feat(Texture): implement TextureBuilder API

ZenKit/Native.cs

@@ -684,6 +684,18 @@ public static extern void ZkModelMesh_enumerateAttachments(UIntPtr slf, ZkAttach
 		[DllImport(DllName)]
 		public static extern ulong ZkTexture_getMipmapRgba(UIntPtr slf, ulong level, byte[] buf, ulong size);
 
+		[DllImport(DllName)]
+		public static extern UIntPtr ZkTextureBuilder_new(ulong width, ulong height);
+
+		[DllImport(DllName)]
+		public static extern void ZkTextureBuilder_del(UIntPtr slf);
+
+		[DllImport(DllName)]
+		public static extern bool ZkTextureBuilder_addMipmap(UIntPtr slf, byte[] buf, ulong size, TextureFormat fmt);
+
+		[DllImport(DllName)]
+		public static extern UIntPtr ZkTextureBuilder_build(UIntPtr slf, TextureFormat fmt);
+
 		[DllImport(DllName)]
 		public static extern UIntPtr ZkMorphMesh_load(UIntPtr buf);
 

ZenKit/Texture.cs

@@ -112,10 +112,10 @@ public Texture(Vfs vfs, string name)
 			if (Handle == UIntPtr.Zero) throw new Exception("Failed to load texture");
 		}
 
-		internal Texture(UIntPtr handle)
+		internal Texture(UIntPtr handle, bool delete = false)
 		{
 			Handle = handle;
-			_delete = false;
+			_delete = delete;
 		}
 
 		public TextureFormat Format => Native.ZkTexture_getFormat(Handle);
@@ -221,4 +221,28 @@ public int GetHeight(int level)
 			if (_delete) Native.ZkTexture_del(Handle);
 		}
 	}
-}
+
+	public class TextureBuilder
+	{
+		private readonly UIntPtr _handle;
+		public TextureBuilder(int width, int height)
+		{
+			_handle = Native.ZkTextureBuilder_new((ulong)width, (ulong)height);
+		}
+
+		~TextureBuilder()
+		{
+			Native.ZkTextureBuilder_del(_handle);
+		}
+
+		public bool AddMipmap(byte[] image, TextureFormat fmt)
+		{
+			return Native.ZkTextureBuilder_addMipmap(_handle, image, (ulong)image.LongLength, fmt);
+		}
+
+		public Texture Build(TextureFormat fmt)
+		{
+			return new Texture(Native.ZkTextureBuilder_build(_handle, fmt), true);
+		}
+	}
+}