BIG big commit, tweak physics parameters. Fix beat detection bug.

Scale down particle sprite. Fix sitelen pona rendering, fix text rendering.
Invert white border feedback, more intuitive semantics.
&c. &c.

.gitignore

@@ -1,2 +1,3 @@
 build/
+screenshots/
 cover.png

audio.lua

@@ -4,20 +4,26 @@ local failChimes = {}
 local drones = {}
 local N = 8
 
+love.audio.setDistanceModel( "exponentclamped" )
+
 local function StartDrones()
   love.audio.setEffect( "droneReverb", {
       type = "reverb",
-      volume = 1.0, }
+      volume = 1.0,
+      decaytime = 20}
 
-)
+  )
 
   drones.bass = love.audio.newSource("sounds/drone.flac", "stream")  
   drones.alto = love.audio.newSource("sounds/drone.flac", "stream")
   drones.bass:setVolume( 0 )
-  drones.bass:setPitch( 0.25 )
+  drones.bass:setPitch( 0.125 )
   drones.alto:setVolume( 0 )
-  drones.bass:setPitch( 0.5 )
+  drones.bass:setPitch( 0.25 )
   drones.bass:setEffect( "droneReverb", true )
+  drones.alto:setEffect( "droneReverb", true )
+  drones.bass:stop()
+  drones.alto:stop()
 
   love.audio.play( drones.bass )
   love.audio.play( drones.alto )
@@ -72,6 +78,13 @@ local function OnImpact( impact, score, pass, level )
   if not pass then
     --drones.bass:seek( level )
     -- drones.alto:seek( level )
+  else
+    
+    love.audio.setEffect( "passChimeReverb", {
+    type = "reverb",
+    volume = 1.0, 
+    gain = 0.1 + level / 200} )
+    
   end
 
   local th = impact.th
@@ -81,6 +94,7 @@ local function OnImpact( impact, score, pass, level )
   local chime = pass and GetNextPassChime() or GetNextFailChime()
   chime:setPitch( GetPitch( th ) )
   chime:setPosition( r * math.cos( th ), r * math.sin( th ) )
+  chime:setVolume( 0.1 + level / 200 )
   local highgain = math.max( 0, math.min( score, 1.0 ) - (pass and 0.0 or 0.5))
   chime:setFilter{
     type = "lowpass",
@@ -92,11 +106,22 @@ local function OnImpact( impact, score, pass, level )
 
 end
 
+local function OnVictory( )
+  love.audio.setEffect( "passChimeReverb", {
+      type = "reverb",
+      volume = 1.0,
+      decaytime = 20,} )
+end
+
 --score is the hypothetical "beat score" that would be attained
 --if an impact took place at this instant.
-local function Update( score )
+local function Update( score, level )
-  drones.bass:setVolume( 0.5 * math.sqrt( score ) )
+
-  --drones.alto:setVolume( 0.3 * score )
+  if level > 2 then
+    drones.bass:setVolume( 0.5 * math.sqrt( score ) )
+    drones.alto:setVolume( 0.3 * score )
+  end
+
 end
 
 local function Reset( )
@@ -108,4 +133,4 @@ local function Reset( )
 end
 
 Reset()
-return { OnImpact = OnImpact, Update = Update, Reset = Reset}
+return { OnImpact = OnImpact, Update = Update, Reset = Reset, OnVictory = OnVictory}

main.lua

@@ -10,7 +10,10 @@ local recorder
 local DetectCollision
 local OnImpact
 local OnVictory
-
+local BeatScore
+local Draw
+local ExtrapolateBeatScore
+local _ExtrapolateBeatScore
 
 local state 
 state = {
@@ -22,9 +25,9 @@ state = {
     state.timeToSimulate = 0.0
   end,
 
+  finishTime = 0.0,
   timeToSimulate = 0.0,
   isGameStarted = false,
-  beatScoreThreshold = 1.0,
   lastBeatScore = 0.0,
   currentBeat = 1,
   startTime = 0.0,
@@ -47,11 +50,50 @@ local function UpdateWindowTransform( w, h )
   transform = tf
 end
 
+OnImpact = function( impact )
+  if not impact then return end
+  local score = BeatScore( impact.t )
+  --DEBUG
+  state.lastBeatScore = score
+  local pass = false
+
+  if score > 1.0 then
+
+    pass = true
+    state.currentBeat = state.currentBeat + 1
+    if state.currentBeat >= 120 then
+      return OnVictory()
+    end
+    
+  end
+
+
+  local x, y = math.cos(impact.th), math.sin(impact.th)
+  particles:setPosition( impact.r * x, impact.r * y )
+  particles:setEmissionArea( "normal", 0.1, 0.2, impact.th, true )
+  particles:emit( 50 * score * score )
+
+  audio.OnImpact( impact, score, pass, state.currentBeat )
+  marble.OnImpact( impact )
+  wave.OnImpact( impact, state.currentBeat )
+end
+local _OnImpact = OnImpact
+
+local function NewGame()
+  love.graphics.setBackgroundColor( 245 / 255, 169 / 255, 184 / 255 ) --Trans pink.
+  OnImpact = _OnImpact
+  ExtrapolateBeatScore = _ExtrapolateBeatScore
+  love.draw = Draw
+  particles:reset()
+  state.Reset()
+  marble.Reset()
+  wave.Reset()
+  text.Reset()
+end
+
 function love.load()
   UpdateWindowTransform( love.graphics.getDimensions() )
 
-  love.graphics.setBackgroundColor( 245 / 255, 169 / 255, 184 / 255 ) --Trans pink.
-  --love.graphics.setBackgroundColor( 91 / 255, 206 / 255, 250 / 255 ) --Trans blue.
   
   do--particle system setup
     particles = love.graphics.newParticleSystem(
@@ -84,22 +126,23 @@ function love.load()
   DetectCollision = assert ( require "collision" )
   audio = assert( require "audio" )
   recorder = assert( require "recorder" )
-  return state.Reset()
+  return NewGame()
 
 end
 
-local function ExtrapolateBeatScore( )
+ExtrapolateBeatScore = function( )
   local t = love.timer.getTime()
   local beat = state.beat
   if not beat.t then return 2.0 end
   if not beat.mu then return 2.0 end
   if beat.mu < 0.001 then return 2.0 end
 
-  t = 1.1 * math.sin( math.pi * ( t - beat.t ) / beat.mu )
+  t = 1.1 * math.sin( 0.5 * math.pi * ( t - beat.t ) / beat.mu )
   return t * t * t * t
 end
+_ExtrapolateBeatScore = ExtrapolateBeatScore
 
-local function BeatScore( t )
+BeatScore = function( t )
   local beat = state.beat
 
   --Base case 1: first tap.
@@ -117,73 +160,51 @@ local function BeatScore( t )
     return 2.0
   end
 
-  local score = 1.1 * math.sin( math.pi * dt / beat.mu )
+  local score = 1.1 * math.sin( 0.5 * math.pi * dt / beat.mu )
   score = score * score * score * score
 
   --General case: update average beat length.
-  if dt > 0.2 then
   
-    local WEIGHT = 0.85 --High number makes the last beat more significant.
+  --Debounce: max BPM 200
+  if dt > 60.0 / 200.0 then
+
+    local WEIGHT = 0.75 --High number makes the last beat more significant.
     local mu = ( 1.0 - WEIGHT ) * beat.mu + WEIGHT * dt
     beat.mu = mu
 
+  else
+    score = 0
   end
 
   return score
 end
 
-OnImpact = function( impact )
-  if not impact then return end
-  local score = BeatScore( impact.t )
-  --DEBUG
-  state.lastBeatScore = score
-  local pass = false
-
-  if score > 1.0 then
-
-    pass = true
-    state.currentBeat = state.currentBeat + 1
-    if state.currentBeat >= 120 then
-      return OnVictory()
-    end
-  end
-
-
-  local x, y = math.cos(impact.th), math.sin(impact.th)
-  particles:setPosition( impact.r * x, impact.r * y )
-  particles:setEmissionArea( "normal", 0.1, 0.2, impact.th, true )
-  particles:emit( 50 * score * score )
-
-  audio.OnImpact( impact, score, pass, state.currentBeat )
-  marble.OnImpact( impact )
-  wave.OnImpact( impact )
-end
-local _OnImpact = OnImpact
-
-
-local function NewGame()
-  OnImpact = _OnImpact
-  state.Reset()
-  marble.Reset()
-  wave.Reset()
-end
-
- 
 OnVictory = function()
+  
+  local totalTime = love.timer.getTime() - state.startTime
   OnImpact = function() end
+  love.draw = function()
+    love.graphics.setColor( 1, 1, 1, 1 )
+    
+    text.Draw( 120 )
+      love.graphics.printf( 
+        "your.time:\n"..totalTime,
+        0, 0.5 * love.graphics.getHeight(),
+        love.graphics.getWidth(),
+        "center"
+      )
+      
+    marble.Draw()
+    end
+  marble.OnVictory()
+  love.graphics.setBackgroundColor( 91 / 255, 206 / 255, 250 / 255 ) --Trans blue.
 end
 
-function love.draw()
+Draw = function()
-
-
-  --[[love.graphics.setColor(1.0, 1.0, 1.0)
-  love.graphics.print( state.beat.mu or 0, 0)
-  love.graphics.print( state.beat.t or 0, 0, 10)
-  love.graphics.print( state.beatScoreThreshold, 0, 20)
-  love.graphics.print( state.lastBeatScore, 0, 30 )]]
 
   local score = ExtrapolateBeatScore()
 
+
   love.graphics.push( "transform" )
   love.graphics.applyTransform( transform )
 
@@ -219,10 +240,9 @@ function love.draw()
   end]]
 
   love.graphics.pop()
-
+  sitelenpona.Draw( text.words[state.currentBeat] )
-  sitelenpona.Draw( text.tok[state.currentBeat] )
-
   marble.Draw()
+  text.Draw( state.currentBeat )
 
 
 end
@@ -231,7 +251,7 @@ end
 
 function love.update( dt )
 
-  audio.Update( ExtrapolateBeatScore() )
+  audio.Update( ExtrapolateBeatScore(), state.currentBeat )
   particles:update( dt )
   dt = dt + state.timeToSimulate
 
@@ -270,3 +290,7 @@ function love.resize( w, h )
   UpdateWindowTransform( w, h )
   if marble then marble.Resize() end
 end
+
+function love.mousepressed( x, y, button, istouch, presses )
+  return NewGame()
+end

marble.lua

@@ -1,5 +1,6 @@
 --Character controller. Renders point particle.
 local love = love
+local marble = {}
 local oldBuffer = love.graphics.newCanvas()
 local newBuffer = love.graphics.newCanvas()
 local oldState, curState, newState
@@ -12,14 +13,14 @@ local function State( )
   return { t = 0, x = 0, y = 0, dx = 0, dy = 0 }
 end
 
-local function GetAcceleration( )
-  return ddx, ddy
-end
 
-local function Current() return curState end
+function marble.Current() return curState end
-local function Next() return newState end
 
-local function Integrate( step )
+function marble.Next() return newState end
+
+function marble.GetAcceleration( ) return ddx, ddy end
+
+function marble.Integrate( step )
   newState.t = love.timer.getTime()
   newState.dx = (1.0 - FRICTION) * curState.dx + FRICTION * ddx
   newState.dy = (1.0 - FRICTION) * curState.dy + FRICTION * ddy
@@ -27,7 +28,7 @@ local function Integrate( step )
   newState.y = curState.y + newState.dy * step * MAXSPEED
 end
 
-local function OnImpact( impact )
+function marble.OnImpact( impact )
   --Adjust current trajectory according to collision.
   if not impact.dt then return end
   
@@ -66,14 +67,14 @@ local function OnImpact( impact )
   curState.x, curState.y = x, y
   curState.dx, curState.dy = vxout, vyout
   
-  debugRenderImpact = { xi = x, yi = y, xf = x - vx, yf = y - vy,
+  --[[debugRenderImpact = { xi = x, yi = y, xf = x - vx, yf = y - vy,
     xn = 0.2 * unx + x, yn = 0.2 * uny + y,
-    vxout = x + vxout, vyout = y + vyout}
+    vxout = x + vxout, vyout = y + vyout}]]
   
-  return Integrate( math.max( impact.dt , 1 / 120 ) ) --Hmm! Maybe this should be a fixed step instead for stability's sake.
+  return marble.Integrate( math.max( impact.dt , 1 / 120 ) ) --Hmm! Maybe this should be a fixed step instead for stability's sake.
 end
 
-local function Update()
+function marble.Update()
   --Roll the log.
   for k, v in pairs( oldState ) do
     oldState[k] = curState[k]
@@ -83,7 +84,7 @@ end
 
 
 
-local function OnKey()
+function marble.OnKey()
   ddx = (love.keyboard.isScancodeDown( "d" ) and 1.0 or 0.0) - (love.keyboard.isScancodeDown( "a" ) and 1.0 or 0.0)
   ddy = (love.keyboard.isScancodeDown( "w" ) and 1.0 or 0.0) - (love.keyboard.isScancodeDown( "s" ) and 1.0 or 0.0)
   
@@ -92,11 +93,35 @@ local function OnKey()
   ddx, ddy = ddx / n, ddy / n
 end
 
-local function Draw()
+function marble.OnVictory()
+  
+  marble.Draw = function()
   
   --Extrapolate forward for slightly smoother rendering.
   local dt = love.timer.getTime() - curState.t 
-  Integrate( dt + 1 / 60.0 )
+  marble.Integrate( dt + 1 / 60.0 )
+  
+  local xp, yp = transform:transformPoint( oldState.x, oldState.y )
+  local xc, yc = transform:transformPoint( curState.x, curState.y )
+  local xn, yn = transform:transformPoint( newState.x, newState.y )
+  
+  love.graphics.setColor( 91 / 255, 206 / 255, 250 / 255, 1.0 ) --Trans blue.  
+  love.graphics.setLineJoin( "bevel" )
+  love.graphics.setLineStyle( "smooth" )
+  love.graphics.setLineWidth( 8.0 )
+  love.graphics.line( xp, yp, xc, yc, xn, yn)
+  love.graphics.circle( "fill", xn, yn, 4.0 )
+  love.graphics.setCanvas()
+  
+    
+  end
+end
+
+function marble.Draw()
+
+  --Extrapolate forward for slightly smoother rendering.
+  local dt = love.timer.getTime() - curState.t 
+  marble.Integrate( dt + 1 / 60.0 )
   
   local xp, yp = transform:transformPoint( oldState.x, oldState.y )
   local xc, yc = transform:transformPoint( curState.x, curState.y )
@@ -130,12 +155,14 @@ local function Draw()
 
 end
 
-local function Impact( impact )
+marble._Draw = marble.Draw
+
+function marble.Impact( impact )
   
 end
 
 --Window resize.
-local function Resize()
+function marble.Resize()
   newBuffer = love.graphics.newCanvas()
   --TODO: render oldBuffer to new newBuffer, but scaled down.
   oldBuffer = love.graphics.newCanvas()
@@ -143,25 +170,18 @@ local function Resize()
 
 end
 
-local function Reset()  
+function marble.Reset()  
   oldState, curState, newState = State(), State(), State()
-  Resize()
+  marble.Resize()
+  marble.Draw = marble._Draw
+end
+
+function marble.Canvas()
+  return newBuffer
 end
 
 
 
-Reset()
+marble.Reset()
 
-return {
+return marble
-  Integrate = Integrate,
-  OnImpact = OnImpact,
-  Update = Update,
-  OnKey = OnKey,
-  Draw = Draw,
-  Impact = Impact,
-  Reset = Reset,
-  Resize = Resize,
-  Current = Current,
-  Next = Next,
-  GetAcceleration = GetAcceleration,
-}

sitelenpona.lua

@@ -6,12 +6,32 @@ local info = love.filesystem.getInfo( "sitelenpona" )
 for _, filename in ipairs(love.filesystem.getDirectoryItems( "sitelenpona" )) do
   sp[filename:gsub( ".png", "" )] = love.graphics.newImage( "sitelenpona/"..filename )
 end
---Render one glyph in the center.
+--Render one or two glyphs in the center.
-sp.Draw = function( str )
+sp.Draw = function( t )
-  local w, h = love.graphics.getDimensions()
+  local cx, cy = love.graphics.getDimensions()
-  local x, y = 0.5 * w - 128, 0.5 * h - 128
+  cx, cy = 0.5 * cx, 0.5 * cy
   love.graphics.setColor( 1.0, 1.0, 1.0, 0.5 )
-  love.graphics.draw( sp[str] or sp.q, x, y )
+  
+  if #t == 1 then
+    love.graphics.draw( sp[t[1]] or sp.pilin, cx - 128, cy - 128 )
+  elseif #t == 2 then
+    love.graphics.draw( sp[t[1]] or sp.pilin, cx - 128, cy - 64, 0, 0.5, 0.5 )
+    love.graphics.draw( sp[t[2]] or sp.pilin, cx, cy - 64, 0, 0.5, 0.5 )
+  elseif #t == 3 then
+    love.graphics.draw( sp[t[1]] or sp.pilin, cx - 128, cy - 64, 0, 0.5, 0.5 )
+    love.graphics.draw( sp[t[1]] or sp.pilin, cx - 128, cy - 64, 0, 0.5, 0.5 )
+    love.graphics.draw( sp[t[2]] or sp.pilin, cx, cy - 64, 0, 0.5, 0.5 )
+  end
+  --[[ w in str:gmatch( "%a+") do
+    t[i] = w
+    i = i + 1
+  end
+  for _, str in ipairs( t ) do
+    local w, h = love.graphics.getDimensions()
+    local x, y = 0.5 * w - 128, 0.5 * h - 128
+    
+    love.graphics.draw( sp[str] or sp.pilin, x, y )
+  end]]
 end
 
 

text.lua

@@ -1,17 +1,72 @@
 --Load poems.
 local love = love
-local txt = {}
+local feet = {}
+local feetNL = {}
+local words = {} --Sequence of tables.
+local poem = {[0] = ""}
+local poemLines = {[0] = 0}
 
-local info = love.filesystem.getInfo( "text" )
+local mt = { __index = function() return "linja" end }
-for _, filename in ipairs(love.filesystem.getDirectoryItems( "text" )) do
+
-  local s = love.filesystem.read( "text/"..filename )
+local s = love.filesystem.read( "text/tok.txt" )
-  local t = {}
+local smallFont = love.graphics.setNewFont( "text/linja-sike.ttf", 12 )
-  local i = 1
+local largeFont = love.graphics.setNewFont( "text/linja-sike.ttf", 32 )
-  for w in s:gmatch( "%a+") do
+
-    t[i] = w
+local i = 1
-    i = i + 1
+--Split string into feet.
-  end
+for foot in s:gmatch( ".-%-") do
-  txt[filename:gsub( ".txt", "" )] = t
+  
+  feet[i] = foot:gsub( "-", "" ):gsub( " $", "" ):gsub( "%c", "") --Remove hyphens, trailing spaces, newlines.
+  feetNL[i] = foot:gsub( "-", "" ):gsub(" ", "")--:gsub( "%.", "  " ) --Remove hyphens, spaces, transform periods to spaces
+  
+  
+  poem[i] = poem[ i - 1 ]..feetNL[i]
+  poemLines[i] = poemLines[i - 1] + (feetNL[i]:match( "\n") and 1 or 0)
+
+  
+  i = i + 1
 end
 
-return txt
+--Split string into words.
+i = 1
+local isTe = true
+for foot in s:gmatch( ".-%-" ) do
+  --Split foot into words.
+  local word = {}
+  local j = 1
+
+  for w in foot:gmatch( [["]] ) do
+    word[j] = isTe and "te" or "to"
+    isTe = not( isTe )
+    j = j + 1
+  end
+
+  for w in foot:gmatch( "%a+" ) do
+    word[j] = w
+    j = j + 1
+  end
+  words[i] = word
+  i = i + 1
+end
+
+local function Draw( beat )
+
+  local foot = feet[ beat ]
+
+
+  love.graphics.setColor(1.0, 1.0, 1.0, 1.0)
+  love.graphics.printf( 
+    foot,
+    0, (9/10) * love.graphics.getHeight(),
+    love.graphics.getWidth(),
+    "center")
+
+  love.graphics.setColor(1.0, 1.0, 1.0, 0.5)
+  love.graphics.print( poem[beat], 0, (3 - poemLines[beat]) * 32 )
+
+
+end
+
+local Reset = function() end
+
+return { feet = feet, words = words, feetNL = feetNL, Reset = Reset, Draw = Draw }

text/tok.txt

@@ -1,120 +1,53 @@
-a
+open -la mi -jan pi -toki-
-akesi
+ala -li mu -taso -li ken-
-ala
+ala -pana -toki -pilin-
-alasa
+toki -mu li -wawa -wawa
-ale
+nasa -la jan -ante -li ken-
-anpa
+awen -pona -tawa -mi li-
-ante
+awen -ala-sa e -pona.-
-anu
+moku -mi li -tan jan -pona-
-awen
+mama -mi li -pona -mute-
-e
+mama -tu li -lon. tu -ona-
-en
+o mi -taso. -wile -mute-
-esun
+li lon -sije-lo mi -ike.-
-ijo
+mute -la mi -pilin -nasa-
-ike
+a mi -wile -musi -mute-
-ilo
+wile -mi li -ni: ko -jelo-
-insa
+ni o -kama -tomo -wawa-
-jaki
+tomo -ni li -jo e -poki-
-jan
+poki l-a jan -mi li -lawa-
-jelo
+lawa -la jan -ni li -toki-
-jo
+"tomo -mi li -pona -mute-
-kala
+paka-la o -kama -ala-
-kalama
+weka -o ken -ala -kama"-
-kama
+wile -ala -mi la -ni li-
-kasi
+kama: -jan li -paka-la e-
-ken
+tomo -suli -pona -mi a-
-kepeken
+ni li -ike -tawa -pilin-
-kili
+jan li -ni tan -seme -ike-
-kiwen
+mi ken -ala -sona -pona-
-ko
+wile -toki -li lon -ala-
-kon
+la mi -tawa -mama -kiwen-
-kule
+
-kulupu
+tenpo ni -mute li -kama li -weka la-
-kute
+sijelo -ike li -ante a -mute
-la
+pilin mi -ala li -awen kin -sama-
-lape
+wile mi su-li en wi-le mi li-li li-
-laso
+nasa lon -tenpo ni. -mi kama -suli-
-lawa
+toki pi jan mute li kama ike. jan
-len
+mute li wile e pakala taso
-lete
+lili li wile e sona e nasin
-li
+mute li wile e ni ala. nasa
-lili
+mi toki ala lon poka pi jan ni
-linja
+seme la mi wile alasa toki
-lipu
+jan ni la pilin mi li nasa mute
-loje
+jan ni la musi mi li musi ala
-lon
+seme la mi o lon poka jan ike
-luka
+jan ike ni li ken pona e ala
-lukin
+mute la ona li wile e tawa
-lupa
+ala la wile ona li lon pali
-ma
+mute la mi awen lon insa lawa
-mama
+lawa la mi toki mute e pilin
-mani
+lon lawa ala la mi lukin mute
-meli
+lukin li wile e musi e sona
-mi
+sitelen la m ken moku ni mute
-mije
-moku
-moli
-monsi
-mu
-mun
-musi
-mute
-nanpa
-nasa
-nasin
-nena
-ni
-nimi
-noka
-o
-olin
-ona
-open
-pakala
-pali
-palisa
-pan
-pana
-pi
-pilin
-pimeja
-pini
-pipi
-poka
-poki
-pona
-pu
-sama
-seli
-selo
-seme
-sewi
-sijelo
-sike
-sin
-sina
-sinpin
-sitelen
-sona
-soweli
-suli
-suno
-supa
-suwi
-tan
-taso
-tawa
-telo
-tenpo
-toki
-tomo
-tu
-unpa
-uta
-utala
-walo
-wan
-waso
-wawa
-weka
-wile

wave.lua

@@ -1,9 +1,9 @@
 --Render and simulate 1D wave equation.
 local love = love
 local N = 33
-local SOUNDSPEED = 0.5
+local SOUNDSPEED
-local IMPULSESIZE = 5
+local IMPULSESIZE
-local DAMPING = 0.01
+local DAMPING
 
 
 local old, cur, new --States add beginning of last tick, current tick, and next tick respectively.
@@ -47,8 +47,9 @@ local shader = love.graphics.newShader([[
     p.y = -p.y;
 
     float r = r( atan(p.y, p.x) ) - length( p );
+    float q = float( r < 0.01 ) * clamp( 1.0 - score, 0.0, 1.0 ) ;
 
-    return vec4( (1.0 + float(score > 1.0) * r * 0.1) * color.xyz, float(r > -0.01)) ;
+    return vec4( q + (1.0 + clamp( score, 0.0, 1.0 ) * r * r * 0.2) * color.xyz, float(r > 0.0)) ;
 }
   ]])
 
@@ -146,9 +147,15 @@ local function AliasedSinc( theta, x )
   return n / d
 end
 
---Apply bandlimited impulse to wave.
+--Apply bandlimited impulse to wave, adjust free parameters according to game state.
-local function OnImpact( impact )
+local function OnImpact( impact, level )
   
+  IMPULSESIZE = 10.0 * math.sqrt( level / 120.0 )
+  SOUNDSPEED = 50.0 - 35 *  level / 120 
+  DAMPING = 0.03 * ( 1.0 - 0.4 * level / 120 )
+
+
+  --Apply bandlimited impulse.
   local r = cur.radii
   local theta = impact.th
   local magnitude = IMPULSESIZE * impact.speed
@@ -272,11 +279,14 @@ end
 Integrate = function( step )
 
   for i = 1, N do
+    
     local rxx = cur:SecondDerivative( math.pi * 2.0 * ( i - 1 ) / N )
+    
     local r = ( 1.0 - DAMPING ) * ( 2.0 * cur.radii[i] - old.radii[i] + step * step * SOUNDSPEED * rxx ) --Verlet
     + DAMPING --Damping: oscillate toward 1.
-    if r > 1.5 then r = 1.5 end
+    
-    if r < 0.5 then r = 0.5 end
+    --Avoid explosions.
+    r = math.max( 0.5, math.min( r, 4.0 ) )
     new.radii[i] = r
   end
 
@@ -290,9 +300,9 @@ end
 
 local function Reset()
   
-  SOUNDSPEED = 0.5
+  IMPULSESIZE = 1 / 10.0
-  IMPULSESIZE = 5
+  SOUNDSPEED = 5.0
-  DAMPING = 0.02
+  DAMPING = 0.1 / 1
   
   old = Wave()
   cur = Wave()