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png_loader.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.
 *
 * $URL$
 * $Id$
 *
 */

// Disable symbol overrides so that we can use system headers.
#define FORBIDDEN_SYMBOL_ALLOW_ALL

#include "common/scummsys.h"
#include "common/stream.h"
#include "backends/platform/psp/psppixelformat.h"
#include "backends/platform/psp/display_client.h"
#include "backends/platform/psp/png_loader.h"

//#define __PSP_DEBUG_FUNCS__ /* For debugging function calls */
//#define __PSP_DEBUG_PRINT__ /* For debug printouts */

#include "backends/platform/psp/trace.h"

PngLoader::Status PngLoader::allocate() {
      DEBUG_ENTER_FUNC();
      
      if (!findImageDimensions()) {
            PSP_ERROR("failed to get image dimensions\n");
            return BAD_FILE;
      }

      _buffer->setSize(_width, _height, _sizeBy);

      uint32 bitsPerPixel = _bitDepth * _channels;
      
      if (_paletteSize) {     // 8 or 4-bit image
            if (bitsPerPixel == 4) {
                  _buffer->setPixelFormat(PSPPixelFormat::Type_Palette_4bit);
                  _palette->setPixelFormats(PSPPixelFormat::Type_4444, PSPPixelFormat::Type_Palette_4bit);
                  _paletteSize = 16;      // round up
            } else if (bitsPerPixel == 8) {                 // 8-bit image
                  _buffer->setPixelFormat(PSPPixelFormat::Type_Palette_8bit);
                  _palette->setPixelFormats(PSPPixelFormat::Type_4444, PSPPixelFormat::Type_Palette_8bit);
                  _paletteSize = 256; // round up
            } else {
                  PSP_ERROR("too many bits per pixel[%d] for a palette\n", bitsPerPixel);
                  return BAD_FILE;
            }

      } else {    // 32-bit image
            _buffer->setPixelFormat(PSPPixelFormat::Type_8888);
      }

      if (!_buffer->allocate()) {
            PSP_ERROR("failed to allocate buffer\n");
            return OUT_OF_MEMORY;
      }
      if (_buffer->hasPalette() && !_palette->allocate()) {
            PSP_ERROR("failed to allocate palette\n");
            return OUT_OF_MEMORY;
      }
      return OK;
}

bool PngLoader::load() {
      DEBUG_ENTER_FUNC();
      // Try to load the image
      _file->seek(0);   // Go back to start

      if (!loadImageIntoBuffer()) {
            PSP_DEBUG_PRINT("failed to load image\n");
            return false;
      }

      PSP_DEBUG_PRINT("succeded in loading image\n");

      if (_paletteSize == 16)       // 4-bit
            _buffer->flipNibbles(); // required because of PNG 4-bit format
      return true;
}

void PngLoader::warningFn(png_structp png_ptr, png_const_charp warning_msg) {
      // ignore PNG warnings
}

// Read function for png library to be able to read from our SeekableReadStream
//
void PngLoader::libReadFunc(png_structp pngPtr, png_bytep data, png_size_t length) {
      Common::SeekableReadStream *file;

      file = (Common::SeekableReadStream *)pngPtr->io_ptr;

      file->read(data, length);
}

bool PngLoader::basicImageLoad() {
      DEBUG_ENTER_FUNC();
      _pngPtr = png_create_read_struct(PNG_LIBPNG_VER_STRING, NULL, NULL, NULL);
      if (!_pngPtr)
            return false;

      png_set_error_fn(_pngPtr, (png_voidp) NULL, (png_error_ptr) NULL, warningFn);

      _infoPtr = png_create_info_struct(_pngPtr);
      if (!_infoPtr) {
            png_destroy_read_struct(&_pngPtr, png_infopp_NULL, png_infopp_NULL);
            return false;
      }
      // Set the png lib to use our read function
      png_set_read_fn(_pngPtr, (void *)_file, libReadFunc);

      unsigned int sig_read = 0;

      png_set_sig_bytes(_pngPtr, sig_read);
      png_read_info(_pngPtr, _infoPtr);
      int interlaceType;
      png_get_IHDR(_pngPtr, _infoPtr, (png_uint_32 *)&_width, (png_uint_32 *)&_height, &_bitDepth,
            &_colorType, &interlaceType, int_p_NULL, int_p_NULL);
      _channels = png_get_channels(_pngPtr, _infoPtr);
            
      if (_colorType & PNG_COLOR_MASK_PALETTE)
            _paletteSize = _infoPtr->num_palette;

      return true;
}

/* Get the width and height of a png image */
bool PngLoader::findImageDimensions() {
      DEBUG_ENTER_FUNC();

      bool status = basicImageLoad(); 

      PSP_DEBUG_PRINT("width[%d], height[%d], paletteSize[%d], bitDepth[%d], channels[%d], rowBytes[%d]\n", _width, _height, _paletteSize, _bitDepth, _channels, _infoPtr->rowbytes);
      png_destroy_read_struct(&_pngPtr, &_infoPtr, png_infopp_NULL);
      return status;
}

//
// Load a texture from a png image
//
bool PngLoader::loadImageIntoBuffer() {
      DEBUG_ENTER_FUNC();

      if (!basicImageLoad()) {
            png_destroy_read_struct(&_pngPtr, &_infoPtr, png_infopp_NULL);
            return false;
      }     
      png_set_strip_16(_pngPtr);          // Strip off 16 bit channels in case they occur

      if (_paletteSize) {
            // Copy the palette
            png_colorp srcPal = _infoPtr->palette;
            for (int i = 0; i < _infoPtr->num_palette; i++) {
                  unsigned char alphaVal = (i < _infoPtr->num_trans) ? _infoPtr->trans[i] : 0xFF;     // Load alpha if it's there
                  _palette->setSingleColorRGBA(i, srcPal->red, srcPal->green, srcPal->blue, alphaVal);
                  srcPal++;
            }
      } else {    // Not a palettized image
            if (_colorType == PNG_COLOR_TYPE_GRAY && _bitDepth < 8)
                  png_set_gray_1_2_4_to_8(_pngPtr);   // Round up grayscale images
            if (png_get_valid(_pngPtr, _infoPtr, PNG_INFO_tRNS))
                  png_set_tRNS_to_alpha(_pngPtr);           // Convert trans channel to alpha for 32 bits

            png_set_add_alpha(_pngPtr, 0xff, PNG_FILLER_AFTER);         // Filler for alpha if none exists
      }

      uint32 rowBytes = png_get_rowbytes(_pngPtr, _infoPtr);
      
      // there seems to be a bug in libpng where it doesn't increase the rowbytes or the 
      // channel even after we add the alpha channel
      if (_channels == 3 && (rowBytes / _width) == 3) {
            _channels = 4;
            rowBytes = _width * _channels;            
      }     
      
      PSP_DEBUG_PRINT("rowBytes[%d], channels[%d]\n", rowBytes, _channels);
      
      unsigned char *line = (unsigned char*) malloc(rowBytes);
      if (!line) {
            png_destroy_read_struct(&_pngPtr, png_infopp_NULL, png_infopp_NULL);
            PSP_ERROR("Couldn't allocate line\n");
            return false;
      }

      for (size_t y = 0; y < _height; y++) {
            png_read_row(_pngPtr, line, png_bytep_NULL);
            _buffer->copyFromRect(line, rowBytes, 0, y, _width, 1);     // Copy into buffer
      }
      free(line);
      png_read_end(_pngPtr, _infoPtr);
      png_destroy_read_struct(&_pngPtr, &_infoPtr, png_infopp_NULL);

      return true;
}

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