Fixed organelle models flickering sometimes due to render order (Revo…

…lutionary-Games#2756)

* Calculate different RenderPriorities for the HexPositions.

* updated render priority calculation

* added helper function to get scene material

* PR code cleanups

* return null if no scene loaded

* changed string to NodePath

* made positive modulo more readable

simulation_parameters/Constants.cs

@@ -654,6 +654,11 @@ public static class Constants
     /// </summary>
     public const string SPECIES_NAME_REGEX = "^(?<genus>[^ ]+) (?<epithet>[^ ]+)$";
 
+    /// <summary>
+    ///   Minimum hex distance before the same render priority.
+    /// </summary>
+    public const int HEX_RENDER_PRIORITY_DISTANCE = 4;
+
     /// <summary>
     ///   The duration for which a save is considered recently performed.
     /// </summary>

src/engine/NodeHelpers.cs

@@ -115,4 +115,27 @@ public static void ReParent(this Node node, Node newParent)
         node.GetParent().RemoveChild(node);
         newParent.AddChild(node);
     }
+
+    /// <summary>
+    ///   Get the material of this scene's model.
+    /// </summary>
+    /// <param name="node">Node to get material from.</param>
+    /// <param name="modelPath">Path to model within the scene. If null takes scene root as model.</param>
+    /// <returns>ShaderMaterial of the GeometryInstance.</returns>
+    public static ShaderMaterial GetMaterial(this Node node, NodePath modelPath = null)
+    {
+        GeometryInstance geometry;
+
+        // Fetch the actual model from the scene
+        if (string.IsNullOrEmpty(modelPath))
+        {
+            geometry = (GeometryInstance)node;
+        }
+        else
+        {
+            geometry = node.GetNode<GeometryInstance>(modelPath);
+        }
+
+        return (ShaderMaterial)geometry.MaterialOverride;
+    }
 }

src/general/Hex.cs

@@ -231,19 +231,30 @@ public static Hex FlipHorizontally(Hex hex)
         return new Hex(-hex.Q, hex.Q + hex.R);
     }
 
-    public override bool Equals(object obj)
+    /// <summary>
+    ///   Returns the RenderPriority for the hex.
+    ///   Between 1 and HEX_RENDER_PRIORITY_DISTANCE^2.
+    /// </summary>
+    /// <returns>RenderPriority</returns>
+    public static int GetRenderPriority(Hex hex)
     {
-        if (!(obj is Hex hex))
-            return false;
-
-        return Equals(hex);
+        return hex.Q.PositiveModulo(Constants.HEX_RENDER_PRIORITY_DISTANCE) * Constants.HEX_RENDER_PRIORITY_DISTANCE
+            + hex.R.PositiveModulo(Constants.HEX_RENDER_PRIORITY_DISTANCE) + 1;
     }
 
     public bool Equals(Hex other)
     {
         return Q == other.Q && R == other.R;
     }
 
+    public override bool Equals(object obj)
+    {
+        if (!(obj is Hex hex))
+            return false;
+
+        return Equals(hex);
+    }
+
     public override int GetHashCode()
     {
         var hashCode = -1997189103;

src/general/MathUtils.cs

@@ -74,4 +74,15 @@ public static float Lerp(float from, float to, float weight, float tolerance = M
 
         return Mathf.Lerp(from, to, weight);
     }
+
+    /// <summary>
+    ///   Standard modulo for negative values in C# produces negative results.
+    ///   This function returns modulo values between 0 and mod-1.
+    /// </summary>
+    /// <returns>The positive modulo</returns>
+    public static int PositiveModulo(this int val, int mod)
+    {
+        int result = val % mod;
+        return (result < 0) ? result + mod : result;
+    }
 }

src/general/SceneDisplayer.cs

@@ -21,6 +21,16 @@ public string Scene
         }
     }
 
+    /// <summary>
+    ///   Get the material of this scene's model.
+    /// </summary>
+    /// <param name="modelPath">Path to model within the scene. If null takes scene root as model.</param>
+    /// <returns>ShaderMaterial of the GeometryInstance. Null if no scene.</returns>
+    public ShaderMaterial GetMaterial(NodePath modelPath = null)
+    {
+        return currentlyShown?.GetMaterial(modelPath);
+    }
+
     private void LoadNewScene()
     {
         if (currentlyShown != null)

src/microbe_stage/Membrane.tscn

@@ -10,7 +10,7 @@ size = Vector3( 2, 0.539, 2 )
 
 [sub_resource type="ShaderMaterial" id=2]
 resource_local_to_scene = true
-render_priority = 1
+render_priority = 18
 shader = ExtResource( 2 )
 shader_param/wigglyNess = 1.0
 shader_param/movementWigglyNess = 1.0

src/microbe_stage/Microbe.tscn

@@ -10,7 +10,7 @@
 
 [sub_resource type="ShaderMaterial" id=1]
 resource_local_to_scene = true
-render_priority = 1
+render_priority = 18
 shader = ExtResource( 4 )
 shader_param/wigglyNess = 1.0
 shader_param/movementWigglyNess = 1.0

src/microbe_stage/PlacedOrganelle.cs

@@ -574,26 +574,15 @@ private void SetupOrganelleGraphics()
     {
         var organelleSceneInstance = (Spatial)Definition.LoadedScene.Instance();
 
-        // Store the material of the organelle to be updated
-        GeometryInstance geometry;
-
-        // Fetch the actual model from the scene to get at the material we set the tint on
-        if (string.IsNullOrEmpty(Definition.DisplaySceneModelPath))
-        {
-            geometry = (GeometryInstance)organelleSceneInstance;
-        }
-        else
-        {
-            geometry = organelleSceneInstance.GetNode<GeometryInstance>(Definition.DisplaySceneModelPath);
-        }
-
         // Store animation player for later use
         if (!string.IsNullOrEmpty(Definition.DisplaySceneAnimation))
         {
             OrganelleAnimation = organelleSceneInstance.GetNode<AnimationPlayer>(Definition.DisplaySceneAnimation);
         }
 
-        organelleMaterial = (ShaderMaterial)geometry.MaterialOverride;
+        // Store the material of the organelle to be updated
+        organelleMaterial = organelleSceneInstance.GetMaterial(Definition.DisplaySceneModelPath);
+        organelleMaterial.RenderPriority = Hex.GetRenderPriority(Position);
 
         // There is an intermediate node so that the organelle scene root rotation and scale work
         OrganelleGraphics = new Spatial();
@@ -607,6 +596,7 @@ private void SetupOrganelleGraphics()
         // Position the intermediate node relative to origin of cell
         var transform = new Transform(Quat.Identity,
             Hex.AxialToCartesian(Position) + Definition.CalculateModelOffset());
+
         OrganelleGraphics.Transform = transform;
 
         // For some reason MathUtils.CreateRotationForOrganelle(Orientation) in the above transform doesn't work

src/microbe_stage/editor/MicrobeEditor.cs

@@ -1734,7 +1734,8 @@ private void RenderHighlightedOrganelle(int q, int r, int rotation, OrganelleDef
 
             organelleModel.Visible = true;
 
-            UpdateOrganellePlaceHolderScene(organelleModel, shownOrganelle.DisplayScene);
+            UpdateOrganellePlaceHolderScene(organelleModel, shownOrganelle.DisplayScene,
+                shownOrganelle, Hex.GetRenderPriority(new Hex(q, r)));
         }
     }
 
@@ -2283,7 +2284,7 @@ private void UpdateAlreadyPlacedVisuals()
                 organelleModel.Visible = !MicrobePreviewMode;
 
                 UpdateOrganellePlaceHolderScene(organelleModel,
-                    organelle.Definition.DisplayScene);
+                    organelle.Definition.DisplayScene, organelle.Definition, Hex.GetRenderPriority(organelle.Position));
             }
         }
 
@@ -2304,9 +2305,15 @@ private void UpdateAlreadyPlacedVisuals()
     /// <summary>
     ///   Updates the organelle model displayer to have the specified scene in it
     /// </summary>
-    private void UpdateOrganellePlaceHolderScene(SceneDisplayer organelleModel, string displayScene)
+    private void UpdateOrganellePlaceHolderScene(SceneDisplayer organelleModel,
+        string displayScene, OrganelleDefinition definition, int renderPriority)
     {
         organelleModel.Scene = displayScene;
+        var material = organelleModel.GetMaterial(definition.DisplaySceneModelPath);
+        if (material != null)
+        {
+            material.RenderPriority = renderPriority;
+        }
     }
 
     [DeserializedCallbackAllowed]