Gasman demo
in [Commodore]
|
Prev: MPS 1270A compatibility
Next: plus/4 GEOS questions
From: The Starglider on 17 Jan 2006 11:51 On Tue, 17 Jan 2006 15:25:49 +0000 (UTC), Pasi Ojala <albert(a)pikkukorppi.cs.tut.fi> wrote: >On 2006-01-17, The Starglider <thestarglider(a)wibble.co.uk> wrote: >> That's just nonsense though. If that were the case, any television in PAL >> territories would look wrong, which it doesn't. > >PAL is 50 Hz. Every sports show is 50Hz interlaced. Yes, but it's two of the same image interlaced, so the result is a total of 25fps. > >Especially C64 is 50 Hz. > >> Hell even Star Wars in the >> cinema wouldn't work by your theory, since that ran at only 24fps. > >Actually, 24fps IS very jerky. Take a look at any movie and pay >attention to camera pans. Or if you haven't noticed it already, >maybe you should not pay attention, because it may ruin your >cinema experience. Maybe not completely and maybe not forever. > >Some people don't see it. Fortunately top-of-the-line televisions >upconvert film material to something more appropriate, like 75 Hz. >(Motion detection and interpolation are required.) > I did an experiment here: http://www.thestarglider.pwp.blueyonder.co.uk/fps/ Here you will find 4 videos of exactly the same thing, each running at 17,24,25 and 30fps. Each video is 15 seconds long, and are encoded in XVID format. You can see that even at 24fps, a pan of a cube across the screen is smooth. Hell, even at 17fps (generally accepted to be the lowest you can move something and fool the human eye into smooth motion), the cube moves with quite acceptable smoothness, so your theory of a pan in film is quite wrong. -- **************The Starglider*************** Public E-Mail. * http://www.starglider.dynu.com/radio * Ask for private * Starglider Radio - listen and enjoy! * address. * E-Mail:the_starglider2002(a)wibble.co.uk * _WW_ * CHANGE WIBBLE TO YAHOO TO REPLY * /_ _\ ******************************************* | O O | _____________________________________________________oOO_\/_OOo_____
From: Nick Humphries, via obd on 17 Jan 2006 11:50 On Tue, 17 Jan 2006, Jason wrote: > i seem to remember > the C64 price in the U.K. dropped significantly when they started > manufacturing over here as well, especially when the short-lived Corby plant > went live. That would make sense - how short-lived? Also was the C64 ever a loss-leader? I'm guessing probably not, although C= themselves *were* losing money hand over fist most of the time... -- Nick Humphries, nick(a)egyptus.co.uk http://www.egyptus.co.uk/ Your Sinclair Rock'n'Roll Years http://www.ysrnry.co.uk/ YSRnRY documentary (1985 OUT NOW) http://www.ysrnry.co.uk/tvprog/ The Tipshop http://www.the-tipshop.co.uk/
From: W Marsh on 17 Jan 2006 11:59 On Tue, 17 Jan 2006 16:51:36 GMT, The Starglider <thestarglider(a)wibble.co.uk> wrote: >On Tue, 17 Jan 2006 15:25:49 +0000 (UTC), Pasi Ojala ><albert(a)pikkukorppi.cs.tut.fi> wrote: > >>On 2006-01-17, The Starglider <thestarglider(a)wibble.co.uk> wrote: >>> That's just nonsense though. If that were the case, any television in PAL >>> territories would look wrong, which it doesn't. >> >>PAL is 50 Hz. Every sports show is 50Hz interlaced. > >Yes, but it's two of the same image interlaced, so the result is a total of >25fps. > >> >>Especially C64 is 50 Hz. >> >>> Hell even Star Wars in the >>> cinema wouldn't work by your theory, since that ran at only 24fps. >> >>Actually, 24fps IS very jerky. Take a look at any movie and pay >>attention to camera pans. Or if you haven't noticed it already, >>maybe you should not pay attention, because it may ruin your >>cinema experience. Maybe not completely and maybe not forever. >> >>Some people don't see it. Fortunately top-of-the-line televisions >>upconvert film material to something more appropriate, like 75 Hz. >>(Motion detection and interpolation are required.) >> >I did an experiment here: > >http://www.thestarglider.pwp.blueyonder.co.uk/fps/ > >Here you will find 4 videos of exactly the same thing, each running at 17,24,25 >and 30fps. Each video is 15 seconds long, and are encoded in XVID format. You >can see that even at 24fps, a pan of a cube across the screen is smooth. > >Hell, even at 17fps (generally accepted to be the lowest you can move something >and fool the human eye into smooth motion), the cube moves with quite acceptable >smoothness, so your theory of a pan in film is quite wrong. The cube is moving very slowly - this isn't a very good example.
From: Jason on 17 Jan 2006 12:22 A936(a)hotmail.com wrote: > Actually I was thinking of the raster tricks being played > to get more than the supported 8 sprites, since the context > was a 24 sprite demo. To play any raster tricks you have > to do things each frame or there will be flicker. Am I okay > now :-) ? Well, one sprite takes less than one scanline to position or reposition, so it's hardly a massive overhead. If the multiplex isn't moving, some of the really good ones'll even disable the sort to save CPU time time and the pre-sorted systems usually used in demos don't have that overhead to start with. [Regarding moving more than once a frame] > Every frame update is important if you have very fast moving > objects on screen, but that is almost never the case because > the game would be impossible to play. Most shoot 'em ups on the C64 will move objects at two, four sometimes even eight pixels a frame, Uridium for example has a top speed of about eight pixels a frame (oh, and it uses software sprites for the bullets and background starfield so i believe it can do around 16 sprites a scanline and is capable of more, s'just that the bullets are spread out vertically =-) so if the sprites are travelling in the opposite direction as the player they can be doing upwards of twelve pixels a frame. > Just FYI: I am not aware of a single Spectrum game that > is full frame rate. The games known for their ultra smoothness > (Zynaps, Ghouls 'n' Ghosts come to mind) are updated every > two frames and are not the worse for it. Certainly have a peak > at Zynaps as it's worth a look for its scrolling. i'm pretty well versed with Spectrum games and have played Zynaps and R-Type (another good example for the scrolling, i thought) quite a bit. And no, i've not seen a game scroll a significant amount of screen at full framerate, but i believe lots of static screen titles move their sprites either every or every other frame; our own first Spectrum game Reaxion (a port of the C64 original) runs every frame, for example. [About software compared to hardware sprites] > 96 times or 112 times what? More bytes transferred per sprite; moving a C64 sprite takes at most three writes to memory and to get as close an equivalent as possible in software the routine needs to read the background, AND mask, OR in the data and write and then repair the damage. EOR'd or unmasked soft sprites are faster (although still nowhere near as fast as software sprites) but it's probably best to consider them "cheating" if the claim is they're as good as hardware - they're taking a *significant* hit of CPU power, so they're not. > Those are big numbers but I think you are seriously overestimating the > processor equivalent of the c64 sprite hw. Actually, i'm *under* calculating because i'm assuming 16x16 pixel objects at the Spectrum end; that's only two thirds the size of the C64's hardware sprites. My roughed maths didn't take into consideration live pixel shifting (i pre-roll my software sprites for speed) of the sprite data, configuring the read/writes or anything else like that either. > Anyways, go ahead and up the speed to 100 times and > see the blazing fast motion in the demo. So no, I don't > think the cpu needs to be 96-112 times faster to > match the c64 sprite hw :-)) You're not really getting the point; to move a sprite up, down, left or right can, if the MSB isn't considered for a moment, take as little as six cycles, one DEC or INC command to the appropriate register. With 63 cycles a scanline that's all eight sprites moved in that one scanline and even with the MSB in use and some more complex calculations that leaves over scanlines 300 left to do things like scroll the screen, plot software sprite bullets, run the game logic, whatever else is needed > With 8 hw sprites, it would seem to me to be impossible > to have more than 8 in the same raster at the same time. > Which is why I find moving 24 sprites in a sinusoidal shape > a little disingenuous for even a "like for like" comparison. > Maybe it would be more interesting just to have 24 > sprites moving up and down on the same pixel row? For game use, the chances that every single sprite wants to exist on the same scanline are pretty low and, if there are cases where more sprites are needed per line, there's nothing to stop the C64 resorting to software sprites as well or more commonly a mixture. i've already mentioned Uridium and that does properly masked sprites for the bullets, but try Salamander on the C64 as well - the player's bullets are software sprites that "cheat" and move in character steps for speed but there's still a *lot* per a scanline sometimes if you bunch the multiples up under the ship. Salamander lobs more than eight hardware sprites around, scrolls almost the entire screen and still moves at full framerate unless things get really busy. And for demo use, cheat like *buggery* and hope the viewer doesn't notice. =-) -- ______________________________ _________________________________ / /\/ ___/ / ___/ / / ___/\ / Website: www.cosine.org.uk / / /\_/ / /__ / / / / __/\\/ / ICQ: 44373717 IRC: TMR{C0S} / / /__/ / / / / / / / / /\ /_____________________________/ /_____/_____/_____/__/__/__/_____/ / \_____________________________\/\_____\_____\_____\__\__\__\_____\/TMR
From: The Starglider on 17 Jan 2006 12:26
On Tue, 17 Jan 2006 16:59:41 +0000, W Marsh <wayne.marsh(a)gmail.com> wrote: >On Tue, 17 Jan 2006 16:51:36 GMT, The Starglider >>> >>I did an experiment here: >> >>http://www.thestarglider.pwp.blueyonder.co.uk/fps/ >> >>Here you will find 4 videos of exactly the same thing, each running at 17,24,25 >>and 30fps. Each video is 15 seconds long, and are encoded in XVID format. You >>can see that even at 24fps, a pan of a cube across the screen is smooth. >> >>Hell, even at 17fps (generally accepted to be the lowest you can move something >>and fool the human eye into smooth motion), the cube moves with quite acceptable >>smoothness, so your theory of a pan in film is quite wrong. > >The cube is moving very slowly - this isn't a very good example. Okay, faster versions are now available to view. Do remember this though, a movie shown on a TV is shown at the framerate of the TV system it's on. In the UK, television stations will show a 24fps film at 25fps, and the same happens to NTSC areas too. So anyone who is thinking of looking carefully at a video (DVD is fine) will not get an accurate comparison. Also, these videos are not interlaced. That can have an effect on quality too (applies to all videos except films in the cinema, they are not interlaced). -- **************The Starglider*************** Public E-Mail. * http://www.starglider.dynu.com/radio * Ask for private * Starglider Radio - listen and enjoy! * address. * E-Mail:the_starglider2002(a)wibble.co.uk * _WW_ * CHANGE WIBBLE TO YAHOO TO REPLY * /_ _\ ******************************************* | O O | _____________________________________________________oOO_\/_OOo_____ |