Decoder for the DCC image format. More...

#include <dcc.h>

Classes
struct	Direction

struct	DirectionHeader
	Represents a direction header. More...

struct	FrameHeader

struct	Header
	The header of the file, contains global information about the encoded image. More...

Public Member Functions
bool	initDecoder (StreamPtr &&streamPtr)
	Start decoding the stream and preparing data. More...

void	reset ()
	Resets the decoder and frees resources.

bool	readDirection (Direction &outDir, uint32_t dirIndex, IImageProvider< uint8_t > &imgProvider)
	Decodes a direction of the file into memory. More...

const Header &	getHeader () const
	Returns the header of the file read by extractHeaderAndOffsets.

Static Public Attributes
static constexpr unsigned	bitsWidthTable [16]
	An array that maps an encoded 4-bit size to the real size in bits. More...

Protected Member Functions
size_t	getDirectionSize (uint32_t dirIndex)

bool	extractHeaderAndOffsets ()

Protected Attributes
StreamPtr	stream = nullptr

Header	header

Vector< uint32_t >	directionsOffsets
	Offset of each direction header in the file, follows the Header. More...

Vector< uint32_t >	framePointers

Detailed Description

Decoder for the DCC image format.

The DCC format is a compressed sprite image format. It can store multiple directions and frames in a single file. A palette is used to generate the colors, but the file itself doesn't have any information about the palette to use, it is up to the user to know which one to use.

See Also: WorldStone::Palette

This format is usually used with COF files, which describe the animations and blending of multiple DCC files.

Layout of a DCC file:

Name	Type	Size in Bytes	Offsets
header	DCC::Header	15	0x00
directionsOffsets	uint32_t[dirs]	4 * header.directions	0x0F
First Direction	DCC::Direction	directionsOffsets[1] - directionsOffsets[0]	directionsOffsets[0]
***
Last Direction	DCC::Direction	filesize - directionsOffsets[directions-1]	directionsOffsets[directions-1]

Direction layout:

Name	Type	Size
dirHeader[0]	DCC::DirectionHeader	32 + 30 bits

frameHeader[0]	DCC::FrameHeader	Based on the DirectionHeader values
***
frameHeader[framesPerDir-1]	DCC::FrameHeader	Based on the DirectionHeader values

align	(unused)	Align to byte if any frame has additionnal data
Frame 0 additionnal data	byte[]	frameHeader[0].optionalBytes
***
Last frame additionnal data	byte[]	frameHeader[framesPerDir-1].optionalBytes

equalCellsBitStreamSize	uint20_t	20 bits (only if compressEqualCells is true)
pixelMaskBitStreamSize	uint20_t	20 bits
encodingTypeBitsreamSize	uint20_t	20 bits (only if hasRawPixelEncoding is true)
rawPixelCodesBitStreamSize	uint20_t	20 bits (only if hasRawPixelEncoding is true)
codeToPixelValue	bitset<256>	256 bits
equalCellBitStream	BitStream	equalCellsBitStreamSize
pixelMaskBitStream	BitStream	pixelMaskBitStreamSize
rawPixelUsageBitStream	BitStream	encodingTypeBitsreamSize
rawPixelCodesBitStream	BitStream	rawPixelCodesBitStreamSize
pixelCodesDisplacementBitStream	BitStream	Until end of the direction

Tests:

Definition at line 46 of file dcc.h.

Member Function Documentation

bool WorldStone::DCC::initDecoder ( StreamPtr && streamPtr )

Start decoding the stream and preparing data.

Returns: true on success

Prepares the decoder to read the frames using readDirection. Basically calls extractHeaderAndOffsets, so that you can call getHeader.

Definition at line 44 of file dcc.cpp.

bool WorldStone::DCC::readDirection	(	Direction &	outDir,
		uint32_t	dirIndex,
		IImageProvider< uint8_t > &	imgProvider
	)

Decodes a direction of the file into memory.

Parameters

outDir	Will hold the Direction information obtained during decoding.
dirIndex	The number of the direction in the file.
imgProvider	The image provider to be used when allocating frames data.

Returns: true on success

Use getHeader and the Header::directions member to know how many directions are in the file. The frames will be allocated+decoded in order, hence using the images allocated using the image provider will be in the order of the file.

Definition at line 618 of file dcc.cpp.

Member Data Documentation

constexpr unsigned WorldStone::DCC::bitsWidthTable

static

Initial value:

= {0, 1, 2, 4, 6, 8, 10, 12,

14, 16, 20, 24, 26, 28, 30, 32}

An array that maps an encoded 4-bit size to the real size in bits.

The values are { 0, 1, 2, 4, 6, 8, 10, 12, 14, 16, 20, 24, 26, 28, 30, 32 }

Definition at line 160 of file dcc.h.

Vector<uint32_t> WorldStone::DCC::directionsOffsets

protected

Offset of each direction header in the file, follows the Header.

Actually holds directions+1 values, the last one being the size of the file It lets us compute the size of a direction by substracting the next offset by the current one.

Definition at line 171 of file dcc.h.

The documentation for this class was generated from the following files:

source/decoders/include/dcc.h
source/decoders/src/dcc.cpp

Classes

Public Member Functions

Static Public Attributes

Protected Member Functions

Protected Attributes

Detailed Description

Member Function Documentation

Member Data Documentation