emuhawk - add experimental prescale option to display manager

BizHawk.Client.Common/config/Config.cs

@@ -215,6 +215,8 @@ public enum ClientProfile
 		public bool DispFixScaleInteger = true;
 		public bool DispFullscreenHacks = true;
 
+		public int DispPrescale = 1;
+
 		//warning: we dont even want to deal with changing this at runtime. but we want it changed here for config purposes. so dont check this variable. check in GlobalWin or something like that.
 		public EDispMethod DispMethod = EDispMethod.OpenGL;
 

BizHawk.Client.EmuHawk/DisplayManager/DisplayManager.cs

@@ -200,6 +200,12 @@ FilterProgram BuildDefaultChain(Size chain_insize, Size chain_outsize, bool incl
 			//add lua layer 'emu'
 			AppendLuaLayer(chain, "emu");
 
+			if (Global.Config.DispPrescale != 1)
+			{
+				Filters.PrescaleFilter fPrescale = new Filters.PrescaleFilter() { Scale = Global.Config.DispPrescale };
+				chain.AddFilter(fPrescale, "prescale");
+			}
+
 			//add user-selected retro shader
 			if (selectedChain != null)
 				AppendRetroShaderChain(chain, "retroShader", selectedChain, selectedChainProperties);

BizHawk.Client.EmuHawk/DisplayManager/Filters/BaseFilter.cs

@@ -35,7 +35,7 @@ public class BaseFilter
 		public virtual void Initialize() { }
 		public virtual Size PresizeInput(string channel, Size size) { return size; }
 		public virtual Size PresizeOutput(string channel, Size size) { return size; }
-		public virtual void SetInputFormat(string channel, SurfaceState state) { }
+		public virtual void SetInputFormat(string channel, SurfaceState state) { } //TODO - why a different param order than DeclareOutput?
 		public Dictionary<string, object> Parameters = new Dictionary<string, object>();
 
 		//runtime signals
@@ -85,6 +85,7 @@ protected void YieldOutput(Texture2d tex)
 		//setup utilities
 		protected IOSurfaceInfo DeclareInput(SurfaceDisposition disposition = SurfaceDisposition.Unspecified, string channel = "default") { return DeclareIO(SurfaceDirection.Input, channel, disposition); }
 		protected IOSurfaceInfo DeclareOutput(SurfaceDisposition disposition = SurfaceDisposition.Unspecified, string channel = "default") { return DeclareIO(SurfaceDirection.Output, channel, disposition); }
+		//TODO - why a different param order than DeclareOutput?
 
 		protected IOSurfaceInfo DeclareOutput(SurfaceState state, string channel = "default")
 		{

BizHawk.Client.EmuHawk/DisplayManager/Filters/Gui.cs

@@ -310,6 +310,36 @@ public override void Run()
 		}
 	}
 
+	//TODO - turn this into a NOP at 1x, just in case something accidentally activates it with 1x
+	public class PrescaleFilter : BaseFilter
+	{
+		public int Scale;
+
+		public override void Initialize()
+		{
+			DeclareInput(SurfaceDisposition.Texture);
+		}
+
+		public override void SetInputFormat(string channel, SurfaceState state)
+		{
+			var OutputSize = state.SurfaceFormat.Size;
+			OutputSize.Width *= Scale;
+			OutputSize.Height *= Scale;
+			var ss = new SurfaceState(new SurfaceFormat(OutputSize), SurfaceDisposition.RenderTarget);
+			DeclareOutput(ss, channel);
+		}
+
+		public override void Run()
+		{
+			var outSize = FindOutput().SurfaceFormat.Size;
+			FilterProgram.GuiRenderer.Begin(outSize);
+			FilterProgram.GuiRenderer.SetBlendState(FilterProgram.GL.BlendNoneCopy);
+			FilterProgram.GuiRenderer.Modelview.Scale(Scale);
+			FilterProgram.GuiRenderer.Draw(InputTexture);
+			FilterProgram.GuiRenderer.End();
+		}
+	}
+
 	public class LuaLayer : BaseFilter
 	{
 		public override void Initialize()