Author Topic: ChinnyVision - A new Youtube Channel  (Read 2692 times)

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Offline MacDeath

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Re: ChinnyVision - A new Youtube Channel
« Reply #25 on: 10:28, 22 June 14 »
Sorry that this topic derailed into another speccyport analizis  :laugh:
Quote
32x16 characters, but only uses 28x15.5 characters of it for the CPC.
is this because of the border frame ?
you know, the red frame around the playfield ?
seems to be 4 characters (2x2) on the sides and 4 black lines (2x2) vertically.


From all we say, it really seems this game is a pure CPU waster...
If the speccy version has some free space on the 48K, I guess a proper CPC version in 64K may even be able to perform real double buffering.

Just don't use a 1bpp pre buffer in addition to screen RAM and you gain almost 1/2 screen in RAM.

Also I guess that to get rid of the side-frame may help as well.
the screen RAM would need 1 common HUD zone, and 2 playfield zones (double buffer) that would be reduced in size anyway, and just re-address when you come to the scanline for the playfield or the HUD.

with double buffering you may then use another scrolling method, have quite more smooth animation or whatever.

But not sure all this would fit the 64k.
got to check the weight for all the graphic tiles, be it in speccy or CPC format...

8bit wars style
www.youtube.com/watch?v=nDUccFcY25w

Amstrad CPC
www.youtube.com/watch?v=uMnUKhcfhgU

Speccy
www.youtube.com/watch?v=4t7adS-1Kx8


funny, the Speccy version actually featues some sort of paralax : on the lower part of the playfield there is a character line running at different speed than the rest of the screen.
Also is it me or youtube glitches, or does the starfield react differently on both version ?

seems some stars can be seen through the dithered foreground on some levels on CPC... but not on speccy...

Actually this port needed quite a lot of modifications on CPC.

« Last Edit: 11:01, 22 June 14 by MacDeath »

Offline TMR

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Re: ChinnyVision - A new Youtube Channel
« Reply #26 on: 11:09, 22 June 14 »
I guess on the original Spectrum the process avoids both flicker and tearing with that kind of screen size, if that's what you meant?

Not exactly, i was assuming that it builds a back buffer elsewhere in memory over one or two frames and then spent the next frame racing the raster to dump that into display RAM so, apart from the conversion, not much different to what the CPC code is doing.

is this because of the border frame ?
you know, the red frame around the playfield ?
seems to be 4 characters (2x2) on the sides and 4 black lines (2x2) vertically.

The play area is already a reduced area on the Spectrum - my estimate previously of a 224 by 128 pixel (28 by 16 character) area is based on a quick screen grab from there rather than the Amstrad.

If the speccy version has some free space on the 48K, I guess a proper CPC version in 64K may even be able to perform real double buffering.

Just don't use a 1bpp pre buffer in addition to screen RAM and you gain almost 1/2 screen in RAM.

Also I guess that to get rid of the side-frame may help as well.

Quoted because this is what i was thinking too. If i had the Z80 skills... =-)

Offline MacDeath

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Re: ChinnyVision - A new Youtube Channel
« Reply #27 on: 11:33, 22 June 14 »
Quote
Quoted because this is what i was thinking too. If i had the Z80 skills... =-)
Lol i don't even have any z80 skill, just guessing with my crude logic knowledge...

This said I guess then framed the game on CPC in a way to get more colours on screen and cheat the fact they reduced even more the playfield.

perhaps a way to get it running not too sluggish or to get it actually work in 64k.

I mean :

speccy :
32x16 characters = 256x128 = 512 characters
was a classical small playfield size on speccy... this 1/3 HUD was a cheap way to gain on both CPU or RAM as it doesn't scroll, use less tiles, rarely changes colour attributes and so on...

on CPC :
28x15.5(chars) = 224x124 = 434 characters in playfield
this makes up for quite less characters/bytes to convert/move/scroll...
512-434 = 78 chars less to handle...
This said I think they reduced the playfield a whole vertical character from the speccy : the line which scroll at  different speed. got to measure it more properly I guess... ;D

 on CPC, framing the playfield was probably a way to :
=cover the scrolling decal
=add some colours
=visual impact : you less see that the screen is freaking small
=limit the fact the border is black as well so graphics don't seem to appear from nowhere...

look at kickoff on Atari ST :
www.youtube.com/watch?v=bwmK9QyTXAw
half assed effort :
the rasters for the border make you believe there is no border but the display actually appears from nowhere...
I prefer when border is a real border : other colour so you can clearly see the limit...
If playing on a good monitor you could magnify t he screen so there would be no border, on a TV you could not and it was not good to not see the real limits of the screen I think.

« Last Edit: 11:51, 22 June 14 by MacDeath »

Offline Axelay

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Re: ChinnyVision - A new Youtube Channel
« Reply #28 on: 16:03, 22 June 14 »
Not exactly, i was assuming that it builds a back buffer elsewhere in memory over one or two frames and then spent the next frame racing the raster to dump that into display RAM so, apart from the conversion, not much different to what the CPC code is doing.

Hmm, I'm not sure that's different to what I meant either.  :)



speccy :
32x16 characters = 256x128 = 512 characters
was a classical small playfield size on speccy... this 1/3 HUD was a cheap way to gain on both CPU or RAM as it doesn't scroll, use less tiles, rarely changes colour attributes and so on...

TMR is correct about the spectrum version being reduced from 32 chars wide to 28 already.  I incorrectly assumed from the 32 character wide back buffer on the CPC version, and the Spectrum version appearing to have less border on the sides, that it had been the full 32 characters wide on the spectrum.  Going back and counting the tiles, I'm seeing only 14 tiles across, and they're 16 pixels wide so it looks like the only difference with CPC screen size is it being shorter half a character & missing the little parallax effect layer.

Offline Gryzor

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Re: ChinnyVision - A new Youtube Channel
« Reply #29 on: 18:57, 22 June 14 »
Kick Off on the ST a "half-arsed effort"? Lol...

Offline MacDeath

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Re: ChinnyVision - A new Youtube Channel
« Reply #30 on: 19:34, 22 June 14 »
never liked those footies games... :P I'm not into foot fetishism...

Offline Gryzor

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Re: ChinnyVision - A new Youtube Channel
« Reply #31 on: 20:25, 23 June 14 »
That's not KO's fault, then :p