Hi community,

I was watching some old-days demos done by some MSX masters. Some of these demos feature a rotating cube or a sinus wave moving very smoothly on the foreground while the background remains intact.
What's the trick behind that? How can you give this rotating box, sinus wave, etc. the quality of a sprite which can move without destroying the background while maintain very smooth motion???

Fast copy, paste involved? Please somebody explain.

this should in the development section I believe.

Are you talking about the vector demos or the demos which featured scroll with a picture or anything like that?

name some demos please

If you are referring to those rotating squares in Unknown Reality, that's simply page cycling..

Ppl did tricks with color-cycling as well, or stretching the screen using screensplits, or waving the screen using scroll-registers and screensplits..

the key-rule is: if it looks good on an MSX, it's a trick.

Except if I wrote it

..yeah, than it's a pile of crap!

Quote:

Hi community, I was watching some old-days demos done by some MSX masters. Some of these demos feature a rotating cube or a sinus wave moving very smoothly on the foreground while the background remains intact. What's the trick behind that? How can you give this rotating box, sinus wave, etc. the quality of a sprite which can move without destroying the background while maintain very smooth motion??? Fast copy, paste involved? Please somebody explain.

What demo are you talking about ? Different techniques are used in different demos... In most cases it's a visual "trick" as Wolf said.

Quote:

..yeah, than it's a pile of crap!

Of course it's a visual trick ,
And Yes I'm talking about 'Calculus' and 'MSX 21 Anniversary Demo', and all other text-scrooling stuffs.
I saw some games on PC featuring multi-plans scroll, and of course it's a visual trick, or does the video card support mutli-plans?
I just wonder how these tricks could be done with my slow, very-resource-limited, poor MSX.
And what is page-cycle anyway?

Best regards to all

we don't have multilayers ... only the GFX9000 has native multilayers.. if things look like a multilayer (take level 1 from Space Manbow for example) then it's a trick again

page-cycle is: we have 4 pages in screen 5, each page displays a frame of a rotation, when we cycle through those pages, you can see the 'rotation' in action..

"If it looks good on MSX, it's a trick" - Don't you think that's a bit negative? As if it's a bad thing to use tricks, or as if it's not hard to think of which tricks to use to accomplish the effects you want to show. Coding visually stunning effects on MSX is pure art, dude

Don't know about Calculus but in 20th Anniversary MSX demo it works like this:

The Rotating cube over checkboard is Magnified sprites (mode 2) made of 2 layers (3 colors). So it's 4*32(*2 layers) pixels wide = 128 pix wide. The background is screen 4 redefined patterns.

For the big scrolly on the checkboard, it's screen5. The checkboard underneath the scroll is made of different colors (12341234...) and it is also scrolling but because the color palette is being redefined, it looks like it's not moving... So it's definetly a trick. Wicked

Well, any program in BASIC to illustrate the concept of page cycle showing a moving object on a background of a landscape for example?

Not really a full Basic example but it is quite easy to create. In plain text:

You have your background picture, you load it on page 3 (screen 5)
You have the calculations to draw a vector image, like a rotating cube.
You copy the background image to pages 1 and 2
On page 1 you draw the first frame of the cube onto the background image
You make page 1 the active page
On page 2 you draw the second frame of the cube onto the background image
You make page 2 the active page
You copy the blank background that is still on page 3 to page 1
You draw the third frame of the cube on page 1
You make page 1 the active page
You copy the blank background that is still on page 3 to page 2
You draw the fourth frame of the cube on page 2
etc. etc. etc.

Another much used solution is to pre-calculate the vector image and use sprites to create the illusion of a real-time 3D calculated vector shape. The vertex balls used in ANMA's most amazing demo (was it the Source of Power?) are done that way. Only in one part of the demo do they have one actual real-time vertex ball.

it was RELAX, and Magoo/IOD OR Michi (can't remember) did that trick later in another demo a bit bigger

Euhm, nope, Relax looked definitely quite a bit more impressive than the SWISS demo. Especially since Relax was an ordinary MSX2 demo after all