Added mod requirement checking.

Assets/Scripts/Mod.cs

@@ -5,8 +5,11 @@
 using System.Linq;
 using System.Reflection;
 using System.Xml.Linq;
+using Assets.Scripts.Craft.Parts.Modifiers;
 using Assets.Scripts.Vizzy;
+using ModApi.Craft;
 using ModApi.Craft.Program;
+using ModApi.Craft.Program.Instructions;
 using ModApi.Mods;
 using ModApi.Ui;
 using ModApi.Ui.Events;
@@ -109,6 +112,10 @@ private Mod() {
         /// <value>The singleton instance of the mod object.</value>
         public static Mod Instance { get; } = GetModInstance<Mod>();
 
+        public override Boolean IsModRequiredForCraft(CraftData craft) {
+            return base.IsModRequiredForCraft(craft) || DoesCraftUseVizzyGL(craft);
+        }
+
         protected override void OnModInitialized() {
             var ui = ModApi.Common.Game.Instance.UserInterface;
 
@@ -117,6 +124,78 @@ protected override void OnModInitialized() {
             base.OnModInitialized();
         }
 
+        private static Boolean DoesCraftUseVizzyGL(CraftData craft) {
+            Debug.Log($"Checking craft {craft.Name} for VizzyGL usage.");
+            if (craft.Assembly != null) {
+                foreach (var part in craft.Assembly.Parts) {
+                    var flightProgramData = part.GetModifier<FlightProgramData>();
+
+                    if (flightProgramData?.FlightProgramXml != null) {
+                        try {
+                            var flightProgram = flightProgramData.Script.FlightProgram ??
+                                new ProgramSerializer().DeserializeFlightProgram(flightProgramData.FlightProgramXml);
+                            if (ContainsVizzyGL(flightProgram.RootInstructions) ||
+                                ContainsVizzyGL(flightProgram.RootExpressions) ||
+                                ContainsVizzyGL(flightProgram.CustomExpressions) ||
+                                ContainsVizzyGL(flightProgram.CustomInstructions)) {
+                                Debug.Log($"Flight Program on part {part.Name} contains VizzyGL.");
+                                return true;
+                            } else {
+                                Debug.Log($"Flight Program on part {part.Name} does not contain VizzyGL.");
+                            }
+                        } catch (Exception ex) {
+                            Debug.LogWarning($"Unable to deserialize Flight Program: {flightProgramData.FlightProgramXml}");
+                            Debug.LogError(ex);
+                        }
+                    }
+                }
+            } else {
+                Debug.LogWarning("Unable to check craft for VizzyGL because Assembly is null.");
+            }
+
+            return false;
+        }
+
+        private static Boolean ContainsVizzyGL(IEnumerable<ProgramInstruction> instructions) {
+            var instructionStack = new Stack<ProgramInstruction>(instructions);
+            while (instructionStack.Count > 0) {
+                var instruction = instructionStack.Pop();
+                if (instruction is IVizzyGLProgramNode) {
+                    return true;
+                }
+
+                if (instruction.Expressions != null && ContainsVizzyGL(instruction.Expressions)) {
+                    return true;
+                }
+
+                if (instruction.Next != null) {
+                    instructionStack.Push(instruction.Next);
+                }
+
+                if (instruction.SupportsChildren) {
+                    instructionStack.Push(instruction.FirstChild);
+                }
+            }
+
+            return false;
+        }
+
+        private static Boolean ContainsVizzyGL(IEnumerable<ProgramExpression> expressions) {
+            var expressionStack = new Stack<ProgramExpression>(expressions);
+            while (expressionStack.Count > 0) {
+                var expression = expressionStack.Pop();
+                if (expression is IVizzyGLProgramNode) {
+                    return true;
+                } else if (expression.Expressions != null) {
+                    foreach (var child in expression.Expressions.Reverse()) {
+                        expressionStack.Push(child);
+                    }
+                }
+            }
+
+            return false;
+        }
+
         private void UiOnUserInterfaceLoading(object sender, UserInterfaceLoadingEventArgs e) {
             var vizzyUI = e.XmlLayout.GameObject.GetComponent<VizzyUIController>();
             if (e.UserInterfaceId == UserInterfaceIds.Vizzy) {

Assets/Scripts/Vizzy/IVizzyGLProgramNode.cs

@@ -0,0 +1,4 @@
+namespace Assets.Scripts.Vizzy {
+    public interface IVizzyGLProgramNode {
+    }
+}

Assets/Scripts/Vizzy/VizzyGLInstructionBase.cs

@@ -3,7 +3,7 @@
 using UnityEngine;
 
 namespace Assets.Scripts.Vizzy {
-    public abstract class VizzyGLInstructionBase : ProgramInstruction {
+    public abstract class VizzyGLInstructionBase : ProgramInstruction, IVizzyGLProgramNode {
         protected IVizzyGLContext DrawingContext { get; private set; }
 
         public override ProgramInstruction Execute(IThreadContext context) {