grf.cpp

Go to the documentation of this file.
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 #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 "../core/math_func.hpp"
00020 #include "grf.hpp"
00021 
00022 extern const byte _palmap_w2d[];
00023 
00032 static bool WarnCorruptSprite(uint8 file_slot, size_t file_pos, int line)
00033 {
00034   static byte warning_level = 0;
00035   if (warning_level == 0) {
00036     SetDParamStr(0, FioGetFilename(file_slot));
00037     ShowErrorMessage(STR_NEWGRF_ERROR_CORRUPT_SPRITE, INVALID_STRING_ID, WL_ERROR);
00038   }
00039   DEBUG(sprite, warning_level, "[%i] Loading corrupted sprite from %s at position %i", line, FioGetFilename(file_slot), (int)file_pos);
00040   warning_level = 6;
00041   return false;
00042 }
00043 
00044 bool SpriteLoaderGrf::LoadSprite(SpriteLoader::Sprite *sprite, uint8 file_slot, size_t file_pos, SpriteType sprite_type)
00045 {
00046   /* Open the right file and go to the correct position */
00047   FioSeekToFile(file_slot, file_pos);
00048 
00049   /* Read the size and type */
00050   int num = FioReadWord();
00051   byte type = FioReadByte();
00052 
00053   /* Type 0xFF indicates either a colourmap or some other non-sprite info; we do not handle them here */
00054   if (type == 0xFF) return false;
00055 
00056   sprite->height = FioReadByte();
00057   sprite->width  = FioReadWord();
00058   sprite->x_offs = FioReadWord();
00059   sprite->y_offs = FioReadWord();
00060 
00061   /* 0x02 indicates it is a compressed sprite, so we can't rely on 'num' to be valid.
00062    *  In case it is uncompressed, the size is 'num' - 8 (header-size). */
00063   num = (type & 0x02) ? sprite->width * sprite->height : num - 8;
00064 
00065   byte *dest_orig = AllocaM(byte, num);
00066   byte *dest = dest_orig;
00067   const int dest_size = num;
00068 
00069   /* Read the file, which has some kind of compression */
00070   while (num > 0) {
00071     int8 code = FioReadByte();
00072 
00073     if (code >= 0) {
00074       /* Plain bytes to read */
00075       int size = (code == 0) ? 0x80 : code;
00076       num -= size;
00077       if (num < 0) return WarnCorruptSprite(file_slot, file_pos, __LINE__);
00078       for (; size > 0; size--) {
00079         *dest = FioReadByte();
00080         dest++;
00081       }
00082     } else {
00083       /* Copy bytes from earlier in the sprite */
00084       const uint data_offset = ((code & 7) << 8) | FioReadByte();
00085       if (dest - data_offset < dest_orig) return WarnCorruptSprite(file_slot, file_pos, __LINE__);
00086       int size = -(code >> 3);
00087       num -= size;
00088       if (num < 0) return WarnCorruptSprite(file_slot, file_pos, __LINE__);
00089       for (; size > 0; size--) {
00090         *dest = *(dest - data_offset);
00091         dest++;
00092       }
00093     }
00094   }
00095 
00096   if (num != 0) return WarnCorruptSprite(file_slot, file_pos, __LINE__);
00097 
00098   sprite->AllocateData(sprite->width * sprite->height);
00099 
00100   /* When there are transparency pixels, this format has another trick.. decode it */
00101   if (type & 0x08) {
00102     for (int y = 0; y < sprite->height; y++) {
00103       bool last_item = false;
00104       /* Look up in the header-table where the real data is stored for this row */
00105       int offset = (dest_orig[y * 2 + 1] << 8) | dest_orig[y * 2];
00106 
00107       /* Go to that row */
00108       dest = dest_orig + offset;
00109 
00110       do {
00111         if (dest + 2 > dest_orig + dest_size) {
00112           free(sprite->data);
00113           return WarnCorruptSprite(file_slot, file_pos, __LINE__);
00114         }
00115 
00116         SpriteLoader::CommonPixel *data;
00117         /* Read the header:
00118          *  0 .. 14  - length
00119          *  15       - last_item
00120          *  16 .. 31 - transparency bytes */
00121         last_item  = ((*dest) & 0x80) != 0;
00122         int length =  (*dest++) & 0x7F;
00123         int skip   =   *dest++;
00124 
00125         data = &sprite->data[y * sprite->width + skip];
00126 
00127         if (skip + length > sprite->width || dest + length > dest_orig + dest_size) {
00128           free(sprite->data);
00129           return WarnCorruptSprite(file_slot, file_pos, __LINE__);
00130         }
00131 
00132         for (int x = 0; x < length; x++) {
00133           switch (sprite_type) {
00134             case ST_NORMAL: data->m = _palette_remap_grf[file_slot] ? _palmap_w2d[*dest] : *dest; break;
00135             case ST_FONT:   data->m = min(*dest, 2u); break;
00136             default:        data->m = *dest; break;
00137           }
00138           dest++;
00139           data++;
00140         }
00141       } while (!last_item);
00142     }
00143   } else {
00144     if (dest_size < sprite->width * sprite->height) {
00145       free(sprite->data);
00146       return WarnCorruptSprite(file_slot, file_pos, __LINE__);
00147     }
00148 
00149     if (dest_size > sprite->width * sprite->height) {
00150       static byte warning_level = 0;
00151       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);
00152       warning_level = 6;
00153     }
00154 
00155     dest = dest_orig;
00156 
00157     for (int i = 0; i < sprite->width * sprite->height; i++) {
00158       switch (sprite_type) {
00159         case ST_NORMAL: sprite->data[i].m = _palette_remap_grf[file_slot] ? _palmap_w2d[dest[i]] : dest[i]; break;
00160         case ST_FONT:   sprite->data[i].m = min(dest[i], 2u); break;
00161         default:        sprite->data[i].m = dest[i]; break;
00162       }
00163     }
00164   }
00165 
00166   /* Make sure to mark all transparent pixels transparent on the alpha channel too */
00167   for (int i = 0; i < sprite->width * sprite->height; i++) {
00168     if (sprite->data[i].m != 0) sprite->data[i].a = 0xFF;
00169   }
00170 
00171   return true;
00172 }