From 438336cc61c0091f134296353e543d14fa3ef879 Mon Sep 17 00:00:00 2001
From: Louis Capitanchik <contact@louiscap.co>
Date: Sat, 22 Jul 2023 15:47:47 +0100
Subject: [PATCH] Implement basic physics for kinematic bodies
---
game_core/src/debug/mod.rs | 20 ++++++++
game_core/src/entities/mod.rs | 6 ++-
game_core/src/entities/physics.rs | 83 +++++++++++++++++++++++++++++++
game_core/src/entities/player.rs | 40 ++++++++++-----
game_core/src/lib.rs | 1 +
game_core/src/main.rs | 1 +
game_core/src/system/mod.rs | 2 +
7 files changed, 140 insertions(+), 13 deletions(-)
create mode 100644 game_core/src/debug/mod.rs
create mode 100644 game_core/src/entities/physics.rs
diff --git a/game_core/src/debug/mod.rs b/game_core/src/debug/mod.rs
new file mode 100644
index 0000000..81957b1
--- /dev/null
+++ b/game_core/src/debug/mod.rs
@@ -0,0 +1,20 @@
+mod _plugin {
+ use crate::system::AppState;
+ use bevy::prelude::*;
+ use bevy_rapier2d::prelude::*;
+
+ pub struct DebugPlugin;
+ impl Plugin for DebugPlugin {
+ fn build(&self, app: &mut App) {
+ app.add_systems(OnEnter(AppState::InGame), |mut commands: Commands| {
+ commands.spawn((
+ TransformBundle::from_transform(Transform::from_xyz(0.0, -400.0, 0.0)),
+ RigidBody::Fixed,
+ Collider::cuboid(200.0, 50.0),
+ ));
+ });
+ }
+ }
+}
+
+pub use _plugin::DebugPlugin;
diff --git a/game_core/src/entities/mod.rs b/game_core/src/entities/mod.rs
index a25fe93..e48802a 100644
--- a/game_core/src/entities/mod.rs
+++ b/game_core/src/entities/mod.rs
@@ -1,3 +1,4 @@
+mod physics;
mod player;
mod _plugin {
@@ -7,9 +8,12 @@ mod _plugin {
pub struct EntityPluginSet;
impl PluginGroup for EntityPluginSet {
fn build(self) -> PluginGroupBuilder {
- PluginGroupBuilder::start::<Self>().add(super::player::PlayerSetupPlugin)
+ PluginGroupBuilder::start::<Self>()
+ .add(super::player::PlayerSetupPlugin)
+ .add(super::physics::PhysicsPlugin)
}
}
}
pub use _plugin::EntityPluginSet;
+pub use physics::{Acceleration, PhysicsLimits, PhysicsSet, Velocity, GRAVITY_ACC, GRAVITY_VEC};
diff --git a/game_core/src/entities/physics.rs b/game_core/src/entities/physics.rs
new file mode 100644
index 0000000..c862b46
--- /dev/null
+++ b/game_core/src/entities/physics.rs
@@ -0,0 +1,83 @@
+use crate::system::run_in_game;
+use bevy::prelude::*;
+use bevy_rapier2d::prelude::KinematicCharacterController;
+
+pub const GRAVITY_ACC: f32 = -384.0;
+pub const GRAVITY_VEC: Vec2 = Vec2::new(0.0, GRAVITY_ACC);
+
+#[derive(Clone, Copy, Debug, Eq, PartialEq, Hash, SystemSet)]
+pub struct PhysicsSet;
+
+#[derive(Component, Clone, Copy, Debug, Default, Deref, DerefMut)]
+pub struct Velocity(Vec2);
+
+#[derive(Component, Clone, Copy, Debug, Default, Deref, DerefMut)]
+pub struct Acceleration(Vec2);
+
+#[derive(Component, Clone, Copy, Debug, Default)]
+pub struct PhysicsLimits {
+ pub velocity: (Option<Vec2>, Option<Vec2>),
+ pub acceleration: (Option<Vec2>, Option<Vec2>),
+}
+
+impl PhysicsLimits {
+ pub fn limit_velocity(&self, velocity: Vec2) -> Vec2 {
+ match self.velocity {
+ (None, None) => velocity,
+ (Some(min), None) => velocity.max(min),
+ (None, Some(max)) => velocity.min(max),
+ (Some(min), Some(max)) => velocity.min(max).max(min),
+ }
+ }
+ pub fn limit_acceleration(&self, acceleration: Vec2) -> Vec2 {
+ match self.acceleration {
+ (None, None) => acceleration,
+ (Some(min), None) => acceleration.max(min),
+ (None, Some(max)) => acceleration.min(max),
+ (Some(min), Some(max)) => acceleration.min(max).max(min),
+ }
+ }
+}
+
+impl Acceleration {
+ pub fn gravity() -> Self {
+ Acceleration(GRAVITY_VEC)
+ }
+}
+
+fn apply_acceleration(
+ time: Res<Time>,
+ mut query: Query<(&mut Velocity, &Acceleration, Option<&PhysicsLimits>)>,
+) {
+ let dt = time.delta_seconds();
+ for (mut velocity, acceleration, limits) in &mut query {
+ **velocity += **acceleration * dt;
+ **velocity = limits
+ .copied()
+ .unwrap_or_default()
+ .limit_velocity(**velocity);
+ }
+}
+
+fn apply_velocity_to_kinematics(
+ time: Res<Time>,
+ mut query: Query<(&mut KinematicCharacterController, &Velocity)>,
+) {
+ let dt = time.delta_seconds();
+ for (mut controller, velocity) in &mut query {
+ controller.translation = Some(**velocity * dt);
+ }
+}
+
+pub struct PhysicsPlugin;
+impl Plugin for PhysicsPlugin {
+ fn build(&self, app: &mut App) {
+ app.add_systems(
+ Update,
+ (apply_acceleration, apply_velocity_to_kinematics)
+ .chain()
+ .in_set(PhysicsSet)
+ .run_if(run_in_game),
+ );
+ }
+}
diff --git a/game_core/src/entities/player.rs b/game_core/src/entities/player.rs
index 0d81e7d..3a32b2d 100644
--- a/game_core/src/entities/player.rs
+++ b/game_core/src/entities/player.rs
@@ -2,25 +2,41 @@ use crate::assets::AssetHandles;
use crate::system::AppState;
use bevy::prelude::*;
+use crate::entities::{Acceleration, PhysicsLimits, Velocity, GRAVITY_ACC};
use bevy_rapier2d::prelude::*;
+#[derive(Component, Clone, Copy, Debug)]
+pub struct Player;
+
pub fn spawn_player(mut commands: Commands, assets: Res<AssetHandles>) {
- commands
- .spawn((SpriteSheetBundle {
+ commands.spawn((
+ Player,
+ SpriteSheetBundle {
sprite: TextureAtlasSprite::new(3),
texture_atlas: assets.atlas("beige_blob"),
..Default::default()
- },))
- .with_children(|builder| {
- builder.spawn((
- TransformBundle::from_transform(Transform::from_xyz(0.0, -32.0, 0.0)),
+ },
+ RigidBody::KinematicPositionBased,
+ KinematicCharacterController {
+ custom_shape: Some((
Collider::capsule(Vec2::new(0.0, 8.0), Vec2::new(0.0, -48.0), 48.0),
- KinematicCharacterController {
- offset: CharacterLength::Absolute(0.01),
- ..Default::default()
- },
- ));
- });
+ Vec2::new(0.0, -32.0),
+ 0.0,
+ )),
+ snap_to_ground: Some(CharacterLength::Absolute(0.5)),
+ offset: CharacterLength::Absolute(0.03),
+ ..Default::default()
+ },
+ Acceleration::gravity(),
+ Velocity::default(),
+ PhysicsLimits {
+ velocity: (
+ Some(Vec2::new(f32::NEG_INFINITY, GRAVITY_ACC)),
+ Some(Vec2::new(f32::INFINITY, (-GRAVITY_ACC) * 2.0)),
+ ),
+ acceleration: Default::default(),
+ },
+ ));
}
pub struct PlayerSetupPlugin;
diff --git a/game_core/src/lib.rs b/game_core/src/lib.rs
index 371b2e7..24db231 100644
--- a/game_core/src/lib.rs
+++ b/game_core/src/lib.rs
@@ -1,3 +1,4 @@
pub mod assets;
+pub mod debug;
pub mod entities;
pub mod system;
diff --git a/game_core/src/main.rs b/game_core/src/main.rs
index ef41de5..acc48ff 100644
--- a/game_core/src/main.rs
+++ b/game_core/src/main.rs
@@ -5,6 +5,7 @@ fn main() {
.add_plugins(game_core::assets::AssetLoadingPlugin)
.add_plugins(game_core::system::SystemPluginSet)
.add_plugins(game_core::entities::EntityPluginSet)
+ .add_plugins(game_core::debug::DebugPlugin)
.add_plugins(bevy_rapier2d::plugin::RapierPhysicsPlugin::<()>::pixels_per_meter(128.0))
.add_plugins(micro_banimate::BanimatePluginGroup)
.add_plugins(micro_musicbox::CombinedAudioPlugins::<
diff --git a/game_core/src/system/mod.rs b/game_core/src/system/mod.rs
index f8823a1..0cf6bb6 100644
--- a/game_core/src/system/mod.rs
+++ b/game_core/src/system/mod.rs
@@ -17,6 +17,7 @@ mod _plugin {
pub struct PhysDebugPlugin;
impl Plugin for PhysDebugPlugin {
fn build(&self, app: &mut App) {
+ info!("Including Debug Physics Plugin");
app.add_plugins(bevy_rapier2d::render::RapierDebugRenderPlugin {
mode: DebugRenderMode::all(),
style: DebugRenderStyle::default(),
@@ -36,6 +37,7 @@ mod _plugin {
#[cfg(feature = "phys-debug")]
{
+ info!("Rendering physics debug information");
plugins.add(phys_debug::PhysDebugPlugin)
}
--
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