glium 0.3.3

High-level and safe OpenGL wrapper.
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
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161

use std::default::Default;
use ToGlEnum;
use gl;

/// Function to use for out-of-bounds samples.
///
/// This is how GL must handle samples that are outside the texture.
#[derive(Debug, Clone, Copy, Hash, PartialEq, Eq)]
pub enum SamplerWrapFunction {
    /// Samples at coord `x + 1` map to coord `x`.
    Repeat,

    /// Samples at coord `x + 1` map to coord `1 - x`.
    Mirror,

    /// Samples at coord `x + 1` map to coord `1`.
    Clamp
}

impl ToGlEnum for SamplerWrapFunction {
    fn to_glenum(&self) -> gl::types::GLenum {
        match *self {
            SamplerWrapFunction::Repeat => gl::REPEAT,
            SamplerWrapFunction::Mirror => gl::MIRRORED_REPEAT,
            SamplerWrapFunction::Clamp => gl::CLAMP_TO_EDGE,
        }
    }
}

/// The function that the GPU will use when loading the value of a texel.
#[derive(Debug, Clone, Copy, Hash, PartialEq, Eq)]
pub enum MagnifySamplerFilter {
    /// The nearest texel will be loaded.
    Nearest,

    /// All nearby texels will be loaded and their values will be merged.
    Linear,
}

impl ToGlEnum for MagnifySamplerFilter {
    fn to_glenum(&self) -> gl::types::GLenum {
        match *self {
            MagnifySamplerFilter::Nearest => gl::NEAREST,
            MagnifySamplerFilter::Linear => gl::LINEAR,
        }
    }
}

/// The function that the GPU will use when loading the value of a texel.
#[derive(Debug, Clone, Copy, Hash, PartialEq, Eq)]
pub enum MinifySamplerFilter {
    /// The nearest texel will be loaded.
    ///
    /// Only uses the main texture, mipmaps are totally ignored.
    Nearest,

    /// All nearby texels will be loaded and their values will be merged.
    ///
    /// Only uses the main texture, mipmaps are totally ignored.
    Linear,

    /// The nearest texel of the nearest mipmap will be loaded.
    NearestMipmapNearest,

    /// Takes the nearest texel from the two nearest mipmaps, and merges them.
    LinearMipmapNearest,

    /// Same as `Linear`, but from the nearest mipmap.
    NearestMipmapLinear,

    /// Same as `Linear`, but from the two nearest mipmaps.
    LinearMipmapLinear,
}

impl ToGlEnum for MinifySamplerFilter {
    fn to_glenum(&self) -> gl::types::GLenum {
        match *self {
            MinifySamplerFilter::Nearest => gl::NEAREST,
            MinifySamplerFilter::Linear => gl::LINEAR,
            MinifySamplerFilter::NearestMipmapNearest => gl::NEAREST_MIPMAP_NEAREST,
            MinifySamplerFilter::LinearMipmapNearest => gl::LINEAR_MIPMAP_NEAREST,
            MinifySamplerFilter::NearestMipmapLinear => gl::NEAREST_MIPMAP_LINEAR,
            MinifySamplerFilter::LinearMipmapLinear => gl::LINEAR_MIPMAP_LINEAR,
        }
    }
}

/// A sampler.
pub struct Sampler<'t, T: 't>(pub &'t T, pub SamplerBehavior);

impl<'t, T: 't> Sampler<'t, T> {
    /// Builds a new `Sampler` with default parameters.
    pub fn new(texture: &'t T) -> Sampler<'t, T> {
        Sampler(texture, Default::default())
    }

    /// Changes the wrap functions of all three coordinates.
    pub fn wrap_function(mut self, function: SamplerWrapFunction) -> Sampler<'t, T> {
        self.1.wrap_function = (function, function, function);
        self
    }

    /// Changes the minifying filter of the sampler.
    pub fn minify_filter(mut self, filter: MinifySamplerFilter) -> Sampler<'t, T> {
        self.1.minify_filter = filter;
        self
    }

    /// Changes the magnifying filter of the sampler.
    pub fn magnify_filter(mut self, filter: MagnifySamplerFilter) -> Sampler<'t, T> {
        self.1.magnify_filter = filter;
        self
    }

    /// Changes the magnifying filter of the sampler.
    pub fn anisotropy(mut self, level: u16) -> Sampler<'t, T> {
        self.1.max_anisotropy = level;
        self
    }
}

/// Behavior of a sampler.
// TODO: GL_TEXTURE_BORDER_COLOR, GL_TEXTURE_MIN_LOD, GL_TEXTURE_MAX_LOD, GL_TEXTURE_LOD_BIAS,
//       GL_TEXTURE_COMPARE_MODE, GL_TEXTURE_COMPARE_FUNC
#[derive(Debug, Clone, Copy, Hash, PartialEq, Eq)]
pub struct SamplerBehavior {
    /// Functions to use for the X, Y, and Z coordinates.
    pub wrap_function: (SamplerWrapFunction, SamplerWrapFunction, SamplerWrapFunction),

    /// Filter to use when minifying the texture.
    pub minify_filter: MinifySamplerFilter,

    /// Filter to use when magnifying the texture.
    pub magnify_filter: MagnifySamplerFilter,

    /// `1` means no anisotropic filtering, any value above `1` sets the max anisotropy.
    ///
    /// ## Compatibility
    ///
    /// This parameter is always available. However it is ignored on hardware that does
    /// not support anisotropic filtering.
    ///
    /// If you set the value to a value higher than what the hardware supports, it will
    /// be clamped.
    pub max_anisotropy: u16,
}

impl Default for SamplerBehavior {
    fn default() -> SamplerBehavior {
        SamplerBehavior {
            wrap_function: (
                SamplerWrapFunction::Mirror,
                SamplerWrapFunction::Mirror,
                SamplerWrapFunction::Mirror
            ),
            minify_filter: MinifySamplerFilter::LinearMipmapLinear,
            magnify_filter: MagnifySamplerFilter::Linear,
            max_anisotropy: 1,
        }
    }
}