This utility package allows a programmer to define multicoloured characters or sprites, and move them around the screen at speed with ease.

Usually one's BASIC programs are slowed down by printing characters on the screen using VDU calls. A sprite is printed using direct screen addressing and is much faster. Also, one can define the colour of individual pixels within the sprite and obtain much finer detail than with VDU 23, without having to resort to colour overlaying. 'Simonsoft Sprites' consists of a character definition program, a machine code routine which controls sprite movement, a very comprehensive 12-page manual, and a demonstration game.

On entering a program, you can either define a single sprite or a block of sprites. A grid system is used, and by using the cursor keys one can build the sprite using any of the 16 Mode 2 colours. The character is displayed simultaneously. A left and right image can be defined for each sprite which, if they are different, will give automatic animation when the sprite is moved horizontally. Other methods of animation are also described. There are twelve single sprites which can be defined in this way, each of which can have three 'clones' giving a total of 48 sprites.

Having defined the sprites, one has memory between &1400 and &3000 to write a BASIC program in: the program must run in Mode 2. Each sprite has two variables ascribed to it into which one puts the screen co-ordinates e.g. A%=500:B%=700. To move a sprite, one puts the sprite identification number into the variable Y% and accesses the machine code movement routine with CALL Z%. The sprite is automatically erased from its old position and placed in its new one. EORing with anything else on the screen (so with manipulation of the colour palette one can make the sprites move behind or in front of objects). Screen boundaries are automatically crossed (not always something you may want) and all sprites including clones can be individually moved, removed or replaced.

The speed at which the sprites can travel is truly amazing. Moving the most complex shapes is no problem, and I found it easier to write movement procedures using the sprite routine than by well-tried other methods.

The manual is excellently clear giving many examples, and taking one easily and slowly through the possibilities of the program.

The only major drawback I can see is that I can't effectively list my latest game for you to see how well this package works, since the character definitions are hidden away somewhere in my machine!