From 67dc751cf066ffb409aed61ecec1923aa4afec72 Mon Sep 17 00:00:00 2001
From: yaw-man <ywmn@protonmail.com>
Date: Fri, 20 Jan 2023 09:53:24 -0400
Subject: [PATCH] Deterministic physics!

---
 main.lua   | 16 ++++++++++++----
 marble.lua |  7 +++----
 wave.lua   |  2 +-
 3 files changed, 16 insertions(+), 9 deletions(-)

diff --git a/main.lua b/main.lua
index c2b89d4..12dab25 100644
--- a/main.lua
+++ b/main.lua
@@ -22,11 +22,11 @@ state = {
   Reset = function()
     state.tick = 0
     state.beat = {}
-    state.startTime = love.timer.getTime()
     state.currentBeat = 1
     state.timeToSimulate = 0.0
     state.longestStreak = 0
     state.currentStreak = 0
+    state.lastCollisionTick = 0
   end,
 
   finishTime = 0.0,
@@ -34,7 +34,6 @@ state = {
   isGameStarted = false,
   lastBeatScore = 0.0,
   currentBeat = 1,
-  startTime = 0.0,
   longestStreak = 0,
   currentStreak = 0,
 
@@ -61,6 +60,7 @@ OnImpact = function( impact )
   local score = BeatScore( impact.t )
   --DEBUG
   state.lastBeatScore = score
+  state.lastCollisionTick = state.tick
   local pass = false
 
   if score > 1.0 then
@@ -210,7 +210,11 @@ end
 
 OnVictory = function()
 
-  recorder.Save()
+  if state.isDemo then
+    state.isDemo = false
+  else
+    recorder.Save()
+  end
 
   particles:setParticleLifetime( 0, 30 )
   particles:setSizes( 0.001, 0.0001, 0.0005 )
@@ -230,7 +234,7 @@ OnVictory = function()
   love.graphics.setCanvas( marble.Canvas() )
   love.graphics.setCanvas() 
 
-  local totalTime = love.timer.getTime() - state.startTime
+  local totalTime = state.tick / 120.0
   OnImpact = function() end
   love.update = function( dt )
     while dt > step do
@@ -292,6 +296,10 @@ Draw = function()
   sitelenpona.Draw( text.words[state.currentBeat] )
   marble.Draw()
   text.Draw( state.currentBeat )
+  
+  love.graphics.print( state.tick, 400, 400, 0, 1, 1 )
+  love.graphics.print( state.currentStreak, 400, 450, 0, 1, 1 )
+  love.graphics.print( state.lastCollisionTick, 400, 500, 0, 1, 1 )
 end
 
 
diff --git a/marble.lua b/marble.lua
index 06c8087..067a15d 100644
--- a/marble.lua
+++ b/marble.lua
@@ -22,7 +22,7 @@ function marble.GetAcceleration( ) return ddx, ddy end
 function marble.SetAcceleration( x, y ) ddx = x; ddy = y end
 
 function marble.Integrate( step )
-  newState.t = love.timer.getTime()
+  newState.t = curState.t + step
   newState.dx = (1.0 - INERTIA) * curState.dx + INERTIA * ddx
   newState.dy = (1.0 - INERTIA) * curState.dy + INERTIA * ddy
   newState.x = curState.x + newState.dx * step * MAXSPEED
@@ -75,7 +75,7 @@ function marble.OnImpact( impact, level )
     xn = 0.2 * unx + x, yn = 0.2 * uny + y,
     vxout = x + vxout, vyout = y + vyout}]]
 
-  return marble.Integrate( math.max( impact.dt , 1 / 120 ) ) --Hmm! Maybe this should be a fixed step instead for stability's sake.
+  return marble.Integrate( 1 / 120.0 ) --Hmm! Maybe this should be a fixed step instead for stability's sake.
 end
 
 function marble.Update()
@@ -87,7 +87,6 @@ function marble.Update()
 end
 
 
-
 function marble.OnKey( tick )
   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)
@@ -126,7 +125,7 @@ function marble.Draw()
 
   --Extrapolate forward for slightly smoother rendering.
   local dt = love.timer.getTime() - curState.t 
-  marble.Integrate( dt + 1 / 60.0 )
+  marble.Integrate( 1 / 120.0 )
 
   local xp, yp = transform:transformPoint( oldState.x, oldState.y )
   local xc, yc = transform:transformPoint( curState.x, curState.y )
diff --git a/wave.lua b/wave.lua
index 6c8f493..e6ab268 100644
--- a/wave.lua
+++ b/wave.lua
@@ -159,7 +159,7 @@ local function OnImpact( impact, level )
   local r = cur.radii
   local theta = impact.th
   local magnitude = IMPULSESIZE * impact.speed
-  local dt = math.max( impact.dt, 1 / 120.0 )
+  local dt = 1.0 / 120.0
   for i = 0, N - 1 do
     r[ i + 1 ] = r[ i + 1 ] + dt * magnitude * AliasedSinc(  theta, 2.0 * math.pi * i / N )
   end