From 7325cd8034c1a98e423937303aa7649c44253302 Mon Sep 17 00:00:00 2001
From: Christian Speckner <christian.speckner@mayflower.de>
Date: Mon, 20 Mar 2017 00:31:29 +0100
Subject: [PATCH] Fully match missile starfield to hardware.

---
 src/emucore/tia/Missile.cxx | 28 ++++++++++++++--------------
 src/emucore/tia/Missile.hxx |  6 +++---
 src/emucore/tia/TIA.cxx     | 12 ++++++------
 3 files changed, 23 insertions(+), 23 deletions(-)

diff --git a/src/emucore/tia/Missile.cxx b/src/emucore/tia/Missile.cxx
index 7a0c8498f..672efb8e8 100644
--- a/src/emucore/tia/Missile.cxx
+++ b/src/emucore/tia/Missile.cxx
@@ -151,42 +151,42 @@ void Missile::startMovement()
 }
 
 // - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
-bool Missile::movementTick(uInt32 clock, bool apply)
+bool Missile::movementTick(uInt8 clock, uInt8 hclock, bool apply)
 {
   myLastMovementTick = myCounter;
 
   if (clock == myHmmClocks) myIsMoving = false;
 
   if (myIsMoving && apply) {
-    render();
-    tick(false);
+    render(hclock);
+    tick(hclock);
   }
 
   return myIsMoving;
 }
 
 // - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
-void Missile::render()
+void Missile::render(uInt8 hclock)
 {
-  collision = (myIsRendering && myRenderCounter >= 0 && myIsEnabled) ?
-    myCollisionMaskEnabled :
-    myCollisionMaskDisabled;
+  bool render =
+    myIsRendering &&
+    (myRenderCounter >= 0 || (myIsMoving && myRenderCounter == -1 && ((hclock + 1) % 4 == 3))) &&
+    myIsEnabled;
+
+  collision = render ? myCollisionMaskEnabled : myCollisionMaskDisabled;
 }
 
 // - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
-void Missile::tick(bool isReceivingMclock)
+void Missile::tick(uInt8 hclock)
 {
   if (myDecodes[myCounter]) {
     myIsRendering = true;
     myRenderCounter = Count::renderCounterOffset;
-
   } else if (myIsRendering) {
-      bool starfieldEffect = myIsMoving && isReceivingMclock;
-      uInt8 starfieldDelta = (myCounter + 160 - myLastMovementTick + 2) % 4;
 
-      if (myRenderCounter == -2 && starfieldEffect) {
+      if (myIsMoving && myRenderCounter == -1) {
 
-        switch (starfieldDelta) {
+        switch ((hclock + 1) % 4) {
           case 3:
             myEffectiveWidth = myWidth == 1 ? 2 : myWidth;
             if (myWidth < 4) myRenderCounter++;
@@ -203,7 +203,7 @@ void Missile::tick(bool isReceivingMclock)
 
       }
 
-      if (++myRenderCounter >= (starfieldEffect ? myEffectiveWidth : myWidth)) myIsRendering = false;
+      if (++myRenderCounter >= (myIsMoving ? myEffectiveWidth : myWidth)) myIsRendering = false;
   }
 
   if (++myCounter >= 160) myCounter = 0;
diff --git a/src/emucore/tia/Missile.hxx b/src/emucore/tia/Missile.hxx
index 5634995f0..0670d4d70 100644
--- a/src/emucore/tia/Missile.hxx
+++ b/src/emucore/tia/Missile.hxx
@@ -46,11 +46,11 @@ class Missile : public Serializable
 
     void startMovement();
 
-    bool movementTick(uInt32 clock, bool apply);
+    bool movementTick(uInt8 clock, uInt8 hclock, bool apply);
 
-    void render();
+    void render(uInt8 hclock);
 
-    void tick(bool isReceivingMclock = true);
+    void tick(uInt8 hclock);
 
     void setColor(uInt8 color);
 
diff --git a/src/emucore/tia/TIA.cxx b/src/emucore/tia/TIA.cxx
index 079d9e0bc..c9385dab8 100644
--- a/src/emucore/tia/TIA.cxx
+++ b/src/emucore/tia/TIA.cxx
@@ -897,8 +897,8 @@ void TIA::tickMovement()
     bool m = false;
     uInt8 movementCounter = myMovementClock > 15 ? 0 : myMovementClock;
 
-    m = myMissile0.movementTick(movementCounter, apply) || m;
-    m = myMissile1.movementTick(movementCounter, apply) || m;
+    m = myMissile0.movementTick(movementCounter, myHctr, apply) || m;
+    m = myMissile1.movementTick(movementCounter, myHctr, apply) || m;
     m = myPlayer0.movementTick(movementCounter, apply) || m;
     m = myPlayer1.movementTick(movementCounter, apply) || m;
     m = myBall.movementTick(movementCounter, apply) || m;
@@ -960,16 +960,16 @@ void TIA::renderSprites()
 {
   myPlayer0.render();
   myPlayer1.render();
-  myMissile0.render();
-  myMissile1.render();
+  myMissile0.render(myHctr);
+  myMissile1.render(myHctr);
   myBall.render();
 }
 
 // - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
 void TIA::tickSprites()
 {
-  myMissile0.tick();
-  myMissile1.tick();
+  myMissile0.tick(myHctr);
+  myMissile1.tick(myHctr);
   myPlayer0.tick();
   myPlayer1.tick();
   myBall.tick();