95 lines
2.8 KiB
C++
95 lines
2.8 KiB
C++
/*******************************************************************************
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* The MIT License (MIT)
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*
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* Copyright (c) 2015 David Williams and Matthew Williams
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*
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* Permission is hereby granted, free of charge, to any person obtaining a copy
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* of this software and associated documentation files (the "Software"), to deal
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* in the Software without restriction, including without limitation the rights
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* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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* copies of the Software, and to permit persons to whom the Software is
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* furnished to do so, subject to the following conditions:
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*
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* The above copyright notice and this permission notice shall be included in all
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* copies or substantial portions of the Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
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* SOFTWARE.
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*******************************************************************************/
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#ifndef __PolyVox_Utility_H__
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#define __PolyVox_Utility_H__
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#include "PlatformDefinitions.h"
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#include <cstdint>
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namespace PolyVox
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{
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inline bool isPowerOf2(uint32_t uInput)
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{
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if (uInput == 0)
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return false;
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else
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return ((uInput & (uInput - 1)) == 0);
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}
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//Note: this function only works for inputs which are a power of two and not zero
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//If this is not the case then the output is undefined.
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inline uint8_t logBase2(uint32_t uInput)
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{
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//Release mode validation
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if (uInput == 0)
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{
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POLYVOX_THROW(std::invalid_argument, "Cannot compute the log of zero.");
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}
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if (!isPowerOf2(uInput))
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{
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POLYVOX_THROW(std::invalid_argument, "Input must be a power of two in order to compute the log.");
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}
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uint32_t uResult = 0;
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while ((uInput >> uResult) != 0)
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{
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++uResult;
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}
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return static_cast<uint8_t>(uResult - 1);
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}
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// http://graphics.stanford.edu/~seander/bithacks.html#RoundUpPowerOf2
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inline uint32_t upperPowerOfTwo(uint32_t v)
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{
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v--;
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v |= v >> 1;
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v |= v >> 2;
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v |= v >> 4;
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v |= v >> 8;
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v |= v >> 16;
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v++;
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return v;
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}
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inline int32_t roundTowardsNegInf(float r)
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{
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return (r >= 0.0) ? static_cast<int32_t>(r) : static_cast<int32_t>(r - 1.0f);
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}
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inline int32_t roundToNearestInteger(float r)
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{
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return (r >= 0.0) ? static_cast<int32_t>(r + 0.5f) : static_cast<int32_t>(r - 0.5f);
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}
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template <typename Type>
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inline Type clamp(const Type& value, const Type& low, const Type& high)
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{
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return (std::min)(high, (std::max)(low, value));
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}
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}
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#endif
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