sbm.cpp

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/* xoreos - A reimplementation of BioWare's Aurora engine
 *
 * xoreos is the legal property of its developers, whose names
 * can be found in the AUTHORS file distributed with this source
 * distribution.
 *
 * xoreos 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.
 *
 * xoreos 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 xoreos. If not, see <http://www.gnu.org/licenses/>.
 */

#include <cstring>

#include "src/common/util.h"
#include "src/common/readstream.h"
#include "src/common/error.h"

#include "src/graphics/images/sbm.h"
#include "src/graphics/images/util.h"

namespace Graphics {

SBM::SBM(Common::SeekableReadStream &sbm, bool deswizzle) {
    _compressed = false;
    _hasAlpha   = true;
    _format     = kPixelFormatBGRA;
    _formatRaw  = kPixelFormatRGBA8;
    _dataType   = kPixelDataType8;

    load(sbm, deswizzle);
}

SBM::~SBM() {
}

void SBM::load(Common::SeekableReadStream &sbm, bool deswizzle) {
    try {

        readData(sbm, deswizzle);

    } catch (Common::Exception &e) {
        e.add("Failed reading SBM file");
        throw;
    }
}

void SBM::readData(Common::SeekableReadStream &sbm, bool deswizzle) {
    if ((sbm.size() % 1024) != 0)
        throw Common::Exception("Invalid SBM (%u)", (uint)sbm.size());

    const size_t rowCount = (sbm.size() / 1024);

    _mipMaps.push_back(new MipMap(this));

    _mipMaps[0]->width  = 4 * 32;
    _mipMaps[0]->height = NEXTPOWER2((uint32) rowCount * 32);
    _mipMaps[0]->size   = _mipMaps[0]->width * _mipMaps[0]->height * 4;

    _mipMaps[0]->data.reset(new byte[_mipMaps[0]->size]);

    // SBM data consists of character sized 32 * 32 pixels, with 2 bits per pixel.
    // 4 characters each are on top of each other, occupying the same x/y
    // coordinates but different planes.
    // We'll unpack them and draw them next to each other instead.

    static const int masks [4] = { 0x03, 0x0C, 0x30, 0xC0 };
    static const int shifts[4] = {    0,    2,    4,    6 };

    byte *data = _mipMaps[0]->data.get();
    byte buffer[1024];
    for (size_t c = 0; c < rowCount; c++) {

        if (sbm.read(buffer, 1024) != 1024)
            throw Common::Exception(Common::kReadError);

        for (int y = 0; y < 32; y++) {
            for (int plane = 0; plane < 4; plane++) {
                for (int x = 0; x < 32; x++) {
                    const uint32 offset = deswizzle ? deSwizzleOffset(x, y, 32, rowCount) : (y * 32 + x);

                    const byte a = ((buffer[offset] & masks[plane]) >> shifts[plane]) * 0x55;

                    *data++ = 0xFF; // B
                    *data++ = 0xFF; // G
                    *data++ = 0xFF; // R
                    *data++ = a;    // A
                }
            }
        }
    }

    byte *dataEnd = _mipMaps[0]->data.get() + _mipMaps[0]->size;
    std::memset(data, 0, dataEnd - data);
}

} // End of namespace Graphics