Ghosts 'n' Goblins for MSX
What's with this craze about converting ZX Spectrum games 
Is it somewhat an easy task ?
Respectable effort from the converter but ugly games if you ask me !!
Aha!, much better with static colors option active!, now it plays almost as fast as the original version...
Seeing what you can do with a SPectrum port may also just encourage them to show what could be done with a native MSX version!
BTW
I've just tried the game and I have to say that it works well (in bluemsx with an msx2 emulation)
At least level 1 goes quite smoothly and the scroll isn't as jerky as I was expecting (I'm a "bit" prevented against ZX ports 
.
Even if not as nice as it could have been if developed for msx, it is worth a try.
Well done!
Well, well, well... let's start again...
Metalion: why converting ZX games to MSX? First of all, my first MSX was MSX1 and most games were converted... Then I am somewhat fond of ZX Spectrum games. Also, converting games from Spectrum (GnG was my first full conversion) is not easy, but is exactly the kind of challenge I like to face. I was able to convert this game in about three weeks (about 1 or 2 hours a day of work) - not counting the time to gather all Spectrum information I needed - and two more months to add extra features (most time consuming was music, since the music compressor (PSG -> MPM - MPM being a new format that I'll release the specs soon) plus VRAM with Buffer replayer took me almost a month so I made it work flawless and with the minimum CPU requirements. I simply have no time to create a full-fledge game (nor the good will to cope with boring parts of game programming). Besides, I know several guys that like converted games (me included), so... it's just a matter of point of view.
PingPong: In slow computers (e.g. 3.57MHz) the game already runs in "monochrome" mode. The original version of "Static Colors" was plain black and white. But SLotman suggested that I could paint the screen with some colors when the stage starts and then forget the color paint... this has the same "overhead" as a black and white game, and the visual impact is less obvious (in some places, the game even looks like the "full colored" version... Er... I said full colored? Well, whatever it means on a Spectrum game. 
jltursan: the conversion is not slower only because the colors, there are a lot of problems involved, like the game being a 25FPS game on Spectrum, with two-pixel smooth scroll in both directions... this means I had to update the screen almost every interrupt (and, performance wise, this is a disaster!). At 7MHz, the Z80 code has almost no effect as bottleneck, but the game still needs frameskip (4 by 4 scroll) to keep pace with Spectrum speed; the game runs flawlessly without frameskip, but very slowly. And I could not just "forget about the framebuffer, plot directly on the screen", because the game simply uses the framebuffer to calculate the scroll. The game is so crazy that it even uses PUSH DE instructions to *plot the screen faster* on the VRAM. And every shape is shifted in real time to be placed on the screen, since the RAM space available was very tight. Probably these were the reasons why this game was never ported to MSX (despite the fact it is *old*). As far as I could research, almost all games that uses this kind of PUSH DE trick to plot screen were not ported (besides Astro Marine Corps). The difference here is the fact AMC was a 10~15FPS game, was not *fullscreen* and did not used framebuffer in the way GnG uses (well, AMC is, in my perspective, a supreme job of good conversion... I hope one day I will be able to do something like that!
pitpan: on 7MHz the game is "colorfull". Anyway, in Brazil 7MHz computers are far more common than any other MSX. I don't know how easy is the 7MHz update, but I really think it's very worth the effort. I try my best to make things work nice on 3.57MHz computers (I spent a lot of time adding things to speed up game in slower computers - namely MSX1, which forces me to add even more delay between VDP OUTs ), but I am not a magician nor will try to be. More profound changes in the original code would be as complex as rewriting the game from scratch. I will leave this job to those working on competitions like MSXDev or MRC Challenge.
ARTRAG: as Manuel said, I believe it's not a problem. Dvik's demo is very nice and it would be very cool to have a native GnG version for MSX. I love GnG series and I was missing it in my software collection. Since it was a Speccy 48 game - and a very hard to convert, since it was very videospeed-demanding, I decided it was a good place to start, to develop optimized base conversion functions (screen plot, speaker emulator, keyscan etc). But I really think a native GnG would be 1000% better than this port... at least it could be more colorful, faster and COMPLETE, with all levels.
I just like to say that it is very nice to receive comments after so much work, but I really like correcting/adapting games. So, my project is continue to adapt MSX cassete-only to disk (files) and convert some more Speccy games to MSX. I am sorry if some think this is a time waste, but this is what I like to do, and... since I do it in my free time, as a hobby, it is not a waste of time in any level. At least for myself.
By Zezus
Rookie (26)
12-02-2008, 02:00