From 52764376ae635a418f32ed4e35fe797174746c3a Mon Sep 17 00:00:00 2001
From: Louis Pearson <louispearson@librem.one>
Date: Tue, 4 Jun 2019 10:09:34 -0600
Subject: [PATCH] Use constants and normalized move direction

---
 common/src/sys/inputs.rs | 15 +++++++++++----
 common/src/sys/phys.rs   |  4 +++-
 2 files changed, 14 insertions(+), 5 deletions(-)

diff --git a/common/src/sys/inputs.rs b/common/src/sys/inputs.rs
index 2e340ec7fd..97b88c3e2b 100644
--- a/common/src/sys/inputs.rs
+++ b/common/src/sys/inputs.rs
@@ -24,6 +24,8 @@ const HUMANOID_AIR_SPEED: f32 = 100.0;
 const HUMANOID_JUMP_ACCEL: f32 = 16.0;
 const GLIDE_ACCEL: f32 = 15.0;
 const GLIDE_SPEED: f32 = 45.0;
+// Gravity is 9.81 * 4, so this makes gravity equal to .15
+const GLIDE_ANTIGRAV: f32 = 9.81 * 3.95;
 
 impl<'a> System<'a> for Sys {
     type SystemData = (
@@ -88,11 +90,16 @@ impl<'a> System<'a> for Sys {
                 && vel.0.z <= 0.0;
 
             let gliding = glides.get(entity).is_some() && vel.0.z < 0.0;
+            let move_dir = if control.move_dir.magnitude() > 0.0 {
+                control.move_dir.normalized()
+            } else {
+                control.move_dir
+            };
 
             if on_ground {
                 // Move player according to move_dir
                 if vel.0.magnitude() < HUMANOID_SPEED {
-                    vel.0 += Vec2::broadcast(dt.0) * control.move_dir * HUMANOID_ACCEL;
+                    vel.0 += Vec2::broadcast(dt.0) * move_dir * HUMANOID_ACCEL;
                 }
 
                 // Jump
@@ -101,11 +108,11 @@ impl<'a> System<'a> for Sys {
                     jumps.remove(entity);
                 }
             } else if gliding && vel.0.magnitude() < GLIDE_SPEED {
-                let anti_grav = 9.81 * 3.95 + vel.0.z.powf(2.0) * 0.2;
+                let anti_grav = GLIDE_ANTIGRAV + vel.0.z.powf(2.0) * 0.2;
                 vel.0.z += dt.0 * anti_grav * Vec2::<f32>::from(vel.0 * 0.15).magnitude().min(1.0);
-                vel.0 += Vec2::broadcast(dt.0) * control.move_dir * GLIDE_ACCEL;
+                vel.0 += Vec2::broadcast(dt.0) * move_dir * GLIDE_ACCEL;
             } else if vel.0.magnitude() < HUMANOID_AIR_SPEED {
-                vel.0 += Vec2::broadcast(dt.0) * control.move_dir * HUMANOID_AIR_ACCEL;
+                vel.0 += Vec2::broadcast(dt.0) * move_dir * HUMANOID_AIR_ACCEL;
             }
 
             // Set direction based on velocity
diff --git a/common/src/sys/phys.rs b/common/src/sys/phys.rs
index 738b6e667d..ec07a9a478 100644
--- a/common/src/sys/phys.rs
+++ b/common/src/sys/phys.rs
@@ -14,6 +14,8 @@ use vek::*;
 pub struct Sys;
 
 const GRAVITY: f32 = 9.81 * 4.0;
+const FRIC_GROUND: f32 = 0.15;
+const FRIC_AIR: f32 = 0.015;
 
 // Integrates forces, calculates the new velocity based off of the old velocity
 // dt = delta time
@@ -61,7 +63,7 @@ impl<'a> System<'a> for Sys {
 
             // Integrate forces
             // Friction is assumed to be a constant dependent on location
-            let friction = 50.0 * if on_ground { 0.15 } else { 0.015 };
+            let friction = 50.0 * if on_ground { FRIC_GROUND } else { FRIC_AIR };
             vel.0 = integrate_forces(dt.0, vel.0, friction);
 
             // Movement