Struct HeaderInfo

pub struct HeaderInfo {
    pub gl_type: u32,
    pub gl_type_size: u32,
    pub gl_format: u32,
    pub gl_internal_format: u32,
    pub gl_base_internal_format: u32,
    pub pixel_width: u32,
    pub pixel_height: u32,
    pub pixel_depth: u32,
    pub number_of_array_elements: u32,
    pub number_of_faces: u32,
    pub number_of_mipmap_levels: u32,
    pub key_value_data: KeyValueData,
}

KTX Header Info

Fields

gl_type: u32

For compressed textures, glType must equal 0. For uncompressed textures, glType specifies the type parameter passed to glTex{,Sub}Image*D, usually one of the values from table 8.2 of the OpenGL 4.4 specification [OPENGL44] (UNSIGNED_BYTE, UNSIGNED_SHORT_5_6_5, etc.)

gl_type_size: u32

glTypeSize specifies the data type size that should be used when endianness conversion is required for the texture data stored in the file. If glType is not 0, this should be the size in bytes corresponding to glType. For texture data which does not depend on platform endianness, including compressed texture data, glTypeSize must equal 1.

gl_format: u32

For compressed textures, glFormat must equal 0. For uncompressed textures, glFormat specifies the format parameter passed to glTex{,Sub}Image*D, usually one of the values from table 8.3 of the OpenGL 4.4 specification [OPENGL44] (RGB, RGBA, BGRA, etc.)

gl_internal_format: u32

For compressed textures, glInternalFormat must equal the compressed internal format, usually one of the values from table 8.14 of the OpenGL 4.4 specification [OPENGL44]. For uncompressed textures, glInternalFormat specifies the internalformat parameter passed to glTexStorageD or glTexImageD, usually one of the sized internal formats from tables 8.12 & 8.13 of the OpenGL 4.4 specification [OPENGL44]. The sized format should be chosen to match the bit depth of the data provided. glInternalFormat is used when loading both compressed and uncompressed textures, exceptwhen loading into a context that does not support sized formats, such as an unextended OpenGL ES 2.0 context where the internalformat parameter is required to have the same value as the format parameter.

gl_base_internal_format: u32

For both compressed and uncompressed textures, glBaseInternalFormat specifies the base internal format of the texture, usually one of the values from table 8.11 of the OpenGL 4.4 specification [OPENGL44] (RGB, RGBA, ALPHA, etc.). For uncompressed textures, this value will be the same as glFormat and is used as the internalformat parameter when loading into a context that does not support sized formats, such as an unextended OpenGL ES 2.0 context.

pixel_width: u32

The size of the texture image for level 0, in pixels. No rounding to block sizes should be applied for block compressed textures.

For 1D textures pixelHeight and pixelDepth must be 0. For 2D and cube textures pixelDepth must be 0.

pixel_height: u32

See pixel_width

pixel_depth: u32

See pixel_width

number_of_array_elements: u32

numberOfArrayElements specifies the number of array elements. If the texture is not an array texture, numberOfArrayElements must equal 0.

number_of_faces: u32

numberOfFaces specifies the number of cubemap faces. For cubemaps and cubemap arrays this should be 6. For non cubemaps this should be 1. Cube map faces are stored in the order: +X, -X, +Y, -Y, +Z, -Z.

number_of_mipmap_levels: u32

numberOfMipmapLevels must equal 1 for non-mipmapped textures. For mipmapped textures, it equals the number of mipmaps. Mipmaps are stored in order from largest size to smallest size. The first mipmap level is always level 0. A KTX file does not need to contain a complete mipmap pyramid. If numberOfMipmapLevels equals 0, it indicates that a full mipmap pyramid should be generated from level 0 at load time (this is usually not allowed for compressed formats).

key_value_data: KeyValueData

keyAndValue contains 2 separate sections. First it contains a key encoded in UTF-8 without a byte order mark (BOM). The key must be terminated by a NUL character (a single 0x00 byte). Keys that begin with the 3 ascii characters ‘KTX’ or ‘ktx’ are reserved and must not be used except as described by this spec (this version of the KTX spec defines a single key). Immediately following the NUL character that terminates the key is the Value data.

The Value data may consist of any arbitrary data bytes. Any byte value is allowed. It is encouraged that the value be a NUL terminated UTF-8 string but this is not required. UTF-8 strings must not contain BOMs. If the Value data is binary, it is a sequence of bytes rather than of words. It is up to the vendor defining the key to specify how those bytes are to be interpreted (including the endianness of any encoded numbers). If the Value data is a string of bytes then the NUL termination should be included in the keyAndValueByteSize byte count (but programs that read KTX files must not rely on this).

Implementations

impl HeaderInfo

pub fn mipmap_size(&self, level: u32) -> (u32, u32, u32)

Trait Implementations

impl Clone for HeaderInfo

fn clone(&self) -> HeaderInfo

Returns a copy of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for HeaderInfo

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.