SpritesMind.Net

Hi SpritesMind,

Is anyone here from the UK? This may be of interest:


BarCamp Canterbury is an unconference that is a completely free
to attend and based loosely around the theme of technology.

As an unconference, the content of BarCamp Canterbury is provided by you,
the attendees! Meet with ...

So, I seem to have fixed this issue by implementing column scrolling mode in the VDP.

However, there are a couple of thiings which don't match up with the VDP docs. Namely, it seems that something strange happens with the leftmost columns. Digging in the genplus gx code, I found the following ...

The above change badly breaks Street Racer and Sonic 3 (probably others too).

FWIW, here is the code that we are dealing with:
http://dgen.git.sourceforge.net/git/gitweb.cgi?p=dgen/dgen;a=blob_plain;f=ras-drawplane.h;hb=HEAD

It is not pretty I warn you. It's a header file that is included with ...

I guess I'd look how the offset into the name table is calculated for column scrolling and verify it isn't going out of bounds. As a reference remember that the offsets into the name table wrap after 8K, so when games set weird sizes like 128x128 or 64x128, the real playfield size is truncated. E ...

Thanks for the info. Adding debugging features is exactly what we are doing. I think you are right. Some kind of sprite and tile browser is what we need.

(OT):

This week we have been adding VDP debugging features.
We have added the ability to turn on and off planes and sprites. Zamaz just send me ...

Hi,

As you guys know, I have been plugging away at VDP bugs in dgen. Here is another I would appreciate your opinions on.

In some games planes which should be scrolling vertically corrupt. Blocks of the plane are missing. Games that seem broken in this way:

Sonic 3 - Gumball bonus stage
Gunstar ...

Cool. Let me know how you get on.

KanedaFr: The debugger mostly supports m68k debugging at the moment. You can set break points and watch points. I also added YM2612 support that allows us to examine the OPN parameters from the FM chip. Be sure to configure with --enable-debugger to get these goodies. Run the emulator from a ...

Dgen has loads of issues emulating street racer. Many of the sprites are garbled and the colours are often wrong. I need to look into this when I get anything close to free time.

Hi,

Zamaz has just uploaded a new version of dgen.

Changlelog is here:
http://sourceforge.net/news/?group_id=227519

Downloads here:
http://sourceforge.net/projects/dgen/files/dgen/1.31/

Many thanks to the people on this forum for helping us diagnose and fix sprite masking and half submitted VDP ...

Boom!

http://farm9.staticflickr.com/8056/8120503604_5cf7169243_o.png

I had missed a couple of flag clearing cases. Did a load of refactoring whilst I was there. It's in the 'ea_logo' branch of our git repo if anyone is interested.

Big thanks to everyone that helped. I think we plan to make a ...

Hi,

So myself and a friend implemented the following:
- Update address immediately after receiving half a command (first 16-bits)
- Reset the pending flag on register or data read.

This helps a lot, but is still not quite right. Notice that half of the text is missing:

http://farm9 ...

OK, so a VRAM fill would be an operation that could cause "enough IO" right?

So it seems there are three potential issues:

* Writing 32 VRAM address bits, then later only the upper most.
* Latching
* Invalid scroll modes.

In the first, how can you write only the single word to change the lower ...

Hi Charles,

Hope all is well.

Well I see the code attempting to deal with two word vdp writes:
http://dgen.git.sourceforge.net/git/gitweb.cgi?p=dgen/dgen;a=blob;f=mem.cpp;h=271c86d6771f09c584c3ccbc31927c95ac31a637;hb=HEAD#l383

Note the use of coo_waiting. This looks mostly correct (maybe). Or ...

Ah:


In order for the VDP to know if the first or second 16-bit half of the
command word has been written to the control port, it maintains an internal
write-pending flag. This flag is updated when these conditions are met:

- It is set when the first half of the command word is written.
- It ...