Saturday, 11 April 2020

Game # 7 : Frogger

Busy today, so just done the background for Frogger. This is probably most of the work though. It already scrolls, though just one way one speed as a bodge, at about 20 frames per second which is plenty. (Later: ESP32 it's more like 11-12 so that's something I'll have to work towards)

A couple of notes. Firstly, in real Frogger the top half, the river, is blue not black (it's near a chemical plant in this game). The system is perfectly capable of this, but at present the lanes are actually a 1 character high tilemap, there's 10 of them. This works quite well but the tilemap implementation currently has the problem that it can only do one background colour for a tilemap. I designed it that way. I might extend it to allow a different colour background but it isn't done this way. I could just write a routine to blit it out, but that would be cheating really. I'm trying to do as much as possible in straightforward BASIC. Just because.

Second point is the sprites are all monochrome. This is a limitation of the current sprite system, but I will probably extend it to do multi colour sprites at some time. The downside is because the blitter only blits one colour at a time, two colours requires twice as many blits.

I'll probably use the same trick for Space Invaders - the invaders will be a tilemap, so I can just scroll it or update it with one command.

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