Amiga Tools 5/Amiga Tools 5.iso/tools/developer-tools/amos-tools/eaissue3a/text/r_cross_vu.asc

Text File | 1996-07-13 | 10.4 KB | 307 lines

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                             Programming Routine
                             ~~~~~~~~~~~~~~~~~~~
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                    Cross-style VUMeter Graphic Equalizer

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                     Written by Andrew "Mushroom" Kellett

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        This is a routine that I developed a few weeks ago, whilst working
    on a demo to show the powers of AMOS, featuring lot's of VU power,
    vectors, bullballs, and much much more, all done using simple AMOS
    commands.

        I created this procedure, to emulate all kinds of different kinds
    of shapes, including a nice circle effect, similar to the one in the
    "Jesus on E's" demo, which inspired me to try and copy the effect. I
    am including the routine, as a few people have asked how it was
    actually done.

        The program requires one picture bank, which is the file called
    VU_CROSS, which is stored in the DATA drawer of the first disk. You
    may need to decrunch the file, depending on how much space I have
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    available, and if I had to crunch it down. If you don't have a copy of
    Crunchmania, then you can use the RTDD program in the C: drawer of
    disk one, load in the bank to AMOS, and then re-save it as an
    uncrunched file. RTDD is a run-time decruncher, and requires the
    CRM.LIBRARY file to run, which is in the LIBS: drawer of disk 1.

        The FULL AMOS program, is situated on disk 2. The program is
    freely useable, as long as I get a mention in the credits somewhere if
    you copy the routine. Now, onto the description on how the listing
    actually operates.

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        Dim P(31)
        Global SETTING,P()

        F$=Fsel$("","","Select a Pro/Sound/Noise","Tracker module to use")

        Hide On
        If F$="" : Edit : End If


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        If Exist(F$)
           Track Load F$,3 : Track Play 3
           Track Loop On : Led Off
        Else
           Edit
        End If

        Proc PREPARE

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    Sets up the initialization of the program. The screen used requires
    one array, which holds all the colours of the screen. SETTING is a
    number which can be assigned, and the routine quits out after that
    number of updates. If there is no information to be displayed
    on-screen, then the setting reaches it's target faster.

    The program then asks for you to give it a music module, in the form
    of either a Sound/Pro/Noisetracker module. This is then started to
    play, to make the VUMeter command start registering. Proc PREPARE is
    then called to initiate the screen.

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        Do
           Proc _VU5[200]
        Loop

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    This part of the program is the bit which does all the main work. It
    will access the routine for 200 loops, before quitting out. I have set
    the delay to a short one, as you will have seen in the demo, with the
    changing colours. See the _VU5 routine for more details.

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        Procedure PREPARE
           Unpack 8 To 0 : Screen Hide 0 : For N=0 To 31 : Colour N,0 :
           Next N
        End Proc

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    The program automatically presumes that bank 8 contains the picture of
    the cross. All the colours are then cleared from the screen, to begin
    the routine to draw the picture back in a special way. If you want to
    save on a bit of memory, then an ERASE 8 can be used after the UNPACK
    command.

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        Procedure _VU5[SETTING]
           TLP=0
           G=Rnd(3)

           If G=0
              DAT2:
              Data $0,$FFF,$EEE,$DDD,$CCC,$BBB,$AAA,$999,$FFF,$EEE,$DDD,$CCC
              Data $BBB,$AAA,$999,$999,$888,$666,$555,$444,$222,$333,$999
              Data $888,$777,$666,$555,$444,$333,$58C,$BB0,$99F
              Restore DAT2 : For OO=0 To 31 : Read P(OO) : Next OO
           End If

           If G=1
              DAT3:
              Data $0,$49,$3A,$3B,$2C,$1D,$1E,$F,$FFF,$EEE,$DDD,$CCC,$BBB
              Data $AAA,$999,$999,$888,$666,$555,$444,$222,$333,$900,$A00
              Data $B00,$C00,$D00,$E00,$F00,$58C,$BB0,$99F
              Restore DAT3 : For OO=0 To 31 : Read P(OO) : Next OO
           End If

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           If G=2
              DAT4:
              Data $0,$999,$888,$777,$666,$555,$444,$333,$999,$888,$777,$666
              Data $555,$444,$333,$999,$888,$777,$666,$555,$444,$333,$999
              Data $888,$777,$666,$555,$444,$333,$58C,$BB0,$99F
              Restore DAT4 : For OO=0 To 31 : Read P(OO) : Next OO
           End If

           If G=3
              DAT5:
              Data $0,$900,$A00,$B00,$C00,$D00,$E00,$F00,$90,$A0,$B0,$C0
              Data $D0,$E0,$F0,$990,$AA0,$BB0,$CC0,$DD0,$EE0,$FF0,$49,$3A
              Data $3B,$2C,$1D,$1E,$F,$58C,$BB0,$99F
              Restore DAT5 : For OO=0 To 31 : Read P(OO) : Next OO
           End If

           For N=0 To 31 : Colour N,0 : Next N
           Wait Vbl : Screen To Front 0 : Screen Show 0

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    When the routine is first called, the program decides on a random
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    colour in which to use. If you saw the routine running before you read
    this file, you would notice the equalizer "Appear" to be changing
    colours. This is all done randomly, and the computer decides on a
    number from 0-3 and changes the palette array accordingly. The screen
    is then cleared of all colours, and brings it into view in case any
    other routine has caused the screen to be hid.

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           Do
              Gosub ACQUIRE
              If TLP=>SETTING*2 : Exit : End If
              Inc TLP
           Loop

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    This is the main loop inside the routine. It is constantly calling the
    routine ACQUIRE, which draws the current VU settings on the screen.
    The variable TLP is increased, until it is doubled the value assigned,
    then the program exits the loop, and calls a POP PROC, which exits it
    out of the procedure.

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           Pop Proc
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           ACQUIRE:
           A=(Vumeter(0))+1 : CH1=0 : B=(Vumeter(1))+1 : CH2=0
           C=(Vumeter(2))+1 : CH3=0 : D=(Vumeter(3))+1 : CH4=0

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    A, B, C, and D are the numbers recieved from the VUmeter channels at
    the time of reading, and will range from the value of 0 - 63.

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           If A>A1 Then A1=A
           If A>A1 Then CH1=1
           If B>B1 Then B1=B
           If B>B1 Then CH2=1
           If C>C1 Then C1=C
           If C>C1 Then CH3=1
           If D>D1 Then D1=D
           If D>D1 Then CH4=1

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    If the values read are higher than the ones which are in memory, then
    they are loaded with the appropriate figures. If the number is lower,
    then nothing is changed.
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           If CH1=0 Then A1=A1-1
           If CH2=0 Then B1=B1-1
           If CH3=0 Then C1=C1-1
           If CH4=0 Then D1=D1-1

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    If no numbers were added to any of the channels in memory, then the
    CH1 - 4 will be 0, and this deducts 1 from the memory value on the
    channels which did not have any increases to them. This gives the
    on-screen effect of the equalizer dropping down slowly if there is no
    action there.

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           If A1<0 Then A1=0
           If B1<0 Then B1=0
           If C1<0 Then C1=0
           If D1<0 Then D1=0

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    If any of the channels drops below 0 for some reason, then this piece
    of the program will take it back to 0 to make the program work
    correctly, especially if it is looking for a value of 0.
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           P=A1/10 : If A1=>62 : P=7 : End If : Gosub _DRAW1
           P=B1/10 : If B1=>62 : P=7 : End If : Gosub _DRAW2
           P=C1/10 : If C1=>62 : P=7 : End If : Gosub _DRAW3
           P=D1/10 : If D1=>62 : P=7 : End If : Gosub _DRAW4
           Return

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    Now, the program calls a draw routine for each of the four channels.
    The value of P is assigned a variable of 0 - 5, or is assigned to 7 if
    the VUmeter reading is at it's maximum. Looking at the draw routines
    below, you will see why I have had to use 1-7. Although you will set
    the value to 7, you may not actually see the effect on-screen, as the
    updates are made so quickly, especially when it has been compiled.

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           _DRAW1:
           If P=0 : Colour 1,0 : End If
           If P>0
              For N=1 To P : Colour N,P(N) : Next N
              If P<7 : For N=P+1 To 7 : Colour N,0 : Next N : End If
           End If
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           Return

           _DRAW2:
           If P=0 : Colour 8,0 : End If
           If P>0
              For N=1 To P : Colour N+7,P(N+7) : Next N
              If P<7 : For N=7+(P+1) To 13 : Colour N,0 : Next N : End If
           End If
           Return

           _DRAW3:
           If P=0 : Colour 15,0 : End If
           If P>0
              For N=1 To P : Colour N+14,P(N+14) : Next N
              If P<7 : For N=14+(P+1) To 20 : Colour N,0 : Next N : End If
           End If
           Return

           _DRAW4:
           If P=0 : Colour 22,0 : End If
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           If P>0
              For N=1 To P : Colour N+21,P(N+21) : Next N
              If P<7 : For N=21+(P+1) To 27 : Colour N,0 : Next N : End If
           End If
           Return
        End Proc

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    These are the 4 draw routines, seperated into individual routines to
    make it easier for you to follow. The program looks at the number in
    P, and assigns the first P of 6 colours with the correct value, for
    the appropriate character. If the number in P is less than 6, then the
    rest are filled with 0, to clear any unwanted debris off the screen.
    Each bar has 7 colours to use, as I decided to use a 32 colour screen.
    Any bigger, and the effects would have started getting slower, however
    a HAM screen compiled, would not be a bad idea. Maybe I will get to
    that.




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        Well, there you have it. A fully-functional VU cross demo. If you
    are having problems with this routine, then why not drop me a line at
    the Mushroom PD address, or give me a call. The address is scattered
    around various different parts of the magazine.

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        If you have any excellent routines which you would like to
    include, then why not send me the AMOS listing, and a documented
    procedure breakdown, like this, and I will include it. Remember, you
    will receive a FREE copy of the first issue your article appears in.

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        All mail sent to me will be replied to as soon as possible,
    depending on how busy I am. If you are sending disks, then why not
    fill them with your AMOS programs and PD so I can include them in the
    library. The address is scattered around various articles.

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EOF