add font API

.gitmodules

@@ -7,3 +7,6 @@
 [submodule "lib/RefreshCS"]
 	path = lib/RefreshCS
 	url = https://gitea.moonside.games/MoonsideGames/RefreshCS.git
+[submodule "lib/WellspringCS"]
+	path = lib/WellspringCS
+	url = https://gitea.moonside.games/MoonsideGames/WellspringCS.git

MoonWorks.csproj

@@ -14,6 +14,7 @@
 		<ProjectReference Include=".\lib\SDL2-CS\SDL2-CS.Core.csproj" />
 		<ProjectReference Include=".\lib\RefreshCS\RefreshCS.csproj" />
 		<ProjectReference Include=".\lib\FAudio\csharp\FAudio-CS.Core.csproj" />
+		<ProjectReference Include="lib\WellspringCS\WellspringCS.csproj" />
 	</ItemGroup>
 
 	<ItemGroup>

MoonWorks.sln

@@ -14,6 +14,10 @@ Project("{9A19103F-16F7-4668-BE54-9A1E7A4F7556}") = "FAudio-CS.Core", "lib\FAudi
 EndProject
 Project("{9A19103F-16F7-4668-BE54-9A1E7A4F7556}") = "RefreshCS", "lib\RefreshCS\RefreshCS.csproj", "{AD7C94E4-0AFA-44CA-889C-110142369893}"
 EndProject
+Project("{2150E333-8FDC-42A3-9474-1A3956D46DE8}") = "lib", "lib", "{69D3788D-6C57-44F7-A912-B201AE6D7C04}"
+EndProject
+Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "WellspringCS", "lib\WellspringCS\WellspringCS.csproj", "{0DD7B866-773C-4A86-8580-F436DAA28989}"
+EndProject
 Global
 	GlobalSection(SolutionConfigurationPlatforms) = preSolution
 		Debug|x64 = Debug|x64
@@ -36,6 +40,10 @@ Global
 		{AD7C94E4-0AFA-44CA-889C-110142369893}.Debug|x64.Build.0 = Debug|x64
 		{AD7C94E4-0AFA-44CA-889C-110142369893}.Release|x64.ActiveCfg = Release|x64
 		{AD7C94E4-0AFA-44CA-889C-110142369893}.Release|x64.Build.0 = Release|x64
+		{0DD7B866-773C-4A86-8580-F436DAA28989}.Debug|x64.ActiveCfg = Debug|x64
+		{0DD7B866-773C-4A86-8580-F436DAA28989}.Debug|x64.Build.0 = Debug|x64
+		{0DD7B866-773C-4A86-8580-F436DAA28989}.Release|x64.ActiveCfg = Release|x64
+		{0DD7B866-773C-4A86-8580-F436DAA28989}.Release|x64.Build.0 = Release|x64
 	EndGlobalSection
 	GlobalSection(SolutionProperties) = preSolution
 		HideSolutionNode = FALSE
@@ -43,4 +51,7 @@ Global
 	GlobalSection(ExtensibilityGlobals) = postSolution
 		SolutionGuid = {C3D68FAA-3165-43C7-95B3-D845F0DAA918}
 	EndGlobalSection
+	GlobalSection(NestedProjects) = preSolution
+		{0DD7B866-773C-4A86-8580-F436DAA28989} = {69D3788D-6C57-44F7-A912-B201AE6D7C04}
+	EndGlobalSection
 EndGlobal

lib/WellspringCS

@@ -0,0 +1 @@
+Subproject commit 4b21707900c6d75184f0d5373a0676fe31da956b

src/Graphics/CommandBuffer.cs

@@ -21,6 +21,8 @@ namespace MoonWorks.Graphics
 			Handle = handle;
 		}
 
+		// FIXME: we can probably use the NativeMemory functions to not have to generate arrays here
+
 		/// <summary>
 		/// Begins a render pass.
 		/// All render state, resource binding, and draw commands must be made within a render pass.

src/Graphics/Font/Packer.cs

@@ -0,0 +1,76 @@
+using System;
+using System.IO;
+using System.Runtime.InteropServices;
+using WellspringCS;
+
+namespace MoonWorks.Graphics.Font
+{
+	public class Packer : IDisposable
+	{
+		public IntPtr Handle { get; }
+		public Texture Texture { get; }
+
+		private bool IsDisposed;
+
+		public unsafe Packer(GraphicsDevice graphicsDevice, string path, uint textureWidth, uint textureHeight, uint padding = 1)
+		{
+			var bytes = File.ReadAllBytes(path);
+			fixed (byte* pByte = &bytes[0])
+			{
+				Handle = Wellspring.Wellspring_CreatePacker((IntPtr) pByte, (uint) bytes.Length, textureWidth, textureHeight, 0, padding);
+			}
+
+			Texture = Texture.CreateTexture2D(graphicsDevice, textureWidth, textureHeight, TextureFormat.R8, TextureUsageFlags.Sampler);
+		}
+
+		public unsafe bool PackFontRanges(params FontRange[] fontRanges)
+		{
+			fixed (FontRange *pFontRanges = &fontRanges[0])
+			{
+				var nativeSize = fontRanges.Length * Marshal.SizeOf<Wellspring.FontRange>();
+				void* fontRangeMemory = NativeMemory.Alloc((nuint) fontRanges.Length, (nuint) Marshal.SizeOf<Wellspring.FontRange>());
+				System.Buffer.MemoryCopy(pFontRanges, fontRangeMemory, nativeSize, nativeSize);
+
+				var result = Wellspring.Wellspring_PackFontRanges(Handle, (IntPtr) fontRangeMemory, (uint) fontRanges.Length);
+
+				NativeMemory.Free(fontRangeMemory);
+
+				return result > 0;
+			}
+		}
+
+		public unsafe void SetTextureData(CommandBuffer commandBuffer)
+		{
+			var pixelDataPointer = Wellspring.Wellspring_GetPixelDataPointer(Handle);
+			commandBuffer.SetTextureData(Texture, pixelDataPointer, Texture.Width * Texture.Height);
+		}
+
+		protected virtual void Dispose(bool disposing)
+		{
+			if (!IsDisposed)
+			{
+				if (disposing)
+				{
+					Texture.Dispose();
+				}
+
+				Wellspring.Wellspring_DestroyPacker(Handle);
+
+				IsDisposed = true;
+			}
+		}
+
+		~Packer()
+		{
+		    // Do not change this code. Put cleanup code in 'Dispose(bool disposing)' method
+		    Dispose(disposing: false);
+		}
+
+		public void Dispose()
+		{
+			// Do not change this code. Put cleanup code in 'Dispose(bool disposing)' method
+			Dispose(disposing: true);
+			GC.SuppressFinalize(this);
+		}
+	}
+}

src/Graphics/Font/Structs.cs

@@ -0,0 +1,23 @@
+using System.Runtime.InteropServices;
+using MoonWorks.Math;
+
+namespace MoonWorks.Graphics.Font
+{
+	[StructLayout(LayoutKind.Sequential)]
+	public struct FontRange
+	{
+		uint FontSize;
+		uint FirstCodepoint;
+		uint NumChars;
+		byte OversampleH;
+		byte OversampleV;
+	}
+
+	[StructLayout(LayoutKind.Sequential)]
+	public struct Vertex
+	{
+		public Vector3 Position;
+		public Vector2 TexCoord;
+		public Color Color;
+	}
+}

src/Graphics/Font/TextBatch.cs

@@ -0,0 +1,87 @@
+using System;
+using WellspringCS;
+
+namespace MoonWorks.Graphics.Font
+{
+	public class TextBatch
+	{
+		private GraphicsDevice GraphicsDevice { get; }
+		public IntPtr Handle { get; }
+
+		public Buffer VertexBuffer { get; protected set; } = null;
+		public Buffer IndexBuffer { get; protected set; } = null;
+		public Texture Texture { get; protected set; }
+
+		public TextBatch(GraphicsDevice graphicsDevice)
+		{
+			GraphicsDevice = graphicsDevice;
+			Handle = Wellspring.Wellspring_CreateTextBatch();
+		}
+
+		public void Start(Packer packer)
+		{
+			Wellspring.Wellspring_StartTextBatch(Handle, packer.Handle);
+			Texture = packer.Texture;
+		}
+
+		public unsafe void Draw(float x, float y, float depth, Color color, string text)
+		{
+			fixed (char* chars = text)
+			{
+				var byteCount = System.Text.Encoding.UTF8.GetByteCount(text);
+				var bytes = stackalloc byte[byteCount];
+				System.Text.Encoding.UTF8.GetBytes(chars, text.Length, bytes, byteCount);
+
+				var result = Wellspring.Wellspring_Draw(
+					Handle,
+					x,
+					y,
+					depth,
+					new Wellspring.Color { R = color.R, G = color.G, B = color.B, A = color.A },
+					(IntPtr) bytes,
+					(uint) byteCount
+				);
+
+				if (result == 0)
+				{
+					throw new System.ArgumentException("Could not decode string!");
+				}
+			}
+		}
+
+		// Call this after you have made all the Draw calls you want.
+		public unsafe void UploadBufferData(CommandBuffer commandBuffer)
+		{
+			Wellspring.Wellspring_GetBufferData(
+				Handle,
+				out IntPtr vertexDataPointer,
+				out uint vertexDataLengthInBytes,
+				out IntPtr indexDataPointer,
+				out uint indexDataLengthInBytes
+			);
+
+			if (VertexBuffer == null)
+			{
+				VertexBuffer = new Buffer(GraphicsDevice, BufferUsageFlags.Vertex, vertexDataLengthInBytes);
+			}
+			else if (VertexBuffer.Size < vertexDataLengthInBytes)
+			{
+				VertexBuffer.Dispose();
+				VertexBuffer = new Buffer(GraphicsDevice, BufferUsageFlags.Vertex, vertexDataLengthInBytes);
+			}
+
+			if (IndexBuffer == null)
+			{
+				IndexBuffer = new Buffer(GraphicsDevice, BufferUsageFlags.Index, indexDataLengthInBytes);
+			}
+			else if (IndexBuffer.Size < indexDataLengthInBytes)
+			{
+				IndexBuffer.Dispose();
+				IndexBuffer = new Buffer(GraphicsDevice, BufferUsageFlags.Index, indexDataLengthInBytes);
+			}
+
+			commandBuffer.SetBufferData(VertexBuffer, vertexDataPointer, 0, vertexDataLengthInBytes);
+			commandBuffer.SetBufferData(IndexBuffer, indexDataPointer, 0, indexDataLengthInBytes);
+		}
+	}
+}