Initial commit: OpenRA game engine

Fork from OpenRA/OpenRA with one-click launch script (start-ra.cmd)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

OpenRA.Mods.Cnc/SpriteLoaders/ShpTDLoader.cs

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+#region Copyright & License Information
+/*
+ * Copyright (c) The OpenRA Developers and Contributors
+ * This file is part of OpenRA, which is free software. It is made
+ * available to you under the terms of the GNU General Public License
+ * as published by the Free Software Foundation, either version 3 of
+ * the License, or (at your option) any later version. For more
+ * information, see COPYING.
+ */
+#endregion
+
+using System;
+using System.Collections.Generic;
+using System.IO;
+using System.Linq;
+using OpenRA.Graphics;
+using OpenRA.Mods.Cnc.FileFormats;
+using OpenRA.Primitives;
+
+namespace OpenRA.Mods.Cnc.SpriteLoaders
+{
+	public class ShpTDLoader : ISpriteLoader
+	{
+		static bool IsShpTD(Stream s)
+		{
+			var start = s.Position;
+
+			// First word is the image count
+			var imageCount = s.ReadUInt16();
+			if (imageCount == 0)
+			{
+				s.Position = start;
+				return false;
+			}
+
+			// Last offset should point to the end of file
+			var finalOffset = start + 14 + 8 * imageCount;
+			if (finalOffset > s.Length)
+			{
+				s.Position = start;
+				return false;
+			}
+
+			s.Position = finalOffset;
+			var eof = s.ReadUInt32();
+			if (eof != s.Length)
+			{
+				s.Position = start;
+				return false;
+			}
+
+			// Check the format flag on the first frame
+			s.Position = start + 17;
+			var b = s.ReadUInt8();
+
+			s.Position = start;
+			return b == 0x20 || b == 0x40 || b == 0x80;
+		}
+
+		public bool TryParseSprite(Stream s, string filename, out ISpriteFrame[] frames, out TypeDictionary metadata)
+		{
+			metadata = null;
+			if (!IsShpTD(s))
+			{
+				frames = null;
+				return false;
+			}
+
+			frames = new ShpTDSprite(s).Frames.ToArray();
+			return true;
+		}
+	}
+
+	public class ShpTDSprite
+	{
+		enum Format : ushort { XORPrev = 0x20, XORLCW = 0x40, LCW = 0x80 }
+
+		sealed class TrimmedFrame : ISpriteFrame
+		{
+			public SpriteFrameType Type => SpriteFrameType.Indexed8;
+			public Size Size { get; }
+			public Size FrameSize { get; }
+			public float2 Offset { get; }
+			public byte[] Data { get; }
+			public bool DisableExportPadding { get { return false; } }
+
+			public TrimmedFrame(ImageHeader header)
+			{
+				var origData = header.Data;
+				var origSize = header.Size;
+				var top = origSize.Height - 1;
+				var bottom = 0;
+				var left = origSize.Width - 1;
+				var right = 0;
+
+				// Scan frame data to find left-, top-, right-, bottom-most
+				// rows/columns with non-zero pixel data.
+				var i = 0;
+				for (var y = 0; y < origSize.Height; y++)
+				{
+					for (var x = 0; x < origSize.Width; x++, i++)
+					{
+						if (origData[i] != 0)
+						{
+							top = Math.Min(y, top);
+							bottom = Math.Max(y, bottom);
+							left = Math.Min(x, left);
+							right = Math.Max(x, right);
+						}
+					}
+				}
+
+				var trimmedWidth = right - left + 1;
+				var trimmedHeight = bottom - top + 1;
+
+				// We must be careful to subract an even number
+				// of rows/columns to avoid sub-pixel offsets.
+				if ((trimmedWidth - origSize.Width) % 2 != 0)
+				{
+					if (left > 0)
+						left--;
+					else
+						right++;
+
+					trimmedWidth++;
+				}
+
+				if ((trimmedHeight - origSize.Height) % 2 != 0)
+				{
+					if (top > 0)
+						top--;
+					else
+						bottom++;
+
+					trimmedHeight++;
+				}
+
+				if (trimmedWidth == origSize.Width && trimmedHeight == origSize.Height)
+				{
+					// Nothing to trim, so copy old data directly.
+					Size = header.Size;
+					FrameSize = header.FrameSize;
+					Offset = header.Offset;
+					Data = header.Data;
+				}
+				else if (trimmedWidth > 0 && trimmedHeight > 0)
+				{
+					// Trim frame.
+					Data = new byte[trimmedWidth * trimmedHeight];
+					for (var y = 0; y < trimmedHeight; y++)
+						Array.Copy(origData, (y + top) * origSize.Width + left, Data, y * trimmedWidth, trimmedWidth);
+
+					Size = new Size(trimmedWidth, trimmedHeight);
+					FrameSize = origSize;
+					Offset = 0.5f * new float2(
+						left + right - origSize.Width + 1,
+						top + bottom - origSize.Height + 1);
+
+					if (Offset.X % 1 != 0 || Offset.Y % 1 != 0)
+						throw new InvalidDataException("Trimmed frame has non-integer offset.");
+				}
+			}
+		}
+
+		sealed class ImageHeader : ISpriteFrame
+		{
+			public SpriteFrameType Type => SpriteFrameType.Indexed8;
+			public Size Size => reader.Size;
+			public Size FrameSize => reader.Size;
+			public float2 Offset => float2.Zero;
+			public byte[] Data { get; set; }
+			public bool DisableExportPadding => false;
+
+			public uint FileOffset;
+			public Format Format;
+
+			public readonly uint RefOffset;
+			public readonly Format RefFormat;
+			public ImageHeader RefImage;
+
+			readonly ShpTDSprite reader;
+
+			// Used by ShpWriter
+			public ImageHeader() { }
+
+			public ImageHeader(Stream stream, ShpTDSprite reader)
+			{
+				this.reader = reader;
+				var data = stream.ReadUInt32();
+				FileOffset = data & 0xffffff;
+				Format = (Format)(data >> 24);
+
+				RefOffset = stream.ReadUInt16();
+				RefFormat = (Format)stream.ReadUInt16();
+			}
+
+			public void WriteTo(BinaryWriter writer)
+			{
+				writer.Write(FileOffset | ((uint)Format << 24));
+				writer.Write((ushort)RefOffset);
+				writer.Write((ushort)RefFormat);
+			}
+		}
+
+		public IReadOnlyList<ISpriteFrame> Frames { get; }
+		public readonly Size Size;
+
+		int recurseDepth = 0;
+		readonly int imageCount;
+
+		readonly long shpBytesFileOffset;
+		readonly byte[] shpBytes;
+
+		public ShpTDSprite(Stream stream)
+		{
+			imageCount = stream.ReadUInt16();
+			stream.Position += 4;
+			var width = stream.ReadUInt16();
+			var height = stream.ReadUInt16();
+			Size = new Size(width, height);
+
+			stream.Position += 4;
+			var headers = new ImageHeader[imageCount];
+			for (var i = 0; i < headers.Length; i++)
+				headers[i] = new ImageHeader(stream, this);
+
+			// Skip eof and zero headers
+			stream.Position += 16;
+
+			var offsets = headers.ToDictionary(h => h.FileOffset, h => h);
+			for (var i = 0; i < imageCount; i++)
+			{
+				var h = headers[i];
+				if (h.Format == Format.XORPrev)
+					h.RefImage = headers[i - 1];
+				else if (h.Format == Format.XORLCW && !offsets.TryGetValue(h.RefOffset, out h.RefImage))
+					throw new InvalidDataException($"Reference doesn't point to image data {h.FileOffset}->{h.RefOffset}");
+			}
+
+			shpBytesFileOffset = stream.Position;
+			shpBytes = stream.ReadBytes((int)(stream.Length - stream.Position));
+
+			foreach (var h in headers)
+				Decompress(h);
+
+			Frames = headers.Select(f => (ISpriteFrame)new TrimmedFrame(f)).ToArray();
+		}
+
+		void Decompress(ImageHeader h)
+		{
+			// No extra work is required for empty frames
+			if (h.Size.Width == 0 || h.Size.Height == 0)
+				return;
+
+			if (recurseDepth > imageCount)
+				throw new InvalidDataException("Format20/40 headers contain infinite loop");
+
+			switch (h.Format)
+			{
+				case Format.XORPrev:
+				case Format.XORLCW:
+				{
+					if (h.RefImage.Data == null)
+					{
+						++recurseDepth;
+						Decompress(h.RefImage);
+						--recurseDepth;
+					}
+
+					h.Data = CopyImageData(h.RefImage.Data);
+					XORDeltaCompression.DecodeInto(shpBytes, h.Data, (int)(h.FileOffset - shpBytesFileOffset));
+					break;
+				}
+
+				case Format.LCW:
+				{
+					var imageBytes = new byte[Size.Width * Size.Height];
+					LCWCompression.DecodeInto(shpBytes, imageBytes, (int)(h.FileOffset - shpBytesFileOffset));
+					h.Data = imageBytes;
+					break;
+				}
+
+				default:
+					throw new InvalidDataException();
+			}
+		}
+
+		byte[] CopyImageData(byte[] baseImage)
+		{
+			var imageData = new byte[Size.Width * Size.Height];
+			Array.Copy(baseImage, imageData, imageData.Length);
+			return imageData;
+		}
+
+		public static void Write(Stream s, Size size, IEnumerable<byte[]> frames)
+		{
+			var compressedFrames = frames.Select(LCWCompression.Encode).ToList();
+
+			// note: end-of-file and all-zeroes headers
+			var dataOffset = 14 + (compressedFrames.Count + 2) * 8;
+
+			using (var bw = new BinaryWriter(s))
+			{
+				bw.Write((ushort)compressedFrames.Count);
+				bw.Write((ushort)0);
+				bw.Write((ushort)0);
+				bw.Write((ushort)size.Width);
+				bw.Write((ushort)size.Height);
+				bw.Write(0U);
+
+				foreach (var f in compressedFrames)
+				{
+					var ih = new ImageHeader { Format = Format.LCW, FileOffset = (uint)dataOffset };
+					dataOffset += f.Length;
+
+					ih.WriteTo(bw);
+				}
+
+				var eof = new ImageHeader { FileOffset = (uint)dataOffset };
+				eof.WriteTo(bw);
+
+				var allZeroes = new ImageHeader();
+				allZeroes.WriteTo(bw);
+
+				foreach (var f in compressedFrames)
+					bw.Write(f);
+			}
+		}
+	}
+}