newgrf_canal.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 "debug.h"
#include "newgrf_spritegroup.h"
#include "newgrf_canal.h"
#include "water.h"
#include "water_map.h"
 
#include "safeguards.h"

std::array<WaterFeature, CF_END> _water_feature;

struct CanalScopeResolver : public ScopeResolver {
  TileIndex tile; 
 
  CanalScopeResolver(ResolverObject &ro, TileIndex tile)
    : ScopeResolver(ro), tile(tile)
  {
  }
 
  uint32_t GetRandomBits() const override;
  uint32_t GetVariable(uint8_t variable, [[maybe_unused]] uint32_t parameter, bool &available) const override;
};

struct CanalResolverObject : public ResolverObject {
  CanalScopeResolver canal_scope;
  CanalFeature feature;
 
  CanalResolverObject(CanalFeature feature, TileIndex tile,
      CallbackID callback = CBID_NO_CALLBACK, uint32_t callback_param1 = 0, uint32_t callback_param2 = 0);
 
  ScopeResolver *GetScope(VarSpriteGroupScope scope = VSG_SCOPE_SELF, uint8_t relative = 0) override
  {
    switch (scope) {
      case VSG_SCOPE_SELF: return &this->canal_scope;
      default: return ResolverObject::GetScope(scope, relative);
    }
  }
 
  GrfSpecFeature GetFeature() const override;
  uint32_t GetDebugID() const override;
};
 
/* virtual */ uint32_t CanalScopeResolver::GetRandomBits() const
{
  /* Return random bits only for water tiles, not station tiles */
  return IsTileType(this->tile, TileType::Water) ? GetWaterTileRandomBits(this->tile) : 0;
}
 
/* virtual */ uint32_t CanalScopeResolver::GetVariable(uint8_t variable, [[maybe_unused]] uint32_t parameter, bool &available) const
{
  switch (variable) {
    /* Height of tile */
    case 0x80: {
      int z = GetTileZ(this->tile);
      /* Return consistent height within locks */
      if (IsTileType(this->tile, TileType::Water) && IsLock(this->tile) && GetLockPart(this->tile) == LockPart::Upper) z--;
      return z;
    }
 
    /* Terrain type */
    case 0x81: return GetTerrainType(this->tile);
 
    /* Dike map: Connectivity info for river and canal tiles
     *
     * Assignment of bits to directions defined in agreement with
     * http://projects.tt-forums.net/projects/ttdpatch/repository/revisions/2367/entry/trunk/patches/water.asm#L879
     *         7
     *      3     0
     *   6     *     4
     *      2     1
     *         5
     */
    case 0x82: {
      uint32_t connectivity =
          (!IsWateredTile(TileAddXY(tile, -1,  0), DIR_SW) << 0)  // NE
        + (!IsWateredTile(TileAddXY(tile,  0,  1), DIR_NW) << 1)  // SE
        + (!IsWateredTile(TileAddXY(tile,  1,  0), DIR_NE) << 2)  // SW
        + (!IsWateredTile(TileAddXY(tile,  0, -1), DIR_SE) << 3)  // NW
        + (!IsWateredTile(TileAddXY(tile, -1,  1), DIR_W)  << 4)  // E
        + (!IsWateredTile(TileAddXY(tile,  1,  1), DIR_N)  << 5)  // S
        + (!IsWateredTile(TileAddXY(tile,  1, -1), DIR_E)  << 6)  // W
        + (!IsWateredTile(TileAddXY(tile, -1, -1), DIR_S)  << 7); // N
      return connectivity;
    }
 
    /* Random data for river or canal tiles, otherwise zero */
    case 0x83: return IsTileType(this->tile, TileType::Water) ? GetWaterTileRandomBits(this->tile) : 0;
  }
 
  Debug(grf, 1, "Unhandled canal variable 0x{:02X}", variable);
 
  available = false;
  return UINT_MAX;
}
 
GrfSpecFeature CanalResolverObject::GetFeature() const
{
  return GSF_CANALS;
}
 
uint32_t CanalResolverObject::GetDebugID() const
{
  return this->feature;
}

CanalResolverObject::CanalResolverObject(CanalFeature feature, TileIndex tile,
    CallbackID callback, uint32_t callback_param1, uint32_t callback_param2)
    : ResolverObject(_water_feature[feature].grffile, callback, callback_param1, callback_param2), canal_scope(*this, tile), feature(feature)
{
  this->root_spritegroup = _water_feature[feature].group;
}

SpriteID GetCanalSprite(CanalFeature feature, TileIndex tile)
{
  CanalResolverObject object(feature, tile);
  const auto *group = object.Resolve<ResultSpriteGroup>();
  if (group == nullptr || group->num_sprites == 0) return 0;
 
  return group->sprite;
}

static uint16_t GetCanalCallback(CallbackID callback, uint32_t param1, uint32_t param2, CanalFeature feature, TileIndex tile, std::span<int32_t> regs100 = {})
{
  CanalResolverObject object(feature, tile, callback, param1, param2);
  return object.ResolveCallback(regs100);
}

uint GetCanalSpriteOffset(CanalFeature feature, TileIndex tile, uint cur_offset)
{
  if (_water_feature[feature].callback_mask.Test(CanalCallbackMask::SpriteOffset)) {
    uint16_t cb = GetCanalCallback(CBID_CANALS_SPRITE_OFFSET, cur_offset, 0, feature, tile);
    if (cb != CALLBACK_FAILED) return cur_offset + cb;
  }
  return cur_offset;
}