Search found 141 matches

by metalages
Mon Feb 17, 2020 7:26 am
Forum: Coding
Topic: Decreasing colours (algorithm)
Replies: 17
Views: 1058

Re: Decreasing colours (algorithm)

by metalages
Wed Feb 12, 2020 7:09 am
Forum: Games - General
Topic: Lotus Esprit Turbo Challenge - STE enhanced (WIP)
Replies: 51
Views: 10642

Re: Lotus Esprit Turbo Challenge - STE enhanced (WIP)

Blitter is good at interleaving and looping. My thought was using DmA in stereo. One channel for each player (if I well understand the need). Revs need to be stored interlaced then use shift and masks to do the right thing.
by metalages
Tue Feb 11, 2020 9:22 pm
Forum: Games - General
Topic: Lotus Esprit Turbo Challenge - STE enhanced (WIP)
Replies: 51
Views: 10642

Re: Lotus Esprit Turbo Challenge - STE enhanced (WIP)

Glad you like the engine sound! Happy to sort the other sound effects too if wanted. There are some lines in that source I commented out (lines 61, 105, 107, 121, 122, 124, 126 and 138), if they're uncommented you'll get more steps but it's a bit clicky because it has to restart the sample, otherwi...
by metalages
Mon Aug 26, 2019 8:16 pm
Forum: Demos - General
Topic: "We Were @" demo question
Replies: 19
Views: 4401

Re: "We Were @" demo question

:) thanks for the great work :)
by metalages
Mon Aug 26, 2019 6:22 pm
Forum: Demos - General
Topic: "We Were @" demo question
Replies: 19
Views: 4401

Re: "We Were @" demo question

troed wrote:Ok. Sounds like there indeed are a bunch of 2MB STEs - so at least that work was in order :) Also shows that not all effects were just animations from RAM ;)


yey

smaller ram implies more real time ;)
by metalages
Mon Aug 26, 2019 6:25 am
Forum: Demos - General
Topic: "We Were @" demo question
Replies: 19
Views: 4401

Re: "We Were @" demo question

I have 2mb on my ste ;)
by metalages
Tue Aug 13, 2019 9:26 pm
Forum: Discussion
Topic: Using 4096 colours
Replies: 20
Views: 12241

Re: Using 4096 colours

Speaking of DML's work, there is also the other 16 colors approach using his Cryptochrome tool.
by metalages
Fri Aug 09, 2019 1:14 pm
Forum: Discussion
Topic: Using 4096 colours
Replies: 20
Views: 12241

Re: Using 4096 colours

You can have a look at this piece of software by Zerkman
https://github.com/zerkman/mpp
by metalages
Thu May 30, 2019 7:17 am
Forum: C / PASCAL etc.
Topic: Pure C (demo) coding
Replies: 18
Views: 12653

Re: Pure C (demo) coding

I have shared some source here https://github.com/gibs75/demOS
It is a mix of pure c and asm. I have made a customized version of startup code in order to compile without any standard lib and being able to run from bootsector.
by metalages
Wed Jan 02, 2019 8:56 pm
Forum: Ym rockin'
Topic: Ayumi: a new emulator of AY-3-8910 and YM2149 chips
Replies: 5
Views: 12659

Re: Ayumi: a new emulator of AY-3-8910 and YM2149 chips

I wonder : is it close from what is used into emulators (Hatari, Steem...) ? I have used this one https://github.com/floooh/headeronly-perf/blob/master/orig/ay38910.h but it renders a bit differently from ST emulators, in particular about dephasing between enveloppe and squares from what I have noti...
by metalages
Fri Nov 16, 2018 7:33 pm
Forum: 680x0
Topic: efficient polygon drawing
Replies: 24
Views: 16299

Re: efficient polygon drawing

in my routine I draw in order A -> B -> C -> D -> ... -> A have you tried drawing from x1 to < x2 ? instead of <= x2 ? I think I do something like that because of this part : if dx = 0 => do nothing and if dy = 0 => hline trace: lea -pitch.w,a2 * sub.w d2,d0 * d0: width beq.s return * if dx = 0 => d...
by metalages
Fri Nov 16, 2018 7:16 am
Forum: 680x0
Topic: efficient polygon drawing
Replies: 24
Views: 16299

Re: efficient polygon drawing

Does your testgetpixel gives 0 when y == -1 ?
by metalages
Thu Nov 15, 2018 11:04 pm
Forum: 680x0
Topic: efficient polygon drawing
Replies: 24
Views: 16299

Re: efficient polygon drawing

I have not made special checks / cases except : - for the clipping routine : when the polygon exits the screen at top, I draw an horizontal line y=0 for the corresponding abscisses - as said before, for lines where dy > dx, I have a different line routine that draw only one pixel for each x But exce...
by metalages
Tue Nov 13, 2018 5:39 pm
Forum: Chat forum [ENG]
Topic: .sndh playback on Android devices?
Replies: 20
Views: 13106

Re: .sndh playback on Android devices?

Do you know if there is a reason why Droidsound-E is no more available on Google play ?
by metalages
Fri Nov 09, 2018 8:34 pm
Forum: 680x0
Topic: efficient polygon drawing
Replies: 24
Views: 16299

Re: efficient polygon drawing

Another trick to have this working is to draw the lines using "xor" instead of "or" to avoid having 1 pixel edges
In your case it means you would have an outline looking like this :

001100
010010
000000
010010
001100
by metalages
Thu Nov 08, 2018 11:14 pm
Forum: 680x0
Topic: efficient polygon drawing
Replies: 24
Views: 16299

Re: efficient polygon drawing

Here i only draw the outline of the letter and do a xor pass to fillb the rotating logo. https://youtu.be/iNbVcFThTxY?t=18 You just have to be careful when drawing lines when dy is greater than dx. In this case you need a line draw than put only one pixel for each x. This is not a regular line draw ...
by metalages
Wed Nov 07, 2018 10:31 pm
Forum: 680x0
Topic: efficient polygon drawing
Replies: 24
Views: 16299

Re: efficient polygon drawing

you copy a full bitplane on itself in xor mode with blitter with destadr = sourceadr + line size (160 bytes for instance). what it does is to make the horizontal borders of the outline working as a toggle fill / do not fill
by metalages
Mon Oct 22, 2018 9:52 pm
Forum: 680x0
Topic: efficient polygon drawing
Replies: 24
Views: 16299

Re: efficient polygon drawing

Thanks mlynn.
Feel free to ask if you need more info.
by metalages
Thu Oct 11, 2018 7:55 pm
Forum: 680x0
Topic: efficient polygon drawing
Replies: 24
Views: 16299

Re: efficient polygon drawing

If you can use the blitter, there is a way to just draw the outline of the polygon, then make a xor pass vertically from one screen plane on itself one line lower => it will fill the polygon. I do this here : https://youtu.be/iNbVcFThTxY?t=18 Sources are here : https://github.com/gibs75/demOS/blob/m...
by metalages
Mon Aug 20, 2018 9:45 pm
Forum: Coding
Topic: Blitter sound routine
Replies: 79
Views: 35172

Re: Blitter sound routine

Thanks :)
by metalages
Fri Aug 03, 2018 7:39 pm
Forum: Coding
Topic: Blitter sound routine
Replies: 79
Views: 35172

Re: Blitter sound routine

The score is interpreted at each frame (50hz). The $F (15 in decimal) effect allow to specify how many frames a line into the score will last. For lowest tempos there is another calculation method as described in the mod format http://www.textfiles.com/programming/FORMATS/mod-form.txt (look at 15 Se...
by metalages
Thu Aug 02, 2018 9:28 pm
Forum: Coding
Topic: Blitter sound routine
Replies: 79
Views: 35172

Re: Blitter sound routine

It uses a format that is close to Amiga .MOD format (reason why I currently use regular soundtrackers to edit songs). In this file format you have both a samples table and then score data. Score data is composed of a list of patterns that tells which sample to play on which key, which effect to appl...
by metalages
Thu Aug 02, 2018 8:53 pm
Forum: Coding
Topic: Blitter sound routine
Replies: 79
Views: 35172

Re: Blitter sound routine

Thanx :) My first goal with this routine was to have a sound routine : - using STe DMA sound - that do not take too much CPU time in order to be used in a demo or a game. Currently it fits into the upper border (50hz) which is really convenient... - that can fits some minutes of musik on a floppy, w...
by metalages
Wed Aug 01, 2018 9:43 pm
Forum: Coding
Topic: Blitter sound routine
Replies: 79
Views: 35172

Re: Blitter sound routine

Hi Mark, Thanks for the great feedback :) It will take time for me to analyze all this ;) Some elements to begin : About the DMA timing I have received great advices from Nicolas Pomarede. Currently the routine expects the DMA to play between 2000 and 2004 samples per 20 ms frame and adapt dynamical...

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