68 lines
1.3 KiB
C++
68 lines
1.3 KiB
C++
/* util.hh
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* vim: set tw=80:
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* Eryn Wells <eryn@erynwells.me>
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*/
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#ifndef __BASICS_UTIL_HH__
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#define __BASICS_UTIL_HH__
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#include <cmath>
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/**
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* A very small constant. If a value is between EPSILON and 0.0, it is
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* considered to be zero.
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*/
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const Double EPSILON = 1.0e-10;
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/**
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* The maximum distance a ray can travel. This is the maximum value t can be.
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*/
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const Double MAX_DISTANCE = 1.0e7;
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/**
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* Determine if the value is "close enough" to zero. Takes the absolute value
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* and compares it to `EPSILON`.
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*
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* @see EPSILON
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*
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* @param [in] value The value to check
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* @returns `true` if the value is close enough to zero
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*/
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template <typename T>
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inline bool
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NearZero(T value)
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{
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return std::fabs(value) < EPSILON;
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}
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/**
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* Determine if two values are "close enough" to be considered equal. Subtracts
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* one from the other and checks if the result is near zero.
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*
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* @see NearZero
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*
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* @param [in] left The left parameter
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* @param [in] right The right parameter
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* @returns `true` if the values are close enough to be equal
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*/
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template <typename T, typename U>
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inline bool
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NearlyEqual(T left,
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U right)
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{
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return NearZero(left - right);
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}
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inline bool
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TooFar(const Double& value)
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{
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return value > MAX_DISTANCE;
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}
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#endif /* __BASICS_UTIL_HH__ */
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