From 001ce7e98c125addfbb6d3c7cc953c1de2234a3f Mon Sep 17 00:00:00 2001
From: Felix Ableitner <me@nutomic.com>
Date: Sun, 3 Jan 2021 17:16:39 +0100
Subject: [PATCH] Implement basic jumping

---
 src/player.rs | 41 +++++++++++++++++++++++++++++++----------
 1 file changed, 31 insertions(+), 10 deletions(-)

diff --git a/src/player.rs b/src/player.rs
index bad44e4..7ffc50f 100644
--- a/src/player.rs
+++ b/src/player.rs
@@ -1,13 +1,10 @@
-use bevy::{
-  input::mouse::MouseMotion,
-  prelude::*,
-};
+use bevy::{input::mouse::MouseMotion, prelude::*};
 use bevy_rapier3d::{
   na::{clamp, wrap, Matrix3x1},
-  physics::RigidBodyHandleComponent,
+  physics::{ColliderHandleComponent, RigidBodyHandleComponent},
   rapier::{
     dynamics::{RigidBody, RigidBodyBuilder, RigidBodySet},
-    geometry::ColliderBuilder,
+    geometry::{ColliderBuilder, NarrowPhase},
   },
 };
 use std::f32::consts::{FRAC_PI_2, PI};
@@ -73,16 +70,40 @@ fn init_player(commands: &mut Commands) {
     });
 }
 
+// TODO: this is incomplete, currently just checks that the player is touching anything
+fn is_on_ground(
+  narrow_phase: &Res<NarrowPhase>,
+  collider_handle: &ColliderHandleComponent,
+) -> bool {
+  if let Some(n1) = narrow_phase.contacts_with(collider_handle.handle()) {
+    for _n2 in n1 {
+      return true;
+    }
+  }
+  return false;
+}
+
 fn player_movement_system(
   time: Res<Time>,
-  mut bodies: ResMut<RigidBodySet>,
+  mut rigid_body_set: ResMut<RigidBodySet>,
   keyboard_input: Res<Input<KeyCode>>,
+  narrow_phase: Res<NarrowPhase>,
   camera_transform_query: Query<&Transform, With<CameraData>>,
-  mut player_query: Query<&RigidBodyHandleComponent, With<PlayerMarker>>,
+  mut player_physics_query: Query<
+    (&RigidBodyHandleComponent, &ColliderHandleComponent),
+    With<PlayerMarker>,
+  >,
 ) {
   for camera_transform in camera_transform_query.iter() {
-    for body_handle in player_query.iter_mut() {
-      let body: &mut RigidBody = bodies.get_mut(body_handle.handle()).unwrap();
+    for (body_handle, collider_handle) in player_physics_query.iter_mut() {
+      let is_on_ground = is_on_ground(&narrow_phase, collider_handle);
+      if !is_on_ground {
+        continue;
+      }
+      let body: &mut RigidBody = rigid_body_set.get_mut(body_handle.handle()).unwrap();
+      if keyboard_input.pressed(KeyCode::Space) {
+        body.apply_impulse(Matrix3x1::new(0.0, 0.5, 0.0), true);
+      }
 
       let axis_strafe = movement_axis(&keyboard_input, KeyCode::D, KeyCode::A);
       let axis_straight = movement_axis(&keyboard_input, KeyCode::S, KeyCode::W);