[+] Added MissileType::ParabolCoefficient, to control curve coefficient in MissileParabolic

[*] All calculations in MissileParabolic now use doubles instead of ints

src/include/missile.h

@@ -379,6 +379,7 @@ public:
 
 	int Class;                 /// missile class
 	int NumBounces;            /// number of bounces
+	int ParabolCoefficient;    /// parabol coefficient in parabolic missile
 	int StartDelay;            /// missile start delay
 	int Sleep;                 /// missile sleep
 	int Speed;                 /// missile speed

src/missile/missile.cpp

@@ -1231,7 +1231,8 @@ MissileType::MissileType(const std::string &ident) :
 	Ident(ident), Transparency(0), DrawLevel(0),
 	SpriteFrames(0), NumDirections(0), ChangeVariable(-1), ChangeAmount(0), ChangeMax(false),
 	CorrectSphashDamage(false), Flip(false), CanHitOwner(false), FriendlyFire(false),
-	AlwaysFire(false), Pierce(false), PierceOnce(false), Class(), NumBounces(0), StartDelay(0),
+	AlwaysFire(false), Pierce(false), PierceOnce(false), Class(), NumBounces(0),
+	ParabolCoefficient(2048), StartDelay(0),
 	Sleep(0), Speed(0), TTL(-1), Damage(0), ReduceFactor(100), SmokePrecision(0),
 	Range(0), SplashFactor(0),
 	ImpactParticle(NULL), SmokeParticle(NULL), OnImpact(NULL),

src/missile/missile_parabolic.cpp

@@ -55,10 +55,10 @@
 static bool ParabolicMissile(Missile &missile)
 {
 	// Should be initialised by an other method (computed with distance...)
-	const int k = -2048; //-1024; // Coefficient of the parabol.
-	const int zprojToX = 4;    // Projection of Z axis on axis X.
-	const int zprojToY = 1024; // Projection of Z axis on axis Y.
-	int z;        // should be missile.Z later.
+	const double k = -missile.Type->ParabolCoefficient; // Coefficient of the parabol.
+	const double zprojToX = 4.0;    // Projection of Z axis on axis X.
+	const double zprojToY = 1024.0; // Projection of Z axis on axis Y.
+	double z;        // should be missile.Z later.
 
 	MissileInitMove(missile);
 	if (missile.TotalStep == 0) {
@@ -73,10 +73,10 @@ static bool ParabolicMissile(Missile &missile)
 	missile.position = missile.source + diff * missile.CurrentStep / missile.TotalStep;
 
 	Assert(k != 0);
-	z = missile.CurrentStep * (missile.TotalStep - missile.CurrentStep) / k;
+	z = (double)missile.CurrentStep * (missile.TotalStep - missile.CurrentStep) / k;
 	// Until Z is used for drawing, modify X and Y.
-	missile.position.x += z * zprojToX / 64;
-	missile.position.y += z * zprojToY / 64;
+	missile.position.x += (int)(z * zprojToX / 64.0);
+	missile.position.y += (int)(z * zprojToY / 64.0);
 	missile.MissileNewHeadingFromXY(missile.position - orig_pos);
 	for (; pos.x * sign.x <= missile.position.x * sign.x
 		 && pos.y * sign.y <= missile.position.y * sign.y;

src/missile/script_missile.cpp

@@ -130,6 +130,8 @@ void MissileType::Load(lua_State *l)
 			}
 		} else if (!strcmp(value, "NumBounces")) {
 			this->NumBounces = LuaToNumber(l, -1);
+		} else if (!strcmp(value, "ParabolCoefficient")) {
+			this->ParabolCoefficient = LuaToNumber(l, -1);
 		} else if (!strcmp(value, "Delay")) {
 			this->StartDelay = LuaToNumber(l, -1);
 		} else if (!strcmp(value, "Sleep")) {