From 132967bf9dc724297485091bdc1fc282d49f9842 Mon Sep 17 00:00:00 2001
From: UnknownShadow200 <unknownshadow200@gmail.com>
Date: Fri, 10 Feb 2017 23:54:08 +1100
Subject: [PATCH] Now hold air instead of 255 in survival, fixes invalid block
 type 255

---
 ClassicalSharp/Game/PickingHandler.cs      | 5 ++---
 ClassicalSharp/GraphicsAPI/IGraphicsApi.cs | 1 +
 ClassicalSharp/Mode/Survival.cs            | 6 +++---
 ClassicalSharp/Network/Protocols/CPE.cs    | 6 ++++--
 4 files changed, 10 insertions(+), 8 deletions(-)

diff --git a/ClassicalSharp/Game/PickingHandler.cs b/ClassicalSharp/Game/PickingHandler.cs
index 13123726f..063d778df 100644
--- a/ClassicalSharp/Game/PickingHandler.cs
+++ b/ClassicalSharp/Game/PickingHandler.cs
@@ -32,9 +32,8 @@ namespace ClassicalSharp {
 				input.ButtonStateChanged(MouseButton.Middle, middle);
 			}
 			
-			int buttonsDown = (left ? 1 : 0) + (right ? 1 : 0) + (middle ? 1 : 0);
-			if (buttonsDown > 1 || game.Gui.ActiveScreen.HandlesAllInput ||
-			    inv.HeldBlock == Block.Air) return;
+			int btns = (left ? 1 : 0) + (right ? 1 : 0) + (middle ? 1 : 0);
+			if (btns > 1 || game.Gui.ActiveScreen.HandlesAllInput || inv.HeldBlock == Block.Invalid) return;
 			
 			// always play delete animations, even if we aren't picking a block.
 			if (left) {
diff --git a/ClassicalSharp/GraphicsAPI/IGraphicsApi.cs b/ClassicalSharp/GraphicsAPI/IGraphicsApi.cs
index 31a8f5dcf..00babb88c 100644
--- a/ClassicalSharp/GraphicsAPI/IGraphicsApi.cs
+++ b/ClassicalSharp/GraphicsAPI/IGraphicsApi.cs
@@ -58,6 +58,7 @@ namespace ClassicalSharp.GraphicsAPI {
 			if (!Utils.IsPowerOf2(bmp.Width) || !Utils.IsPowerOf2(bmp.Height)) {
 				throw new ArgumentOutOfRangeException("Bitmap must have power of two dimensions");
 			}
+			if (LostContext) throw new InvalidOperationException("Cannot create texture when context lost");
 			
 			if (!bmp.IsLocked) bmp.LockBits();		
 			int texId = CreateTexture(bmp.Width, bmp.Height, bmp.Scan0, managedPool);
diff --git a/ClassicalSharp/Mode/Survival.cs b/ClassicalSharp/Mode/Survival.cs
index 29295077a..31c4fdb80 100644
--- a/ClassicalSharp/Mode/Survival.cs
+++ b/ClassicalSharp/Mode/Survival.cs
@@ -39,7 +39,7 @@ namespace ClassicalSharp.Mode {
 			if (invCount[index] != 0) return;
 			
 			// bypass HeldBlock's normal behaviour
-			game.Inventory.Hotbar[index] = Block.Invalid;
+			game.Inventory.Hotbar[index] = Block.Air;
 			game.Events.RaiseHeldBlockChanged();
 		}
 		
@@ -83,7 +83,7 @@ namespace ClassicalSharp.Mode {
 			}
 			if (index == -1) {
 				for (int i = hotbar.Length - 1; i >= 0; i--) {
-					if (hotbar[i] == Block.Invalid) index = i;
+					if (hotbar[i] == Block.Air) index = i;
 				}
 			}
 			if (index == -1) return; // no free slots
@@ -116,7 +116,7 @@ namespace ClassicalSharp.Mode {
 			this.game = game;
 			byte[] hotbar = game.Inventory.Hotbar;
 			for (int i = 0; i < hotbar.Length; i++)
-				hotbar[i] = Block.Invalid;
+				hotbar[i] = Block.Air;
 			hotbar[hotbar.Length - 1] = Block.TNT;
 		}
 		
diff --git a/ClassicalSharp/Network/Protocols/CPE.cs b/ClassicalSharp/Network/Protocols/CPE.cs
index f76e4e513..3ea4a6929 100644
--- a/ClassicalSharp/Network/Protocols/CPE.cs
+++ b/ClassicalSharp/Network/Protocols/CPE.cs
@@ -83,10 +83,12 @@ namespace ClassicalSharp.Network.Protocols {
 		}
 		
 		void HandleHoldThis() {
-			byte blockType = reader.ReadUInt8();
+			byte block = reader.ReadUInt8();
+			if (block == Block.Air) block = Block.Invalid;
 			bool canChange = reader.ReadUInt8() == 0;
+			
 			game.Inventory.CanChangeHeldBlock = true;
-			game.Inventory.HeldBlock = blockType;
+			game.Inventory.HeldBlock = block;
 			game.Inventory.CanChangeHeldBlock = canChange;
 		}