i have noticed that hardly any of the cd-rom2 or super cd-rom games that i have played have any parallax scrolling compared to the hu card games which seem to have a ton. can any tec-savy pc-engine owners out there explain this?
It's just the selection of games you've played. There are many CD games that have backgrounds which are good to go for Air Zonk style parallax, which requires no extra graphics (
unless they want the odd overlap using non animating sprites)... but I guess the developers were just clueless on how to do it.
The type of overlapping backgrounds that the PCE doesn't have hardware support for the way that the MD and SFC do, is usually achieved with animated background tiles (Ninja Spirit stages 1 & 2).
The problem overall was development tools. Across the different PCE formats, it seems that every developer only knew how to do
some tricks, but very few games do most. Now every game doesn't need to cram in special effects just for the sake of it, but I'm talking about games where it stands out that a particular effect should be used... and often the same game will have something else spectacular going on elsewhere that seems less common than the missing effect.
In theory, if all developers knew how to do everything, you'd likely see more animated tile effects in CD games than HuCards, because overall space wouldn't be an issue. Based on my own experience having played most PCE games, I think it's safe to say that there are more CD games than HuCards that have parallax. But many parallax friendly games aren't well known to most people (
neither is the PC Engine for that matter 
).
uh....from a tech point of view....i don't see any reason why a hucard can out perform a CDrom game (aside from the loadtimes). Hucards top up at 16 or 20 with StreetFighter2 being the big one, and CDrom games measuring in at 500-600megs? The only thing could be some companys got lazy and wasted all the memory on a CD, and just plugged it with nice cut scenes and music, where the HUcards they had to use some smart programming to really pump out the most they can get out of a HU, IMO. 
HuCards actually have a
huge advantage over CDs and the only limitation HuCards have is economic. CD games are technically limited by the amount of space they get to fill up in a single load. A Super CD can use 4 times as much as a CD2 game and an Arcade Card game can use 36 times as much as a CD2 game. A HuCard is
limitless. Bank switching (or something) was required when the memory size limit was reached, same as MD & SFC carts, but in theory you could have a 1TB HuCard that can access any part of the rom at any time (
although still limited by the hardware bottlenecks that also affect CD games).
Street Fighter II' is the perfect example. A straight port of the SFC model couldn't be done on Super CD within it's 2 meg space. I believe that SFII home ports needed the sprite frames to be uncompressed to run fast enough or something. An Arcade Card port could've looked "arcade perfect" for the time and could almost fit the entire SFII' HuCard within a single load.
Topic: a serious question about parallax scrolling in super cd-rom games (Read 1217 times)