png.cpp

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00001 /* $Id: png.cpp 18809 2010-01-15 16:41:15Z 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   snprintf(png_file, sizeof(png_file), "sprites" PATHSEP "%s" PATHSEP "%d%s.png", filename, id, mask ? "m" : "");
00043   if (FioCheckFileExists(png_file)) {
00044     FioOpenFile(PNG_SLOT, png_file);
00045     return true;
00046   }
00047 
00048   /* TODO -- Add TAR support */
00049   return false;
00050 }
00051 
00052 static bool LoadPNG(SpriteLoader::Sprite *sprite, const char *filename, uint32 id, volatile bool mask)
00053 {
00054   png_byte header[8];
00055   png_structp png_ptr;
00056   png_infop info_ptr, end_info;
00057   uint bit_depth, colour_type;
00058   uint i, pixelsize;
00059   SpriteLoader::CommonPixel *dst;
00060 
00061   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
00062 
00063   /* Check the header */
00064   FioReadBlock(header, 8);
00065   if (png_sig_cmp(header, 0, 8) != 0) return false;
00066 
00067   /* Create the reader */
00068   png_ptr = png_create_read_struct(PNG_LIBPNG_VER_STRING, (png_voidp)NULL, png_my_error, png_my_warning);
00069   if (png_ptr == NULL) return false;
00070 
00071   /* Create initial stuff */
00072   info_ptr = png_create_info_struct(png_ptr);
00073   if (info_ptr == NULL) {
00074     png_destroy_read_struct(&png_ptr, (png_infopp)NULL, (png_infopp)NULL);
00075     return false;
00076   }
00077   end_info = png_create_info_struct(png_ptr);
00078   if (end_info == NULL) {
00079     png_destroy_read_struct(&png_ptr, &info_ptr, (png_infopp)NULL);
00080     return false;
00081   }
00082 
00083   /* Make sure that upon error, we can clean up graceful */
00084   if (setjmp(png_jmpbuf(png_ptr))) {
00085     png_destroy_read_struct(&png_ptr, &info_ptr, &end_info);
00086     return false;
00087   }
00088 
00089   /* Read the file */
00090   png_set_read_fn(png_ptr, NULL, png_my_read);
00091   png_set_sig_bytes(png_ptr, 8);
00092 
00093   png_read_info(png_ptr, info_ptr);
00094 
00095   if (!mask) {
00096     /* Read the text chunks */
00097     png_textp text_ptr;
00098     int num_text = 0;
00099     png_get_text(png_ptr, info_ptr, &text_ptr, &num_text);
00100     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);
00101     for (int i = 0; i < num_text; i++) {
00102       /* x_offs and y_offs are in the text-chunk of PNG */
00103       if (strcmp("x_offs", text_ptr[i].key) == 0) sprite->x_offs = strtol(text_ptr[i].text, NULL, 0);
00104       if (strcmp("y_offs", text_ptr[i].key) == 0) sprite->y_offs = strtol(text_ptr[i].text, NULL, 0);
00105     }
00106 
00107     sprite->height = png_get_image_height(png_ptr, info_ptr);
00108     sprite->width  = png_get_image_width(png_ptr, info_ptr);
00109     sprite->AllocateData(sprite->width * sprite->height);
00110   }
00111 
00112   bit_depth  = png_get_bit_depth(png_ptr, info_ptr);
00113   colour_type = png_get_color_type(png_ptr, info_ptr);
00114 
00115   if (mask && (bit_depth != 8 || colour_type != PNG_COLOR_TYPE_PALETTE)) {
00116     DEBUG(misc, 0, "Ignoring mask for SpriteID %d as it isn't a 8 bit palette image", id);
00117     return true;
00118   }
00119 
00120   if (!mask) {
00121     if (bit_depth == 16) png_set_strip_16(png_ptr);
00122 
00123     if (colour_type == PNG_COLOR_TYPE_PALETTE) {
00124       png_set_palette_to_rgb(png_ptr);
00125       colour_type = PNG_COLOR_TYPE_RGB;
00126     }
00127     if (colour_type == PNG_COLOR_TYPE_GRAY || colour_type == PNG_COLOR_TYPE_GRAY_ALPHA) {
00128       png_set_gray_to_rgb(png_ptr);
00129       colour_type = PNG_COLOR_TYPE_RGB;
00130     }
00131 
00132     if (colour_type == PNG_COLOR_TYPE_RGB) {
00133       png_set_filler(png_ptr, 0xff, PNG_FILLER_AFTER);
00134     }
00135 
00136     pixelsize = sizeof(uint32);
00137   } else {
00138     pixelsize = sizeof(uint8);
00139   }
00140 
00141   png_bytep row_pointer = AllocaM(png_byte, png_get_image_width(png_ptr, info_ptr) * pixelsize);
00142 
00143   for (i = 0; i < png_get_image_height(png_ptr, info_ptr); i++) {
00144     png_read_row(png_ptr, row_pointer, NULL);
00145 
00146     dst = sprite->data + i * png_get_image_width(png_ptr, info_ptr);
00147 
00148     for (uint x = 0; x < png_get_image_width(png_ptr, info_ptr); x++) {
00149       if (mask) {
00150         if (row_pointer[x * sizeof(uint8)] != 0) {
00151           dst[x].r = 0;
00152           dst[x].g = 0;
00153           dst[x].b = 0;
00154           /* Alpha channel is used from the original image (to allow transparency in remap colours) */
00155           dst[x].m = row_pointer[x * sizeof(uint8)];
00156         }
00157       } else {
00158         dst[x].r = row_pointer[x * sizeof(uint32) + 0];
00159         dst[x].g = row_pointer[x * sizeof(uint32) + 1];
00160         dst[x].b = row_pointer[x * sizeof(uint32) + 2];
00161         dst[x].a = row_pointer[x * sizeof(uint32) + 3];
00162         dst[x].m = 0;
00163       }
00164     }
00165   }
00166 
00167   png_destroy_read_struct(&png_ptr, &info_ptr, &end_info);
00168 
00169   return true;
00170 }
00171 
00172 bool SpriteLoaderPNG::LoadSprite(SpriteLoader::Sprite *sprite, uint8 file_slot, size_t file_pos, SpriteType sprite_type)
00173 {
00174   const char *filename = FioGetFilename(file_slot);
00175   if (!LoadPNG(sprite, filename, (uint32)file_pos, false)) return false;
00176   if (!LoadPNG(sprite, filename, (uint32)file_pos, true)) return false;
00177   return true;
00178 }
00179 
00180 #endif /* WITH_PNG */

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