Edge Grinder Scrolling Routine

[Axel]

Hello folks. 

You probably also know the 1-level demo of the horizontal shooter game "Edge Grinder" or "Super Edge Grinder", which came out around 2011.
To this day I think it's a shame that it never became a complete game with several levels, a few extra weapons and so on.

Because the scrolling of this game is phenomenal, you could also say in C64 quality. 
In addition, it also has beautiful graphics and very good in-game music.


Also I wanted to ask whether the technology behind this scrolling is now in a drawer forever or whether it will one day be used again?
I would also be interested in the limitations of this technology. 
Edge Grinder doesn't seem to compromise on colors, the sprites also seem large enough, although perhaps the number is limited?

[trocoloco]

Without a doubt Edge Grinder was conversion was coded by @Axelay, with masterful knowledge of the CPC and its CRTC scrolling capabilities, and not everything is lost!
The source code is available for everyone to check it out and learn from it and hopefully be used for new games. It can be downloaded at cpc-power or cpc-rulez just by searching Edge Grinder 

[andycadley]

It wasn't really a demo, but part of a sort of mini competition. The idea was that people would implement the same basic game on different platforms to try and compare them. The Speccy version never quite surfaced I don't think and the idea never progressed to other titles (and won't now with the passing of TMR)

The actual scrolling is a well known technique using R3 to increase the resolution of horizontal hardware scrolling. Other games could use it, though it's not without its complexities.

[dodogildo]

Indeed, CPC version looks great. It scrolls as good as C64 (maybe slightly better): 

C64:
https://www.youtube.com/watch?v=z0jw2MuMthE
CPC: 
https://www.youtube.com/watch?v=BcZ7-E7Mx-Y

[jesusdelmas]

Indeed, CPC version looks great. It scrolls as good as C64 (maybe slightly better):

C64:
https://www.youtube.com/watch?v=z0jw2MuMthE
CPC:
https://www.youtube.com/watch?v=BcZ7-E7Mx-Y

Yes! The cpc has a little better scrolling and a more vibrant colors than the c64 i didnt know that

[Axelay]

I would also be interested in the limitations of this technology.
Edge Grinder doesn't seem to compromise on colors, the sprites also seem large enough, although perhaps the number is limited?

I guess the most obvious limitation is that using R3 wont work on most/all flat panels, or through some modulators I believe.  From a game design point of view, the particular technique used (not related to using R3) does make stopping/starting the scrolling a challenge, depending on other requirements.

As it stands it is doing as much as it can with the sprites you see at 25fps with little free cpu time to spare.  But it has been built around the original C64 design, so even though the game mostly takes place against a largely blank background with foreground that is mostly avoided by the sprites, it still had situations where all sprites could overlap graphical background, so it is blanket preserving/restoring background for all sprites at all times.

A more CPC specific design would be to ensure only the player sprite needs to preserve background and so free up a lot of time by only needing to blank other sprites old positions.  There are other options for making speed gains as well, though most come with there own considerations to deal with, but increasing the sprite count would absolutely be possible.