Trait ktx::header::KtxInfo

pub trait KtxInfo {
    fn big_endian(&self) -> bool;
    fn gl_type(&self) -> u32;
    fn gl_type_size(&self) -> u32;
    fn gl_format(&self) -> u32;
    fn gl_internal_format(&self) -> u32;
    fn gl_base_internal_format(&self) -> u32;
    fn pixel_width(&self) -> u32;
    fn pixel_height(&self) -> u32;
    fn pixel_depth(&self) -> u32;
    fn array_elements(&self) -> u32;
    fn faces(&self) -> u32;
    fn mipmap_levels(&self) -> u32;
    fn bytes_of_key_value_data(&self) -> u32;
}

KTX texture storage format parameters.

See the specification.

Required methods

fn big_endian(&self) -> bool

endianness contains the number 0x04030201 written as a 32 bit integer. If the file is little endian then this is represented as the bytes 0x01 0x02 0x03 0x04. If the file is big endian then this is represented as the bytes 0x04 0x03 0x02 0x01. When reading endianness as a 32 bit integer produces the value 0x04030201 then the endianness of the file matches the the endianness of the program that is reading the file and no conversion is necessary. When reading endianness as a 32 bit integer produces the value 0x01020304 then the endianness of the file is opposite the endianness of the program that is reading the file, and in that case the program reading the file must endian convert all header bytes and, if glTypeSize > 1, all texture data to the endianness of the program (i.e. a little endian program must convert from big endian, and a big endian program must convert to little endian).

fn gl_type(&self) -> 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.)

fn gl_type_size(&self) -> 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.

fn gl_format(&self) -> 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.)

fn gl_internal_format(&self) -> 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, except when 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.

fn gl_base_internal_format(&self) -> 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.

fn pixel_width(&self) -> u32

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

fn pixel_height(&self) -> u32

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

For 1D textures this must be 0.

fn pixel_depth(&self) -> u32

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

For 1D textures this must be 0. For 2D and cube textures this must be 0.

fn array_elements(&self) -> u32

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

fn faces(&self) -> 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.

Due to GL_OES_compressed_paletted_texture OESCPT not defining the interaction between cubemaps and its GL_PALETTE* formats, if glInternalFormat is one of its GL_PALETTE* format, numberOfFaces must be 1

fn mipmap_levels(&self) -> 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).

fn bytes_of_key_value_data(&self) -> u32

keyAndValueByteSize is the number of bytes of combined key and value data in one key/value pair following the header. This includes the size of the key, the NUL byte terminating the key, and all the bytes of data in the value. If the value is a UTF-8 string it should be NUL terminated and the keyAndValueByteSize should include the NUL character (but code that reads KTX files must not assume that value fields are NUL terminated). keyAndValueByteSize does not include the bytes in valuePadding.

Implementors

impl<T> KtxInfo for T where
    T: AsRef<KtxHeader>,