ported from perforce

DonkeysAndDroids.Godot/Background.cs

@@ -0,0 +1,29 @@
+using Godot;
+
+public partial class Background : Control
+{
+    public override void _Ready()
+    {
+        var rect = GetNode<ColorRect>("SwirlRect");
+        m_SwirlMaterial = rect.Material as ShaderMaterial;
+
+        m_Particles = GetNode<GpuParticles2D>("DustParticles");
+        m_ParticlesProcess = m_Particles.ProcessMaterial as ParticleProcessMaterial;
+    }
+
+    public override void _Process(double delta)
+    {
+        m_Particles.Position = Size / 2;
+        ((ParticleProcessMaterial)m_Particles.ProcessMaterial).EmissionBoxExtents = new(Size.X / 2, Size.Y / 2, 1);
+        Refresh();
+    }
+
+    public void Refresh()
+    {
+    }
+
+    private GpuParticles2D m_Particles;
+    private ParticleProcessMaterial m_ParticlesProcess;
+
+    private ShaderMaterial m_SwirlMaterial;
+}