What if V9938 never existed?

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By PingPong

Prophet (3459)

PingPong's picture

26-05-2019, 13:18

Quote:

Actually the z80 is pretty busy in filling the borders while the vdp is copying the screen slice by slice.
The scroll speed is up to 1 pixel per frame at 60Hz

This is surprising me. If seen on youtube a video where the cpu time was clearly showed using the border color trick.
In the video i assume the blue color is the CPU consuption, being very low.
https://www.youtube.com/watch?v=OE1Z5cDPqdY
or is the black part the cpu usage?

By ARTRAG

Enlighted (6275)

ARTRAG's picture

26-05-2019, 13:53

The blue bar is measuring CPU time for a task I cannot remember now.
But the rest of the time is busy as well

By Manuel

Ascended (15807)

Manuel's picture

26-05-2019, 14:34

artrag: what is actually stopping you from releasing Uridium 2? The game engine looks complete at first sight...

By ARTRAG

Enlighted (6275)

ARTRAG's picture

26-05-2019, 15:26

Yes. It is almost finished.I should make a game on it

By hit9918

Prophet (2868)

hit9918's picture

26-05-2019, 19:25

Juan Luis wrote:

A few moths ago I was programming Moonsound OPL4, and I have to say that the longer sample Moonsound can reproduce is 64 KBytes

wow, the background of this weeks pages of naysaying is again some coding problem.

possibilities:
- interleave multiple channels to get longer samples. on the SCC this concept was already tried.
- reload the SCC in OPL interrupt, samples are in main RAM
- make the "mp3" thing like the speech pack on nemesis. endless samples fit in main RAM.

By PAC

Guardian (5307)

PAC's picture

26-05-2019, 19:47

ARTRAG wrote:

Yes. It is almost finished.I should make a game on it

I hope so! Too good to be forgotten. Wink

By Grauw

Ascended (8507)

Grauw's picture

26-05-2019, 20:22

Juan Luis wrote:

A few moths ago I was programming Moonsound OPL4, and I have to say that the longer sample Moonsound can reproduce is 64 KBytes. When Paula ends the sample reproduction interrupts CPU giving the opportunity of reprogramming Paula registers to reproduce another piece of sample. Moonsound only interrupts MSX CPU when OPL timers expire. If you want to reproduce a sample with more than 64KB in a Moonsound, you have to calculate the duration of the 64KBytes sample piece taking account the played frecuency. Although Moonsound have two timers with different resolutions (80 microseconds, and 323.1 microseconds). You have to do some calculations and it can be hard to reproduce a long sample without cuts. Paula does this kind of things easier.

And MoonSound does 24-channel PCM + 18-channel FM easier Smile. Pros and cons.

Juan Luis wrote:

One very important thing about Amiga blitter that it is not mentioned by the author is the Amiga blitter only supports copies of rectangular sections with vertical flip (with negative modulus), but Amiga blitter doesn't support horizontal flip :-D. Graeme Cowie or McGeezer, the author of Amiga version of Rygar stores all the poses of all characters looking in both directions because he doesn't have other better option. However, MSX2 blitter can do flip X and flip Y, reducing memory consumption Smile

The V9938 command engine can’t flip. Rather, the DIX / DIY flags negate both the source and destination increment, so the image orientation stays as it is. The flags exist to support overlapping copies without repetition (copy (0, 0)-(255,210) to (0,1)).

On the original question;

PingPong wrote:

Following the what if tendence i post also my question.
Let's imagine that msx2 have used from the beginning a V9958 instead of V9938.
Do you think that this could have been changed the destiny of MSX in a sensible way ?
I mean for example the availability of games or interest in msx before users moved to other system?

I think we would’ve seen more smooth horizontally scrolling games. However I don’t think it would’ve saved MSX (just like any of the other 80s computers).

hit9918 wrote:

wow, the background of this weeks pages of naysaying is again some coding problem.

Some interesting coding discussions, figuring out new cool things the MSX / VDP could do, would be nicer to read.

By Juan Luis

Resident (63)

Juan Luis's picture

26-05-2019, 21:41

hit9918 wrote:
Juan Luis wrote:

A few moths ago I was programming Moonsound OPL4, and I have to say that the longer sample Moonsound can reproduce is 64 KBytes

wow, the background of this weeks pages of naysaying is again some coding problem.

possibilities:
- interleave multiple channels to get longer samples. on the SCC this concept was already tried.
- reload the SCC in OPL interrupt, samples are in main RAM
- make the "mp3" thing like the speech pack on nemesis. endless samples fit in main RAM.

Of course. All pieces of the long sample are in Moonsound RAM, but it's the same using the same channel for all pieces of the long sample or using multiple channels. The problem is to calculate when it's the exact instant to start to reproduce the next piece of the long sample because the sample duration depends on the frequency you are playing the sample.

By Juan Luis

Resident (63)

Juan Luis's picture

26-05-2019, 21:51

Quote:

And MoonSound does 24-channel PCM + 18-channel FM easier . Pros and cons.

I think YMF278 of Moonsound is clearly better than Paula. Lots of FM and PCM channel. It's not needed to play a sound FX silencing one of the music channels in a game. There are channels for everything. The only thing I can't understand it's why Yamaha didn't add ADPCM support in YMF278B. Olders OPL chips like Y8950 supported ADPCM, so Yamaha had the technology to impement it on YMF278B. With ADPCM, it's possible to store long samples in 3 or 4 times less space.

Quote:

The V9938 command engine can’t flip. Rather, the DIX / DIY flags negate both the source and destination increment, so the image orientation stays as it is. The flags exist to support overlapping copies without repetition (copy (0, 0)-(255,210) to (0,1)).

Fuck! Isn't there any VDP with flip X support for computers? Are all VDP with flip X support for consoles?

By hit9918

Prophet (2868)

hit9918's picture

26-05-2019, 21:59

you told the problem again. I had posted 3 ideas.

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