sprite_file.h

/* ScummVM - Graphic Adventure Engine
 *
 * ScummVM is the legal property of its developers, whose names
 * are too numerous to list here. Please refer to the COPYRIGHT
 * file distributed with this source distribution.
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 *
 */

 //=============================================================================
 //
 // SpriteFile class handles sprite file parsing and streaming sprites.
 // SpriteFileWriter manages writing sprites into the output stream one by one,
 // accumulating index information, and may therefore be suitable for a variety
 // of situations.
 //
 //=============================================================================

#ifndef AGS_SHARED_AC_SPRITE_FILE_H
#define AGS_SHARED_AC_SPRITE_FILE_H

#include "ags/shared/core/types.h"
#include "common/std/memory.h"
#include "common/std/vector.h"
#include "ags/shared/util/stream.h"
#include "ags/globals.h"

namespace AGS3 {
namespace AGS {
namespace Shared {

class Bitmap;

// TODO: research old version differences
enum SpriteFileVersion {
    kSprfVersion_Undefined = 0,
    kSprfVersion_Uncompressed = 4,
    kSprfVersion_Compressed = 5,
    kSprfVersion_Last32bit = 6,
    kSprfVersion_64bit = 10,
    kSprfVersion_HighSpriteLimit = 11,
    kSprfVersion_StorageFormats = 12,
    kSprfVersion_Current = kSprfVersion_StorageFormats
};

enum SpriteIndexFileVersion {
    kSpridxfVersion_Initial = 1,
    kSpridxfVersion_Last32bit = 2,
    kSpridxfVersion_64bit = 10,
    kSpridxfVersion_HighSpriteLimit = 11,
    kSpridxfVersion_Current = kSpridxfVersion_HighSpriteLimit
};

// Instructions to how the sprites are allowed to be stored
enum SpriteStorage {
    // When possible convert the sprite into another format for less disk space
    // e.g. save 16/32-bit images as 8-bit colormaps with palette
    kSprStore_OptimizeForSize = 0x01
};

// Format in which the sprite's pixel data is stored
enum SpriteFormat {
    kSprFmt_Undefined = 0, // undefined, or keep as-is
    // Encoded as a 8-bit colormap with palette of 24-bit RGB values
    kSprFmt_PaletteRgb888 = 32,
    // Encoded as a 8-bit colormap with palette of 32-bit ARGB values
    kSprFmt_PaletteArgb8888 = 33,
    // Encoded as a 8-bit colormap with palette of 16-bit RGB565 values
    kSprFmt_PaletteRgb565 = 34
};

enum SpriteCompression {
    kSprCompress_None = 0,
    kSprCompress_RLE,
    kSprCompress_LZW
};

typedef int32_t sprkey_t;

// SpriteFileIndex contains sprite file's table of contents
struct SpriteFileIndex {
    int SpriteFileIDCheck = 0; // tag matching sprite file and index file
    std::vector<int16_t> Widths;
    std::vector<int16_t> Heights;
    std::vector<soff_t>  Offsets;

    inline size_t GetCount() const {
        return Offsets.size();
    }
    inline sprkey_t GetLastSlot() const {
        return (sprkey_t)GetCount() - 1;
    }
};

// Invidual sprite data header (as read from the file)
struct SpriteDatHeader {
    int BPP = 0; // color depth (bytes per pixel); or input format
    SpriteFormat SFormat = kSprFmt_Undefined; // storage format
    uint32_t PalCount = 0; // palette length, if applicable to storage format
    SpriteCompression Compress = kSprCompress_None; // compression type
    int Width = 0; // sprite's width
    int Height = 0; // sprite's height

    SpriteDatHeader() = default;
    SpriteDatHeader(int bpp, SpriteFormat sformat = kSprFmt_Undefined,
        uint32_t pal_count = 0, SpriteCompression compress = kSprCompress_None,
        int w = 0, int h = 0) : BPP(bpp), SFormat(sformat), PalCount(pal_count),
        Compress(compress), Width(w), Height(h) {
    }
};

// SpriteFile opens a sprite file for reading, reports general information,
// and lets read sprites in any order.
class SpriteFile {
public:
    // Standart sprite file and sprite index names
    static const char *DefaultSpriteFileName;
    static const char *DefaultSpriteIndexName;

    SpriteFile();
    // Loads sprite reference information and inits sprite stream
    HError      OpenFile(const String &filename, const String &sprindex_filename,
        std::vector<Size> &metrics);
    // Closes stream; no reading will be possible unless opened again
    void        Close();

    int         GetStoreFlags() const;
    // Tells if bitmaps in the file are compressed
    SpriteCompression GetSpriteCompression() const;
    // Tells the highest known sprite index
    sprkey_t    GetTopmostSprite() const;

    // Loads sprite index file
    bool        LoadSpriteIndexFile(const String &filename, int expectedFileID,
        soff_t spr_initial_offs, sprkey_t topmost, std::vector<Size> &metrics);
    // Rebuilds sprite index from the main sprite file
    HError      RebuildSpriteIndex(Stream *in, sprkey_t topmost,
        std::vector<Size> &metrics);

    // Loads an image data and creates a ready bitmap
    HError      LoadSprite(sprkey_t index, Bitmap *&sprite);
    // Loads a raw sprite element data into the buffer, stores header info separately
    HError      LoadRawData(sprkey_t index, SpriteDatHeader &hdr, std::vector<uint8_t> &data);

private:
    // Seek stream to sprite
    void        SeekToSprite(sprkey_t index);

    // Internal sprite reference
    struct SpriteRef {
        soff_t Offset = 0; // data offset
        size_t RawSize = 0; // file size of element, in bytes
        // TODO: RawSize is currently unused, due to incompleteness of spriteindex format
    };

    // Array of sprite references
    std::vector<SpriteRef> _spriteData;
    std::unique_ptr<Stream> _stream; // the sprite stream
    SpriteFileVersion _version = kSprfVersion_Current;
    int _storeFlags = 0; // storage flags, specify how sprites may be stored
    SpriteCompression _compress = kSprCompress_None; // sprite compression typ
    sprkey_t _curPos; // current stream position (sprite slot)
};

// SpriteFileWriter class writes a sprite file in a requested format.
// Start using it by calling Begin, write ready bitmaps or copy raw sprite data
// over slot by slot, then call Finalize to let it close the format correctly.
class SpriteFileWriter {
public:
    SpriteFileWriter(std::unique_ptr<Stream> &out);
    ~SpriteFileWriter() {
    }

    // Get the sprite index, accumulated after write
    const SpriteFileIndex &GetIndex() const {
        return _index;
    }

    // Initializes new sprite file format;
    // store_flags are SpriteStorage;
    // optionally hint how many sprites will be written.
    void Begin(int store_flags, SpriteCompression compress, sprkey_t last_slot = -1);
    // Writes a bitmap into file, compressing if necessary
    void WriteBitmap(Bitmap *image);
    // Writes an empty slot marker
    void WriteEmptySlot();
    // Writes a raw sprite data without any additional processing
    void WriteRawData(const SpriteDatHeader &hdr, const uint8_t *data, size_t data_sz);
    // Finalizes current format; no further writing is possible after this
    void Finalize();

private:
    // Writes prepared image data in a proper file format, following explicit data_bpp rule
    void WriteSpriteData(const SpriteDatHeader &hdr,
        const uint8_t *im_data, size_t im_data_sz, int im_bpp,
        const uint32_t palette[256]);

    std::unique_ptr<Stream> &_out;
    int _storeFlags = 0;
    SpriteCompression _compress = kSprCompress_None;
    soff_t _lastSlotPos = -1; // last slot save position in file
    // sprite index accumulated on write for reporting back to user
    SpriteFileIndex _index;
    // compression buffer
    std::vector<uint8_t> _membuf;
};

// Saves all sprites to file; fills in index data for external use.
// TODO: refactor to be able to save main file and index file separately (separate function for gather data?)
// Accepts available sprites as pairs of bool and Bitmap pointer, where boolean value
// tells if sprite exists and Bitmap pointer may be null;
// If a sprite's bitmap is missing, it will try reading one from the input file stream.
int SaveSpriteFile(const String &save_to_file,
    const std::vector<std::pair<bool, Bitmap *> > &sprites,
    SpriteFile *read_from_file, // optional file to read missing sprites from
    int store_flags, SpriteCompression compress, SpriteFileIndex &index);
// Saves sprite index table in a separate file
extern int SaveSpriteIndex(const String &filename, const SpriteFileIndex &index);

} // namespace Shared
} // namespace AGS
} // namespace AGS3

#endif