Slopes - Done!

Assets/Scripts/MovingSphere.cs

@@ -9,23 +9,35 @@ public class MovingSphere : MonoBehaviour
     private float maxAcceleration = 10f, maxAirAcceleration = 1f;
 
     [SerializeField, Range(0f, 10f)]
-    float jumpHeight = 2f;
+    private float jumpHeight = 2f;
 
     [SerializeField, Range(0, 5)]
-    int maxAirJumps = 0;
+    private int maxAirJumps = 0;
+
+    [SerializeField, Range(0f, 90f)]
+    private float maxGroundAngle = 25f;
 
     private Rigidbody body;
 
     private Vector3 desiredVelocity = new Vector3(0f, 0f, 0f);
     private bool desiredJump = false;
 
-    private bool onGround;
+    private int groundContactCount;
+    private bool onGround => groundContactCount > 0;
     private int jumpPhase;
     private Vector3 velocity;
+    private Vector3 contactNormal;
+    private float minGroundDotProduct;
+
+    private void OnValidate()
+    {
+        minGroundDotProduct = Mathf.Cos(maxGroundAngle * Mathf.Deg2Rad);
+    }
 
     private void Awake()
     {
         body = GetComponent<Rigidbody>();
+        OnValidate();
     }
 
     private void Update()
@@ -43,10 +55,7 @@ public class MovingSphere : MonoBehaviour
     {
         UpdateState();
 
-        float acceleration = onGround ? maxAcceleration : maxAirAcceleration;
-        float maxSpeedChange = acceleration * Time.deltaTime;
-        velocity.x = Mathf.MoveTowards(velocity.x, desiredVelocity.x, maxSpeedChange);
-        velocity.z = Mathf.MoveTowards(velocity.z, desiredVelocity.z, maxSpeedChange);
+        AdjustVelocity();
 
         if (desiredJump)
         {
@@ -56,7 +65,7 @@ public class MovingSphere : MonoBehaviour
 
         body.velocity = velocity;
 
-        onGround = false;
+        ClearState();
     }
 
     private void UpdateState()
@@ -65,6 +74,14 @@ public class MovingSphere : MonoBehaviour
         if (onGround)
         {
             jumpPhase = 0;
+            if (groundContactCount > 1)
+            {
+                contactNormal.Normalize();
+            }
+        }
+        else
+        {
+            contactNormal = Vector3.up;
         }
     }
 
@@ -83,7 +100,11 @@ public class MovingSphere : MonoBehaviour
         for (int i = 0; i < collision.contactCount; i++)
         {
             var normal = collision.GetContact(i).normal;
-            onGround |= normal.y >= 0.9f;
+            if (normal.y >= minGroundDotProduct)
+            {
+                groundContactCount += 1;
+                contactNormal += normal;
+            }
         }
     }
 
@@ -93,12 +114,42 @@ public class MovingSphere : MonoBehaviour
         {
             jumpPhase++;
             float jumpSpeed = Mathf.Sqrt(-2f * Physics.gravity.y * jumpHeight);
-            if (velocity.y > 0f)
+            float alignedSpeed = Vector3.Dot(velocity, contactNormal);
+            if (alignedSpeed > 0f)
             {
-                jumpSpeed = Mathf.Max(jumpSpeed - velocity.y, 0f);
+                jumpSpeed = Mathf.Max(jumpSpeed - alignedSpeed, 0f);
             }
-            velocity.y += jumpSpeed;
+            velocity += contactNormal * jumpSpeed;
         }
     }
 
+    private void AdjustVelocity()
+    {
+        Vector3 xAxis = ProjectOnContactPlane(Vector3.right).normalized;
+        Vector3 zAxis = ProjectOnContactPlane(Vector3.forward).normalized;
+
+        float currentX = Vector3.Dot(velocity, xAxis);
+        float currentZ = Vector3.Dot(velocity, zAxis);
+        
+        float acceleration = onGround ? maxAcceleration : maxAirAcceleration;
+        float maxSpeedChange = acceleration * Time.deltaTime;
+
+        float newX =
+            Mathf.MoveTowards(currentX, desiredVelocity.x, maxSpeedChange);
+        float newZ =
+            Mathf.MoveTowards(currentZ, desiredVelocity.z, maxSpeedChange);
+
+        velocity += xAxis * (newX - currentX) + zAxis * (newZ - currentZ);
+    }
+
+    private Vector3 ProjectOnContactPlane(Vector3 vector)
+    {
+        return vector - contactNormal * Vector3.Dot(vector, contactNormal);
+    }
+
+    void ClearState()
+    {
+        groundContactCount = 0;
+        contactNormal = Vector3.zero;
+    }
 }