From 346e4c4395af554562e76c742598e9bfaf576101 Mon Sep 17 00:00:00 2001
From: Kevin Gadd <kevin.gadd@gmail.com>
Date: Mon, 25 Feb 2013 05:24:15 -0800
Subject: [PATCH] Make the buffer argument to LayoutString optional. Fix
 GeometryBatches with 0 draw calls in them.

---
 Squared/RenderLib/RenderGeometry.cs | 38 +++++++++++++++--------------
 Squared/RenderLib/RenderText.cs     | 17 +++++++++----
 2 files changed, 32 insertions(+), 23 deletions(-)

diff --git a/Squared/RenderLib/RenderGeometry.cs b/Squared/RenderLib/RenderGeometry.cs
index 778ffc706..4f8912ec3 100644
--- a/Squared/RenderLib/RenderGeometry.cs
+++ b/Squared/RenderLib/RenderGeometry.cs
@@ -217,30 +217,32 @@ internal static GeometryDrawCallPreparer
         }
 
         public override void Issue (DeviceManager manager) {
-            using (manager.ApplyMaterial(Material))
-            try {
-                var buffers = _BufferGenerator.GetBuffer();
+            if (Count > 0) {
+                using (manager.ApplyMaterial(Material))
+                try {
+                    var buffers = _BufferGenerator.GetBuffer();
                 
-#if PSM
-                var g = manager.Device._graphics;
+    #if PSM
+                                    var g = manager.Device._graphics;
                 g.SetVertexBuffer(0, buffers);
                 
                 foreach (var da in _DrawArguments)
                     g.DrawArrays(PSSHelper.ToDrawMode(da.PrimitiveType), da.IndexOffset, da.IndexCount, 1);
-#else
-                manager.Device.SetVertexBuffer(buffers.Vertices);
-                manager.Device.Indices = buffers.Indices;
+    #else
+                    manager.Device.SetVertexBuffer(buffers.Vertices);
+                    manager.Device.Indices = buffers.Indices;
                 
-                foreach (var da in _DrawArguments)
-                    manager.Device.DrawIndexedPrimitives(da.PrimitiveType, 0, da.VertexOffset, da.VertexCount, da.IndexOffset, da.PrimitiveCount);
-#endif
-            } finally {
-#if PSM
-                manager.Device._graphics.SetVertexBuffer(0, null);
-#else
-                manager.Device.SetVertexBuffer(null);
-                manager.Device.Indices = null;
-#endif
+                    foreach (var da in _DrawArguments)
+                        manager.Device.DrawIndexedPrimitives(da.PrimitiveType, 0, da.VertexOffset, da.VertexCount, da.IndexOffset, da.PrimitiveCount);
+    #endif
+                } finally {
+    #if PSM
+                    manager.Device._graphics.SetVertexBuffer(0, null);
+    #else
+                    manager.Device.SetVertexBuffer(null);
+                    manager.Device.Indices = null;
+    #endif
+                }
             }
 
             _DrawArgumentsListPool.Release(ref _DrawArguments);
diff --git a/Squared/RenderLib/RenderText.cs b/Squared/RenderLib/RenderText.cs
index 5e8a353dc..7433a14b7 100644
--- a/Squared/RenderLib/RenderText.cs
+++ b/Squared/RenderLib/RenderText.cs
@@ -12,13 +12,20 @@
 namespace Squared.Render {
     public static class SpriteFontExtensions {
         public static ArraySegment<BitmapDrawCall> LayoutString (
-            this SpriteFont font, string text, ArraySegment<BitmapDrawCall> buffer,
+            this SpriteFont font, string text, ArraySegment<BitmapDrawCall>? buffer,
             Vector2? position = null, Color? color = null, float scale = 1, float sortKey = 0,
             int characterSkipCount = 0, int characterLimit = int.MaxValue
         ) {
             if (text == null)
                 throw new ArgumentNullException("text");
-            if (buffer.Count < text.Length)
+
+            ArraySegment<BitmapDrawCall> _buffer;
+            if (buffer.HasValue)
+                _buffer = buffer.Value;
+            else
+                _buffer = new ArraySegment<BitmapDrawCall>(new BitmapDrawCall[text.Length]);
+
+            if (_buffer.Count < text.Length)
                 throw new ArgumentException("buffer too small", "buffer");
 
             var spacing = font.Spacing;
@@ -36,7 +43,7 @@ public static class SpriteFontExtensions {
             float rectScaleX = 1f / glyphSource.Texture.Width;
             float rectScaleY = 1f / glyphSource.Texture.Height;
 
-            int bufferWritePosition = buffer.Offset;
+            int bufferWritePosition = _buffer.Offset;
             int drawCallsWritten = 0;
 
             bool firstCharacterOfLine = true;
@@ -86,7 +93,7 @@ public static class SpriteFontExtensions {
                         actualPosition.Y + (glyph.Cropping.Y + characterOffset.Y) * scale
                     );
 
-                    buffer.Array[bufferWritePosition] = drawCall;
+                    _buffer.Array[bufferWritePosition] = drawCall;
 
                     bufferWritePosition += 1;
                     drawCallsWritten += 1;
@@ -100,7 +107,7 @@ public static class SpriteFontExtensions {
             }
 
             return new ArraySegment<BitmapDrawCall>(
-                buffer.Array, buffer.Offset, drawCallsWritten
+                _buffer.Array, _buffer.Offset, drawCallsWritten
             );
         }
     }