half_float.h Source File - ClanLib SDK
Description: half_float.h Source File

half_float.h
1/*
2** ClanLib SDK
3** Copyright (c) 1997-2020 The ClanLib Team
4**
5** This software is provided 'as-is', without any express or implied
6** warranty. In no event will the authors be held liable for any damages
7** arising from the use of this software.
8**
9** Permission is granted to anyone to use this software for any purpose,
10** including commercial applications, and to alter it and redistribute it
11** freely, subject to the following restrictions:
12**
13** 1. The origin of this software must not be misrepresented; you must not
14** claim that you wrote the original software. If you use this software
15** in a product, an acknowledgment in the product documentation would be
16** appreciated but is not required.
17** 2. Altered source versions must be plainly marked as such, and must not be
18** misrepresented as being the original software.
19** 3. This notice may not be removed or altered from any source distribution.
20**
21** Note: Some of the libraries ClanLib may link to may have additional
22** requirements or restrictions.
23**
24** File Author(s):
25**
26** Magnus Norddahl
27*/
28
29#pragma once
30
31namespace clan
32{
35
36 class HalfFloat
37 {
38 public:
39 HalfFloat() : value(0)
40 {
41 }
42
43 HalfFloat(const HalfFloat &other) = default;
44
45 HalfFloat(float v) : value(float_to_half(v))
46 {
47 }
48
49 HalfFloat &operator =(const HalfFloat &other) = default;
50
51 HalfFloat &operator =(const float v)
52 {
53 return from_float(v);
54 }
55
56 operator float() const
57 {
58 return to_float();
59 }
60
61 float to_float() const
62 {
63 return half_to_float(value);
64 }
65
66 HalfFloat &from_float(float v)
67 {
68 value = float_to_half(v);
69 return *this;
70 }
71
73 static float half_to_float_simple(unsigned short hf)
74 {
75 unsigned int float_value = ((hf & 0x8000) << 16) | (((hf & 0x7c00) + 0x1C000) << 13) | ((hf & 0x03FF) << 13);
76 void *ptr = static_cast<void*>(&float_value);
77 return *static_cast<float*>(ptr);
78 }
79
81 static unsigned short float_to_half_simple(float float_value)
82 {
83 void *ptr = static_cast<void*>(&float_value);
84 unsigned int f = *static_cast<unsigned int*>(ptr);
85 return ((f >> 16) & 0x8000) | ((((f & 0x7f800000) - 0x38000000) >> 13) & 0x7c00) | ((f >> 13) & 0x03ff);
86 }
87
88 static float half_to_float(unsigned short hf)
89 {
90 unsigned int float_value = mantissa_table[offset_table[hf >> 10] + (hf & 0x3ff)] + exponent_table[hf >> 10];
91 void *ptr = static_cast<void*>(&float_value);
92 return *static_cast<float*>(ptr);
93 }
94
95 static unsigned short float_to_half(float float_value)
96 {
97 void *ptr = static_cast<void*>(&float_value);
98 unsigned int f = *static_cast<unsigned int*>(ptr);
99 return base_table[(f >> 23) & 0x1ff] + ((f & 0x007fffff) >> shift_table[(f >> 23) & 0x1ff]);
100 }
101
102 private:
103 unsigned short value;
104
105 static unsigned int mantissa_table[2048];
106 static unsigned int exponent_table[64];
107 static unsigned short offset_table[64];
108
109 static unsigned short base_table[512];
110 static unsigned char shift_table[512];
111 };
112
114}
clan::HalfFloat::half_to_float
static float half_to_float(unsigned short hf)
Definition half_float.h:88
clan::HalfFloat::float_to_half_simple
static unsigned short float_to_half_simple(float float_value)
Only works for 'normal' half-float values.
Definition half_float.h:81
clan::HalfFloat::HalfFloat
HalfFloat()
Definition half_float.h:39
clan::HalfFloat::to_float
float to_float() const
Definition half_float.h:61
clan::HalfFloat::float_to_half
static unsigned short float_to_half(float float_value)
Definition half_float.h:95
clan::HalfFloat::HalfFloat
HalfFloat(const HalfFloat &other)=default
clan::HalfFloat::half_to_float_simple
static float half_to_float_simple(unsigned short hf)
Only works for 'normal' half-float values.
Definition half_float.h:73
clan::HalfFloat::from_float
HalfFloat & from_float(float v)
Definition half_float.h:66
clan::HalfFloat::operator=
HalfFloat & operator=(const HalfFloat &other)=default
clan::HalfFloat::HalfFloat
HalfFloat(float v)
Definition half_float.h:45
clan
Definition clanapp.h:36
clan::Key::f
@ f
Definition keys.h:86
clan::Key::v
@ v
Definition keys.h:102