ESP - Enhanced Sliding Puzzle
by Richard Taylor

You may well have seen the traditional sliding puzzle where the numbers 1 to 15 must be arranged in order. This application takes the idea a step further, with smooth dragging of pieces, multi-size and multi-difficulty puzzles, and the facility to split up and use any sprites which are loaded in.

The application is loaded in the standard way: double-click on its icon in the Filer window (or choose it from the RISC User menu) and it will be installed on the icon bar. Clicking Menu over the icon bar icon shows the usual Info and Quit choices while clicking Select on the icon opens the main Slide window. You should see a grid of tiles with one empty space. The object of the puzzle is to rearrange these pieces in order so that they form a complete picture. Tiles are moved about by dragging them into the empty space. Two or more tiles in a row or column can be dragged together, if they are in line with the empty space. The sprite you are aiming to put together can be seen in its entirety by clicking on the icon at the bottom of the window. Click on the icon again to go back to the puzzle.

Clicking Menu anywhere over the window brings up the main ESP menu. The remaining options are now described under the headings of the four main menu items. 


Randomise

This randomises the tiles according to the current difficulty level (see 'Options' below). It may be chosen at any time, not just when the puzzle is completed.


Position

The submenu of this menu entry allows the current position of the pieces to be recorded, recalled and saved as a file to be reloaded later. Recall is only available if a position has been previously recorded, loaded or saved. Remember that clicking on Recall or loading a new position will lose the current position of the puzzle. A few example files have been saved in the directory 'Positions' which can be found by opening up the ESP application directory: hold Shift down while double-clicking on the !ESP icon. The positions will probably look the most interesting if they are used with the first sprite displayed.


Sprites

Choosing this entry will bring up a dialogue box, allowing you to select the sprite to be split up and used in the puzzle. Simply click on the arrows to step through all the available sprites, the number of which is shown at the top of the window. Click on the 'Update' icon when you have found the one you want. The program has two default sprites and more sprites can be added to the ones available by dragging a sprite file to any window belonging to the application or to its icon bar icon. There are some sprites which can be used in the directory called 'Pictures' which is again found inside the ESP application directory.

When a sprite file is loaded in, the first sprite in the file is chosen for display and it will be scaled to fit the window if necessary. It is displayed as accurately as is possible in the current mode: its true mode is shown in the 'Sprites' dialogue box. Any previous sprites may still be re-selected as long as they did not have the same name as a sprite in the new file. Note that there are a lot of sprites called 'screen', 'image' or 'screendump'.

The number of default sprites, which are available at the beginning, may be easily added to. Simply create a file called 'Sprites' (not '!Sprites') inside the the application directory. It may contain as many sprites as you like and will be automatically used next time the application is run.


Options

This will produce another dialogue box. The first group of 'radio' icons allow you to select the size of the puzzle while the second group changes the difficulty of puzzle produced by subsequent restarts. With large puzzles you must use a sprite with sufficient detail to ensure every piece is different, otherwise the puzzle may appear completed when in fact certain pieces have swapped positions. Note that the difficulty setting has little effect on very small puzzles.

You must click on 'Update' to implement the changes, while clicking on the 'Save' icon will implement and then save them inside the application directory, to be used next time the program is run. When the options are updated the puzzle is automatically randomised and your current position will be lost.

N.B. The first three difficulty levels are produced by starting the puzzle in its completed position and then simulating the movement of pieces. This is done an increasing number of times for each increasing level. This results in the 'Easy' level leaving most of the pieces in their correct positions, while the 'Hard' level moves virtually all the tiles but often leaves them near to where they belong. The 'Very hard' level, however, uses the completely different technique of randomly swapping the positions of pairs of tiles in the puzzle, a large but even amount of times. (Incidentally, an odd number of swaps would render it insoluble.) 


 RISC User 1993
