Ptex
Public Member Functions | Static Public Member Functions | Public Attributes | Static Private Member Functions | Static Private Attributes | List of all members
PtexHalf Class Reference

Half-precision (16-bit) floating-point type. More...

#include <PtexHalf.h>

Public Member Functions

 PtexHalf ()
 Default constructor, value is undefined. More...
 
 PtexHalf (float val)
 
 PtexHalf (double val)
 
 operator float () const
 
PtexHalf & operator= (float val)
 

Static Public Member Functions

static float toFloat (uint16_t h)
 
static uint16_t fromFloat (float val)
 

Public Attributes

uint16_t bits
 

Static Private Member Functions

static uint16_t fromFloat_except (uint32_t val)
 Handle exceptional cases for half-to-float conversion. More...
 

Static Private Attributes

static uint32_t h2fTable [65536]
 
static uint16_t f2hTable [512]
 

Detailed Description

Half-precision (16-bit) floating-point type.

This type should be compatible with opengl, openexr, and IEEE 754r. The range is [-65504.0, 65504.0] and the precision is about 1 part in 2000 (3.3 decimal places).

From OpenGL spec 2.1.2:

A 16-bit floating-point number has a 1-bit sign (S), a 5-bit exponent (E), and a 10-bit mantissa (M). The value of a 16-bit floating-point number is determined by the following:

     (-1)^S * 0.0,                        if E == 0 and M == 0,
     (-1)^S * 2^-14 * (M/2^10),           if E == 0 and M != 0,
     (-1)^S * 2^(E-15) * (1 + M/2^10),    if 0 < E < 31,
     (-1)^S * INF,                        if E == 31 and M == 0, or
     NaN,                                 if E == 31 and M != 0

Definition at line 88 of file PtexHalf.h.

Constructor & Destructor Documentation

◆ PtexHalf() [1/3]

PtexHalf::PtexHalf ( )
inline

Default constructor, value is undefined.

Definition at line 92 of file PtexHalf.h.

◆ PtexHalf() [2/3]

PtexHalf::PtexHalf ( float  val)
inline

Definition at line 93 of file PtexHalf.h.

◆ PtexHalf() [3/3]

PtexHalf::PtexHalf ( double  val)
inline

Definition at line 94 of file PtexHalf.h.

Member Function Documentation

◆ fromFloat()

static uint16_t PtexHalf::fromFloat ( float  val)
inlinestatic

Definition at line 105 of file PtexHalf.h.

References f2hTable, and fromFloat_except().

Referenced by operator=().

◆ fromFloat_except()

PTEX_NAMESPACE_BEGIN uint16_t PtexHalf::fromFloat_except ( uint32_t  val)
staticprivate

Handle exceptional cases for half-to-float conversion.

Definition at line 44 of file PtexHalf.cpp.

Referenced by fromFloat().

◆ operator float()

PtexHalf::operator float ( ) const
inline

Definition at line 95 of file PtexHalf.h.

References bits, and toFloat().

◆ operator=()

PtexHalf& PtexHalf::operator= ( float  val)
inline

Definition at line 96 of file PtexHalf.h.

References bits, and fromFloat().

◆ toFloat()

static float PtexHalf::toFloat ( uint16_t  h)
inlinestatic

Definition at line 98 of file PtexHalf.h.

References h2fTable.

Referenced by operator float().

Member Data Documentation

◆ bits

uint16_t PtexHalf::bits

Definition at line 89 of file PtexHalf.h.

Referenced by operator float(), and operator=().

◆ f2hTable

PTEXAPI uint16_t PtexHalf::f2hTable
staticprivate

Definition at line 121 of file PtexHalf.h.

Referenced by fromFloat().

◆ h2fTable

PTEXAPI uint32_t PtexHalf::h2fTable
staticprivate

Definition at line 120 of file PtexHalf.h.

Referenced by toFloat().

The documentation for this class was generated from the following files:
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