for i=1 to keydown(0) ' start of the key testing loop
  ...

  switch=0
  for x=28 to 44
    if tpress$=ta$(x) then switch=1
  next x

next i ' end of the key testing loop

' The value of switch here is the one for the last key tested
if switch=0 goto Screenstart

If s1=1 and keys>0 then Play Sound 1,B,Q,freq1(tnr(1)+okt1)+tune1,volume
if s1=2 and Keys>0 then play Sound 1,B,S,freq1(tnr(1)+okt1)+tune1,volume

If s2=1 and keys>1 then Play Sound 2,B,Q,freq2(tnr(2)+okt2)+tune2,volume
if s2=2 and keys>1 then play Sound 2,B,S,freq2(tnr(2)+okt2)+tune2,volume

If s3=1 and keys>2 then Play Sound 3,B,Q,freq3(tnr(3)+okt3)+tune3,volume
if s3=2 and keys>2 then play Sound 3,B,S,freq3(tnr(3)+okt3)+tune3,volume

If s4=1 and keys>3 then Play Sound 4,B,Q,freq4(tnr(4)+okt4)+tune4,volume
if s4=2 and keys>3 then play Sound 4,B,S,freq4(tnr(4)+okt4)+tune4,volume

' Mr. Polysynth
' Code by "TweakerRay"
' Messed about with for the CMM2 Welcome Tape by "thwill"

Option Explicit On
Option Base 1

'#Include "../../common/welcome.inc"

cls
color rgb(40,255,20)

?" Hi ! This is my small Polysynth V1"
?" "
?" You can play the synth with your keyboard:"
?" Just imagine the Keys from Q-P as White Keys and the numberkeys above as Black keys of a Piano"
?" "
?"  2  3        5  6  7     9  0     <----- Black Keys"
?" "
?" Q  W  E  R  T  Z  U  I  O  P      <----- White Keys"
?" "
?" The Synth can play up to 4 Notes simultaneously. All sounds come from both Speakers."
?" "
?" You can change the okaves on the 4 Notes independently:"
?" "
?" F1 / F2  Oktave up / down on Note 1"
?" F3 / F4  Oktave up / down on Note 2"
?" F5 / F6  Oktave up / down on Note 3"
?" F7 / F8  Oktave up / down on Note 4"
?" F9 / F10 Oktave up / down on ALL 4 Notes"
?" F11  Reset All oktaves to Zero   "
?" F12  Reset Tuning to Zero     "
?" "
?" Change the Sound on the Channel:"
?" "
?" A / S / D / F  -  Sound change + on Channel 1 / 2 / 3 / 4 (Square or Sine)"
?" Y / X / C / V  -  Sound change - on Channel 1 / 2 / 3 / 4 (Square or Sine)"
?" "
?" Detune Channels with:"
?" "
?" G / H / J / K  -  Detune + on Note 1 / 2 / 3 / 4"
?" B / N / M / ,  -  Detune - on Note 1 / 2 / 3 / 4"
?" "
?" "
?" Press [Esc] to Quit"

do while inkey$<>"" : loop
do while inkey$="" : loop

cls

dim freq(88)
dim i
dim k(4)
dim keys
dim layout$ = mm.info$(option usbkeyboard)
dim notes
dim okt(4)
dim s(4) ' 1=square, 2=sine, 3=noise
dim tnr(4) = (28,28,28,28) ' For if okt would be pressed before a key we set the key to C2
dim tune(4)
dim volume=12 ' Volume 1-25

freq(01)=27.5000 : freq(11)=48.9995 : freq(21)=87.3071 : freq(31)=155.563
freq(02)=29.1353 : freq(12)=51.9130 : freq(22)=92.4986 : freq(32)=164.814
freq(03)=30.8677 : freq(13)=55.0000 : freq(23)=97.9989 : freq(33)=174.614
freq(04)=32.7032 : freq(14)=58.2705 : freq(24)=103.826 : freq(34)=184.997
freq(05)=34.6479 : freq(15)=61.7354 : freq(25)=110.000 : freq(35)=195.998
freq(06)=36.7081 : freq(16)=65.4064 : freq(26)=116.541 : freq(36)=207.652
freq(07)=38.8909 : freq(17)=69.2957 : freq(27)=123.471 : freq(37)=220.000
freq(08)=41.2035 : freq(18)=73.4162 : freq(28)=130.813 : freq(38)=233.082
freq(09)=43.6536 : freq(19)=77.7817 : freq(29)=138.591 : freq(39)=246.942
freq(10)=46.2493 : freq(20)=82.4069 : freq(30)=146.832 : freq(40)=261.626

freq(41)=277.183 : freq(51)=493.883 : freq(61)=880.000 : freq(71)=1567.98
freq(42)=293.665 : freq(52)=523.251 : freq(62)=932.328 : freq(72)=1661.22
freq(43)=311.127 : freq(53)=554.365 : freq(63)=987.767 : freq(73)=1760.00
freq(44)=329.628 : freq(54)=587.330 : freq(64)=1046.50 : freq(74)=1864.66
freq(45)=349.228 : freq(55)=622.254 : freq(65)=1108.73 : freq(75)=1975.53
freq(46)=369.994 : freq(56)=659.255 : freq(66)=1174.66 : freq(76)=2093.00
freq(47)=391.995 : freq(57)=698.456 : freq(67)=1244.51 : freq(77)=2217.46
freq(48)=415.305 : freq(58)=739.989 : freq(68)=1318.51 : freq(78)=2349.32
freq(49)=440.000 : freq(59)=783.991 : freq(69)=1396.91 : freq(79)=2489.02
freq(50)=466.164 : freq(60)=830.609 : freq(70)=1479.98 : freq(80)=2637.02

freq(81)=2793.83
freq(82)=2959.96
freq(83)=3135.96
freq(84)=3322.44
freq(85)=3520.00
freq(86)=3729.31
freq(87)=3951.07
freq(88)=4186.01

dim ta$(88)
ta$(28)="q"
ta$(29)="2"
ta$(30)="w"
ta$(31)="3"
ta$(32)="e"
ta$(33)="r"
ta$(34)="5"
ta$(35)="t"
ta$(36)="6"
if layout$="DE" then ta$(37)="z" else ta$(37)="y"
ta$(38)="7"
ta$(39)="u"
ta$(40)="i"
ta$(41)="9"
ta$(42)="o"
ta$(43)="0"
ta$(44)="p"

do
 keys=keydown(0)
 notes=keys
 for i = 1 To 4 : k(i) = keydown(i) : next i

 if keys=0 then play stop

 for i=1 to keys
   handle_keypress(i)
 next i

 apply_restrictions()
 update_display()
 play_notes()
loop

sub handle_keypress(i)
 local j, kk$

 kk$=chr$(k(i))

 if kk$=chr$(27) then end ' we.end_program()

 ' Check for keys corresponding to musical notes
 for j=28 to 44
   if kk$=ta$(j) then tnr(i)=j : Exit Sub
 next j

 select case kk$

   ' Channel Oktave up and down
   case chr$(145) : okt(1)=okt(1)-12 ' F1
   case chr$(146) : okt(1)=okt(1)+12 ' F2
   case chr$(147) : okt(2)=okt(2)-12 ' F3
   case chr$(148) : okt(2)=okt(2)+12 ' F4
   case chr$(149) : okt(3)=okt(3)-12 ' F5
   case chr$(150) : okt(3)=okt(3)+12 ' F6
   case chr$(151) : okt(4)=okt(4)-12 ' F7
   case chr$(152) : okt(4)=okt(4)+12 ' F8

   ' All four Channels Oktave up and down
   case chr$(153) : for j=1 to 4 : okt(j)=okt(j)-12 : next j ' F9
   case chr$(154) : for j=1 to 4 : okt(j)=okt(j)+12 : next j ' F10

   ' Reset Tuning + Reset Oktaves
   case chr$(155) : for j=1 to 4 : okt(j)=0 : next j ' F11
   case chr$(156) : for j=1 to 4 : tune(j)=0 : next j ' F12

   ' Sound changes 1-4
   case "a"      : s(1)=s(1)+1
   ' If "y" or "z" corresponds to a musical note key then this sub will already have exited.
   case "y", "z" : s(1)=s(1)-1
   case "s"      : s(2)=s(2)+1
   case "x"      : s(2)=s(2)-1
   case "d"      : s(3)=s(3)+1
   case "c"      : s(3)=s(3)-1
   case "f"      : s(4)=s(4)+1
   case "v"      : s(4)=s(4)-1

   ' Detune channels 1-4
   case "g" : tune(1)=tune(1)+0.1
   case "b" : tune(1)=tune(1)-0.1
   case "h" : tune(2)=tune(2)+0.1
   case "n" : tune(2)=tune(2)-0.1
   case "j" : tune(3)=tune(3)+0.1
   case "m" : tune(3)=tune(3)-0.1
   case "k" : tune(4)=tune(4)+0.1
   case "," : tune(4)=tune(4)-0.1

   case else : exit sub

 end select

 notes=notes-1
 pause 100
end sub

sub apply_restrictions()
 local i

 ' Restrict ocatave values.
 for i = 1 to 4
   if okt(i) > 48 then okt(i) = 48
   if okt(i) < -24 then okt(i) = -24
 next i

 ' Restrict sound values.
 ' Only sounds 1 & 2 are useful, 3 and 4 are noise.
 for i = 1 to 4
   if s(i) <= 1 then s(i)=1 else s(i)=2
 next i

 ' Restrict frequency.
 for i = 1 to 4
   if okt(i)=48 and tnr(i) > 40 then tnr(i)=40
 next i
end sub

sub update_display()
 local i

 font 2

 color rgb(rnd()*255,rnd()*255,rnd()*255)
 print @(12,1) "* * * * * * * * * Mr. Polysynth by TweakerRay * * * * * * * * *"
 color rgb(0,255,0)

 print @(10,100) "Keydown   :" format$(keys, "%4g") format$(notes, "%4g")

 print @(10,120) "Frequency :";
 for i = 1 To 4 : print format$(freq(tnr(i)), "%10g"); : next i : print

 print @(10,160) "Tuning    :";
 for i = 1 to 4 : print format$(tune(i), "%4g"); : next i : print

 print @(10,180) "Oktave    :";
 for i = 1 to 4 : print format$(okt(i), "%4g"); : next i : print

 print @(10,200) "Key num   :";
 for i = 1 to 4 : print format$(tnr(i)+okt(i), "%4g"); : next i : print

 print @(10,220) "Sound     :";
 for i = 1 To 4 : print format$(s(i), "%4g"); : next i : print

 print @(10,240) "Layout    :  ";layout$

 font 1
 print @(10,320) "More music at http://tweakerray.bandcamp,com"
 print @(10,340) "And follow at http://www.youtube.com/tweakerray"
end sub

sub play_notes()
 local i

 for i=1 to notes
   if s(i)=1 then
     play sound 1,B,Q,freq(tnr(i)+okt(i))+tune(i),volume
   elseif s(i)=2 then
     play sound 1,B,S,freq(tnr(i)+okt(i))+tune(i),volume
   endif
 next i
end sub