grf.cpp

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/*
 * This file is part of OpenTTD.
 * 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.
 * 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.
 * 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 <https://www.gnu.org/licenses/old-licenses/gpl-2.0>.
 */
 
#include "../stdafx.h"
#include "../gfx_func.h"
#include "../debug.h"
#include "../settings_type.h"
#include "../strings_func.h"
#include "../error.h"
#include "../spritecache.h"
#include "grf.hpp"
 
#include "table/strings.h"
 
#include "../safeguards.h"
 
extern const uint8_t _palmap_w2d[];
 
static bool WarnCorruptSprite(const SpriteFile &file, size_t file_pos, int line)
{
  static uint8_t warning_level = 0;
  if (warning_level == 0) {
    ShowErrorMessage(GetEncodedString(STR_NEWGRF_ERROR_CORRUPT_SPRITE, file.GetSimplifiedFilename()), {}, WL_ERROR);
  }
  Debug(sprite, warning_level, "[{}] Loading corrupted sprite from {} at position {}", line, file.GetSimplifiedFilename(), file_pos);
  warning_level = 6;
  return false;
}
 
bool DecodeSingleSprite(SpriteLoader::Sprite *sprite, SpriteFile &file, size_t file_pos, SpriteType sprite_type, int64_t num, uint8_t type, ZoomLevel zoom_lvl, SpriteComponents colour_fmt, uint8_t container_format)
{
  /*
   * Original sprite height was max 255 pixels, with 4x extra zoom => 1020 pixels.
   * Original maximum width for sprites was 640 pixels, with 4x extra zoom => 2560 pixels.
   * Now up to 5 bytes per pixel => 1020 * 2560 * 5 => ~ 12.5 MiB.
   *
   * So, any sprite data more than 64 MiB is way larger that we would even expect; prevent allocating more memory!
   */
  if (num < 0 || num > 64 * 1024 * 1024) return WarnCorruptSprite(file, file_pos, __LINE__);
 
  std::unique_ptr<uint8_t[]> dest_orig = std::make_unique<uint8_t[]>(num);
  uint8_t *dest = dest_orig.get();
  const int64_t dest_size = num;
 
  /* Read the file, which has some kind of compression */
  while (num > 0) {
    int8_t code = file.ReadByte();
 
    if (code >= 0) {
      /* Plain bytes to read */
      int size = (code == 0) ? 0x80 : code;
      num -= size;
      if (num < 0) return WarnCorruptSprite(file, file_pos, __LINE__);
      for (; size > 0; size--) {
        *dest = file.ReadByte();
        dest++;
      }
    } else {
      /* Copy bytes from earlier in the sprite */
      const uint data_offset = ((code & 7) << 8) | file.ReadByte();
      if (dest - data_offset < dest_orig.get()) return WarnCorruptSprite(file, file_pos, __LINE__);
      int size = -(code >> 3);
      num -= size;
      if (num < 0) return WarnCorruptSprite(file, file_pos, __LINE__);
      for (; size > 0; size--) {
        *dest = *(dest - data_offset);
        dest++;
      }
    }
  }
 
  if (num != 0) return WarnCorruptSprite(file, file_pos, __LINE__);
 
  sprite->AllocateData(zoom_lvl, static_cast<size_t>(sprite->width) * sprite->height);
 
  /* Convert colour depth to pixel size. */
  int bpp = 0;
  if (colour_fmt.Test(SpriteComponent::RGB))     bpp += 3; // Has RGB data.
  if (colour_fmt.Test(SpriteComponent::Alpha))   bpp++;    // Has alpha data.
  if (colour_fmt.Test(SpriteComponent::Palette)) bpp++;    // Has palette data.
 
  /* When there are transparency pixels, this format has another trick.. decode it */
  if (type & 0x08) {
    for (int y = 0; y < sprite->height; y++) {
      bool last_item = false;
      /* Look up in the header-table where the real data is stored for this row */
      int offset;
      if (container_format >= 2 && dest_size > UINT16_MAX) {
        offset = (dest_orig[y * 4 + 3] << 24) | (dest_orig[y * 4 + 2] << 16) | (dest_orig[y * 4 + 1] << 8) | dest_orig[y * 4];
      } else {
        offset = (dest_orig[y * 2 + 1] << 8) | dest_orig[y * 2];
      }
 
      /* Go to that row */
      dest = dest_orig.get() + offset;
 
      do {
        if (dest + (container_format >= 2 && sprite->width > 256 ? 4 : 2) > dest_orig.get() + dest_size) {
          return WarnCorruptSprite(file, file_pos, __LINE__);
        }
 
        SpriteLoader::CommonPixel *data;
        /* Read the header. */
        int length, skip;
        if (container_format >= 2 && sprite->width > 256) {
          /*  0 .. 14  - length
           *  15       - last_item
           *  16 .. 31 - transparency bytes */
          last_item = (dest[1] & 0x80) != 0;
          length    = ((dest[1] & 0x7F) << 8) | dest[0];
          skip      = (dest[3] << 8) | dest[2];
          dest += 4;
        } else {
          /*  0 .. 6  - length
           *  7       - last_item
           *  8 .. 15 - transparency bytes */
          last_item  = ((*dest) & 0x80) != 0;
          length =  (*dest++) & 0x7F;
          skip   =   *dest++;
        }
 
        data = &sprite->data[y * sprite->width + skip];
 
        if (skip + length > sprite->width || dest + length * bpp > dest_orig.get() + dest_size) {
          return WarnCorruptSprite(file, file_pos, __LINE__);
        }
 
        for (int x = 0; x < length; x++) {
          if (colour_fmt.Test(SpriteComponent::RGB)) {
            data->r = *dest++;
            data->g = *dest++;
            data->b = *dest++;
          }
          data->a = colour_fmt.Test(SpriteComponent::Alpha) ? *dest++ : 0xFF;
          if (colour_fmt.Test(SpriteComponent::Palette)) {
            switch (sprite_type) {
              case SpriteType::Normal: data->m = file.NeedsPaletteRemap() ? _palmap_w2d[*dest] : *dest; break;
              case SpriteType::Font:   data->m = std::min<uint8_t>(*dest, 2u); break;
              default:        data->m = *dest; break;
            }
            /* Magic blue. */
            if (colour_fmt == SpriteComponent::Palette && *dest == 0) data->a = 0x00;
            dest++;
          }
          data++;
        }
      } while (!last_item);
    }
  } else {
    int64_t sprite_size = static_cast<int64_t>(sprite->width) * sprite->height * bpp;
    if (dest_size < sprite_size) {
      return WarnCorruptSprite(file, file_pos, __LINE__);
    }
 
    if (dest_size > sprite_size) {
      static uint8_t warning_level = 0;
      Debug(sprite, warning_level, "Ignoring {} unused extra bytes from the sprite from {} at position {}", dest_size - sprite_size, file.GetSimplifiedFilename(), file_pos);
      warning_level = 6;
    }
 
    dest = dest_orig.get();
 
    for (int i = 0; i < sprite->width * sprite->height; i++) {
      uint8_t *pixel = &dest[i * bpp];
 
      if (colour_fmt.Test(SpriteComponent::RGB)) {
        sprite->data[i].r = *pixel++;
        sprite->data[i].g = *pixel++;
        sprite->data[i].b = *pixel++;
      }
      sprite->data[i].a = colour_fmt.Test(SpriteComponent::Alpha) ? *pixel++ : 0xFF;
      if (colour_fmt.Test(SpriteComponent::Palette)) {
        switch (sprite_type) {
          case SpriteType::Normal: sprite->data[i].m = file.NeedsPaletteRemap() ? _palmap_w2d[*pixel] : *pixel; break;
          case SpriteType::Font:   sprite->data[i].m = std::min<uint8_t>(*pixel, 2u); break;
          default:        sprite->data[i].m = *pixel; break;
        }
        /* Magic blue. */
        if (colour_fmt == SpriteComponent::Palette && *pixel == 0) sprite->data[i].a = 0x00;
        pixel++;
      }
    }
  }
 
  return true;
}
 
static ZoomLevels LoadSpriteV1(SpriteLoader::SpriteCollection &sprite, SpriteFile &file, size_t file_pos, SpriteType sprite_type, bool load_32bpp, ZoomLevels &avail_8bpp)
{
  /* Check the requested colour depth. */
  if (load_32bpp) return {};
 
  /* Open the right file and go to the correct position */
  file.SeekTo(file_pos, SEEK_SET);
 
  /* Read the size and type */
  int num = file.ReadWord();
  uint8_t type = file.ReadByte();
 
  /* Type 0xFF indicates either a colourmap or some other non-sprite info; we do not handle them here */
  if (type == 0xFF) return {};
 
  ZoomLevel zoom_lvl = (sprite_type != SpriteType::MapGen) ? ZoomLevel::Normal : ZoomLevel::Min;
  auto &dest_sprite = sprite[zoom_lvl];
 
  dest_sprite.height = file.ReadByte();
  dest_sprite.width = file.ReadWord();
  dest_sprite.x_offs = file.ReadWord();
  dest_sprite.y_offs = file.ReadWord();
  dest_sprite.colours = SpriteComponent::Palette;
 
  if (dest_sprite.width > INT16_MAX) {
    WarnCorruptSprite(file, file_pos, __LINE__);
    return {};
  }
 
  /* 0x02 indicates it is a compressed sprite, so we can't rely on 'num' to be valid.
   * In case it is uncompressed, the size is 'num' - 8 (header-size). */
  num = (type & 0x02) ? dest_sprite.width * dest_sprite.height : num - 8;
 
  if (DecodeSingleSprite(&dest_sprite, file, file_pos, sprite_type, num, type, zoom_lvl, SpriteComponent::Palette, 1)) {
    avail_8bpp.Set(zoom_lvl);
    return avail_8bpp;
  }
 
  return {};
}
 
static ZoomLevels LoadSpriteV2(SpriteLoader::SpriteCollection &sprite, SpriteFile &file, size_t file_pos, SpriteType sprite_type, bool load_32bpp, SpriteCacheCtrlFlags control_flags, ZoomLevels &avail_8bpp, ZoomLevels &avail_32bpp)
{
  static const ZoomLevel zoom_lvl_map[6] = {ZoomLevel::Normal, ZoomLevel::In4x, ZoomLevel::In2x, ZoomLevel::Out2x, ZoomLevel::Out4x, ZoomLevel::Out8x};
 
  /* Is the sprite not present/stripped in the GRF? */
  if (file_pos == SIZE_MAX) return {};
 
  /* Open the right file and go to the correct position */
  file.SeekTo(file_pos, SEEK_SET);
 
  uint32_t id = file.ReadDword();
 
  ZoomLevels loaded_sprites;
  do {
    int64_t num = file.ReadDword();
    size_t start_pos = file.GetPos();
    uint8_t type = file.ReadByte();
 
    /* Type 0xFF indicates either a colourmap or some other non-sprite info; we do not handle them here. */
    if (type == 0xFF) return {};
 
    SpriteComponents colour{type};
    /* Mask out colour component information from type. */
    type &= ~SpriteComponents::MASK;
 
    uint8_t zoom = file.ReadByte();
 
    bool is_wanted_colour_depth = (colour.Any() && (load_32bpp ? colour != SpriteComponent::Palette : colour == SpriteComponent::Palette));
    bool is_wanted_zoom_lvl;
 
    if (sprite_type != SpriteType::MapGen) {
      if (zoom < lengthof(zoom_lvl_map)) {
        ZoomLevel zoom_lvl = zoom_lvl_map[zoom];
        if (colour == SpriteComponent::Palette) avail_8bpp.Set(zoom_lvl);
        if (colour != SpriteComponent::Palette) avail_32bpp.Set(zoom_lvl);
 
        is_wanted_zoom_lvl = true;
        ZoomLevel zoom_min = sprite_type == SpriteType::Font ? ZoomLevel::Min : _settings_client.gui.sprite_zoom_min;
        if (zoom_min >= ZoomLevel::In2x &&
            control_flags.Test(load_32bpp ? SpriteCacheCtrlFlag::AllowZoomMin2x32bpp : SpriteCacheCtrlFlag::AllowZoomMin2xPal) && zoom_lvl < ZoomLevel::In2x) {
          is_wanted_zoom_lvl = false;
        }
        if (zoom_min >= ZoomLevel::Normal &&
            control_flags.Test(load_32bpp ? SpriteCacheCtrlFlag::AllowZoomMin1x32bpp : SpriteCacheCtrlFlag::AllowZoomMin1xPal) && zoom_lvl < ZoomLevel::Normal) {
          is_wanted_zoom_lvl = false;
        }
      } else {
        is_wanted_zoom_lvl = false;
      }
    } else {
      is_wanted_zoom_lvl = (zoom == 0);
    }
 
    if (is_wanted_colour_depth && is_wanted_zoom_lvl) {
      ZoomLevel zoom_lvl = (sprite_type != SpriteType::MapGen) ? zoom_lvl_map[zoom] : ZoomLevel::Min;
 
      if (loaded_sprites.Test(zoom_lvl)) {
        /* We already have this zoom level, skip sprite. */
        Debug(sprite, 1, "Ignoring duplicate zoom level sprite {} from {}", id, file.GetSimplifiedFilename());
        file.SkipBytes(num - 2);
        continue;
      }
 
      auto &dest_sprite = sprite[zoom_lvl];
      dest_sprite.height = file.ReadWord();
      dest_sprite.width = file.ReadWord();
      dest_sprite.x_offs = file.ReadWord();
      dest_sprite.y_offs = file.ReadWord();
 
      if (dest_sprite.width > INT16_MAX || dest_sprite.height > INT16_MAX) {
        WarnCorruptSprite(file, file_pos, __LINE__);
        return {};
      }
 
      /* Convert colour components to pixel size. */
      int bpp = 0;
      if (colour.Test(SpriteComponent::RGB)) bpp += 3;
      if (colour.Test(SpriteComponent::Alpha)) bpp++;
      if (colour.Test(SpriteComponent::Palette)) bpp++;
 
      dest_sprite.colours = colour;
 
      /* For chunked encoding we store the decompressed size in the file,
       * otherwise we can calculate it from the image dimensions. */
      uint decomp_size = (type & 0x08) ? file.ReadDword() : dest_sprite.width * dest_sprite.height * bpp;
 
      bool valid = DecodeSingleSprite(&dest_sprite, file, file_pos, sprite_type, decomp_size, type, zoom_lvl, colour, 2);
      if (file.GetPos() != start_pos + num) {
        WarnCorruptSprite(file, file_pos, __LINE__);
        return {};
      }
 
      if (valid) loaded_sprites.Set(zoom_lvl);
    } else {
      /* Not the wanted zoom level or colour depth, continue searching. */
      file.SkipBytes(num - 2);
    }
 
  } while (file.ReadDword() == id);
 
  return loaded_sprites;
}
 
ZoomLevels SpriteLoaderGrf::LoadSprite(SpriteLoader::SpriteCollection &sprite, SpriteFile &file, size_t file_pos, SpriteType sprite_type, bool load_32bpp, SpriteCacheCtrlFlags control_flags, ZoomLevels &avail_8bpp, ZoomLevels &avail_32bpp)
{
  if (this->container_ver >= 2) {
    return LoadSpriteV2(sprite, file, file_pos, sprite_type, load_32bpp, control_flags, avail_8bpp, avail_32bpp);
  } else {
    return LoadSpriteV1(sprite, file, file_pos, sprite_type, load_32bpp, avail_8bpp);
  }
}