daf3547636
## Objective - Split different types of gizmos into their own files ## Solution - Move `arc_2d` and `Arc2dBuilder` into `arcs.rs` - turns out there's no 3d arc function! I'll add one Soon(TM) in another MR ## Changelog - Changed - moved `gizmos::Arc2dBuilder` to `gizmos::arcs::Arc2dBuilder` ## Migration Guide - `gizmos::Arc2dBuilder` -> `gizmos::arcs::Arc2dBuilder`
109 lines
3.2 KiB
Rust
109 lines
3.2 KiB
Rust
//! Additional [`Gizmos`] Functions -- Arcs
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//!
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//! Includes the implementation of [`Gizmos::arc_2d`],
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//! and assorted support items.
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use crate::circles::DEFAULT_CIRCLE_SEGMENTS;
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use crate::prelude::Gizmos;
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use bevy_math::Vec2;
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use bevy_render::color::Color;
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use std::f32::consts::TAU;
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impl<'s> Gizmos<'s> {
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/// Draw an arc, which is a part of the circumference of a circle, in 2D.
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///
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/// This should be called for each frame the arc needs to be rendered.
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///
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/// # Arguments
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/// - `position` sets the center of this circle.
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/// - `radius` controls the distance from `position` to this arc, and thus its curvature.
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/// - `direction_angle` sets the clockwise angle in radians between `Vec2::Y` and
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/// the vector from `position` to the midpoint of the arc.
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/// - `arc_angle` sets the length of this arc, in radians.
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///
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/// # Example
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/// ```
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/// # use bevy_gizmos::prelude::*;
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/// # use bevy_render::prelude::*;
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/// # use bevy_math::prelude::*;
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/// # use std::f32::consts::PI;
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/// fn system(mut gizmos: Gizmos) {
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/// gizmos.arc_2d(Vec2::ZERO, 0., PI / 4., 1., Color::GREEN);
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///
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/// // Arcs have 32 line-segments by default.
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/// // You may want to increase this for larger arcs.
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/// gizmos
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/// .arc_2d(Vec2::ZERO, 0., PI / 4., 5., Color::RED)
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/// .segments(64);
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/// }
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/// # bevy_ecs::system::assert_is_system(system);
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/// ```
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#[inline]
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pub fn arc_2d(
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&mut self,
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position: Vec2,
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direction_angle: f32,
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arc_angle: f32,
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radius: f32,
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color: Color,
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) -> Arc2dBuilder<'_, 's> {
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Arc2dBuilder {
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gizmos: self,
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position,
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direction_angle,
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arc_angle,
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radius,
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color,
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segments: None,
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}
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}
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}
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/// A builder returned by [`Gizmos::arc_2d`].
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pub struct Arc2dBuilder<'a, 's> {
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gizmos: &'a mut Gizmos<'s>,
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position: Vec2,
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direction_angle: f32,
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arc_angle: f32,
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radius: f32,
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color: Color,
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segments: Option<usize>,
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}
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impl Arc2dBuilder<'_, '_> {
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/// Set the number of line-segments for this arc.
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pub fn segments(mut self, segments: usize) -> Self {
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self.segments = Some(segments);
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self
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}
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}
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impl Drop for Arc2dBuilder<'_, '_> {
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fn drop(&mut self) {
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let segments = match self.segments {
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Some(segments) => segments,
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// Do a linear interpolation between 1 and `DEFAULT_CIRCLE_SEGMENTS`
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// using the arc angle as scalar.
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None => ((self.arc_angle.abs() / TAU) * DEFAULT_CIRCLE_SEGMENTS as f32).ceil() as usize,
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};
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let positions = arc_inner(self.direction_angle, self.arc_angle, self.radius, segments)
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.map(|vec2| (vec2 + self.position));
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self.gizmos.linestrip_2d(positions, self.color);
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}
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}
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fn arc_inner(
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direction_angle: f32,
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arc_angle: f32,
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radius: f32,
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segments: usize,
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) -> impl Iterator<Item = Vec2> {
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(0..segments + 1).map(move |i| {
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let start = direction_angle - arc_angle / 2.;
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let angle = start + (i as f32 * (arc_angle / segments as f32));
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Vec2::from(angle.sin_cos()) * radius
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})
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}
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