast_exponential.inl @@ -0,0 +1,166 @@ +///////////////////////////////////////////////////////////////////////////////////
+/// OpenGL Mathematics (glm.g-truc.net)
+///
+/// Copyright (c) 2005 - 2015 G-Truc Creation (www.g-truc.net)
+/// Permission is hereby granted, free of charge, to any person obtaining a copy
+/// of this software and associated documentation files (the "Software"), to deal
+/// in the Software without restriction, including without limitation the rights
+/// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+/// copies of the Software, and to permit persons to whom the Software is
+/// furnished to do so, subject to the following conditions:
+///
+/// The above copyright notice and this permission notice shall be included in
+/// all copies or substantial portions of the Software.
+///
+/// Restrictions:
+/// By making use of the Software for military purposes, you choose to make
+/// a Bunny unhappy.
+///
+/// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+/// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+/// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+/// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+/// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+/// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+/// THE SOFTWARE.
+///
+/// @ref gtx_fast_exponential
+/// @file glm/gtx/fast_exponential.inl
+/// @date 2006-01-09 / 2011-06-07
+/// @author Christophe Riccio
+///////////////////////////////////////////////////////////////////////////////////////////////////
+
+namespace glm
+{
+ // fastPow:
+ template <typename genType>
+ GLM_FUNC_QUALIFIER genType fastPow(genType x, genType y)
+ {
+ return exp(y * log(x));
+ }
+
+ template <typename T, precision P, template <typename, precision> class vecType>
+ GLM_FUNC_QUALIFIER vecType<T, P> fastPow(vecType<T, P> const & x, vecType<T, P> const & y)
+ {
+ return exp(y * log(x));
+ }
+
+ template <typename T>
+ GLM_FUNC_QUALIFIER T fastPow(T x, int y)
+ {
+ T f = static_cast<T>(1);
+ for(int i = 0; i < y; ++i)
+ f *= x;
+ return f;
+ }
+
+ template <typename T, precision P, template <typename, precision> class vecType>
+ GLM_FUNC_QUALIFIER vecType<T, P> fastPow(vecType<T, P> const & x, vecType<int, P> const & y)
+ {
+ vecType<T, P> Result(uninitialize);
+ for(detail::component_count_t i = 0; i < detail::component_count(x); ++i)
+ Result[i] = fastPow(x[i], y[i]);
+ return Result;
+ }
+
+ // fastExp
+ // Note: This function provides accurate results only for value between -1 and 1, else avoid it.
+ template <typename T>
+ GLM_FUNC_QUALIFIER T fastExp(T x)
+ {
+ // This has a better looking and same performance in release mode than the following code. However, in debug mode it's slower.
+ // return 1.0f + x * (1.0f + x * 0.5f * (1.0f + x * 0.3333333333f * (1.0f + x * 0.25 * (1.0f + x * 0.2f))));
+ T x2 = x * x;
+ T x3 = x2 * x;
+ T x4 = x3 * x;
+ T x5 = x4 * x;
+ return T(1) + x + (x2 * T(0.5)) + (x3 * T(0.1666666667)) + (x4 * T(0.041666667)) + (x5 * T(0.008333333333));
+ }
+ /* // Try to handle all values of float... but often shower than std::exp, glm::floor and the loop kill the performance
+ GLM_FUNC_QUALIFIER float fastExp(float x)
+ {
+ const float e = 2.718281828f;
+ const float IntegerPart = floor(x);
+ const float FloatPart = x - IntegerPart;
+ float z = 1.f;
+
+ for(int i = 0; i < int(IntegerPart); ++i)
+ z *= e;
+
+ const float x2 = FloatPart * FloatPart;
+ const float x3 = x2 * FloatPart;
+ const float x4 = x3 * FloatPart;
+ const float x5 = x4 * FloatPart;
+ return z * (1.0f + FloatPart + (x2 * 0.5f) + (x3 * 0.1666666667f) + (x4 * 0.041666667f) + (x5 * 0.008333333333f));
+ }
+
+ // Increase accuracy on number bigger that 1 and smaller than -1 but it's not enough for high and negative numbers
+ GLM_FUNC_QUALIFIER float fastExp(float x)
+ {
+ // This has a better looking and same performance in release mode than the following code. However, in debug mode it's slower.
+ // return 1.0f + x * (1.0f + x * 0.5f * (1.0f + x * 0.3333333333f * (1.0f + x * 0.25 * (1.0f + x * 0.2f))));
+ float x2 = x * x;
+ float x3 = x2 * x;
+ float x4 = x3 * x;
+ float x5 = x4 * x;
+ float x6 = x5 * x;
+ float x7 = x6 * x;
+ float x8 = x7 * x;
+ return 1.0f + x + (x2 * 0.5f) + (x3 * 0.1666666667f) + (x4 * 0.041666667f) + (x5 * 0.008333333333f)+ (x6 * 0.00138888888888f) + (x7 * 0.000198412698f) + (x8 * 0.0000248015873f);;
+ }
+ */
+
+ template <typename T, precision P, template <typename, precision> class vecType>
+ GLM_FUNC_QUALIFIER vecType<T, P> fastExp(vecType<T, P> const & x)
+ {
+ return detail::functor1<T, T, P, vecType>::call(fastExp, x);
+ }
+
+ // fastLog
+ template <typename genType>
+ GLM_FUNC_QUALIFIER genType fastLog(genType x)
+ {
+ return std::log(x);
+ }
+
+ /* Slower than the VC7.1 function...
+ GLM_FUNC_QUALIFIER float fastLog(float x)
+ {
+ float y1 = (x - 1.0f) / (x + 1.0f);
+ float y2 = y1 * y1;
+ return 2.0f * y1 * (1.0f + y2 * (0.3333333333f + y2 * (0.2f + y2 * 0.1428571429f)));
+ }
+ */
+
+ template <typename T, precision P, template <typename, precision> class vecType>
+ GLM_FUNC_QUALIFIER vecType<T, P> fastLog(vecType<T, P> const & x)
+ {
+ return detail::functor1<T, T, P, vecType>::call(fastLog, x);
+ }
+
+ //fastExp2, ln2 = 0.69314718055994530941723212145818f
+ template <typename genType>
+ GLM_FUNC_QUALIFIER genType fastExp2(genType x)
+ {
+ return fastExp(0.69314718055994530941723212145818f * x);
+ }
+
+ template <typename T, precision P, template <typename, precision> class vecType>
+ GLM_FUNC_QUALIFIER vecType<T, P> fastExp2(vecType<T, P> const & x)
+ {
+ return detail::functor1<T, T, P, vecType>::call(fastExp2, x);
+ }
+
+ // fastLog2, ln2 = 0.69314718055994530941723212145818f
+ template <typename genType>
+ GLM_FUNC_QUALIFIER genType fastLog2(genType x)
+ {
+ return fastLog(x) / 0.69314718055994530941723212145818f;
+ }
+
+ template <typename T, precision P, template <typename, precision> class vecType>
+ GLM_FUNC_QUALIFIER vecType<T, P> fastLog2(vecType<T, P> const & x)
+ {
+ return detail::functor1<T, T, P, vecType>::call(fastLog2, x);
+ }
+}//namespace glm
|