libdgf/LibDgf.Graphics/Aqualead/Image/Conversion/PkmConverter.cs
2021-02-16 01:04:29 -07:00

78 lines
2.5 KiB
C#

using LibDgf.Aqualead.Image;
using System;
using System.Collections.Generic;
using System.IO;
using System.Text;
namespace LibDgf.Aqualead.Image.Conversion
{
public class PkmConverter : IAlImageConverter
{
public string FileExtension => ".pkm";
public void ConvertFromAl(AlImage image, Stream destStream)
{
List<byte[]> mips;
if (image.PixelFormat == "ETC1")
{
mips = image.Mipmaps;
}
else if (image.PixelFormat == "EC1A")
{
// Give first half of the mips
mips = new List<byte[]>();
byte[] newMip = new byte[image.Mipmaps[0].Length / 2];
Buffer.BlockCopy(image.Mipmaps[0], 0, newMip, 0, newMip.Length);
mips.Add(newMip);
}
else
{
throw new ArgumentException("Pixel format not supported.", nameof(image));
}
WritePkm(destStream, mips[0], image.Width, image.Height);
}
public void ConvertFromAlAlt(AlImage image, Stream destStream)
{
if (image.PixelFormat != "EC1A")
throw new ArgumentException("Pixel format does not have alternate representation.", nameof(image));
// Give second half of the mips
byte[] newMip = new byte[image.Mipmaps[0].Length / 2];
Buffer.BlockCopy(image.Mipmaps[0], newMip.Length, newMip, 0, newMip.Length);
WritePkm(destStream, newMip, image.Width, image.Height);
}
public bool CanConvert(string pixelFormat)
{
return pixelFormat == "EC1A" || pixelFormat == "ETC1";
}
public bool HasAlternativeFile(AlImage image)
{
return image.PixelFormat == "EC1A";
}
const ushort ETC1_RGB_NO_MIPMAPS = 0;
static void WritePkm(Stream stream, byte[] data, uint width, uint height)
{
BinaryWriter bw = new BinaryWriter(stream);
bw.Write("PKM 10".ToCharArray());
WriteBeUInt16(bw, ETC1_RGB_NO_MIPMAPS);
WriteBeUInt16(bw, (ushort)((width + 3) & ~3));
WriteBeUInt16(bw, (ushort)((height + 3) & ~3));
WriteBeUInt16(bw, (ushort)width);
WriteBeUInt16(bw, (ushort)height);
bw.Write(data);
}
static void WriteBeUInt16(BinaryWriter bw, ushort value)
{
bw.Write((byte)(value >> 8));
bw.Write((byte)value);
}
}
}