Code quality fixes

shared/_meta.lua

@@ -0,0 +1,15 @@
+function klass()
+ local k={}
+ k.__index=k
+ function k:new(...)
+  local n={}
+  setmetatable(n,k)
+  n:init(...)
+  return n
+ end
+ return k
+end
+
+function assert_range(i,mn,mx,name)
+ assert(i >= mn and i < mx, name.." must be ["..mn..","..mx..")")
+end

shared/nflags.lua

@@ -0,0 +1,41 @@
+nflags=klass()
+function nflags:init(o)
+ self.c = o.c or 0  -- custom
+ self.e = o.e or 0 -- effect
+ self.v = o.v or 0 -- volume
+ self.w = o.w or 0 -- waveform
+ self.p = o.p or 0 -- pitch
+
+ self:validate()
+end
+
+function nflags:validate()
+ local c,e,v,w,p
+  =self.c,self.e,self.v,self.w,self.p
+
+ assert_range(c,0,2,"custom")
+ assert_range(e,0,8,"effect")
+ assert_range(v,0,8,"volume")
+ assert_range(w,0,8,"waveform")
+ assert_range(p,0,64,"pitch")
+end
+
+function nflags:encode()
+ self:validate()
+ local c,e,v,w,p
+  =self.c,self.e,self.v,self.w,self.p
+
+ c &= 0xffff
+ e &= 0xffff
+ v &= 0xffff
+ w &= 0xffff
+ p &= 0xffff
+
+ return (
+  (c << 15) |
+  (e << 12) |
+  (v << 9) |
+  (w << 6) |
+  (p)
+ )
+end

shared/pattern.lua

@@ -0,0 +1,45 @@
+
+pattern=klass()
+function pattern:init(p)
+ self.pflags=pflags:new(p)
+
+ self.nflags={}
+ for i=0,31 do  -- because the user could change the length
+  self.nflags[i]=nflags:new{}
+ end
+end
+function pattern:plot(ix, n)
+ assert_range(ix,0,self.pflags.len,"ix")
+ self.nflags[ix]=nflags:new(n)
+end
+function pattern:silent()
+ for i=0,31 do
+  if (self.nflags[i].v!=0) return
+ end
+ return true
+end
+function pattern:key()
+ local key=0
+ for i=0,self.pflags.len-1 do
+  key ^= self.nflags[i]:encode()>>(i%16)
+ end
+ return key
+end
+function pattern:eq(other)
+ if (self.pflags:encode() != other.pflags:encode()) return
+
+ for i=0,self.pflags.len-1 do
+  if (self.nflags[i]:encode()!= other.nflags[i]:encode()) return
+ end
+ return true
+end
+function pattern:map_to(ix)
+ self.map_ix=ix
+
+ local at=0x3200+ix*68
+ poke4(at+64,self.pflags:encode())
+
+ for i=0,31 do
+  poke2(at+i*2,self.nflags[i]:encode())
+ end
+end

shared/pflags.lua

@@ -0,0 +1,53 @@
+pflags=klass()
+function pflags:init(o)
+ self.speed = o.speed or 15
+ self.len = o.len or 32
+ self.noiz = o.noiz or 0
+ self.buzz = o.buzz or 0
+ self.detune = o.detune or 0
+ self.reverb = o.reverb or 0
+ self.dampen = o.dampen or 0
+ self.editormode = o.editormode or 1
+end
+
+function pflags:validate()
+ local speed,len,noiz,buzz,detune,reverb,dampen,editormode
+  =self.speed,self.len,self.noiz,self.buzz,
+   self.detune,self.reverb,self.dampen,self.editormode
+ 
+ assert_range(speed,1,255,"speed")
+ assert_range(len,1,33,"len")
+ assert_range(noiz,0,2,"noiz")
+ assert_range(buzz,0,2,"buzz")
+ assert_range(detune,0,3,"detune")
+ assert_range(reverb,0,3,"reverb")
+ assert_range(dampen,0,3,"dampen")
+ assert_range(editormode,0,2,"editormode")
+end
+
+function pflags:encode()
+ local speed,len,noiz,buzz,detune,reverb,dampen,editormode
+  =self.speed,self.len,self.noiz,self.buzz,
+   self.detune,self.reverb,self.dampen,self.editormode
+
+ speed &= 0xffff
+ len &= 0xffff
+ noiz &= 0xffff
+ buzz &= 0xffff
+ detune &= 0xffff
+ reverb &= 0xffff
+ dampen &= 0xffff
+ editormode &= 0xffff
+
+ self:validate()
+ local byte0 = (
+  dampen*72 +
+  reverb*24 +
+  detune*8 +
+  buzz*4 +
+  noiz*2 +
+  editormode  -- "in editor mode" flag
+ )
+ return len | speed>>8 | byte0 >>16
+end
+

shared/track.lua

@@ -0,0 +1,78 @@
+track=klass()
+function track:init()
+ self.frames={}
+ self.ix_to_frame={}
+ self.next_frame_start=0
+end
+function track:add(len)
+ for i=0,len-1 do
+  self.ix_to_frame[self.next_frame_start+i]={#self.frames,i}
+ end
+ add(self.frames,{
+  pattern:new({len=len}),
+  pattern:new({len=len}),
+  pattern:new({len=len}),
+  pattern:new({len=len}),
+ })
+ self.next_frame_start+=len
+end
+
+function track:pattern(channel,offset)
+ offset = offset or -1
+ channel &= 0xffff
+ offset &= 0xffff
+
+ assert_range(channel,0,4,"channel")
+ local n_frames_long=#self.frames
+ assert_range(offset,-n_frames_long,n_frames_long,"offset")
+ if offset<0 then
+  offset+=n_frames_long
+ end
+ return self.frames[offset+1][channel+1]
+end
+
+function track:plot(channel,offset,inst)
+ assert_range(channel,0,4,"channel")
+ assert_range(offset,0,self.next_frame_start,"offset")
+ local tup=self.ix_to_frame[offset]
+ assert(tup)  -- should be unable to fail
+ local frame,offset=unpack(tup)
+ self.frames[frame+1][channel+1]:plot(offset,inst)
+end
+
+function track:build(
+ free_patterns,
+ frame_a,
+ frame_z
+)
+ local n_frames_long = #self.frames
+ if (not frame_z) frame_z = frame_a + n_frames_long
+ assert(frame_z-frame_a == n_frames_long, 
+  "wrong number of frames (must be "..
+  frame_a.." to "..frame_a+n_frames_long..")")
+
+ -- dump patterns and frames
+ local mapped_patterns={}
+ local function map_to_real_pattern(pat)
+  if (pat:silent()) return 0 | (1<<6)
+
+  local key = pat:key()
+  mapped_patterns[key] = mapped_patterns[key] or {}
+  local t = mapped_patterns[key]
+  for other in all(t) do
+   if (pat:eq(other)) return other.map_ix
+  end
+  assert(#free_patterns>0, "out of free patterns")
+  pat:map_to(deli(free_patterns,1))
+  add(t,pat)
+  return pat.map_ix 
+ end
+
+ local fmaddr=0x3100+(frame_a)*4
+ for frame=1,n_frames_long do
+  for i=0,3 do
+   poke(fmaddr+i,map_to_real_pattern(self.frames[frame][i+1]))
+  end
+  fmaddr+=1
+ end
+end