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pal.cpp

/* 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 2
 * 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, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
 *
 * $URL: https://scummvm.svn.sourceforge.net/svnroot/scummvm/scummvm/tags/release-1-0-0/engines/cine/pal.cpp $
 * $Id: pal.cpp 44095 2009-09-15 00:06:44Z lordhoto $
 *
 */

#include "cine/cine.h"
#include "cine/various.h"
#include "cine/pal.h"
#include "common/system.h" // For g_system->setPalette

namespace Cine {

Common::Array<PalEntry> palArray;
static byte paletteBuffer1[16];
static byte paletteBuffer2[16];

void loadPal(const char *fileName) {
      char buffer[20];

      removeExtention(buffer, fileName);

      strcat(buffer, ".PAL");
      palArray.clear();

      Common::File palFileHandle;
      if (!palFileHandle.open(buffer))
            error("loadPal(): Cannot open file %s", fileName);

      uint16 palEntriesCount = palFileHandle.readUint16LE();
      palFileHandle.readUint16LE(); // entry size

      palArray.resize(palEntriesCount);
      for (uint i = 0; i < palArray.size(); ++i) {
            palFileHandle.read(palArray[i].name, 10);
            palFileHandle.read(palArray[i].pal1, 16);
            palFileHandle.read(palArray[i].pal2, 16);
      }
      palFileHandle.close();
}

int16 findPaletteFromName(const char *fileName) {
      char buffer[10];
      uint16 position = 0;
      uint16 i;

      strcpy(buffer, fileName);

      while (position < strlen(fileName)) {
            if (buffer[position] > 'a' && buffer[position] < 'z') {
                  buffer[position] += 'A' - 'a';
            }

            position++;
      }

      for (i = 0; i < palArray.size(); i++) {
            if (!strcmp(buffer, palArray[i].name)) {
                  return i;
            }
      }

      return -1;

}

void loadRelatedPalette(const char *fileName) {
      char localName[16];
      byte i;
      int16 paletteIndex;

      removeExtention(localName, fileName);

      paletteIndex = findPaletteFromName(localName);

      if (paletteIndex == -1) {
            for (i = 0; i < 16; i++) {    // generate default palette
                  paletteBuffer1[i] = paletteBuffer2[i] = (i << 4) + i;
            }
      } else {
            assert(paletteIndex < (int32)palArray.size());
            memcpy(paletteBuffer1, palArray[paletteIndex].pal1, 16);
            memcpy(paletteBuffer2, palArray[paletteIndex].pal2, 16);
      }
}

/*! \brief Shift byte to the left by given amount (Handles negative shifting amounts too, otherwise this would be trivial). */
byte shiftByteLeft(const byte value, const signed shiftLeft) {
      if (shiftLeft >= 0)
            return value << shiftLeft;
      else // right shift with negative shiftLeft values
            return value >> abs(shiftLeft);
}

/*! \brief Is given endian type big endian? (Handles native endian type too, otherwise this would be trivial). */
bool isBigEndian(const EndianType endian) {
      assert(endian == CINE_NATIVE_ENDIAN || endian == CINE_LITTLE_ENDIAN || endian == CINE_BIG_ENDIAN);

      // Handle explicit little and big endian types here
      if (endian != CINE_NATIVE_ENDIAN) {
            return (endian == CINE_BIG_ENDIAN);
      }

      // Handle native endian type here
#if defined(SCUMM_BIG_ENDIAN)
      return true;
#elif defined(SCUMM_LITTLE_ENDIAN)
      return false;
#else
      #error No endianness defined
#endif
}

/*! \brief Calculate byte position of given bit position in a multibyte variable using defined endianness. */
int bytePos(const int bitPos, const int numBytes, const bool bigEndian) {
      if (bigEndian)
            return (numBytes - 1) - (bitPos / 8);
      else // little endian
            return bitPos / 8;
}

// a.k.a. palRotate
Palette &Palette::rotateRight(byte firstIndex, byte lastIndex, signed rotationAmount) {
      assert(rotationAmount == 0 || rotationAmount == 1);

      if (rotationAmount == 1) {
            const Color lastColor = _colors[lastIndex];

            for (int i = lastIndex; i > firstIndex; i--)
                  _colors[i] = _colors[i - 1];

            _colors[firstIndex] = lastColor;
      }
      return *this;
}

bool Palette::empty() const {
      return _colors.empty();
}

uint Palette::colorCount() const {
      return _colors.size();
}

Palette &Palette::fillWithBlack() {
      for (uint i = 0; i < _colors.size(); i++) {
            _colors[i].r = 0;
            _colors[i].g = 0;
            _colors[i].b = 0;
      }

      return *this;
}

// TODO: Add better heuristic for checking whether the color format is valid
bool Palette::isValid() const {
      // Check that the color format has been actually set and not just default constructed.
      // Also check that the alpha channel is discarded.
      return _format != Graphics::PixelFormat() && _format.aLoss == 8;
}

const Graphics::PixelFormat &Palette::colorFormat() const {
      return _format;
}

void Palette::setGlobalOSystemPalette() const {
      byte buf[256 * 4]; // Allocate space for the largest possible palette
      save(buf, sizeof(buf), Cine::kSystemPalFormat, CINE_LITTLE_ENDIAN);
      g_system->setPalette(buf, 0, colorCount());
}

Cine::Palette::Color Palette::getColor(byte index) const {
      return _colors[index];
}

uint8 Palette::getR(byte index) const {
      return _colors[index].r;
}

uint8 Palette::getG(byte index) const {
      return _colors[index].g;
}

uint8 Palette::getB(byte index) const {
      return _colors[index].b;
}

void Palette::setColorFormat(const Graphics::PixelFormat format) {
      _format = format;
}

// a.k.a. transformPaletteRange
Palette &Palette::saturatedAddColor(Palette& output, byte firstIndex, byte lastIndex, signed r, signed g, signed b) {
      assert(firstIndex < colorCount() && lastIndex < colorCount());
      assert(firstIndex < output.colorCount() && lastIndex < output.colorCount());
      assert(output.colorFormat() == colorFormat());

      for (uint i = firstIndex; i <= lastIndex; i++) {
            // WORKAROUND for a valgrind warning on AMD64:
            //
            // The old code read: "output._colors[i] = saturatedAddColor(_colors[i], r, g, b);".
            //
            // It seems g++ 4.1.2, 4.3.4 and 4.4.1 do a 8 byte read when passing _colors[i] as parameter,
            // even though the struct is only 3 bytes, resulting in an invalid read, when accessing indices
            // 14 and 15 of 16 color palettes.
            //
            // To work around this issue, we added an temporary variable, which will have padding so
            // the 8 byte read (which is done when passing src) is assured to be in a valid memory area.
            const Color src = _colors[i];
            output._colors[i] = saturatedAddColor(src, r, g, b);
      }

      return output;
}

Palette &Palette::saturatedAddColor(Palette& output, byte firstIndex, byte lastIndex, signed rSource, signed gSource, signed bSource, const Graphics::PixelFormat &sourceFormat) {
      // Convert the source color to the internal color format ensuring that no divide by zero will happen
      const signed r = ((signed) _format.rMax()) * rSource / MAX<int>(sourceFormat.rMax(), 1);
      const signed g = ((signed) _format.gMax()) * gSource / MAX<int>(sourceFormat.gMax(), 1);
      const signed b = ((signed) _format.bMax()) * bSource / MAX<int>(sourceFormat.bMax(), 1);

      return saturatedAddColor(output, firstIndex, lastIndex, r, g, b);
}

Palette &Palette::saturatedAddNormalizedGray(Palette& output, byte firstIndex, byte lastIndex, int grayDividend, int grayDenominator) {
      assert(grayDenominator != 0);
      const signed r = ((signed) _format.rMax()) * grayDividend / grayDenominator;
      const signed g = ((signed) _format.gMax()) * grayDividend / grayDenominator;
      const signed b = ((signed) _format.bMax()) * grayDividend / grayDenominator;

      return saturatedAddColor(output, firstIndex, lastIndex, r, g, b);
}

// a.k.a. transformColor
// Parameter color components (i.e. r, g and b) are in range [-7, 7]
// e.g. r = 7 sets the resulting color's red component to maximum
// e.g. r = -7 sets the resulting color's red component to minimum (i.e. zero)
Cine::Palette::Color Palette::saturatedAddColor(Cine::Palette::Color baseColor, signed r, signed g, signed b) const {
      Cine::Palette::Color result;
      result.r = CLIP<int>(baseColor.r + r, 0, _format.rMax());
      result.g = CLIP<int>(baseColor.g + g, 0, _format.gMax());
      result.b = CLIP<int>(baseColor.b + b, 0, _format.bMax());
      return result;
}

Palette::Palette(const Graphics::PixelFormat format, const uint numColors) : _format(format), _colors() {
      _colors.resize(numColors);
      fillWithBlack();
}

Palette &Palette::clear() {
      _format = Graphics::PixelFormat();
      _colors.clear();
      return *this;
}

Palette &Palette::load(const byte *buf, const uint size, const Graphics::PixelFormat format, const uint numColors, const EndianType endian) {
      assert(format.bytesPerPixel * numColors <= size); // Make sure there's enough input space
      assert(format.aLoss == 8); // No alpha
      assert(format.rShift / 8 == (format.rShift + MAX<int>(0, format.rBits() - 1)) / 8); // R must be inside one byte
      assert(format.gShift / 8 == (format.gShift + MAX<int>(0, format.gBits() - 1)) / 8); // G must be inside one byte
      assert(format.bShift / 8 == (format.bShift + MAX<int>(0, format.bBits() - 1)) / 8); // B must be inside one byte

      setColorFormat(format);

      _colors.clear();
      _colors.resize(numColors);

      const int rBytePos = bytePos(format.rShift, format.bytesPerPixel, isBigEndian(endian));
      const int gBytePos = bytePos(format.gShift, format.bytesPerPixel, isBigEndian(endian));
      const int bBytePos = bytePos(format.bShift, format.bytesPerPixel, isBigEndian(endian));

      for (uint i = 0; i < numColors; i++) {
            // format.rMax(), format.gMax(), format.bMax() are also used as masks here
            _colors[i].r = (buf[i * format.bytesPerPixel + rBytePos] >> (format.rShift % 8)) & format.rMax();
            _colors[i].g = (buf[i * format.bytesPerPixel + gBytePos] >> (format.gShift % 8)) & format.gMax();
            _colors[i].b = (buf[i * format.bytesPerPixel + bBytePos] >> (format.bShift % 8)) & format.bMax();
      }

      return *this;
}

byte *Palette::save(byte *buf, const uint size, const EndianType endian) const {
      return save(buf, size, colorFormat(), colorCount(), endian);
}

byte *Palette::save(byte *buf, const uint size, const Graphics::PixelFormat format, const EndianType endian) const {
      return save(buf, size, format, colorCount(), endian);
}

byte *Palette::save(byte *buf, const uint size, const Graphics::PixelFormat format, const uint numColors, const EndianType endian, const byte firstIndex) const {
      assert(format.bytesPerPixel * numColors <= size); // Make sure there's enough output space
      assert(format.aLoss == 8); // No alpha
      assert(format.rShift / 8 == (format.rShift + MAX<int>(0, format.rBits() - 1)) / 8); // R must be inside one byte
      assert(format.gShift / 8 == (format.gShift + MAX<int>(0, format.gBits() - 1)) / 8); // G must be inside one byte
      assert(format.bShift / 8 == (format.bShift + MAX<int>(0, format.bBits() - 1)) / 8); // B must be inside one byte

      // Clear the part of the output palette we're going to be writing to with all black
      memset(buf, 0, format.bytesPerPixel * numColors);

      // Calculate how much bit shifting the color components need (for positioning them correctly)
      const signed rShiftLeft = (colorFormat().rLoss - (signed) format.rLoss) + (format.rShift % 8);
      const signed gShiftLeft = (colorFormat().gLoss - (signed) format.gLoss) + (format.gShift % 8);
      const signed bShiftLeft = (colorFormat().bLoss - (signed) format.bLoss) + (format.bShift % 8);

      // Calculate the byte masks for each color component (for masking away excess bits)
      const byte rMask = format.rMax() << (format.rShift % 8);
      const byte gMask = format.gMax() << (format.gShift % 8);
      const byte bMask = format.bMax() << (format.bShift % 8);

      const int rBytePos = bytePos(format.rShift, format.bytesPerPixel, isBigEndian(endian));
      const int gBytePos = bytePos(format.gShift, format.bytesPerPixel, isBigEndian(endian));
      const int bBytePos = bytePos(format.bShift, format.bytesPerPixel, isBigEndian(endian));

      // Save the palette to the output in the specified format
      for (uint i = firstIndex; i < firstIndex + numColors; i++) {
            buf[i * format.bytesPerPixel + rBytePos] |= (shiftByteLeft(_colors[i].r, rShiftLeft) & rMask);
            buf[i * format.bytesPerPixel + gBytePos] |= (shiftByteLeft(_colors[i].g, gShiftLeft) & gMask);
            buf[i * format.bytesPerPixel + bBytePos] |= (shiftByteLeft(_colors[i].b, bShiftLeft) & bMask);
      }

      // Return the pointer to the output palette
      return buf;
}

} // End of namespace Cine

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