# png.cpp

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    00001 /* $Id$ */
    00002
    00003 /*
    00004  * This file is part of OpenTTD.
    00005  * OpenTTD 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, version 2.
    00006  * OpenTTD 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.
    00007  * See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with OpenTTD. If not, see <http://www.gnu.org/licenses/>.
    00008  */
    00009
    00012 #ifdef WITH_PNG
    00013
    00014 #include "../stdafx.h"
    00015 #include "../fileio_func.h"
    00016 #include "../debug.h"
    00017 #include "png.hpp"
    00018 #include <png.h>
    00019
    00020 #define PNG_SLOT 62
    00021
    00022 static void PNGAPI png_my_read(png_structp png_ptr, png_bytep data, png_size_t length)
    00023 {
    00024   FioReadBlock(data, length);
    00025 }
    00026
    00027 static void PNGAPI png_my_error(png_structp png_ptr, png_const_charp message)
    00028 {
    00029   DEBUG(sprite, 0, "ERROR (libpng): %s - %s", message, (char *)png_get_error_ptr(png_ptr));
    00030   longjmp(png_jmpbuf(png_ptr), 1);
    00031 }
    00032
    00033 static void PNGAPI png_my_warning(png_structp png_ptr, png_const_charp message)
    00034 {
    00035   DEBUG(sprite, 0, "WARNING (libpng): %s - %s", message, (char *)png_get_error_ptr(png_ptr));
    00036 }
    00037
    00038 static bool OpenPNGFile(const char *filename, uint32 id, bool mask, ZoomLevel zoom)
    00039 {
    00040   char png_file[MAX_PATH];
    00041
    00042   /* Add path separator after 'sprites' if not present */
    00043   const char *sep = (filename[0] == PATHSEPCHAR) ? "" : PATHSEP;
    00044   snprintf(png_file, sizeof(png_file), "sprites%s%s" PATHSEP "%d_%s%d%s.png", sep, filename, id, "z",zoom,mask ? "m" : "");
    00045   if (FioCheckFileExists(png_file)) {
    00046     FioOpenFile(PNG_SLOT, png_file);
    00047     return true;
    00048   }
    00049   /* if failed, try to find it in the trunk tars, only for default zoom */
    00050   if ( zoom == ZOOM_LVL_NORMAL) {
    00051     snprintf(png_file, sizeof(png_file), "sprites%s%s" PATHSEP "%d%s.png", sep, filename, id, mask ? "m" : "");
    00052     if (FioCheckFileExists(png_file)) {
    00053       FioOpenFile(PNG_SLOT, png_file);
    00054       return true;
    00055     }
    00056   }
    00057   /* TODO -- Add TAR support */
    00058   return false;
    00059 }
    00060
    00061 static bool LoadPNG(SpriteLoader::Sprite *sprite, const char *filename, uint32 id, volatile bool mask, ZoomLevel zoom)
    00062 {
    00063   png_byte header[8];
    00064   png_structp png_ptr;
    00065   png_infop info_ptr, end_info;
    00066   uint bit_depth, colour_type;
    00067   uint i, pixelsize;
    00068   SpriteLoader::CommonPixel *dst;
    00069
    00070   if (!OpenPNGFile(filename, id, mask, zoom)) return mask; // If mask is true, and file not found, continue true anyway, as it isn't a show-stopper
    00071
    00072   /* Check the header */
    00073   FioReadBlock(header, 8);
    00074   if (png_sig_cmp(header, 0, 8) != 0) return false;
    00075
    00076   /* Create the reader */
    00077   png_ptr = png_create_read_struct(PNG_LIBPNG_VER_STRING, (png_voidp)NULL, png_my_error, png_my_warning);
    00078   if (png_ptr == NULL) return false;
    00079
    00080   /* Create initial stuff */
    00081   info_ptr = png_create_info_struct(png_ptr);
    00082   if (info_ptr == NULL) {
    00083     png_destroy_read_struct(&png_ptr, (png_infopp)NULL, (png_infopp)NULL);
    00084     return false;
    00085   }
    00086   end_info = png_create_info_struct(png_ptr);
    00087   if (end_info == NULL) {
    00088     png_destroy_read_struct(&png_ptr, &info_ptr, (png_infopp)NULL);
    00089     return false;
    00090   }
    00091
    00092   /* Make sure that upon error, we can clean up graceful */
    00093   if (setjmp(png_jmpbuf(png_ptr))) {
    00094     png_destroy_read_struct(&png_ptr, &info_ptr, &end_info);
    00095     return false;
    00096   }
    00097
    00098   /* Read the file */
    00099   png_set_read_fn(png_ptr, NULL, png_my_read);
    00100   png_set_sig_bytes(png_ptr, 8);
    00101
    00102   png_read_info(png_ptr, info_ptr);
    00103
    00104   if (!mask) {
    00105     /* Read the text chunks */
    00106     png_textp text_ptr;
    00107     int num_text = 0;
    00108     png_get_text(png_ptr, info_ptr, &text_ptr, &num_text);
    00109     if (num_text == 0) DEBUG(misc, 0, "Warning: PNG Sprite '%s/%d.png' doesn't have x_offs and y_offs; expect graphical problems", filename, id);
    00110     for (int i = 0; i < num_text; i++) {
    00111       /* x_offs and y_offs are in the text-chunk of PNG */
    00112       if (strcmp("x_offs", text_ptr[i].key) == 0) sprite->x_offs = strtol(text_ptr[i].text, NULL, 0);
    00113       if (strcmp("y_offs", text_ptr[i].key) == 0) sprite->y_offs = strtol(text_ptr[i].text, NULL, 0);
    00114     }
    00115
    00116     sprite->height = png_get_image_height(png_ptr, info_ptr);
    00117     sprite->width  = png_get_image_width(png_ptr, info_ptr);
    00118     sprite->AllocateData(sprite->width * sprite->height);
    00119   }
    00120
    00121   bit_depth  = png_get_bit_depth(png_ptr, info_ptr);
    00122   colour_type = png_get_color_type(png_ptr, info_ptr);
    00123
    00124   if (mask && colour_type != PNG_COLOR_TYPE_PALETTE) {
    00125     DEBUG(misc, 0, "Ignoring mask for SpriteID %d as it isn't a 8 bit palette image", id);
    00126     return true;
    00127   }
    00128   /* Convert mask file with bit depth of 1, 2 or 4 into 8 bits */
    00129   if (mask && bit_depth < 8 && colour_type == PNG_COLOR_TYPE_PALETTE) {
    00130     png_set_packing(png_ptr);
    00131   }
    00132
    00133   if (!mask) {
    00134     if (bit_depth == 16) png_set_strip_16(png_ptr);
    00135
    00136     if (colour_type == PNG_COLOR_TYPE_PALETTE) {
    00137       png_set_palette_to_rgb(png_ptr);
    00138       colour_type = PNG_COLOR_TYPE_RGB;
    00139     }
    00140     if (colour_type == PNG_COLOR_TYPE_GRAY || colour_type == PNG_COLOR_TYPE_GRAY_ALPHA) {
    00141       png_set_gray_to_rgb(png_ptr);
    00142       colour_type = PNG_COLOR_TYPE_RGB;
    00143     }
    00144
    00145     if (colour_type == PNG_COLOR_TYPE_RGB) {
    00146       if (png_get_valid(png_ptr, info_ptr, PNG_INFO_tRNS)) {
    00147         /* Create an alpha channel when there is a tRNS chunk */
    00148         png_set_tRNS_to_alpha(png_ptr);
    00149       } else {
    00150         png_set_filler(png_ptr, 0xff, PNG_FILLER_AFTER);
    00151       }
    00152     }
    00153
    00154     pixelsize = sizeof(uint32);
    00155   } else {
    00156     pixelsize = sizeof(uint8);
    00157   }
    00158
    00159   png_bytep row_pointer = AllocaM(png_byte, png_get_image_width(png_ptr, info_ptr) * pixelsize);
    00160
    00161   for (i = 0; i < png_get_image_height(png_ptr, info_ptr); i++) {
    00162     png_read_row(png_ptr, row_pointer, NULL);
    00163
    00164     dst = sprite->data + i * png_get_image_width(png_ptr, info_ptr);
    00165
    00166     for (uint x = 0; x < png_get_image_width(png_ptr, info_ptr); x++) {
    00167       if (mask) {
    00168         if (row_pointer[x * sizeof(uint8)] != 0) {
    00169           /* GeekToo: dont overwrite sprite rgb data if mask is present */
    00170           /* Alpha channel is used from the original image (to allow transparency in remap colours) */
    00171           /* Force the value of the palette if it is not in the correct range */
    00172           if (bit_depth < 8 && (row_pointer[x * sizeof(uint8)] < 196 || row_pointer[x * sizeof(uint8)] > 203)) {
    00173             dst[x].m = 199;
    00174           } else {
    00175             dst[x].m = row_pointer[x * sizeof(uint8)];
    00176           }
    00177         }
    00178       } else {
    00179         dst[x].r = row_pointer[x * sizeof(uint32) + 0];
    00180         dst[x].g = row_pointer[x * sizeof(uint32) + 1];
    00181         dst[x].b = row_pointer[x * sizeof(uint32) + 2];
    00182         dst[x].a = row_pointer[x * sizeof(uint32) + 3];
    00183         dst[x].m = 0;
    00184       }
    00185     }
    00186   }
    00187
    00188   png_destroy_read_struct(&png_ptr, &info_ptr, &end_info);
    00189
    00190   return true;
    00191 }
    00192
    00193 bool SpriteLoaderPNG::LoadSprite(SpriteLoader::Sprite *sprite, uint8 file_slot, size_t file_pos, SpriteType sprite_type, ZoomLevel zoom)
    00194 {
    00195   const char *filename = FioGetFilename(file_slot);
    00196
    00197   if (!LoadPNG(sprite, filename, (uint32)file_pos, false, zoom)) return false;
    00198   if (!LoadPNG(sprite, filename, (uint32)file_pos, true, zoom)) return false;
    00199
    00200   return true;
    00201 }
    00202
    00203 #endif /* WITH_PNG */