Method GetVariable

src/newgrf_object.cpp:262–375

Used by the resolver to get values for feature 0F deterministic spritegroups. */ virtual */

/** Used by the resolver to get values for feature 0F deterministic spritegroups. */
/* virtual */ uint32_t ObjectScopeResolver::GetVariable(uint8_t variable, [[maybe_unused]] uint32_t parameter, bool &available) const
{
	/* We get the town from the object, or we calculate the closest
	 * town if we need to when there's no object. */
	const Town *t = nullptr;

	if (this->obj == nullptr) {
		switch (variable) {
			/* Allow these when there's no object. */
			case 0x41:
			case 0x60:
			case 0x61:
			case 0x62:
			case 0x64:
				break;

			/* Allow these, but find the closest town. */
			case 0x45:
			case 0x46:
				if (!IsValidTile(this->tile)) goto unhandled;
				t = ClosestTownFromTile(this->tile, UINT_MAX);
				break;

			/* Construction date */
			case 0x42: return TimerGameCalendar::date.base();

			/* Object founder information */
			case 0x44: return _current_company.base();

			/* Object view */
			case 0x48: return this->view;

			case 0x7A: return GetBadgeVariableResult(*this->ro.grffile, this->spec->badges, parameter);

			/*
			 * Disallow the rest:
			 * 0x40: Relative position is passed as parameter during construction.
			 * 0x43: Animation counter is only for actual tiles.
			 * 0x47: Object colour is only valid when its built.
			 * 0x63: Animation counter of nearby tile, see above.
			 */
			default:
				goto unhandled;
		}

		/* If there's an invalid tile, then we don't have enough information at all. */
		if (!IsValidTile(this->tile)) goto unhandled;
	} else {
		t = this->obj->town;
	}

	switch (variable) {
		/* Relative position. */
		case 0x40: {
			TileIndex offset = this->tile - this->obj->location.tile;
			uint offset_x = TileX(offset);
			uint offset_y = TileY(offset);
			return offset_y << 20 | offset_x << 16 | offset_y << 8 | offset_x;