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Demptronic NFL Football
http://forums.nesdev.com/viewtopic.php?f=22&t=13500
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Author:  lidnariq [ Tue Jun 27, 2017 5:09 pm ]
Post subject:  Re: Demptronic NFL Football

raydempsey wrote:
Code:
[end of NMI]
   lda #0  ;<-------------------- A
   sta $2005
   lda #0  ;<-------------------- B
   sta $2005
   rts
[... in IRQ for raster split]
   lda #0  ;<--------------- C
   sta $2006
   lda #0  ;<--------------- D
   sta $2005
[... a small delay ...]
   lda #0  ;<--------------- E
   sta $2005
   lda #0  ;<--------------- F
   sta $2006

I have been trying unsuccessfully to create a banner. I don't know what the values in A thru F mean. I tried experimenting and I still don't get it. [...] What do A thru F mean and what should I put where?
A and B: as long as your NMI is short enough, A and B are the lower 8 bits of the X and Y coordinates of the initial (i.e. top of screen) scroll.

C,D,E,F: This is a messy thing that is an artifact of how scrolling works on the NES.
wiki:PPU scrolling#Split X & Y scroll is an exactingly detailed explanation...

The easy ones:
C specifies the nametable, or equivalently the 256s bit of X scroll and the 240s bit of Y scroll
E and D (notice reversed order) are the same as A and B, but for the scroll values desired after the split.
F needs to be a bit-shifted and combined copy of your X and Y scroll values.

Quote:
What should I do to make it so I have a banner that starts 32 scanlines down where the top has no vert or horiz scroll while the last of the scanlines look shifted to the right n pixels.
To the best of my knowledge, this thing you already have:
Code:
   lda #31
   sta $5203
   lda #$80
   sta $5204
should be enough to make something happen 32 scanlines down.

Quote:
What am I doing wrong?
It would help if you told us what you saw instead...

Author:  raydempsey [ Wed Jun 28, 2017 1:02 pm ]
Post subject:  Re: Demptronic NFL Football

OK I got it! Thanks for all the help lidnariq!

Author:  raydempsey [ Fri Sep 15, 2017 9:11 am ]
Post subject:  Re: Demptronic NFL Football

Been working hard on the playbook. Here is a screenshot. It shows a lot of how the offensive playbook looks. Unlike TSB, the defense does not try to guess the offensive play but instead has their own set of formations and plays to choose from.

Attachments:
NFL-0.png
NFL-0.png [ 20.67 KiB | Viewed 300 times ]

Author:  raydempsey [ Sun Oct 01, 2017 5:19 am ]
Post subject:  Re: Demptronic NFL Football

Redesigned the color scheme to make it brighter and easier to read. Will likely complete the playbook within a week or two at the most. The last part about the playbook that needs completion is having the game clock and play clock run realistically.

Attachments:
NFL-1.png
NFL-1.png [ 20.5 KiB | Viewed 192 times ]

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