StandardMaterial easings?

[joncol]

Any plan on adding StandardMaterial as an available easing target? I'm fumbling around with trying it myself, but I'm running into problems due to lack of skills.

Current attempt:

#[derive(Debug, Default)]
struct MyEaseValue<T>(pub T);

impl Lerp for MyEaseValue<StandardMaterial> {
    type Scalar = f32;

    fn lerp(&self, other: &Self, scalar: &Self::Scalar) -> Self {
        MyEaseValue(StandardMaterial {
            albedo: self.0.albedo
                + (other.0.albedo + (self.0.albedo * -1.)) * *scalar,
            albedo_texture: None,
            ..Default::default()
        })
    }
}

Which is more or less copied from your implementation for ColorMaterial. Getting problems with how to add easings for my materials with this.

[joncol]

OK, figured out how to use custom easings finally. Just thought it would be a good idea to summarize what I did, if anyone else stumbles upon this:

#[derive(Debug, Default)]
struct MyEaseValue<T>(pub T);

impl Lerp for MyEaseValue<Color> {
    type Scalar = f32;

    fn lerp(&self, other: &Self, scalar: &Self::Scalar) -> Self {
        MyEaseValue(self.0 + (other.0 + (self.0 * -1.)) * *scalar)
    }
}

And then created a helper function to add an EasingComponent to a specified entity:

#[derive(Debug)]
struct Fade;

fn fade_to(
    commands: &mut Commands,
    entity: Entity,
    from: Color,
    to: Color,
    millis: u64,
) {
    commands.set_current_entity(entity);
    commands.with(Fade).with(MyEaseValue(from)).with(
        MyEaseValue(from).ease_to(
            MyEaseValue(to),
            EaseFunction::QuadraticOut,
            EasingType::Once {
                duration: Duration::from_millis(millis),
            },
        ),
    );
}

Fade in the above is just a component for my fading system to recognize that it should handle this entity:

fn fade(
    mut materials: ResMut<Assets<StandardMaterial>>,
    mut query: Query<
        (&MyEaseValue<Color>, &Handle<StandardMaterial>),
        With<Fade>,
    >,
) {
    for (color, mat_handle) in query.iter_mut() {
        materials.set(mat_handle, color.0.into());
    }
}

Finally, the systems should be added:

app
    .add_system(fade.system())
    .add_system(custom_ease_system::<MyEaseValue<Color>>.system())

Feel free to close this issue. I don't know if it's a good idea to have StandardMaterial easings? Maybe that would not work so well with textures etc...

[mockersf]

great! thank you for digging into this!
doing easing on something that is behind a Handle is not something simple, it depends on which part you want to change... your solution for that is nice!