grf.cpp

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00001 /* $Id: grf.cpp 18683 2010-01-01 18:45:40Z 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 #include "../stdafx.h"
00013 #include "../gfx_func.h"
00014 #include "../fileio_func.h"
00015 #include "../debug.h"
00016 #include "../strings_func.h"
00017 #include "table/strings.h"
00018 #include "../gui.h"
00019 #include "grf.hpp"
00020 
00029 static bool WarnCorruptSprite(uint8 file_slot, size_t file_pos, int line)
00030 {
00031   static byte warning_level = 0;
00032   if (warning_level == 0) {
00033     SetDParamStr(0, FioGetFilename(file_slot));
00034     ShowErrorMessage(STR_NEWGRF_ERROR_CORRUPT_SPRITE, INVALID_STRING_ID, 0, 0);
00035   }
00036   DEBUG(sprite, warning_level, "[%i] Loading corrupted sprite from %s at position %i", line, FioGetFilename(file_slot), (int)file_pos);
00037   warning_level = 6;
00038   return false;
00039 }
00040 
00041 bool SpriteLoaderGrf::LoadSprite(SpriteLoader::Sprite *sprite, uint8 file_slot, size_t file_pos, SpriteType sprite_type)
00042 {
00043   /* Open the right file and go to the correct position */
00044   FioSeekToFile(file_slot, file_pos);
00045 
00046   /* Read the size and type */
00047   int num = FioReadWord();
00048   byte type = FioReadByte();
00049 
00050   /* Type 0xFF indicates either a colourmap or some other non-sprite info; we do not handle them here */
00051   if (type == 0xFF) return false;
00052 
00053   sprite->height = FioReadByte();
00054   sprite->width  = FioReadWord();
00055   sprite->x_offs = FioReadWord();
00056   sprite->y_offs = FioReadWord();
00057 
00058   /* 0x02 indicates it is a compressed sprite, so we can't rely on 'num' to be valid.
00059    *  In case it is uncompressed, the size is 'num' - 8 (header-size). */
00060   num = (type & 0x02) ? sprite->width * sprite->height : num - 8;
00061 
00062   byte *dest_orig = AllocaM(byte, num);
00063   byte *dest = dest_orig;
00064   const int dest_size = num;
00065 
00066   /* Read the file, which has some kind of compression */
00067   while (num > 0) {
00068     int8 code = FioReadByte();
00069 
00070     if (code >= 0) {
00071       /* Plain bytes to read */
00072       int size = (code == 0) ? 0x80 : code;
00073       num -= size;
00074       if (num < 0) return WarnCorruptSprite(file_slot, file_pos, __LINE__);
00075       for (; size > 0; size--) {
00076         *dest = FioReadByte();
00077         dest++;
00078       }
00079     } else {
00080       /* Copy bytes from earlier in the sprite */
00081       const uint data_offset = ((code & 7) << 8) | FioReadByte();
00082       if (dest - data_offset < dest_orig) return WarnCorruptSprite(file_slot, file_pos, __LINE__);
00083       int size = -(code >> 3);
00084       num -= size;
00085       if (num < 0) return WarnCorruptSprite(file_slot, file_pos, __LINE__);
00086       for (; size > 0; size--) {
00087         *dest = *(dest - data_offset);
00088         dest++;
00089       }
00090     }
00091   }
00092 
00093   if (num != 0) return WarnCorruptSprite(file_slot, file_pos, __LINE__);
00094 
00095   sprite->AllocateData(sprite->width * sprite->height);
00096 
00097   /* When there are transparency pixels, this format has another trick.. decode it */
00098   if (type & 0x08) {
00099     for (int y = 0; y < sprite->height; y++) {
00100       bool last_item = false;
00101       /* Look up in the header-table where the real data is stored for this row */
00102       int offset = (dest_orig[y * 2 + 1] << 8) | dest_orig[y * 2];
00103 
00104       /* Go to that row */
00105       dest = dest_orig + offset;
00106 
00107       do {
00108         if (dest + 2 > dest_orig + dest_size) {
00109           free(sprite->data);
00110           return WarnCorruptSprite(file_slot, file_pos, __LINE__);
00111         }
00112 
00113         SpriteLoader::CommonPixel *data;
00114         /* Read the header:
00115          *  0 .. 14  - length
00116          *  15       - last_item
00117          *  16 .. 31 - transparency bytes */
00118         last_item  = ((*dest) & 0x80) != 0;
00119         int length =  (*dest++) & 0x7F;
00120         int skip   =   *dest++;
00121 
00122         data = &sprite->data[y * sprite->width + skip];
00123 
00124         if (skip + length > sprite->width || dest + length > dest_orig + dest_size) {
00125           free(sprite->data);
00126           return WarnCorruptSprite(file_slot, file_pos, __LINE__);
00127         }
00128 
00129         for (int x = 0; x < length; x++) {
00130           switch (sprite_type) {
00131             case ST_NORMAL: data->m = _palette_remap_grf[file_slot] ? _palette_remap[*dest] : *dest; break;
00132             case ST_FONT:   data->m = min(*dest, 2u); break;
00133             default:        data->m = *dest; break;
00134           }
00135           dest++;
00136           data++;
00137         }
00138       } while (!last_item);
00139     }
00140   } else {
00141     if (dest_size < sprite->width * sprite->height) {
00142       free(sprite->data);
00143       return WarnCorruptSprite(file_slot, file_pos, __LINE__);
00144     }
00145 
00146     if (dest_size > sprite->width * sprite->height) {
00147       static byte warning_level = 0;
00148       DEBUG(sprite, warning_level, "Ignoring %i unused extra bytes from the sprite from %s at position %i", dest_size - sprite->width * sprite->height, FioGetFilename(file_slot), (int)file_pos);
00149       warning_level = 6;
00150     }
00151 
00152     dest = dest_orig;
00153 
00154     for (int i = 0; i < sprite->width * sprite->height; i++) {
00155       switch (sprite_type) {
00156         case ST_NORMAL: sprite->data[i].m = _palette_remap_grf[file_slot] ? _palette_remap[dest[i]] : dest[i]; break;
00157         case ST_FONT:   sprite->data[i].m = min(dest[i], 2u); break;
00158         default:        sprite->data[i].m = dest[i]; break;
00159       }
00160     }
00161   }
00162 
00163   /* Make sure to mark all transparent pixels transparent on the alpha channel too */
00164   for (int i = 0; i < sprite->width * sprite->height; i++)
00165     if (sprite->data[i].m != 0) sprite->data[i].a = 0xFF;
00166 
00167   return true;
00168 }

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