The Sinclair QL Forum

tofro wrote:Speed reduction:

Note that, even if the contention created by video circuitry eats a lot of memory bandwidth, the 256 and 64k colour modes are way easier (and faster) to handle than the original QL modes:

Setting a pixel in mode 4 or 8 means

• pick the word containing the pixel from video memory
• Create (or reference) a proper mask that addresses the proper pixel in that word
• Clear the pixel to black
• OR in a properly shifted color mask
• write the screen word back to video memory

In modes 16 and 33 you simply move the pixel color to the proper place in video memory as a .B or .S. Done.

So speed is always relative - from a programming viewpoint, the 256 and 65535 color modes are way faster than the original modes 4 and 8. Probably even if you take into account that you need to modify a lot more pixels at higher resolutions.

Tobias

Considering you might want to plot sprites, there is a way to do that extremely fast, without masks, and most of the time with no loading of the 'background' to insert your sprite shape in it.
The reason I want a Q68 is to adapt what I have completed writing for the Archie ('chunky' or linear mode, like for the Q68 screen modes with same layout).
You can watch here if interested :
https://www.youtube.com/results?search_ ... freload=10

Btw : again all this shouldn't be in this thread.
Maybe creating a specific thread 'plotting data on screen with Q68' would make everything more readable and interesting ?

Giorgio Garabello wrote:

Peter wrote:On http://qlheaven.blogspot.de/ I just read the .....

I did not know this site!
Who handles it?

I don't know Giorgio. I wanted to comment regarding wrong Q60 benchmark figures on that site, but feedback requires a profile that I don't have.

He/she seems quite active and interested in Q60, so I hope he/she might read this and show up.
Peter

Zarchos wrote:

tofro wrote:Speed reduction:
Considering you might want to plot sprites, there is a way to do that extremely fast, without masks, and most of the time with no loading of the 'background' to insert your sprite shape in it.
The reason I want a Q68 is to adapt what I have completed writing for the Archie ('chunky' or linear mode, like for the Q68 screen modes with same layout).
You can watch here if interested :
https://www.youtube.com/results?search_ ... freload=10

Off-topic - but darn! That animation looks great, Zarchos! I'm sure we could do even better with the Q68!

martyn_hill wrote:

Zarchos wrote:

tofro wrote:Speed reduction:
Considering you might want to plot sprites, there is a way to do that extremely fast, without masks, and most of the time with no loading of the 'background' to insert your sprite shape in it.
The reason I want a Q68 is to adapt what I have completed writing for the Archie ('chunky' or linear mode, like for the Q68 screen modes with same layout).
You can watch here if interested :
https://www.youtube.com/results?search_ ... freload=10

Off-topic - but darn! That animation looks great, Zarchos! I'm sure we could do even better with the Q68!

I think so too.
Glad you understood it flickers because of absence of bank switching, and that the colour in the border shows the time taken
to load each time the sprite 'data' and plot them.
But I'll need the help of 68000 programmers here because ahem my 68xxx is rather ... rusted ;-(

Is anybody else but me interested in a highcolour arcade game for the Q68? Or is this totally unrealistic, after no QL arcade game was written in two decades? It sounds like Zarchos optimized routines could help. Could money be an incentive? Something like a mini-kickstarter where 10 people pledge 100€ each? Or is there another way we could motivate someone? (Off-topic again, sorry Derek! I'll start a new thread if there is interest.)

Sounds great!!

Sorry Peter, that would not be of interest to me. I'm crap at games, alway was. It's how I got into assembly programming. I had to buy Hisoft Devpac 3 for my Spectrum to hack Jet Set Willy and Manic Miner to get infinite lives just so I could get off level 1! I still failed to progress, even with infinite lives.

I have not got a Wii, xbox, play station etc.

Cheers,
Norm

It was worth hacking JSW just to get past Martha wagging her finger! Oh, halcyon days!

Oops - off topic again...

NormanDunbar wrote:I had to buy Hisoft Devpac 3 for my Spectrum to hack Jet Set Willy and Manic Miner to get infinite lives just so I could get off level 1! I still failed to progress, even with infinite lives.

It's a matter of speed! The Q68 has hardware SLUG

Peter wrote:Is anybody else but me interested in a highcolour arcade game for the Q68? Or is this totally unrealistic, after no QL arcade game was written in two decades? It sounds like Zarchos optimized routines could help. Could money be an incentive? Something like a mini-kickstarter where 10 people pledge 100€ each? Or is there another way we could motivate someone? (Off-topic again, sorry Derek! I'll start a new thread if there is interest.)

Please start a new thread, as yes I am interested, in particular if it is a community project.
To me, incentive is the key to dev on retro systems.

I hope what I did is doable for a 68000 based system, but I believe so.
I believe in 2 byte per pixel 'low res' screen mode, the QL68 should be faster than a 12 Mhz Archie in 1 byte per pixel 320 x 256
(just a belief as I haven't really checked the timings, I was just working with timings of a 68000 at 40 Mhz, here we have something different. I'll edit this post later).

What you propose is what I intend to do, more generally, for numerous machines.(but probably excluding the Amiga).
Expect some kind of majeur announcement from me, in let's say, less than 200 hours now on my YT channel.
1st step should be completed at this date. There are many more and they will take time.
But hey from an acorn to an oak, it takes some time.
I had a great opportunity I think I just couldn't miss.
You'll see