png.cpp

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00001 /* $Id: png.cpp 19628 2010-04-14 16:07:17Z rubidium $ */
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)
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.png", sep, filename, id, mask ? "m" : "");
00045   if (FioCheckFileExists(png_file)) {
00046     FioOpenFile(PNG_SLOT, png_file);
00047     return true;
00048   }
00049 
00050   /* TODO -- Add TAR support */
00051   return false;
00052 }
00053 
00054 static bool LoadPNG(SpriteLoader::Sprite *sprite, const char *filename, uint32 id, volatile bool mask)
00055 {
00056   png_byte header[8];
00057   png_structp png_ptr;
00058   png_infop info_ptr, end_info;
00059   uint bit_depth, colour_type;
00060   uint i, pixelsize;
00061   SpriteLoader::CommonPixel *dst;
00062 
00063   if (!OpenPNGFile(filename, id, mask)) return mask; // If mask is true, and file not found, continue true anyway, as it isn't a show-stopper
00064 
00065   /* Check the header */
00066   FioReadBlock(header, 8);
00067   if (png_sig_cmp(header, 0, 8) != 0) return false;
00068 
00069   /* Create the reader */
00070   png_ptr = png_create_read_struct(PNG_LIBPNG_VER_STRING, (png_voidp)NULL, png_my_error, png_my_warning);
00071   if (png_ptr == NULL) return false;
00072 
00073   /* Create initial stuff */
00074   info_ptr = png_create_info_struct(png_ptr);
00075   if (info_ptr == NULL) {
00076     png_destroy_read_struct(&png_ptr, (png_infopp)NULL, (png_infopp)NULL);
00077     return false;
00078   }
00079   end_info = png_create_info_struct(png_ptr);
00080   if (end_info == NULL) {
00081     png_destroy_read_struct(&png_ptr, &info_ptr, (png_infopp)NULL);
00082     return false;
00083   }
00084 
00085   /* Make sure that upon error, we can clean up graceful */
00086   if (setjmp(png_jmpbuf(png_ptr))) {
00087     png_destroy_read_struct(&png_ptr, &info_ptr, &end_info);
00088     return false;
00089   }
00090 
00091   /* Read the file */
00092   png_set_read_fn(png_ptr, NULL, png_my_read);
00093   png_set_sig_bytes(png_ptr, 8);
00094 
00095   png_read_info(png_ptr, info_ptr);
00096 
00097   if (!mask) {
00098     /* Read the text chunks */
00099     png_textp text_ptr;
00100     int num_text = 0;
00101     png_get_text(png_ptr, info_ptr, &text_ptr, &num_text);
00102     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);
00103     for (int i = 0; i < num_text; i++) {
00104       /* x_offs and y_offs are in the text-chunk of PNG */
00105       if (strcmp("x_offs", text_ptr[i].key) == 0) sprite->x_offs = strtol(text_ptr[i].text, NULL, 0);
00106       if (strcmp("y_offs", text_ptr[i].key) == 0) sprite->y_offs = strtol(text_ptr[i].text, NULL, 0);
00107     }
00108 
00109     sprite->height = png_get_image_height(png_ptr, info_ptr);
00110     sprite->width  = png_get_image_width(png_ptr, info_ptr);
00111     sprite->AllocateData(sprite->width * sprite->height);
00112   }
00113 
00114   bit_depth  = png_get_bit_depth(png_ptr, info_ptr);
00115   colour_type = png_get_color_type(png_ptr, info_ptr);
00116 
00117   if (mask && (bit_depth != 8 || colour_type != PNG_COLOR_TYPE_PALETTE)) {
00118     DEBUG(misc, 0, "Ignoring mask for SpriteID %d as it isn't a 8 bit palette image", id);
00119     return true;
00120   }
00121 
00122   if (!mask) {
00123     if (bit_depth == 16) png_set_strip_16(png_ptr);
00124 
00125     if (colour_type == PNG_COLOR_TYPE_PALETTE) {
00126       png_set_palette_to_rgb(png_ptr);
00127       colour_type = PNG_COLOR_TYPE_RGB;
00128     }
00129     if (colour_type == PNG_COLOR_TYPE_GRAY || colour_type == PNG_COLOR_TYPE_GRAY_ALPHA) {
00130       png_set_gray_to_rgb(png_ptr);
00131       colour_type = PNG_COLOR_TYPE_RGB;
00132     }
00133 
00134     if (colour_type == PNG_COLOR_TYPE_RGB) {
00135       if (png_get_valid(png_ptr, info_ptr, PNG_INFO_tRNS)) {
00136         /* Create an alpha channel when there is a tRNS chunk */
00137         png_set_tRNS_to_alpha(png_ptr);
00138       } else {
00139         png_set_filler(png_ptr, 0xff, PNG_FILLER_AFTER);
00140       }
00141     }
00142 
00143     pixelsize = sizeof(uint32);
00144   } else {
00145     pixelsize = sizeof(uint8);
00146   }
00147 
00148   png_bytep row_pointer = AllocaM(png_byte, png_get_image_width(png_ptr, info_ptr) * pixelsize);
00149 
00150   for (i = 0; i < png_get_image_height(png_ptr, info_ptr); i++) {
00151     png_read_row(png_ptr, row_pointer, NULL);
00152 
00153     dst = sprite->data + i * png_get_image_width(png_ptr, info_ptr);
00154 
00155     for (uint x = 0; x < png_get_image_width(png_ptr, info_ptr); x++) {
00156       if (mask) {
00157         if (row_pointer[x * sizeof(uint8)] != 0) {
00158           dst[x].r = 0;
00159           dst[x].g = 0;
00160           dst[x].b = 0;
00161           /* Alpha channel is used from the original image (to allow transparency in remap colours) */
00162           dst[x].m = row_pointer[x * sizeof(uint8)];
00163         }
00164       } else {
00165         dst[x].r = row_pointer[x * sizeof(uint32) + 0];
00166         dst[x].g = row_pointer[x * sizeof(uint32) + 1];
00167         dst[x].b = row_pointer[x * sizeof(uint32) + 2];
00168         dst[x].a = row_pointer[x * sizeof(uint32) + 3];
00169         dst[x].m = 0;
00170       }
00171     }
00172   }
00173 
00174   png_destroy_read_struct(&png_ptr, &info_ptr, &end_info);
00175 
00176   return true;
00177 }
00178 
00179 bool SpriteLoaderPNG::LoadSprite(SpriteLoader::Sprite *sprite, uint8 file_slot, size_t file_pos, SpriteType sprite_type)
00180 {
00181   const char *filename = FioGetFilename(file_slot);
00182   if (!LoadPNG(sprite, filename, (uint32)file_pos, false)) return false;
00183   if (!LoadPNG(sprite, filename, (uint32)file_pos, true)) return false;
00184   return true;
00185 }
00186 
00187 #endif /* WITH_PNG */

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