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Fix definition and use of non-indexed sprite color channels.

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Our SpriteFrameType names refer to the byte channel order rather than
the bit order, meaning that SpriteFrameType.BGRA corresponds to the
standard Color.ToArgb() etc byte order when the (little-endian) integer
is read as 4 individual bytes.

The previous code did not account for the fact that non-indexed Png
uses big-endian storage for its RGBA colours, and that SheetBuilder
had the color channels incorrectly swapped to match and cancel this out.

New SpriteFrameType enums are introduced to distinguish between BGRA
(little-endian) and RGBA (big-endian) formats, and also for 24bit data
without alpha. The channel swizzling / alpha creation is now handled
when copying into the texture atlas, removing the need for non-png
ISpriteLoader implementations to allocate an additional temporary array
and reorder the channels during load.
This commit is contained in:
Paul Chote
2020-12-19 12:05:56 +00:00
committed by abcdefg30
parent 6e7ad9df25
commit ce09b402d0
15 changed files with 205 additions and 142 deletions
Download Patch File Download Diff File Expand all files Collapse all files

104
OpenRA.Game/FileFormats/Png.cs
View File

@@ -17,6 +17,7 @@ using System.Net;
using System.Text;
using ICSharpCode.SharpZipLib.Checksum;
using ICSharpCode.SharpZipLib.Zip.Compression.Streams;
using OpenRA.Graphics;
using OpenRA.Primitives;
namespace OpenRA.FileFormats
@@ -25,12 +26,15 @@ namespace OpenRA.FileFormats
{
static readonly byte[] Signature = { 0x89, 0x50, 0x4e, 0x47, 0x0d, 0x0a, 0x1a, 0x0a };
public int Width { get; set; }
public int Height { get; set; }
public Color[] Palette { get; set; }
public byte[] Data { get; set; }
public int Width { get; private set; }
public int Height { get; private set; }
public Color[] Palette { get; private set; }
public byte[] Data { get; private set; }
public SpriteFrameType Type { get; private set; }
public Dictionary<string, string> EmbeddedData = new Dictionary<string, string>();
public int PixelStride { get { return Type == SpriteFrameType.Indexed ? 1 : Type == SpriteFrameType.RGB ? 3 : 4; } }
public Png(Stream s)
{
if (!Verify(s))
@@ -38,9 +42,8 @@ namespace OpenRA.FileFormats
s.Position += 8;
var headerParsed = false;
var isPaletted = false;
var is24Bit = false;
var data = new List<byte>();
Type = SpriteFrameType.RGBA;
while (true)
{
@@ -65,14 +68,12 @@ namespace OpenRA.FileFormats
var bitDepth = ms.ReadUInt8();
var colorType = (PngColorType)ms.ReadByte();
isPaletted = IsPaletted(bitDepth, colorType);
is24Bit = colorType == PngColorType.Color;
if (IsPaletted(bitDepth, colorType))
Type = SpriteFrameType.Indexed;
else if (colorType == PngColorType.Color)
Type = SpriteFrameType.RGB;
var dataLength = Width * Height;
if (!isPaletted)
dataLength *= 4;
Data = new byte[dataLength];
Data = new byte[Width * Height * PixelStride];
var compression = ms.ReadByte();
/*var filter = */ms.ReadByte();
@@ -133,39 +134,28 @@ namespace OpenRA.FileFormats
{
using (var ds = new InflaterInputStream(ns))
{
var pxStride = isPaletted ? 1 : is24Bit ? 3 : 4;
var srcStride = Width * pxStride;
var destStride = Width * (isPaletted ? 1 : 4);
var pxStride = PixelStride;
var rowStride = Width * pxStride;
var prevLine = new byte[srcStride];
var prevLine = new byte[rowStride];
for (var y = 0; y < Height; y++)
{
var filter = (PngFilter)ds.ReadByte();
var line = ds.ReadBytes(srcStride);
var line = ds.ReadBytes(rowStride);
for (var i = 0; i < srcStride; i++)
for (var i = 0; i < rowStride; i++)
line[i] = i < pxStride
? UnapplyFilter(filter, line[i], 0, prevLine[i], 0)
: UnapplyFilter(filter, line[i], line[i - pxStride], prevLine[i], prevLine[i - pxStride]);
if (is24Bit)
{
// Fold alpha channel into RGB data
for (var i = 0; i < line.Length / 3; i++)
{
Array.Copy(line, 3 * i, Data, y * destStride + 4 * i, 3);
Data[y * destStride + 4 * i + 3] = 255;
}
}
else
Array.Copy(line, 0, Data, y * destStride, line.Length);
Array.Copy(line, 0, Data, y * rowStride, rowStride);
prevLine = line;
}
}
}
if (isPaletted && Palette == null)
if (Type == SpriteFrameType.Indexed && Palette == null)
throw new InvalidDataException("Non-Palette indexed PNG are not supported.");
return;
@@ -175,7 +165,7 @@ namespace OpenRA.FileFormats
}
}
public Png(byte[] data, int width, int height, Color[] palette = null,
public Png(byte[] data, SpriteFrameType type, int width, int height, Color[] palette = null,
Dictionary<string, string> embeddedData = null)
{
var expectLength = width * height;
@@ -185,11 +175,46 @@ namespace OpenRA.FileFormats
if (data.Length != expectLength)
throw new InvalidDataException("Input data does not match expected length");
Type = type;
Width = width;
Height = height;
Palette = palette;
Data = data;
switch (type)
{
case SpriteFrameType.Indexed:
case SpriteFrameType.RGBA:
case SpriteFrameType.RGB:
{
// Data is already in a compatible format
Data = data;
if (type == SpriteFrameType.Indexed)
Palette = palette;
break;
}
case SpriteFrameType.BGRA:
case SpriteFrameType.BGR:
{
// Convert to big endian
Data = new byte[data.Length];
var stride = PixelStride;
for (var i = 0; i < width * height; i++)
{
Data[stride * i] = data[stride * i + 2];
Data[stride * i + 1] = data[stride * i + 1];
Data[stride * i + 2] = data[stride * i + 0];
if (type == SpriteFrameType.BGRA)
Data[stride * i + 3] = data[stride * i + 3];
}
break;
}
default:
throw new InvalidDataException("Unhandled SpriteFrameType {0}".F(type));
}
if (embeddedData != null)
EmbeddedData = embeddedData;
@@ -274,9 +299,8 @@ namespace OpenRA.FileFormats
header.Write(IPAddress.HostToNetworkOrder(Height));
header.WriteByte(8); // Bit depth
var colorType = Palette != null
? PngColorType.Indexed | PngColorType.Color
: PngColorType.Color | PngColorType.Alpha;
var colorType = Type == SpriteFrameType.Indexed ? PngColorType.Indexed | PngColorType.Color :
Type == SpriteFrameType.RGB ? PngColorType.Color : PngColorType.Color | PngColorType.Alpha;
header.WriteByte((byte)colorType);
header.WriteByte(0); // Compression
@@ -286,7 +310,7 @@ namespace OpenRA.FileFormats
WritePngChunk(output, "IHDR", header);
}
bool alphaPalette = false;
var alphaPalette = false;
if (Palette != null)
{
using (var palette = new MemoryStream())
@@ -318,12 +342,12 @@ namespace OpenRA.FileFormats
{
using (var compressed = new DeflaterOutputStream(data))
{
var stride = Width * (Palette != null ? 1 : 4);
var rowStride = Width * PixelStride;
for (var y = 0; y < Height; y++)
{
// Write uncompressed scanlines for simplicity
compressed.WriteByte(0);
compressed.Write(Data, y * stride, stride);
compressed.Write(Data, y * rowStride, rowStride);
}
compressed.Flush();