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Old 19 February 2015, 08:21   #131
Join Date: Jan 2012
Location: Serbia
Posts: 275
Originally Posted by Photon View Post
Just make sure you only post videos (or better, binaries for real vanilla Falcon030 or any cycle-exact emulator) if you intend to make comparisons - just so that others can validate any claims about how fast it runs. You absolutely have to know that it runs at this speed on real hardware.
yes, I already make mistake claiming that one of DHS demos is recorded on ST but in fact, it was recorded on 16MHz Falcon. You are absolutely right.

and I ask what are 3D demos for A1200+FastRAM because many videos lack of this information and I do not have A1200 (have no space to set it up) to try it by my self. e.g. looking at video of Nexus 7 at youtube, to me and to some Atari coders, it looks like it runs on 50MHz 030 (I know it is 14MHz 020 with FastRAM)!

Many people here help me to track A1200+FastRAM demos and I am very grateful for that.

Originally Posted by Photon View Post
That said, the A1200 was a 32-bit computer hampered by bitplane graphics, and the Falcon was still on 16/32-bit but with 16-bit chunky mode which lends itself to exactly the effects that were popular then, and it had a DSP. I don't think many would think it strange that this hardware advantage resulted in better demos, if that's the case. It has certainly been the story both before and since.
and because of this Falcon advantages (chunky mod) and DSP I did not expect that A1200 with FastRAM would be so close to what Falcon can do.

I am trying to understand how things work.
DSP at Falcon can be used at many different ways when come to 3D: Escape made entire 3D engine, including video frame buffer, on DSP:
(ST conversion of same scene by DHS: [ Show youtube player ])
but DSP, in DMA mode can transfer around 800KB/s to main memory. If you employ CPU than you can get around 3,5MB/s so there are many, many different ways to use it since limitation are numerous! Plus DSP is quite bad in logic operation and branching.
...on atari-forum, in same thread, are technical details - I came here to also learn technical details how Amiga coders achieve such impressive 3D stuff on 14MHz 020.

I did not know that A1200 chip bus is clocked only on 7,xxMHz and I still do not know what is speed of A1200 FastRAM.
Is chunk mode necessary if you dealing with 3D and textures or they are some clever ways to use Amiga custom chips to make it faster (like not so clever but obvious, movep on ST for moving pixels from chunk buffer to bitplanes)?
How much time A1200 spent on C2P?
How Amiga coders move pixel data from chunk memory to bitplanes? Is there any tricks to speed this up?

btw I also would like to know how Checkpoint made Thunderdome 3D [ Show youtube player ] ||
that are quite few polygons on models: - 92-130 triangles.
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