Add --warmup option to control physics warmup loops

Create a new --warmup argument to specify the number of warmup loops for physics before export. This allows users to control how many times the animation is pre-processed to stabilize physics.

SpineViewerCLI/SpineViewerCLI.cs

@@ -33,6 +33,7 @@ options:
   --speed FLOAT         Speed of animation (for video), default 1.0
   --color HEX           Background color as a hex RGBA color, default 000000ff (opaque black)
   --quiet               Removes console progress log, default false
+  --warmup INT          Warm Up Physics, default 2 loops before export
 ";
 
         public static void Main(string[] args)
@@ -57,6 +58,8 @@ options:
             float speed = 1;
             Color backgroundColor = Color.Black;
             bool quiet = false;
+            bool warmup = false;
+            int warmUpLoops = 2;
 
             for (int i = 0; i < args.Length; i++)
             {
@@ -126,6 +129,10 @@ options:
                     case "--quiet":
                         quiet = true;
                         break;
+                    case "--warmup":
+                        warmUpLoops = int.Parse(args[++i]);
+                        warmup = true;
+                        break;
                     default:
                         Console.Error.WriteLine($"Unknown argument: {args[i]}");
                         Environment.Exit(2);
@@ -172,6 +179,20 @@ options:
             }
             sp.Update(0);
 
+            if (warmup)
+            {
+                float delta = 1f / fps;
+                for (int i = 0; i < warmUpLoops; i++)
+                {
+                    float t = 0;
+                    while (t < trackEntry.Animation.Duration)
+                    {
+                        sp.Update(delta);
+                        t += delta;
+                    }
+                }
+            }
+
             foreach (var slotName in hideSlots)
             {
                 if (!sp.SetSlotVisible(slotName, false))