67 lines
1.8 KiB
C++
67 lines
1.8 KiB
C++
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/** @file qnan.h
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* @brief Some utilities for our dealings with qnans.
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*
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* @note Some loaders use qnans heavily to mark invalid values (and they're
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* even returned by Gen(Smooth)Normals if normals are undefined for a
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* primitive). Their whole usage is wrapped here, so you can easily
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* fix issues with platforms with a different qnan implementation.
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*/
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#if (!defined AI_QNAN_H_INCLUDED)
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#define AI_QNAN_H_INCLUDED
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// ---------------------------------------------------------------------------
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/** @brief Data structure for the bit pattern of a 32 Bit
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* IEEE 754 floating-point number.
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*/
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union _IEEESingle
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{
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float Float;
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struct
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{
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uint32_t Frac : 23;
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uint32_t Exp : 8;
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uint32_t Sign : 1;
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} IEEE;
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} ;
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// ---------------------------------------------------------------------------
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/** @brief check whether a float is qNaN.
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* @param in Input value
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*/
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AI_FORCE_INLINE bool is_qnan(float in)
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{
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return (in != in);
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}
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// ---------------------------------------------------------------------------
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/** @brief check whether a float is NOT qNaN.
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* @param in Input value
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*/
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AI_FORCE_INLINE bool is_not_qnan(float in)
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{
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return (in == in);
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}
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// ---------------------------------------------------------------------------
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/** @brief check whether a float is either NaN or (+/-) INF.
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*
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* Denorms return false, they're treated like normal values.
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* @param in Input value
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*/
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AI_FORCE_INLINE bool is_special_float(float in)
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{
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return (((_IEEESingle*)&in)->IEEE.Exp == (1u << 8)-1);
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}
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// ---------------------------------------------------------------------------
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/** @brief Get a qnan
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*/
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AI_FORCE_INLINE float get_qnan()
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{
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return std::numeric_limits<float>::quiet_NaN();
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}
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#endif // !! AI_QNAN_H_INCLUDED
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