To the previous poster - there is a wealth of PS2 info at http://playstation2-linux.com (the official site) and http://www.hsfortuna.pwp.blueyonder.co.uk (some great tutorials written by a University lecturer from Abertay, who actually have a PS2 computing lab!)
To the author -
I think you need to be a little more careful! I realise it's easy to make mistakes in tutorials, after all, I wrote a far from perfect series myself. However...
You contradict yourself twice. Here are the quotes:
quote:
EOP occupies bit 15 and specifies whether the following data is the last primitive in a GS packet (End Of Packet). A value of 0 means that more GIFtags with more primitives will be sent after the current primitive. A value of 1 indicates that the following primitive data is the last in the packet.
Which is correct, however you later write
quote:
Since there is no primitive data or GIFtags following our triangle, EOP is set to zero to signal that the following data is the end of the GS packet.
whic is incorrect, and directly contradicts what you actually put in your code (Note: A lot of people skip over the code and just read the explanations)
Then, you also write
quote:
Only one register descriptor is in the REGS field so NREG is set to 0.
which is wrong, again contraditing what you have actually written in the code, and also contradicting your earlier statement:
quote:
NREG occupies bits 60 through 63 and holds the number of register descriptors in the next field, REGS.
There are a number of caveats you skip over, but I can understand why, for instance you don't mention that you can't use the PRIM field of the GIFtag in REGLIST mode, that the NREG field isn't big enough to hold the value 16, so a value of 0 in the NREG field actually means all 16 register descriptors are used, and you don't mention why we can't use those register descriptors directly instead of using what seems to be a more awkward and indirect A&D register.
(For those interested, there are lots of registers available to the GS, but each register descriptor is only 4 bits long, so you can only directly access the first 16 of them, you really do have to use the A&D register to access the others)
Another possible point of confusion is the Q register appended to the RGBA settings. What's that all about you may well ask?
So, a reasonable effort, but perhaps you should run Part 3 past a proof-reader first. Better still, perhaps GameDev.net should actually read articles before they are published to look for authors contradicting themselves?
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Posted - 12/21/2003 4:14:48 PM
Posted - 12/23/2003 1:40:55 PM
