From 71ea2f646afd29cd5ddd843b7fcd0e7933caac5b Mon Sep 17 00:00:00 2001
From: Sollace <sollacea@gmail.com>
Date: Fri, 25 Sep 2020 12:39:10 +0200
Subject: [PATCH] More work on the new flight mechanics

---
 .../player/AeronauticalPlayerPhysics.java     | 50 +++++++++++++++++++
 .../unicopia/entity/player/Aeronautics.java   | 37 +++++++++++---
 2 files changed, 79 insertions(+), 8 deletions(-)
 create mode 100644 src/main/java/com/minelittlepony/unicopia/entity/player/AeronauticalPlayerPhysics.java

diff --git a/src/main/java/com/minelittlepony/unicopia/entity/player/AeronauticalPlayerPhysics.java b/src/main/java/com/minelittlepony/unicopia/entity/player/AeronauticalPlayerPhysics.java
new file mode 100644
index 00000000..9db796ee
--- /dev/null
+++ b/src/main/java/com/minelittlepony/unicopia/entity/player/AeronauticalPlayerPhysics.java
@@ -0,0 +1,50 @@
+package com.minelittlepony.unicopia.entity.player;
+
+import com.minelittlepony.unicopia.util.MutableVector;
+
+import net.minecraft.entity.Entity;
+import net.minecraft.entity.player.PlayerEntity;
+import net.minecraft.util.math.Vec3d;
+
+public class AeronauticalPlayerPhysics extends PlayerPhysics {
+
+    private final Aeronautics auronautics = new Aeronautics();
+
+    private double gravity;
+
+    private int thrustCountdown;
+
+    public AeronauticalPlayerPhysics(Pony pony) {
+        super(pony);
+    }
+
+    @Override
+    public double calcGravity(double worldConstant) {
+        return gravity = super.calcGravity(worldConstant);
+    }
+
+    @Override
+    protected void moveFlying(Entity player, MutableVector velocity) {
+
+        PlayerEntity ply = (PlayerEntity)player;
+
+        auronautics.pitchAngle = 0;
+        auronautics.rollAngle = 0;
+
+        float yaw = player.getYaw(1);
+
+        Vec3d motion = auronautics.calcGravitationalAccelleration(gravity);
+
+        if (ply.forwardSpeed != 0 && thrustCountdown-- <= 0) {
+            thrustCountdown = 20;
+            player.playSound(getWingSound(), 0.4F, 1);
+            motion = motion.add(auronautics.calcThrustVelocity(-100));
+        }
+
+        motion = motion.rotateY(yaw).add(velocity.toImmutable()).multiply(1 - auronautics.getDrag());
+
+        velocity.x = motion.x;
+        velocity.y = motion.y;
+        velocity.z = motion.z;
+    }
+}
diff --git a/src/main/java/com/minelittlepony/unicopia/entity/player/Aeronautics.java b/src/main/java/com/minelittlepony/unicopia/entity/player/Aeronautics.java
index 494171f5..8f37d15e 100644
--- a/src/main/java/com/minelittlepony/unicopia/entity/player/Aeronautics.java
+++ b/src/main/java/com/minelittlepony/unicopia/entity/player/Aeronautics.java
@@ -14,20 +14,41 @@ public class Aeronautics {
      * Gets the normalized direction vector
      */
     private Vec3d getMomentVector() {
-        Vec3d bankVector = new Vec3d(0, Math.sin(rollAngle), Math.cos(rollAngle));
+        // sine(angle) = y/h
+        // cos(angle) = x/h
+
         Vec3d climbVector = new Vec3d(Math.cos(pitchAngle), Math.sin(pitchAngle), 0);
+        Vec3d bankVector =  new Vec3d(0,                    Math.sin(rollAngle),  Math.cos(rollAngle));
+
+        return bankVector.add(climbVector).normalize();
+    }
+
+    /**
+     * Gets the normalized perpendicular vector.
+     */
+    private Vec3d getNormal() {
+        // sine(angle) = y/h
+        // cos(angle) = x/h
+
+        Vec3d climbVector = new Vec3d(Math.cos(pitchAngle), Math.sin(pitchAngle), 0);
+        Vec3d bankVector =  new Vec3d(0,                    Math.sin(rollAngle),  Math.cos(rollAngle));
 
         return bankVector.crossProduct(climbVector).normalize();
     }
 
     /**
-     * Returns the acceleration vector due to gravity in the direction of
-     * the incline described by the roll and pitch components.
+     * Returns the acceleration vector due to gravity
+     * parallel to the slope of the incline described
+     * by the roll and pitch components.
      *
      * @param gravity The global gravitation constant C
      */
     public Vec3d calcGravitationalAccelleration(double gravity) {
-        return getMomentVector().multiply(-gravity);
+        return getMomentVector().multiply(
+               -gravity * Math.signum(pitchAngle),
+               -gravity,
+               -gravity * Math.signum(rollAngle)
+        );
     }
 
     /**
@@ -37,10 +58,10 @@ public class Aeronautics {
      * @param forwards The forwards thrust speed
      * @param velocity The current motion vector
      */
-    public Vec3d calcThrustVelocity(double forwards, Vec3d velocity) {
-        velocity = velocity.normalize().multiply(forwards);
-
-        return getMomentVector().multiply(velocity.x, velocity.y, 0).multiply(getDrag());
+    public Vec3d calcThrustVelocity(double forwards) {
+        return getNormal().add(getMomentVector())
+                .normalize()
+                .multiply(forwards * (1 - getDrag()));
     }
 
     /**