Struct TextureTransform 

pub struct TextureTransform {
    pub offset: [f32; 2],
    pub rotation: f32,
    pub scale: [f32; 2],
    pub uv_set: Option<u32>,
}

Typed per-texture-reference UV transform, aligned with the ratified KHR_texture_transform extension.

The transform maps a primitive’s stored UV coordinates into the coordinates actually sampled — the standard mechanism for texture atlasing (offset + scale select an atlas region) and for axis flips (scale: [1.0, -1.0] with offset: [0.0, 1.0] inverts the T axis for a bottom-left-origin source). The applied mapping is the affine composition translation · rotation · scale on homogeneous UV coordinates:

uv' = T(offset) · R(rotation) · S(scale) · [u, v, 1]ᵀ

i.e. scale first, then rotate counter-clockwise about the UV origin, then offset. Per the extension, the result is generally only meaningful when the sampler wraps with WrapMode::Repeat or when the transformed coordinates stay inside [0, 1]. Remember the UV origin (0, 0) is the top-left corner of the image, so a counter-clockwise UV rotation reads as a clockwise image rotation.

All fields default to the extension’s normative defaults (zero offset, zero rotation, unit scale, no texCoord override), so TextureTransform::default() is the identity mapping.

Fields

offset: [f32; 2]

Offset of the UV origin as a factor of the texture dimensions (offset). Default [0.0, 0.0].

rotation: f32

Rotation applied to the UVs, in radians counter-clockwise around the origin (rotation). Default 0.0.

scale: [f32; 2]

Scale factor applied to the UV components (scale). Default [1.0, 1.0]. Negative components are legal and mirror the respective axis.

uv_set: Option<u32>

UV-set override (texCoord): when Some, replaces the TextureRef::uv_set of the reference carrying this transform. None (the default) keeps the reference’s own set.

Implementations

impl TextureTransform

pub const IDENTITY: Self

The identity transform — every field at its normative default.

pub fn new() -> Self

Construct the identity transform (same as default()).

pub fn with_offset(self, offset: [f32; 2]) -> Self

Builder-style offset setter.

pub fn with_rotation(self, rotation: f32) -> Self

Builder-style rotation setter (radians counter-clockwise).

pub fn with_scale(self, scale: [f32; 2]) -> Self

Builder-style scale setter.

pub fn with_uv_set(self, uv_set: u32) -> Self

Builder-style UV-set (texCoord) override setter.

pub fn is_identity(&self) -> bool

true when this transform is a complete no-op: the affine part is the identity and there is no UV-set override (a transform that only re-targets texCoord still changes sampling, so it is not an identity).

pub fn is_finite(&self) -> bool

true when every affine component (offset, rotation, scale) is finite. A non-finite component would poison every transformed coordinate; Scene3D::validate reports it.

pub fn to_matrix(&self) -> [[f32; 3]; 3]

The transform as a row-major 3×3 homogeneous matrix acting on column vectors [u, v, 1]ᵀ — the product T(offset) · R(rotation) · S(scale):

⎡ cos·sx  −sin·sy  ox ⎤
⎢ sin·sx   cos·sy  oy ⎥
⎣   0        0      1 ⎦

Same row-major column-vector convention as the crate’s 4×4 node matrices.

pub fn apply(&self, uv: [f32; 2]) -> [f32; 2]

Apply the transform to one UV coordinate: scale, then rotate counter-clockwise about the origin, then offset — exactly to_matrix times [u, v, 1]ᵀ.

pub fn apply_channel(&self, uvs: &[[f32; 2]]) -> Vec<[f32; 2]>

Apply the transform to a whole UV channel — the baking helper for exporters targeting a format without per-reference UV transforms: replace the primitive’s channel with the baked coordinates (and drop the transform, e.g. via Material::map_texture_refs). Pure; the input is untouched.

Trait Implementations

impl Clone for TextureTransform

fn clone(&self) -> TextureTransform

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Copy for TextureTransform

impl Debug for TextureTransform

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

Formats the value using the given formatter.

impl Default for TextureTransform

fn default() -> Self

Returns the “default value” for a type.

impl PartialEq for TextureTransform

fn eq(&self, other: &TextureTransform) -> bool

Equality operator ==.

fn ne(&self, other: &Rhs) -> bool

Inequality operator !=.

impl StructuralPartialEq for TextureTransform