bevy/crates/bevy_ui/src/focus.rs

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use crate::Node;
use bevy_app::{EventReader, Events};
use bevy_core::FloatOrd;
use bevy_ecs::prelude::*;
use bevy_input::{mouse::MouseButton, Input};
use bevy_math::Vec2;
use bevy_transform::components::Transform;
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use bevy_window::CursorMoved;
#[derive(Copy, Clone, Eq, PartialEq, Debug)]
pub enum Click {
Released,
Pressed,
}
impl Default for Click {
fn default() -> Self {
Click::Released
}
}
#[derive(Copy, Clone, Eq, PartialEq, Debug)]
pub enum Hover {
Hovered,
NotHovered,
}
impl Default for Hover {
fn default() -> Self {
Hover::NotHovered
}
}
#[derive(Copy, Clone, Eq, PartialEq, Debug)]
pub enum FocusPolicy {
Block,
Pass,
}
impl Default for FocusPolicy {
fn default() -> Self {
FocusPolicy::Block
}
}
#[derive(Default)]
pub struct State {
cursor_moved_event_reader: EventReader<CursorMoved>,
cursor_position: Vec2,
hovered_entity: Option<Entity>,
}
pub fn ui_focus_system(
mut state: Local<State>,
mouse_button_input: Res<Input<MouseButton>>,
cursor_moved_events: Res<Events<CursorMoved>>,
mut node_query: Query<(
Entity,
&Node,
&Transform,
Option<&mut Click>,
Option<&mut Hover>,
Option<&FocusPolicy>,
)>,
) {
if let Some(cursor_moved) = state.cursor_moved_event_reader.latest(&cursor_moved_events) {
state.cursor_position = cursor_moved.position;
}
if mouse_button_input.just_released(MouseButton::Left) {
for (_entity, _node, _transform, click, _hover, _focus_policy) in &mut node_query.iter() {
if let Some(mut click) = click {
if *click == Click::Pressed {
*click = Click::Released;
}
}
}
}
let mouse_clicked = mouse_button_input.just_pressed(MouseButton::Left);
let mut hovered_entity = None;
{
let mut query_iter = node_query.iter();
let mut moused_over_z_sorted_nodes = query_iter
.iter()
.filter_map(|(entity, node, transform, click, hover, focus_policy)| {
let position = transform.value.w_axis();
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let ui_position = position.truncate().truncate();
let extents = node.size / 2.0;
let min = ui_position - extents;
let max = ui_position + extents;
// if the current cursor position is within the bounds of the node, consider it for clicking
if (min.x()..max.x()).contains(&state.cursor_position.x())
&& (min.y()..max.y()).contains(&state.cursor_position.y())
{
Some((entity, focus_policy, click, hover, FloatOrd(position.z())))
} else {
if let Some(mut hover) = hover {
if *hover == Hover::Hovered {
*hover = Hover::NotHovered;
}
}
None
}
})
.collect::<Vec<_>>();
moused_over_z_sorted_nodes.sort_by_key(|(_, _, _, _, z)| -*z);
for (entity, focus_policy, click, hover, _) in moused_over_z_sorted_nodes {
if mouse_clicked {
// only consider nodes with ClickState "clickable"
if let Some(mut click) = click {
if *click == Click::Released {
*click = Click::Pressed;
}
}
}
// only consider nodes with Hover "hoverable"
if let Some(mut hover) = hover {
if *hover == Hover::NotHovered {
*hover = Hover::Hovered;
}
hovered_entity = Some(entity);
}
match focus_policy.cloned().unwrap_or(FocusPolicy::Block) {
FocusPolicy::Block => {
break;
}
FocusPolicy::Pass => { /* allow the next node to be hovered/clicked */ }
}
}
}
// if there is a new hovered entity, but an entity is currently hovered, unhover the old entity
if let Some(new_hovered_entity) = hovered_entity {
if let Some(old_hovered_entity) = state.hovered_entity {
if new_hovered_entity != old_hovered_entity {
if let Ok(mut hover) = node_query.get_mut(old_hovered_entity) {
if *hover == Hover::Hovered {
*hover = Hover::NotHovered;
}
}
state.hovered_entity = None;
}
}
state.hovered_entity = hovered_entity;
}
}