From b072701a223a4d8884fd50199efac13c9da4d957 Mon Sep 17 00:00:00 2001
From: Recrown <yunyangdeng@gmail.com>
Date: Mon, 11 Feb 2019 23:21:35 -0600
Subject: [PATCH] strip primitives now works.

---
 RecrownedAthenaeum/Render/PrimitiveBatch.cs | 37 ++++++++++-----------
 1 file changed, 18 insertions(+), 19 deletions(-)

diff --git a/RecrownedAthenaeum/Render/PrimitiveBatch.cs b/RecrownedAthenaeum/Render/PrimitiveBatch.cs
index d796444..275f9f2 100644
--- a/RecrownedAthenaeum/Render/PrimitiveBatch.cs
+++ b/RecrownedAthenaeum/Render/PrimitiveBatch.cs
@@ -11,19 +11,14 @@ namespace RecrownedAthenaeum.Render
     /// </summary>
     public class PrimitiveBatch : IDisposable
     {
-        List<VertexPositionColor> vertices;
-        /// <summary>
-        /// The maximum vertices expected. The further off this expectancy is from the true value, the less efficient.
-        /// </summary>
-        public int MaxVertices { get { return vertices.Capacity; } set { vertices.Capacity = value; } }
+        VertexPositionColor[] vertices;
         int bufferPosition;
+        int maxVertices;
+
         BasicEffect basicEffect;
         PrimitiveType primitiveType;
-        
-        /// <summary>
-        /// The vertices per primitive. Can be ignored if using any of the list primitive types. Otherwise, needs to be manually set.
-        /// </summary>
-        public int verticesPerPrimitive;
+
+        int verticesPerPrimitive;
         GraphicsDevice graphicsDevice;
         bool began;
         bool disposed;
@@ -41,7 +36,8 @@ namespace RecrownedAthenaeum.Render
             this.camera = camera ?? (Configuration.Camera2D);
             basicEffect = new BasicEffect(this.graphicsDevice);
             basicEffect.VertexColorEnabled = true;
-            vertices = new List<VertexPositionColor>(verticesPerBatch);
+            vertices = new VertexPositionColor[verticesPerBatch+1];
+            maxVertices = verticesPerBatch;
         }
 
         /// <summary>
@@ -58,7 +54,7 @@ namespace RecrownedAthenaeum.Render
             {
                 case PrimitiveType.LineList: verticesPerPrimitive = 2; break;
                 case PrimitiveType.TriangleList: verticesPerPrimitive = 3; break;
-                default: verticesPerPrimitive = -1; break;
+                default: verticesPerPrimitive = 1; break;
             }
 
             basicEffect.World = camera.worldMatrix;
@@ -88,18 +84,23 @@ namespace RecrownedAthenaeum.Render
         {
             if (!began) throw new InvalidOperationException("Begin needs to be called before adding vertex.");
             if (disposed) throw new ObjectDisposedException(this.GetType().Name);
-            if (bufferPosition + verticesPerPrimitive >= MaxVertices && (bufferPosition % MaxVertices == 0))
+            if (primitiveType != PrimitiveType.LineStrip && primitiveType != PrimitiveType.TriangleStrip)
             {
-                if (primitiveType != PrimitiveType.LineStrip && primitiveType != PrimitiveType.TriangleStrip)
+                if (bufferPosition + verticesPerPrimitive > maxVertices && (bufferPosition % maxVertices == 0))
                 {
                     Flush();
                 }
                 else
                 {
-                    throw new InvalidOperationException("Buffer size isn't large enough.");
+                    throw new InvalidOperationException("Buffer size doesn't match with primitive type.");
                 }
             }
-            vertices.Add(new VertexPositionColor(new Vector3(vertex, 0), color));
+            else if (bufferPosition + verticesPerPrimitive > maxVertices)
+            {
+                throw new InvalidOperationException("Buffer size isn't large enough.");
+            }
+
+            vertices[bufferPosition] = new VertexPositionColor(new Vector3(vertex, 0), color);
             bufferPosition++;
         }
 
@@ -111,9 +112,7 @@ namespace RecrownedAthenaeum.Render
             if (!began) throw new InvalidOperationException("Begin needs to be called before flushing.");
             if (disposed) throw new ObjectDisposedException(this.GetType().Name);
             if (bufferPosition == 0) return;
-            if (verticesPerPrimitive == -1) throw new InvalidOperationException("Vertices per primitive variable not set and using primitive type other than list.");
-            graphicsDevice.DrawUserPrimitives(primitiveType, vertices.ToArray(), 0, bufferPosition / verticesPerPrimitive);
-            vertices.Clear();
+            graphicsDevice.DrawUserPrimitives(PrimitiveType.LineStrip, vertices, 0, bufferPosition / verticesPerPrimitive);
             bufferPosition = 0;
         }