Struct gramit::transform::Transform

#[repr(transparent)]
pub struct Transform { /* fields omitted */ }

A builder struct for homogeneous transformation matrices.

A Transform is used to construct arbitrary affine transformations starting from the identity transformation, primarily by composing translation, scaling, shear, and rotation transformations. The final matrix is obtained via the finish() method.

Example

use gramit::transform::Transform;

// `mat` is a matrix that represents the effect of _first_ shearing the x axis 1 unit in the
// y direction, _then_ rotating about the y axis 180 degrees.
let mat: Mat4 = Transform::new()
    .shear_x(1.0, 0.0)
    .rotate(Vec3::y(), Angle::from_degrees(180.0))
    .finish();

//assert_approx_eq!(
//    (mat * vec3!(1.0, 0.0, 0.0).homogeneous()).homogenize(),
//    vec3!(1.0, -1.0, 0.0));

Note that each builder method applies its transformation after those of preceding builder methods. In matrix terms, this corresponds to multiplying the new transformation on the left, rather than the right. In other words, the above code computes the following matrix:

ROT((1, 0, 0), 180°) * SHEAR_X(1)

where ROT(axis, angle) is a rotation about axis axis by angle angle and SHEAR_X(dist) is a shear by distance dist that fixes the x-axis.

Methods

impl Transform

pub fn new() -> Transform

Create a new Transform.

Tranforms initially represent the identity transformation (i.e. no transformation at all), and are built into more useful transformations via other methods on the struct.

pub fn translate(self, offset: Vec3) -> Transform

Translate by the given offset.

pub fn scale(self, factor: Vec3) -> Transform

Scale by the given factors.

The scaling is performed independently per-axis, using the corresponding factor from the factor vector.

pub fn shear_x(self, y_amount: f32, z_amount: f32) -> Transform

Shear by the given amount, fixing the yz plane.

This will shear the x axis by the given amounts along the y and z axes.

pub fn shear_y(self, x_amount: f32, z_amount: f32) -> Transform

Shear by the given amount, fixing the xz plane.

This will shear the y axis by the given amounts along the x and z axes.

pub fn shear_z(self, x_amount: f32, y_amount: f32) -> Transform

Shear by the given amount, fixing the xy plane.

This will shear the z axis by the given amounts along the x and y axes.

pub fn rotate(self, axis: Vec3, angle: Angle) -> Transform

Rotate about the given axis by the given angle.

pub fn arbitrary(self, transform: Mat4) -> Transform

Apply an arbitrary affine transformation, represented by a homogenous matrix.

pub fn finish(&self) -> Mat4

Consume the Transform and acquire the resulting homogeneous transformation matrix.

Trait Implementations

impl Clone for Transform

fn clone(&self) -> Transform

Returns a copy of the value.

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

Performs copy-assignment from source.

impl Copy for Transform

impl Default for Transform

fn default() -> Transform

Returns the "default value" for a type.

impl PartialEq<Transform> for Transform

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

This method tests for self and other values to be equal, and is used by ==.

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

This method tests for !=.

impl Debug for Transform

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

Formats the value using the given formatter.

impl StructuralPartialEq for Transform