tweak to mesh sprite draws

Data/MeshSpriteDrawData.cs

@@ -0,0 +1,24 @@
+using Microsoft.Xna.Framework;
+
+namespace Kav.Data
+{
+    public struct MeshSpriteDrawData 
+    {
+        public MeshSprite MeshSprite { get; }
+        public SpriteBillboardConstraint BillboardConstraint { get; }
+        public Matrix TransformMatrix { get; }
+        public UVOffsets UVOffsets { get; }
+
+        public MeshSpriteDrawData(
+            MeshSprite meshSprite,
+            SpriteBillboardConstraint billboardConstraint,
+            Matrix transformMatrix,
+            UVOffsets uVOffsets
+        ) {
+            MeshSprite = meshSprite;
+            BillboardConstraint = billboardConstraint;
+            TransformMatrix = transformMatrix;
+            UVOffsets = uVOffsets;
+        }
+    }
+}

Data/UVOffsets.cs

@@ -0,0 +1,22 @@
+using Microsoft.Xna.Framework;
+
+namespace Kav.Data
+{
+    public struct UVOffsets
+    {
+        public static UVOffsets Default { get; } = new UVOffsets(
+            new Vector2(0, 0), new Vector2(1, 1)
+        );
+        
+        // (start / width), (end / width)
+        public Vector2 StartUV { get; }
+        // (start / height), (end / height)
+        public Vector2 EndUV { get; }
+
+        public UVOffsets(Vector2 startUV, Vector2 endUV)
+        {
+            StartUV = startUV;
+            EndUV = endUV;
+        }
+    }
+}

Renderer.cs

@@ -1,6 +1,7 @@
 using System;
 using System.Collections.Generic;
 using System.IO;
+using Kav.Data;
 using Microsoft.Xna.Framework;
 using Microsoft.Xna.Framework.Graphics;
 
@@ -117,7 +118,7 @@ namespace Kav
         public void MeshSpriteRender(
             RenderTarget2D renderTarget,
             PerspectiveCamera camera,
-            IEnumerable<(MeshSprite, SpriteBillboardConstraint, Matrix)> meshSpriteBillboardTransforms,
+            IEnumerable<MeshSpriteDrawData> meshSpriteDrawDatas,
             AmbientLight ambientLight,
             IEnumerable<PointLight> pointLights,
             DirectionalLight? directionalLight
@@ -158,17 +159,24 @@ namespace Kav
 
             var boundingFrustum = new BoundingFrustum(camera.View * camera.Projection);
 
-            foreach (var (sprite, transform) in FrustumCull(boundingFrustum, BillboardTransforms(camera, meshSpriteBillboardTransforms)))
+            foreach (var data in meshSpriteDrawDatas)
             {
-                DiffuseLitSpriteEffect.NormalMapEnabled = sprite.Normal != null;
+                var matrix = BillboardTransforms(camera, data.TransformMatrix, data.BillboardConstraint);
 
-                DiffuseLitSpriteEffect.World = transform;
+                if (FrustumCull(boundingFrustum, data.MeshSprite, matrix))
+                {
+                    continue;
+                }
 
-                GraphicsDevice.Textures[0] = sprite.Texture;
+                DiffuseLitSpriteEffect.NormalMapEnabled = data.MeshSprite.Normal != null;
-                GraphicsDevice.Textures[1] = sprite.Normal;
 
-                GraphicsDevice.SetVertexBuffer(sprite.VertexBuffer);
+                DiffuseLitSpriteEffect.World = matrix;
-                GraphicsDevice.Indices = sprite.IndexBuffer;
+
+                GraphicsDevice.Textures[0] = data.MeshSprite.Texture;
+                GraphicsDevice.Textures[1] = data.MeshSprite.Normal;
+
+                GraphicsDevice.SetVertexBuffer(data.MeshSprite.VertexBuffer);
+                GraphicsDevice.Indices = data.MeshSprite.IndexBuffer;
 
                 foreach (var pass in DiffuseLitSpriteEffect.CurrentTechnique.Passes)
                 {
@@ -178,7 +186,7 @@ namespace Kav
                         PrimitiveType.TriangleList,
                         0,
                         0,
-                        sprite.VertexBuffer.VertexCount,
+                        data.MeshSprite.VertexBuffer.VertexCount,
                         0,
                         2
                     );
@@ -186,36 +194,34 @@ namespace Kav
             }
         }
 
-        private static IEnumerable<(MeshSprite, Matrix)> BillboardTransforms(
+        private static Matrix BillboardTransforms(
             PerspectiveCamera camera,
-            IEnumerable<(MeshSprite, SpriteBillboardConstraint, Matrix)> meshSpriteBillboardTransforms
+            Matrix transform,
+            SpriteBillboardConstraint billboardConstraint
         ) {
-            foreach (var (sprite, billboardConstraint, transform) in meshSpriteBillboardTransforms)
-            {
             if (billboardConstraint == SpriteBillboardConstraint.None)
             {
-                    yield return (sprite, transform);
+                return transform;
             }
             else if (billboardConstraint == SpriteBillboardConstraint.Horizontal)
             {
-                    yield return (sprite, Matrix.CreateConstrainedBillboard(
+                return Matrix.CreateConstrainedBillboard(
                     transform.Translation,
                     camera.Position,
                     Vector3.Up,
                     camera.Forward,
                     camera.Position - transform.Translation
-                    ));
+                );
             }
             else
             {
-                    yield return (sprite, Matrix.CreateConstrainedBillboard(
+                return Matrix.CreateConstrainedBillboard(
                     transform.Translation,
                     camera.Position,
                     Vector3.Up,
                     null,
                     null
-                    ));
+                );
-                }
             }
         }
 
@@ -924,21 +930,14 @@ namespace Kav
             }
         }
 
-        private static IEnumerable<Matrix> FrustumCull<T>(
+        private static bool FrustumCull<T>(
             BoundingFrustum boundingFrustum,
             T cullable,
-            IEnumerable<Matrix> transforms
+            Matrix transform
-        ) where T : ICullable
+        ) where T : ICullable {
-        {
-            foreach (var transform in transforms)
-            {
             var boundingBox = TransformedBoundingBox(cullable.BoundingBox, transform);
             var containment = boundingFrustum.Contains(boundingBox);
-                if (containment != ContainmentType.Disjoint)
+            return (containment == ContainmentType.Disjoint);
-                {
-                    yield return transform;
-                }
-            }
         }
 
         private static BoundingBox TransformedBoundingBox(BoundingBox boundingBox, Matrix matrix)