/// <summary>
/// Decode the provided png file to a BGRA pixel array, Y flipped.
/// </summary>
/// <param name="pngData">The png file as bytes.</param>
/// <param name="fileHeader">The png file's header.</param>
/// <returns>The RGBA pixel data from the png.</returns>
public static byte[] Decode(ReadOnlyMemory <byte> pngData, out PngFileHeader fileHeader)
{
fileHeader = new PngFileHeader();
if (!IsPng(pngData))
{
Engine.Log.Warning("Tried to decode a non-png image!", MessageSource.ImagePng);
return(null);
}
using var stream = new ByteReader(pngData);
stream.Seek(8, SeekOrigin.Current); // Increment by header bytes.
// Read chunks while there are valid chunks.
var dataStream = new ReadOnlyLinkedMemoryStream();
PngChunk currentChunk;
var endChunkReached = false;
ReadOnlyMemory <byte> palette = null, paletteAlpha = null;
int width = 0, height = 0;
while ((currentChunk = new PngChunk(stream)).Valid)
{
if (endChunkReached)
{
Engine.Log.Warning("Image did not end with an end chunk...", MessageSource.ImagePng);
continue;
}
switch (currentChunk.Type)
{
case PngChunkTypes.HEADER:
{
ByteReader chunkReader = currentChunk.ChunkReader;
width = chunkReader.ReadInt32BE();
height = chunkReader.ReadInt32BE();
fileHeader.Size = new Vector2(width, height);
fileHeader.BitDepth = chunkReader.ReadByte();
fileHeader.ColorType = chunkReader.ReadByte();
fileHeader.CompressionMethod = chunkReader.ReadByte();
fileHeader.FilterMethod = chunkReader.ReadByte();
fileHeader.InterlaceMethod = chunkReader.ReadByte();
break;
}
case PngChunkTypes.DATA:
dataStream.AddMemory(currentChunk.ChunkReader.Data);
break;
case PngChunkTypes.PALETTE:
palette = currentChunk.ChunkReader.Data;
break;
case PngChunkTypes.PALETTE_ALPHA:
paletteAlpha = currentChunk.ChunkReader.Data;
break;
case PngChunkTypes.END:
endChunkReached = true;
break;
}
}
// Decompress data.
PerfProfiler.ProfilerEventStart("PNG Decompression", "Loading");
byte[] data = ZlibStreamUtility.Decompress(dataStream);
PerfProfiler.ProfilerEventEnd("PNG Decompression", "Loading");
if (data == null)
{
return(null);
}
var channelsPerColor = 0;
int bytesPerPixelOutput = 4;
ColorReader reader;
fileHeader.PixelFormat = PixelFormat.Bgra; // Default.
switch (fileHeader.ColorType)
{
case 0:
// Grayscale - No Alpha
channelsPerColor = 1;
bytesPerPixelOutput = 1;
reader = Grayscale;
fileHeader.PixelFormat = PixelFormat.Red;
break;
case 2:
// RGB
channelsPerColor = 3;
reader = Rgb;
break;
case 3:
// Palette
channelsPerColor = 1;
reader = (rowPixels, row, imageDest, destRow) => { Palette(palette.Span, paletteAlpha.Span, rowPixels, row, imageDest, destRow); };
break;
case 4:
// Grayscale - Alpha
channelsPerColor = 2;
reader = GrayscaleAlpha;
break;
case 6:
// RGBA
channelsPerColor = 4;
reader = Rgba;
fileHeader.PixelFormat = PixelFormat.Rgba;
break;
default:
reader = null;
break;
}
// Unknown color mode.
if (reader == null)
{
Engine.Log.Warning($"Unsupported color type - {fileHeader.ColorType}", MessageSource.ImagePng);
return(new byte[width * height * bytesPerPixelOutput]);
}
// Calculate the bytes per pixel.
var bytesPerPixel = 1;
if (fileHeader.BitDepth == 0 || fileHeader.BitDepth == 3)
{
Engine.Log.Warning("Invalid bit depth.", MessageSource.ImagePng);
return(null);
}
if (fileHeader.BitDepth != 8)
{
Engine.Log.Warning("Loading PNGs with a bit depth different than 8 will be deprecated in future versions.", MessageSource.ImagePng);
}
if (fileHeader.BitDepth >= 8)
{
bytesPerPixel = channelsPerColor * fileHeader.BitDepth / 8;
}
// Check interlacing.
if (fileHeader.InterlaceMethod == 1)
{
Engine.Log.Warning("Loading interlaced PNGs will be deprecated in future versions. Convert your images!", MessageSource.ImagePng);
return(ParseInterlaced(data, fileHeader, bytesPerPixel, channelsPerColor, reader));
}
int scanlineLength = GetScanlineLength(fileHeader, channelsPerColor) + 1;
int scanLineCount = data.Length / scanlineLength;
return(Parse(scanlineLength, scanLineCount, data, bytesPerPixel, fileHeader, reader, bytesPerPixelOutput));
}
protected override void CreateInternal(ReadOnlyMemory <byte> data)
{
var str = new ReadOnlyLinkedMemoryStream();
str.AddMemory(data);
_assContext ??= new AssimpContext();
Scene scene = _assContext.ImportFileFromStream(str,
PostProcessSteps.Triangulate |
PostProcessSteps.FlipUVs |
PostProcessSteps.OptimizeGraph |
PostProcessSteps.OptimizeMeshes);
var embeddedTextures = new List <Texture>();
for (var i = 0; i < scene.TextureCount; i++)
{
EmbeddedTexture assTexture = scene.Textures[i];
var embeddedTexture = new TextureAsset();
embeddedTexture.Create(assTexture.CompressedData);
embeddedTextures.Add(embeddedTexture.Texture);
}
_materials = new List <MeshMaterial>();
for (var i = 0; i < scene.MaterialCount; i++)
{
Material material = scene.Materials[i];
Color4D diffColor = material.ColorDiffuse;
bool embeddedTexture = material.HasTextureDiffuse && embeddedTextures.Count > material.TextureDiffuse.TextureIndex;
var emotionMaterial = new MeshMaterial
{
Name = material.Name,
DiffuseColor = new Color(new Vector4(diffColor.R, diffColor.G, diffColor.B, diffColor.A)),
DiffuseTextureName = embeddedTexture ? $"EmbeddedTexture{material.TextureDiffuse.TextureIndex}" : null,
DiffuseTexture = embeddedTexture ? embeddedTextures[material.TextureDiffuse.TextureIndex] : null
};
_materials.Add(emotionMaterial);
}
_animations = new List <SkeletalAnimation>();
ProcessAnimations(scene);
_meshes = new List <Mesh>();
Node rootNode = scene.RootNode;
SkeletonAnimRigNode animRigRoot = ProcessNode(scene, rootNode);
animRigRoot.LocalTransform *= Matrix4x4.CreateRotationX(-90 * Maths.DEG2_RAD); // Convert to right handed Z is up.
Entity = new MeshEntity
{
Name = Name,
Meshes = _meshes.ToArray(),
Animations = _animations.ToArray(),
AnimationRig = animRigRoot
};
object scaleData = scene.RootNode.Metadata.GetValueOrDefault("UnitScaleFactor").Data;
var scaleF = 1f;
if (scaleData is float f)
{
scaleF = f;
}
Entity.Scale = scaleF;
}
