(61d00a474) v0.9.7.1

2020-03-04 13:04:10 +01:00
parent 3c50efa5c9
commit 3c09ebe02f
5086 changed files with 786063 additions and 295871 deletions
@@ -0,0 +1,57 @@
+/* Original source Farseer Physics Engine:
+ * Copyright (c) 2014 Ian Qvist, http://farseerphysics.codeplex.com
+ * Microsoft Permissive License (Ms-PL) v1.1
+ */
+
+using Microsoft.Xna.Framework;
+
+namespace FarseerPhysics.Fluids
+{
+    //TODO: Could be struct?
+
+    public class Spring
+    {
+        public FluidParticle P0;
+        public FluidParticle P1;
+
+        public Spring(FluidParticle p0, FluidParticle p1)
+        {
+            Active = true;
+            P0 = p0;
+            P1 = p1;
+        }
+
+        public bool Active { get; set; }
+        public float RestLength { get; set; }
+
+        public void Update(float timeStep, float kSpring, float influenceRadius)
+        {
+            if (!Active)
+                return;
+
+            Vector2 dir = P1.Position - P0.Position;
+            float distance = dir.Length();
+            dir.Normalize();
+
+            // This is to avoid imploding simulation with really springy fluids
+            if (distance < 0.5f * influenceRadius)
+            {
+                Active = false;
+                return;
+            }
+            if (RestLength > influenceRadius)
+            {
+                Active = false;
+                return;
+            }
+            
+            //Algorithm 3
+            float displacement = timeStep * timeStep * kSpring * (1.0f - RestLength / influenceRadius) * (RestLength - distance) * 0.5f;
+
+            dir *= displacement;
+
+            P0.Position -= dir;
+            P1.Position += dir;
+        }
+    }
+}