pbrt 0.1.5

Rust implementation of https://pbrt.org/
Documentation 
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132

// Copyright 2018 Google LLC
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     https://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

//! The spectrum module houses two main types, [RGBSpectrum] and [SampledSpectrum] used to represent color. The default [Spectrum] type is defined as `RGBSpectrum` or `SampledSpectrum` based on the compile time feature `sampled-spectrum`.
//!
//! [RGBSpectrum]: crate::core::spectrum::RGBSpectrum
//! [SampledSpectrum]: crate::core::spectrum::SampledSpectrum
//! [Spectrum]: crate::core::spectrum::Spectrum
use std::cmp;
use std::fmt;

use crate::Float;

macro_rules! common_implementation {
    ($($t:ty, $n:expr)*) => ($(
impl Default for $t {
    fn default() -> $t {
     Self {
            c: [0.; $n],
        }
    }
}

impl From<Float> for $t {
    fn from(value: Float) -> Self {
        Self {
            c: [value; $n],
        }
    }
}

impl $t {
    fn has_nans(&self) -> bool {
        for i in 0..$n {
            if self.c[i].is_nan() {
                return true;
            }
        }
        false
    }
}

    )*)
}

const N_SPECTRAL_SAMPLES: usize = 60;
/// `SampledSpectrum` is a spectrum represented by `N_SPECTRAL_SAMPLES` (currently 60) values
/// evenly spread across 400 nm to 700 nm.
pub struct SampledSpectrum {
    c: [Float; N_SPECTRAL_SAMPLES],
}

common_implementation!(SampledSpectrum, N_SPECTRAL_SAMPLES);

impl fmt::Debug for SampledSpectrum {
    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        write!(f, "SampledSpectrum({:?})", &self.c[..])
    }
}

impl cmp::PartialEq for SampledSpectrum {
    fn eq(&self, other: &SampledSpectrum) -> bool {
        let mut it = self.c.iter().zip(other.c.iter());
        while let Some((&l, &r)) = it.next() {
            if l != r {
                return false;
            }
        }
        true
    }
}

/// Convert tristimulus values in the XYZ color space (as defined by CIE) matching the human eye's
/// response to RGB values in the sRGB color space.
pub fn xyz_to_rgb(xyz: [Float; 3]) -> [Float; 3] {
    [
        3.240479 * xyz[0] - 1.537150 * xyz[1] - 0.498535 * xyz[2],
        -0.969256 * xyz[0] + 1.875991 * xyz[1] + 0.041556 * xyz[2],
        0.055648 * xyz[0] - 0.204043 * xyz[1] + 1.057311 * xyz[2],
    ]
}

/// Convert tristimulus values in the sRGB color space values to the XYZ color space (as defined by
/// CIE) matching the human eye's response.
pub fn rgb_to_xyz(rgb: [Float; 3]) -> [Float; 3] {
    [
        0.412453 * rgb[0] + 0.357580 * rgb[1] + 0.180423 * rgb[2],
        0.212671 * rgb[0] + 0.715160 * rgb[1] + 0.072169 * rgb[2],
        0.019334 * rgb[0] + 0.119193 * rgb[1] + 0.950227 * rgb[2],
    ]
}

/// `RGBSpectrum` is a sample implemented with 3 values at red, green and blue points in the
/// spectrum.
#[derive(Debug, Clone, PartialEq)]
pub struct RGBSpectrum {
    c: [Float; 3],
}

common_implementation!(RGBSpectrum, 3);

#[cfg(not(feature = "sampled-spectrum"))]
/// Define the `Spectrum` type to be `RGBSpectrum` when compiling without the `sampled-spectrum` feature enabled.
pub type Spectrum = RGBSpectrum;

impl RGBSpectrum {
    /// extract this `RGBSpectrum`'s value in the XYZ color space.
    pub fn to_xyz(&self) -> [Float; 3] {
        rgb_to_xyz(self.c)
    }
    /// create an `RGBSpectrum` from the given tristimulus values in sRGB color space.
    pub fn from_rgb(c: [Float; 3]) -> RGBSpectrum {
        let s = RGBSpectrum { c };
        debug_assert!(!s.has_nans(), "c {:?}", s);
        s
    }
}

#[cfg(feature = "sampled-spectrum")]
/// Define the `Spectrum` type to be `SampledSpectrum` when compiling with the `sampled-spectrum` feature enabled.
pub type Spectrum = SampledSpectrum;