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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
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41
OpenRA.Game/Graphics/CursorManager.cs
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@@ -69,9 +69,16 @@ namespace OpenRA.Graphics
// Hotspot is specified relative to the center of the frame
var hotspot = f.Offset.ToInt2() - kv.Value.Hotspot - new int2(f.Size) / 2;
// SheetBuilder expects data in BGRA
var data = FrameToBGRA(kv.Key, f, palette);
c.Sprites[c.Length++] = sheetBuilder.Add(data, f.Size, 0, hotspot);
// Resolve indexed data to real colours
var data = f.Data;
var type = f.Type;
if (type == SpriteFrameType.Indexed)
{
data = ConvertIndexedToBgra(kv.Key, f, palette);
type = SpriteFrameType.BGRA;
}
c.Sprites[c.Length++] = sheetBuilder.Add(data, type, f.Size, 0, hotspot);
// Bounds relative to the hotspot
c.Bounds = Rectangle.Union(c.Bounds, new Rectangle(hotspot, f.Size));
@@ -217,33 +224,27 @@ namespace OpenRA.Graphics
Update();
}
public static byte[] FrameToBGRA(string name, ISpriteFrame frame, ImmutablePalette palette)
public static byte[] ConvertIndexedToBgra(string name, ISpriteFrame frame, ImmutablePalette palette)
{
// Data is already in BGRA format
if (frame.Type == SpriteFrameType.BGRA)
return frame.Data;
if (frame.Type != SpriteFrameType.Indexed)
throw new ArgumentException("ConvertIndexedToBgra requires input frames to be indexed.", nameof(frame));
// Cursors may be either native BGRA or Indexed.
// Indexed sprites are converted to BGRA using the referenced palette.
// All palettes must be explicitly referenced, even if they are embedded in the sprite.
if (frame.Type == SpriteFrameType.Indexed && palette == null)
if (palette == null)
throw new InvalidOperationException("Cursor sequence `{0}` attempted to load an indexed sprite but does not define Palette".F(name));
var width = frame.Size.Width;
var height = frame.Size.Height;
var data = new byte[4 * width * height];
for (var j = 0; j < height; j++)
unsafe
{
for (var i = 0; i < width; i++)
// Cast the data to an int array so we can copy the src data directly
fixed (byte* bd = &data[0])
{
var rgba = palette[frame.Data[j * width + i]];
var k = 4 * (j * width + i);
// Convert RGBA to BGRA
data[k] = (byte)(rgba >> 16);
data[k + 1] = (byte)(rgba >> 8);
data[k + 2] = (byte)(rgba >> 0);
data[k + 3] = (byte)(rgba >> 24);
var rgba = (uint*)bd;
for (var j = 0; j < height; j++)
for (var i = 0; i < width; i++)
rgba[j * width + i] = palette[frame.Data[j * width + i]];
}
}