From 7f986c546a3b508410b2daabb5deded55bb213ba Mon Sep 17 00:00:00 2001
From: cosmonaut <evan@moonside.games>
Date: Sun, 6 Dec 2020 19:36:00 -0800
Subject: [PATCH] abstract frustum culling

---
 Geometry/Interfaces/ICullable.cs |  9 +++++++++
 Geometry/MeshSprite.cs           |  2 +-
 Geometry/Model.cs                | 14 +++++++-------
 Renderer.cs                      | 27 ++++++---------------------
 4 files changed, 23 insertions(+), 29 deletions(-)
 create mode 100644 Geometry/Interfaces/ICullable.cs

diff --git a/Geometry/Interfaces/ICullable.cs b/Geometry/Interfaces/ICullable.cs
new file mode 100644
index 0000000..831fc83
--- /dev/null
+++ b/Geometry/Interfaces/ICullable.cs
@@ -0,0 +1,9 @@
+using Microsoft.Xna.Framework;
+
+namespace Kav
+{
+    public interface ICullable
+    {
+        BoundingBox BoundingBox { get; }
+    }
+}
diff --git a/Geometry/MeshSprite.cs b/Geometry/MeshSprite.cs
index a7cca6c..e53d5dc 100644
--- a/Geometry/MeshSprite.cs
+++ b/Geometry/MeshSprite.cs
@@ -4,7 +4,7 @@ using Microsoft.Xna.Framework.Graphics;
 
 namespace Kav
 {
-    public class MeshSprite
+    public class MeshSprite : ICullable
     {
         private static readonly int PixelScale = 40;
         private static readonly short[] Indices = new short[]
diff --git a/Geometry/Model.cs b/Geometry/Model.cs
index 6ffe912..3acbb44 100644
--- a/Geometry/Model.cs
+++ b/Geometry/Model.cs
@@ -2,14 +2,14 @@ using Microsoft.Xna.Framework;
 
 namespace Kav
 {
-    public class Model
+    public class Model : ICullable
     {
         public Mesh[] Meshes { get; }
         public BoundingBox BoundingBox { get; }
 
-        public Color Albedo 
-        { 
-            set 
+        public Color Albedo
+        {
+            set
             {
                 foreach (var mesh in Meshes)
                 {
@@ -32,7 +32,7 @@ namespace Kav
                         meshPart.Metallic = value;
                     }
                 }
-            }   
+            }
         }
 
         public float Roughness
@@ -46,7 +46,7 @@ namespace Kav
                         meshPart.Roughness = value;
                     }
                 }
-            }   
+            }
         }
 
         public Model(Mesh[] meshes)
@@ -83,7 +83,7 @@ namespace Kav
                 }
             }
         }
-        
+
         public void DisableMetallicRoughnessMaps()
         {
             foreach (var mesh in Meshes)
diff --git a/Renderer.cs b/Renderer.cs
index b45ac9a..08c673e 100644
--- a/Renderer.cs
+++ b/Renderer.cs
@@ -836,32 +836,17 @@ namespace Kav
             }
         }
 
-        private static IEnumerable<(Model, Matrix)> FrustumCull(
+        private static IEnumerable<(T, Matrix)> FrustumCull<T>(
             BoundingFrustum boundingFrustum,
-            IEnumerable<(Model, Matrix)> modelTransforms
-        ) {
-            foreach (var modelTransform in modelTransforms)
+            IEnumerable<(T, Matrix)> cullableTransforms
+        ) where T : ICullable {
+            foreach (var (cullable, transform) in cullableTransforms)
             {
-                var boundingBox = TransformedBoundingBox(modelTransform.Item1.BoundingBox, modelTransform.Item2);
+                var boundingBox = TransformedBoundingBox(cullable.BoundingBox, transform);
                 var containment = boundingFrustum.Contains(boundingBox);
                 if (containment != ContainmentType.Disjoint)
                 {
-                    yield return modelTransform;
-                }
-            }
-        }
-
-        private static IEnumerable<(MeshSprite, Matrix)> FrustumCull(
-            BoundingFrustum boundingFrustum,
-            IEnumerable<(MeshSprite, Matrix)> meshSpriteTransforms
-        ) {
-            foreach (var (meshSprite, transform) in meshSpriteTransforms)
-            {
-                var boundingBox = TransformedBoundingBox(meshSprite.BoundingBox, transform);
-                var containment = boundingFrustum.Contains(boundingBox);
-                if (containment != ContainmentType.Disjoint)
-                {
-                    yield return (meshSprite, transform);
+                    yield return (cullable, transform);
                 }
             }
         }