From 0aca8dbf9df4bef692286aa996cda128cb91c8c1 Mon Sep 17 00:00:00 2001
From: Regalis <regalis@undertowgames.com>
Date: Thu, 11 May 2017 21:30:33 +0300
Subject: [PATCH] Humanoid animations work better on uneven floors (e.g. "fake
 stairs" made from wall pieces).

If the floor in front of the character is higher than where the character is standing, the character slows down and lifts its feet more. The position of the feet is also clamped below the waist, preventing the character from doing a backwards somersault when running over "fake stairs".
---
 .../Animation/HumanoidAnimController.cs       | 40 ++++++++++++-------
 .../Source/Characters/Animation/Ragdoll.cs    | 10 +++--
 2 files changed, 32 insertions(+), 18 deletions(-)

diff --git a/Subsurface/Source/Characters/Animation/HumanoidAnimController.cs b/Subsurface/Source/Characters/Animation/HumanoidAnimController.cs
index 5316f9db0..a234bb697 100644
--- a/Subsurface/Source/Characters/Animation/HumanoidAnimController.cs
+++ b/Subsurface/Source/Characters/Animation/HumanoidAnimController.cs
@@ -237,7 +237,7 @@ namespace Barotrauma
 
             Limb leftLeg = GetLimb(LimbType.LeftLeg);
             Limb rightLeg = GetLimb(LimbType.RightLeg);
-
+            
             float getUpSpeed = 0.3f;
             float walkCycleSpeed = movement.X * walkAnimSpeed;
             if (stairs != null)
@@ -322,8 +322,11 @@ namespace Barotrauma
             torso.pullJoint.Enabled = true;
             head.pullJoint.Enabled = true;
             waist.pullJoint.Enabled = true;
+            
+            float floorPos = GetFloorY(colliderPos + new Vector2(Math.Sign(movement.X) * 0.5f, 1.0f));
+            bool onSlope = floorPos > GetColliderBottom().Y + 0.05f;
 
-            if (stairs != null)
+            if (stairs != null || onSlope)
             {
                 torso.pullJoint.WorldAnchorB = new Vector2(
                     MathHelper.SmoothStep(torso.SimPosition.X, footMid + movement.X * 0.25f, getUpSpeed * 0.8f),
@@ -369,20 +372,23 @@ namespace Barotrauma
                 //progress the walking animation
                 walkPos -= (walkCycleSpeed / runningModifier) * 0.8f;
 
-                MoveLimb(leftFoot,
-                    colliderPos + new Vector2(
-                        stepSize.X,
-                        (stepSize.Y > 0.0f) ? stepSize.Y : -0.15f),
-                    15.0f, true);
+                for (int i = -1; i < 2; i += 2)
+                {
+                    Limb foot = i == -1 ? leftFoot : rightFoot;
+                    Limb leg = i == -1 ? leftLeg : rightLeg;
 
-                MoveLimb(rightFoot,
-                    colliderPos + new Vector2(
-                        -stepSize.X,
-                        (-stepSize.Y > 0.0f) ? -stepSize.Y : -0.15f),
-                    15.0f, true);
+                    Vector2 footPos = stepSize * -i;
+                    if (stepSize.Y > 0.0f) stepSize.Y = -0.15f;
 
-                leftFoot.body.SmoothRotate(leftLeg.body.Rotation + MathHelper.PiOver2 * Dir * 1.6f, 20.0f * runningModifier);
-                rightFoot.body.SmoothRotate(rightLeg.body.Rotation + MathHelper.PiOver2 * Dir * 1.6f, 20.0f * runningModifier);
+                    if (onSlope && stairs == null)
+                    {
+                        footPos.Y *= 2.0f;
+                    }
+                    footPos.Y = Math.Min(waist.SimPosition.Y - colliderPos.Y - 0.4f, footPos.Y);
+
+                    MoveLimb(foot, footPos + colliderPos, 15.0f, true);
+                    foot.body.SmoothRotate(leg.body.Rotation + MathHelper.PiOver2 * Dir * 1.6f, 20.0f * runningModifier);
+                }
 
                 if (runningModifier > 1.0f)
                 {
@@ -453,7 +459,11 @@ namespace Barotrauma
                     {
                         footPos = new Vector2(GetCenterOfMass().X + stepSize.X * i * 0.2f, colliderPos.Y - 0.1f);
                     }
-                    
+
+                    if (stairs == null)
+                    {
+                        footPos.Y = Math.Max(Math.Min(floorPos, footPos.Y + 0.5f), footPos.Y);
+                    }
 
                     var foot = i == -1 ? rightFoot : leftFoot;
 
diff --git a/Subsurface/Source/Characters/Animation/Ragdoll.cs b/Subsurface/Source/Characters/Animation/Ragdoll.cs
index 3b4b2ea8a..29165fbaa 100644
--- a/Subsurface/Source/Characters/Animation/Ragdoll.cs
+++ b/Subsurface/Source/Characters/Animation/Ragdoll.cs
@@ -1096,7 +1096,12 @@ namespace Barotrauma
         {
             PhysicsBody refBody = refLimb == null ? Collider : refLimb.body;
 
-            Vector2 rayStart = refBody.SimPosition; 
+            return GetFloorY(refBody.SimPosition);            
+        }
+
+        protected float GetFloorY(Vector2 simPosition)
+        {
+            Vector2 rayStart = simPosition;
             Vector2 rayEnd = rayStart - new Vector2(0.0f, TorsoPosition);
 
             var lowestLimb = FindLowestLimb();
@@ -1125,7 +1130,7 @@ namespace Barotrauma
                 }
 
                 return closestFraction;
-            } 
+            }
             , rayStart, rayEnd);
 
 
@@ -1137,7 +1142,6 @@ namespace Barotrauma
             {
                 return rayStart.Y + (rayEnd.Y - rayStart.Y) * closestFraction;
             }
-            
         }
 
         public void SetPosition(Vector2 simPosition, bool lerp = false)