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

use crate::header::*;
use byteorder::{BigEndian, ByteOrder, LittleEndian};
use core::{fmt, ops::Deref};

/// KTX texture storage format data stored in a complete slice.
/// Provides [`KtxInfo`](../header/trait.KtxInfo.html).
///
/// See the [specification](https://www.khronos.org/registry/KTX/specs/1.0/ktxspec_v1.html).
///
/// # Example
/// ```
/// # use ktx::*;
/// let image: Ktx<_> = include_ktx!("../tests/babg-bc3.ktx");
/// let texture_levels: Vec<&[u8]> = image.textures().collect();
/// ```
#[derive(Clone, Copy)]
pub struct Ktx<D> {
    header: KtxHeader,
    ktx_data: D,
    texture_start: u32,
}

impl<D> AsRef<KtxHeader> for Ktx<D> {
    #[inline]
    fn as_ref(&self) -> &KtxHeader {
        &self.header
    }
}

impl<D> fmt::Debug for Ktx<D> {
    fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
        fmt.debug_struct("Ktx")
            .field("header", &self.header)
            .finish()
    }
}

impl<D> Ktx<D>
where
    D: Deref<Target = [u8]>,
{
    /// Parses a complete KTX data slice and returns a `Ktx` instance.
    #[inline]
    pub fn new(ktx_data: D) -> Self {
        let header = KtxHeader::new(&ktx_data);
        let texture_start = 64 + header.bytes_of_key_value_data();
        Self {
            header,
            ktx_data,
            texture_start,
        }
    }

    /// Returns texture data at the input level, starting at `0`.
    ///
    /// # Panics
    ///
    /// Input level is >= the `mipmap_levels` value.
    #[inline]
    pub fn texture_level(&self, level: u32) -> &[u8] {
        self.textures().nth(level as _).expect("invalid level")
    }

    /// Returns an iterator over the texture levels starting at level 0.
    #[inline]
    pub fn textures(&self) -> Textures<'_, D> {
        Textures {
            parent: self,
            next_level: 0,
            level_end: self.texture_start as _,
        }
    }
}

impl<D> From<D> for Ktx<D>
where
    D: Deref<Target = [u8]>,
{
    #[inline]
    fn from(d: D) -> Self {
        Ktx::new(d)
    }
}

/// Iterator over texture level data.
///
/// For cubemap textures each level will contain all 6 faces
/// in order: +X, -X, +Y, -Y, +Z, -Z.
#[derive(Debug)]
pub struct Textures<'a, D> {
    parent: &'a Ktx<D>,
    next_level: u32,
    level_end: usize,
}

impl<'a, D> Iterator for Textures<'a, D>
where
    D: Deref<Target = [u8]>,
{
    type Item = &'a [u8];

    fn next(&mut self) -> Option<Self::Item> {
        if self.next_level >= self.parent.mipmap_levels() {
            None
        } else {
            self.next_level += 1;

            let l_end = self.level_end;
            let mut next_lvl_len = if self.parent.big_endian() {
                BigEndian::read_u32(&self.parent.ktx_data[l_end..l_end + 4])
            } else {
                LittleEndian::read_u32(&self.parent.ktx_data[l_end..l_end + 4])
            };

            if self.parent.array_elements() == 0 && self.parent.faces() == 6 {
                // Multiply for each face, see https://www.khronos.org/registry/KTX/specs/1.0/ktxspec_v1.html#2.16
                next_lvl_len *= 6;
            }

            self.level_end = l_end + 4 + next_lvl_len as usize;
            Some(&self.parent.ktx_data[l_end + 4..self.level_end])
        }
    }
}

impl<D> core::iter::FusedIterator for Textures<'_, D> where D: Deref<Target = [u8]> {}

/// Wrapper for `include_bytes!` returning `Ktx<'static [u8]>`
///
/// # Example
/// ```
/// use ktx::{include_ktx, Ktx};
/// let image: Ktx<&'static [u8]> = include_ktx!("../tests/babg-bc3.ktx");
/// ```
#[macro_export]
macro_rules! include_ktx {
    ($path:tt) => {
        $crate::Ktx::new(include_bytes!($path) as &[u8])
    };
}