Basic Questions and Answers Thread

I'm trying to figure out how to do a Tails only double jump for my Sonic 2 hack, but haven't had any luck, yet. Best results I've gotten is either causing Tails to be able to jump as many times as you want at the cost of losing momentum, or no jump at all but instead slingshotting him on slopes.

What am I missing, here?
(And yes, I'm aware I did clone the regular jump code to make this hot garbage, but it's the best I could do.)

Code:

Tails_DoubleJump:
    andi.b    #button_B_mask|button_C_mask|button_A_mask,d0 ; is A, B or C pressed?
    beq.w    Tails_DoubleJumpFinish    ; if not, return
    btst    d0,(Last_jump_press).w        ; did Tails jump again?
    beq.w    Tails_DoubleJumpFinish    ; if yes, Tails should not triple jump. ...Hopefully!
    moveq    #0,d0
    move.b    angle(a0),d0
    addi.b    #$80,d0
    bsr.w    CalcRoomOverHead
    cmpi.w    #6,d1        ; does Tails have enough room to jump?
    blt.w    Tails_DoubleJumpFinish    ; if not, branch
    move.w    #$680,d2
    btst    #6,status(a0)    ; Test if underwater
    beq.s    +
    move.w    #$380,d2    ; set lower jump speed if underwater
+
    moveq    #0,d0
    move.b    angle(a0),d0
    subi.b    #$40,d0
    jsr    (CalcSine).l
    muls.w    d2,d1
    asr.l    #8,d1
    add.w    d1,x_vel(a0)    ; make Tails jump (in X... this adds nothing on level ground)
    muls.w    d2,d0
    asr.l    #8,d0
    add.w    d0,y_vel(a0)    ; make Tails jump (in Y)
    bset    #1,status(a0)
    bclr    #5,status(a0)
    addq.l    #4,sp
    move.b    #1,jumping(a0)
    clr.b    stick_to_convex(a0)
    move.w    #SndID_DoubleJump,d0
    jsr    (PlaySound).l    ; play double jumping sound
    move.b    #$F,y_radius(a0)
    move.b    #9,x_radius(a0)
    btst    #2,status(a0)
    bne.s    Tails_RollJumpDouble
    move.b    #$E,y_radius(a0)
    move.b    #7,x_radius(a0)
    move.b    #AniIDSonAni_Spring,anim(a0)    ; use "jumping" animation
    bset    #2,status(a0)
    addq.w    #1,y_pos(a0)

Tails_DoubleJumpFinish:
    rts
; ---------------------------------------------------------------------------
; loc_1C6C4:
Tails_RollJumpDouble:
    bset    #4,status(a0) ; set the rolling+jumping flag
    rts

Edit: You may have noticed the conflicting spring animation used against the jumping animation comment, uhh... That's semi-intentional.

 

You need to use a flag or SST for it. And after that, you'll need to clear it when touching the floor. For Tails is Tails_ResetOnFloor

 

To fix the infinite jump, you clear the jumping(a0) flag

 

Call me stupid on this one, but... Where would I have to clear the jumping flag?

 

In the double jump, instead of setting it, you clear it.

Please tell me if you have more questions.

 

What does "smpsModSet" do in asm?

 

smpsModSet sets modulation. It takes 4 1-byte parameters: wait speed before modulation starts, the modulation speed, the change per step, and the number of steps.

 

So, I was implementing an DPLC system to the signpost but, when I try to go to the signpost's location and touch it, this message appears.
The fact that appears in Clownacy's clownmdemu, but not in Kega nor Gens makes me think this is an "odd address" error, but cause of the usage of an older version of the sonic 1 disasm I had since a long time ago, I can't see the location of that error but thanks to the 68k disassembler, I can see that is one of the new funtions i added: Perform_DPLC from S3K

Code:

loc_8504A:
        move.w    (a2)+,d3        ; Art source offset
        move.l    d3,d1
        andi.w    #$FFF0,d1        ; Isolate all but lower 4 bits
        add.w    d1,d1
        add.l    a3,d1            ; Get final source address of art
        move.w    d4,d2            ; Destination VRAM address
        andi.w    #$F,d3
        addq.w    #1,d3
        lsl.w    #4,d3            ; d3 is the total number of words to transfer (maximum 16 tiles per transaction)
        add.w    d3,d4
        add.w    d3,d4
        jsr    (QueueDMATransfer).l    ; Add to queue
        dbf    d5,loc_8504A        ; Keep going

Still can't see what I did wrong

 

Anyone know why this happens? It always happens after I edit something in SonLVL...

 

@BL3H

 

hey

Lately I've been experimenting with Sonic 1 and it turned out pretty well.

But while preparing for the elemental shields something strange happens to me when following a guide that you must follow.

https://forums.sonicretro.org/index.php?threads/how-to-optimize-shield-art-loading-in-sonic-1.32900/

I followed the guide and everything was going well until the moment of testing invincibility



now the stars that come out when you pick up the monitor have disappeared

 

Is the code to load it still in obj2E_Invinc? Or is part of its code loaded for the shields instead?

 

Hmm...

Working for sonic encore...Well...Before that spindash error wasn't there...

 

You should move Art_Dust (The dust art) closer to the spindash routine

 

It helped me, thx

 

More than likely, you are running into a bug with the Genesis' VDP DMA. When you set up a DMA, like you do with the spindash dust art, the source address will be the location of that in ROM divided by 2. As it copies the data, it will increment that address by 1 for each 16-bit word read. However, it seems to only properly increment the lower 16 bits of that source address, but not take into account the upper byte. As a result, for instance, if the address ends up going to $1FFFF, it will end up wrapping back around to $10000, instead of incrementing the 1 to make it $20000. In terms of raw addresses (multiplying the VDP DMA source address value by 2), this means that $3FFFE will become $20000. If you have a piece of art that crosses a $20000 byte (128 KiB) boundary like that, then you will get that corruption.

The easiest thing to do is to keep the art within a $20000 boundary (i.e. 0-$1FFFF, $20000-$3FFFF, $40000-$5FFFF, etc.). You can figure out where a thing is located in the built ROM by taking a look at the associated listing file (they usually have the .lst file extenstion). Moving it closer to the spindash code seems to have done just that for you.

Another thing you can do is make the DMA queueing function detect boundary crosses, and have it split a single DMA function into 2, so that the wrapping bug never occurs, preventing future issues with this sort of thing automatically. You can find such an implementation in the Sonic 3 & Knuckles disassembly (at function
Add_To_DMA_Queue, when Sonic3_Complete is set), or Flamewing's Ultra DMA Queue.

 

Unfortunately, I haven't heard from anyone who has made it possible to move this to github.. (I work in the AS branch)

PD: I would have made an answer but the help system was bugged

 

Both are made for use with AS. You should be able to get either implemented with some configuration and naming changes. Try giving it a shot yourself! Could help you understand porting things from one thing to another better.

 

A couple of hours ago I adapted the ultra dma queque without modifying much of its options...

What followed was a failed build where the game died when loading the level.

 

Try to use deltawoolo's tutorial but using the Original "DMA queue" file from here. Also, there's an instance of "VDP_port_control". change it to be only be lowercase. That worked for me