Function CalcFirstTilePosition

Source/engine/render/scrollrt.cpp:1030–1073

int tileRows;

void CalcFirstTilePosition(Point &position, Displacement &offset)
{
	// Adjust by player offset and tile grid alignment
	Player &myPlayer = *MyPlayer;
	offset = tileOffset;
	if (myPlayer.isWalking())
		offset += GetOffsetForWalking(myPlayer.AnimInfo, myPlayer._pdir, true);

	position += tileShift;

	// Skip rendering parts covered by the panels
	if (CanPanelsCoverView() && (IsLeftPanelOpen() || IsRightPanelOpen())) {
		int multiplier = (*sgOptions.Graphics.zoom) ? 1 : 2;
		position += Displacement(Direction::East) * multiplier;
		offset.deltaX += -TILE_WIDTH * multiplier / 2 / 2;

		if (IsLeftPanelOpen() && !*sgOptions.Graphics.zoom) {
			offset.deltaX += SidePanelSize.width;
			// SidePanelSize.width accounted for in Zoom()
		}
	}

	// Draw areas moving in and out of the screen
	if (myPlayer.isWalking()) {
		switch (myPlayer._pdir) {
		case Direction::North:
		case Direction::NorthEast:
			offset.deltaY -= TILE_HEIGHT;
			position += Direction::North;
			break;
		case Direction::SouthWest:
		case Direction::West:
			offset.deltaX -= TILE_WIDTH;
			position += Direction::West;
			break;
		case Direction::NorthWest:
			offset.deltaX -= TILE_WIDTH / 2;
			offset.deltaY -= TILE_HEIGHT / 2;
			position += Direction::NorthWest;
		default:
			break;
		}
	}
}

/**
 * @brief Configure render and process screen rows