# RadialWave

> Circular waves from every point of sources, amplitude sin(k r - ω t) each, summed where they meet.

Page: https://fframes-kit.pages.dev/docs/physics/radial-wave/
Cargo feature: `physics` (`fframes-kit = { version = "..", features = ["physics"] }`)

Circular waves from every point of `sources`, `amplitude sin(k r - ω t)` each, summed where
they meet. In 2D the crests are rings and the troughs dashed rings, clipped to `x_range` by
`y_range`; where the rings of two sources cross, the waves add up. With `front` (the
default) the rings leave the sources on the figure's clock. `displacement(x, y, t)` gives the
height. With the `3d` feature the same wave goes into a `ThreeDView` as a surface
(`resolution` pieces a side, `amplitude` high); only `enter` applies there. Gallery scenes:
`RadialWave`, and `RadialWave3D` with the gallery's `three-d` feature (on by default).

Gallery clip of `RadialWave`: https://fframes-kit.pages.dev/media/scenes/RadialWave-a0175948.mp4

Gallery clip of `RadialWave3D`: https://fframes-kit.pages.dev/media/scenes/RadialWave3D-48b91984.mp4

```rust
use fframes_kit::prelude::*;

fn figure<'a>(ui: &mut Ui<'a, '_, '_>) -> Svgr<'a> {
    ui.show(RadialWave {
        sources: vec![(-1.6, 0.0), (1.6, 0.0)],
        wavelength: 1.1,
        speed: 1.6,
        x_range: (-7.0, 7.0),
        y_range: (-4.0, 4.0),
        ..ui.defaults()
    })
}
```

## API

Components are plain structs. Set the fields you need and fill the rest with `..ui.defaults()`: the defaults below come from the current theme (`theme.` values are fields of `Theme`).

### RadialWave

| Field | Type | Default | Description |
| --- | --- | --- | --- |
| `sources` | `Vec<(f64, f64)>` | `vec![(0.0, 0.0)]` | The points the waves spread from, in units of `ui.space`. |
| `wavelength` | `f64` | `1.0` | Units of `ui.space` between two crests. |
| `speed` | `f64` | `1.0` | Speed of the rings in units of `ui.space` per second. |
| `amplitude` | `f64` | `0.3` | Largest height of one wave in units of `ui.space`; it sets the height of the 3D surface. |
| `front` | `bool` | `true` | The water is at rest at the start and the rings leave the sources on the clock; off fills the area from the start. |
| `x_range` | `(f64, f64)` | `(-7.0, 7.0)` | Left and right edges of the area the rings are drawn in, in units of `ui.space`. |
| `y_range` | `(f64, f64)` | `(-4.0, 4.0)` | Bottom and top edges of the area the rings are drawn in, in units of `ui.space`. |
| `troughs` | `bool` | `true` | Draws the troughs as dashed rings, a quarter wavelength from the crests. |
| `show_sources` | `bool` | `true` | Draws a dot at each source. |
| `resolution` | `usize` | `96` | Pieces along each side of the 3D surface; ignored in 2D. |
| `delay` | `f32` | `0.0` | Seconds after the container's start before the waves begin. |
| `time_scale` | `f32` | `1.0` | Speed of the motion over local time; 2 runs twice as fast, 1 is real time. |
| `color` | `Color` | `theme.colors.accent` | Colour of the crest rings. |
| `trough_color` | `Color` | `theme.colors.muted` | Colour of the trough rings. |
| `source_color` | `Color` | `theme.colors.highlight` | Colour of the source dots. |
| `stroke_width` | `f32` | `theme.stroke.regular` | Width of the crest rings in pixels; troughs use the theme's thin width. |
| `enter` | `Option<FadeIn>` | `None` | Fade in at the start; `None` for none. |
| `exit` | `Option<FadeOut>` | `None` | Fade out before the end; `None` for none. |

Methods:

- `fn displacement(&self, x: f64, y: f64, t: f64) -> f64`: The height of the water at `(x, y)` after `t` seconds: the sum over the sources of `amplitude sin(k r - ω t)`, without the sources the front has not reached yet.

Feature `physics` · [Source](https://github.com/khanhthanhdev/fframes-kit/blob/main/fframes-kit/src/kits/physics/waves_ii.rs#L31)