Struct ExternalTextureParams

#[repr(C)]
pub struct ExternalTextureParams {
    pub yuv_conversion_matrix: [f32; 16],
    pub gamut_conversion_matrix: [f32; 12],
    pub src_transfer_function: ExternalTextureTransferFunction,
    pub dst_transfer_function: ExternalTextureTransferFunction,
    pub sample_transform: [f32; 6],
    pub load_transform: [f32; 6],
    pub size: [u32; 2],
    pub num_planes: u32,
    pub _padding: [u8; 4],
}

Parameters provided to shaders via a uniform buffer of the type NagaExternalTextureParams, describing an ExternalTexture resource binding.

Fields

yuv_conversion_matrix: [f32; 16]

4x4 column-major matrix with which to convert sampled YCbCr values to RGBA.

This is ignored when num_planes is 1.

gamut_conversion_matrix: [f32; 12]

3x3 column-major matrix to transform linear RGB values in the source color space to linear RGB values in the destination color space. In combination with Self::src_transfer_function and Self::dst_transfer_function this can be used to ensure that ImageSample and ImageLoad operations return values in the desired destination color space rather than the source color space of the underlying planes.

Includes a padding element after each column.

src_transfer_function: ExternalTextureTransferFunction

Transfer function for the source color space. The inverse of this will be applied to decode non-linear RGB to linear RGB in the source color space.

dst_transfer_function: ExternalTextureTransferFunction

Transfer function for the destination color space. This will be applied to encode linear RGB to non-linear RGB in the destination color space.

sample_transform: [f32; 6]

Transform to apply to ImageSample coordinates.

This is a 3x2 column-major matrix representing an affine transform from normalized texture coordinates to the normalized coordinates that should be sampled from the external texture’s underlying plane(s).

This transform may scale, translate, flip, and rotate in 90-degree increments, but the result of transforming the rectangle (0,0)..(1,1) must be an axis-aligned rectangle that falls within the bounds of (0,0)..(1,1).

load_transform: [f32; 6]

Transform to apply to ImageLoad coordinates.

This is a 3x2 column-major matrix representing an affine transform from non-normalized texel coordinates to the non-normalized coordinates of the texel that should be loaded from the external texture’s underlying plane 0. For planes 1 and 2, if present, plane 0’s coordinates are scaled according to the textures’ relative sizes.

This transform may scale, translate, flip, and rotate in 90-degree increments, but the result of transforming the rectangle (0,0)..size must be an axis-aligned rectangle that falls within the bounds of (0,0)..size.

size: [u32; 2]

Size of the external texture.

This is the value that should be returned by size queries in shader code; it does not necessarily match the dimensions of the underlying texture(s). As a special case, if this is [0, 0], the actual size of plane 0 should be used instead.

This must be consistent with sample_transform: it should be the size in texels of the rectangle covered by the square (0,0)..(1,1) after sample_transform has been applied to it.

num_planes: u32

Number of planes. 1 indicates a single RGBA plane. 2 indicates a Y plane and an interleaved CbCr plane. 3 indicates separate Y, Cb, and Cr planes.

_padding: [u8; 4]

Implementations

impl ExternalTextureParams

pub fn from_desc<L>(desc: &ExternalTextureDescriptor<L>) -> Self

Trait Implementations

impl Clone for ExternalTextureParams

fn clone(&self) -> ExternalTextureParams

Returns a copy of the value.

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

Performs copy-assignment from source.

impl Zeroable for ExternalTextureParams

fn zeroed() -> Self

Calls zeroed.

impl Copy for ExternalTextureParams

impl Pod for ExternalTextureParams