Originally posted by: Mega Mario Man

I pasted a lot of code, so I just did a pastebin.

Here is the issue, when I run this code in the ENGINETITLE section:
  LDA #$01
  STA ChangeColor       ;Flag to tell the system to run UpdateColor Subroutine in the NMI section (00=Skip ColorUpdate, 01=Run ColorUpdate)
  LDA #$29                     
  STA attribute_RAM     ;Color to change to $29

My background goes to all zeros. If I take it out, the background loads just fine, but I my color won't go back to color $29.

Basically, I am changing 1 color of the palette duing game play, specifically address #3F11, and I want to reset it to the default value for the Title Screen. In trying to do so, it breaks my LoadBackround Routine and I get all Zeros. The wierd thing is, the background should be loaded well before this point hits. I cannot for the life of me figure out what I am doing wrong.

I have added a pastebin of the relevant code to the 3 process (Color Change, Switching Gamestates, and Loading Backgrounds). I do run the ColorUpdate Subroutine during gameplay to update some colors when the D-Pad is pressed and everything works fine there. It's only at the Title Screen where it breaks it.

http://pastebin.com/Z785aqBB

Thanks! Hope this makes sense.

Originally posted by: KHAN Games

 Is there other code that only allows that flag to be set at a certain event?

I would try setting those two variables to their respective values as you're changing the gamestate back to the title, and not when it's actually already in the title gamestate.
 

Originally posted by: 3GenGames

Moving forward and not understanding is why you don't get it. Just gonna point out a logical error too: You don't disable the PPU then not enable it. You have to enable it (Or at MINIMUM NMI's) forit to be enabled. Your NMI might cause glitches if you don't remember, it can and does happen. Disabling, then having an NMI happen when "off" in the middle of doing stuff will lead to nasty bugs.

Originally posted by: 3GenGames

Moving forward and not understanding is why you don't get it.

Originally posted by: Roth



Some people learn in different ways. Sometimes advancing beyond your means is helpful and you start to understand more as you go on. I can't tell you how long it was that I didn't even understand how my controls were working with eor and and'ing and all that jazz. But I moved on to learn more stuff. I ended up catching on to that kind of thing. Like I said, some people learn in different ways. No need to talk to the dude like that.
 

Originally posted by: 3GenGames

Is it a douchy thing to help? Really?

Originally posted by: 3GenGames

Yeah, I was that way in math, but there's a certain level of understanding you need. If you don't understand WHY a chip does what it does, you're missing something fundamental that you NEED to know.

And MRN, I was just pointing out stuff I saw in his code, why bust my balls? Is it a douchy thing to help? Really?

Originally posted by: GradualGames


You just need to learn to state things in a less flatly dismissive way is all.

Originally posted by: 3GenGames

Yeah, I was that way in math, but there's a certain level of understanding you need. If you don't understand WHY a chip does what it does, you're missing something fundamental that you NEED to know.

And MRN, I was just pointing out stuff I saw in his code, why bust my balls? Is it a douchy thing to help? Really?

Originally posted by: 3GenGames

Moving forward and not understanding is why you don't get it. Just gonna point out a logical error too: You don't disable the PPU then not enable it. You have to enable it (Or at MINIMUM NMI's) forit to be enabled. Your NMI might cause glitches if you don't remember, it can and does happen. Disabling, then having an NMI happen when "off" in the middle of doing stuff will lead to nasty bugs.

Originally posted by: Mega Mario Man

No worries, all. I'm thick skinned. Sometimes a good slap to the back of the head with and calling me an idiot is just what i need.

I understand what they set of code does, but I am getting lost breaking it down line by line. For example, WTF is this guy doing except sitting there spinning in circles:

.loop
  LDA sleeping
  BNE .loop

I just can't grasp the concept why it must be there. And there are other things as well, such as pointers and the random [] around some of them, what's up with the period in from of .loop, and many other things. But then I realize, it works, I can repllcate it in other parts of my code and it works, so why worry. I usually learn what they do when I break the code and I have to relearn it.

Now, since this is a coding question thread, I have one for you all. I'm playing with a new way to write text to the screen. I have 100% written this code by hand trying to understand pointers. It kind of works, however, when it comes time to write the word PAUSE on the screen or erase it, I get 0000000000000000000000000000000000000000000 all the way across the screen in the row where PAUSE should show up. I'm trying to do it this way so I can reuse the loop for future text I want to display.

***NOTE*** Ignore the line comments of the code. I robbed this code from other sections of my code and haven't cleaned it up yet.

;Variables Section
TEXTLENGTH .rs 1
TEXTLOWBYTE .rs 1
TEXTHIGBYTE .rs 1
Text_Pointer .rs 1

;Code I added to my Write Pause Subroutine
  LDA #$05
  STA TEXTLENGTH
 
  LDA #$0E
  STA TEXTLOWBYTE
 
  LDA #$21
  STA TEXTHIGBYTE
 
  LDA #$00
  TAX
 
  LDA Texts,x           ;Load the Main Program Pointer
  STA Text_Pointer
 
  JSR LoadText
 
 

;Load Text Loop

LoadText:
  LDA $2002             ; read PPU status to reset the high/low latch
  LDA #TEXTHIGBYTE                                                                                              ; variable
  STA $2006             ; write the high byte of $2000 address
  LDA #TEXTLOWBYTE                                                                                             ; variable
  STA $2006             ; write the low byte of $2000 address
  LDX #$00              ; start out at 0

LoadTextLoop:
  LDA Text_Pointer, x     ; load data from address (background + the value in x)                          ;variable
  STA $2007             ; write to PPU
  INX                   ; X = X + 1
  CPX #TEXTLENGTH           ; Compare X to hex $80, decimal 128 - copying 128 bytes                         ; variable - Character Length
  BNE LoadTextLoop  ; Branch to LoadBackgroundLoop if compare was Not Equal to zero
  RTS
 

;Databases
 
Texts:
  .word PauseText,UnDrawPauseText
 
PauseText:
 .db  $19,$0A,$1E,$1C,$0E     ;PAUSE
UnDrawPauseText:
 .db  $24,$24,$24,$24,$24     ;Undraw Pause

Originally posted by: Mega Mario Man


I don't think it will be a problem because nothing really happens between that code and the NMI. I was enabling the PPU right after the LoadBackground and it was wigging out my screen. Since going this route, my screen issues have fixed. If it breaks future code, then I guess I will be forced to cross that bridge when it happens. The NMI is still and enigma to me, so any advice helps!

Originally posted by: Roth

A pointer is going to be a 16-bit number. So where you have.... lda texts, x  sta Text_Pointer... you are loading an 8-bit value. To be super generic about it, you could just do:

lda <#PauseText
sta Text_Pointer+0
lda >#PauseText
sta Text_Pointer+1

Then you would have to use the Y register and not the X. Since the address is in zero page, using (), y will get you want you want:

lda (Text_Pointer), y
sta $2007
iny
;etc etc

Be sure to change Text_Pointer to .res 2, because you want to reserve 2 bytes for it since it is going to be used as a 16-bit address.

Dunno if there's errors in what I said, but that's what it looks like needs to be done to me. Hope it helps! Oh, and the syntax I use is for ca65, you may need to adjust for whatever assembler you use.

Originally posted by: KHAN Games


Only difference for the NESASM compiler is he'll have to use [] instead of ().  (Assuming he keeps the beginning of his old routine the same.)