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Xenox
Registered: Jun 2003
Posts: 87 |
Datastorm Demo effects - awesome!
I'm really shocked about the very good quality of the demos released at the Datastorm2014, really, really great stuff, the gfx are amazing with very good code and music...!
I really, really, like the bg Datastorm bitmap picture in "We are all connected" at the beginning...
My question is, how do they do that moving the bitmaps... i'm really impressed...!
We Are All Connected
Frank |
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algorithm
Registered: May 2002
Posts: 705 |
Quoting PerplexQuoting algorithmIf you need more cpu time for other things, then 1 pixel scroll per frame should be much more than sufficient.
Unless you want to do loading, decrunching and perhaps some other stuff at the same time, of course.
Why would that be an issue? :-) |
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JackAsser
Registered: Jun 2002
Posts: 2014 |
Guys... come on.
A hires bitmap is 9000 bytes colors included. If you move in 25fps like in the demo you will have 16 frames to render a new offscreen page scrolled one char. In total you'll need to perform 9000 lda+sta = 9000*8 = 72000 cycles. Divided on 16 frames => 4500 cycles per frame. I.e. about 20%-25% of available CPU-time. I.e. LOTs of time left for anything else, loading included. |
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TPM
Registered: Jan 2004
Posts: 110 |
Quote: Quoting algorithmIf you need more cpu time for other things, then 1 pixel scroll per frame should be much more than sufficient.
Unless you want to do loading, decrunching and perhaps some other stuff at the same time, of course.
i know the feeling ;) did lda/sta, 2 frames in http://csdb.dk/release/?id=105226, takes almost half the screen .. but like We Are Connected it's not thát hard.. memory management is harder, i think. |
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Perplex
Registered: Feb 2009
Posts: 255 |
Quoting TPMmemory management is harder, i think.
Indeed. |
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Perplex
Registered: Feb 2009
Posts: 255 |
Quoting JackAsserIn total you'll need to perform 9000 lda+sta = 9000*8 = 72000 cycles. Divided on 16 frames => 4500 cycles per frame. I.e. about 20%-25% of available CPU-time. I.e. LOTs of time left for anything else, loading included.
Yup, plenty of time, I have not claimed otherwise.
Double the scrolling speed though, and not only do you have to spend twice as many cycles on moving bitmap and screen data, you also have to load and decrunch new data twice as fast to keep up with the scrolling, and with much less free cpu time in which to do it. |
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JackAsser
Registered: Jun 2002
Posts: 2014 |
Quote: Quoting JackAsserIn total you'll need to perform 9000 lda+sta = 9000*8 = 72000 cycles. Divided on 16 frames => 4500 cycles per frame. I.e. about 20%-25% of available CPU-time. I.e. LOTs of time left for anything else, loading included.
Yup, plenty of time, I have not claimed otherwise.
Double the scrolling speed though, and not only do you have to spend twice as many cycles on moving bitmap and screen data, you also have to load and decrunch new data twice as fast to keep up with the scrolling, and with much less free cpu time in which to do it.
Well... that's why you don't normally scroll in 50fps for a bitmap scroller unless you resort to VSP. |
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Killsquad
Account closed
Registered: Jun 2005
Posts: 17 |
Quoting JackAsserWell... that's why you don't normally scroll in 50fps for a bitmap scroller unless you resort to VSP.
Which takes us back to square one (or post 10) ;-)
Quoting PerplexQuoting algorithmIf you need more cpu time for other things, then 1 pixel scroll per frame should be much more than sufficient.
Unless you want to do loading, decrunching and perhaps some other stuff at the same time, of course. |
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JackAsser
Registered: Jun 2002
Posts: 2014 |
Quote: Quoting JackAsserWell... that's why you don't normally scroll in 50fps for a bitmap scroller unless you resort to VSP.
Which takes us back to square one (or post 10) ;-)
Quoting PerplexQuoting algorithmIf you need more cpu time for other things, then 1 pixel scroll per frame should be much more than sufficient.
Unless you want to do loading, decrunching and perhaps some other stuff at the same time, of course.
No, square 1 was:
"My question is, how do they do that moving the bitmaps... i'm really impressed...!"
No magic, just 25 fps and lda+sta which gives plenty of time for load and decrunch.
BUT, if you want 50fps you need something else, but that's not square 1. ;) |
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enthusi
Registered: May 2004
Posts: 677 |
Hehe, I did bitmap scroll in 2014 too!
The Forest Deep |
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algorithm
Registered: May 2002
Posts: 705 |
I used it in the intro of Sabrina - The Demo
Large multiple screen tall bitmap with inline decompression in Algotecher
and in mcol-ci interlaced mode in Demolicious (Which needs to process twice the amount of pixels) |
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