94 lines
2.5 KiB
C++
94 lines
2.5 KiB
C++
/*******************************************************************************
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Copyright (c) 2005-2009 David Williams
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This software is provided 'as-is', without any express or implied
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warranty. In no event will the authors be held liable for any damages
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arising from the use of this software.
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Permission is granted to anyone to use this software for any purpose,
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including commercial applications, and to alter it and redistribute it
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freely, subject to the following restrictions:
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1. The origin of this software must not be misrepresented; you must not
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claim that you wrote the original software. If you use this software
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in a product, an acknowledgment in the product documentation would be
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appreciated but is not required.
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2. Altered source versions must be plainly marked as such, and must not be
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misrepresented as being the original software.
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3. This notice may not be removed or altered from any source
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distribution.
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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 "PolyVox/Impl/TypeDef.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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