Ticket #18: advanced_attack-220212.diff

source/simulation2/components/tests/test_RangeManager.h

@@ -50 +50 @@
     virtual bool IsFloating() { return false; }
     virtual CFixedVector3D GetPosition() { return CFixedVector3D(); }
     virtual CFixedVector2D GetPosition2D() { return CFixedVector2D(); }
+    virtual CFixedVector3D GetPreviousPosition() { return CFixedVector3D(); }
+    virtual CFixedVector2D GetPreviousPosition2D() { return CFixedVector2D(); }
     virtual void TurnTo(entity_angle_t UNUSED(y)) { }
     virtual void SetYRotation(entity_angle_t UNUSED(y)) { }
     virtual void SetXZRotation(entity_angle_t UNUSED(x), entity_angle_t UNUSED(z)) { }

source/simulation2/components/ICmpProjectileManager.h

@@ -31 +31 @@
 class ICmpProjectileManager : public IComponent
 {
 public:
-    /**
-     * Launch a projectile from entity @p source to entity @p target.
-     * @param source source entity; the projectile will determined from the "projectile" prop in its actor
-     * @param target target entity; the projectile will automatically track the target to ensure it always hits precisely
-     * @param speed horizontal speed in m/s
-     * @param gravity gravitational acceleration in m/s^2 (determines the height of the ballistic curve)
-     */
-    virtual void LaunchProjectileAtEntity(entity_id_t source, entity_id_t target, fixed speed, fixed gravity) = 0;
 
     /**
      * Launch a projectile from entity @p source to point @p target.
@@ -46 +38 @@
      * @param target target point
      * @param speed horizontal speed in m/s
      * @param gravity gravitational acceleration in m/s^2 (determines the height of the ballistic curve)
+     * @return id of the created projectile 
      */
-    virtual void LaunchProjectileAtPoint(entity_id_t source, CFixedVector3D target, fixed speed, fixed gravity) = 0;
+    virtual uint32_t LaunchProjectileAtPoint(entity_id_t source, CFixedVector3D target, fixed speed, fixed gravity) = 0;
+    
+    /**
+     * Removes a projectile, used when the projectile has hit a target
+     * @param id of the projectile to remove
+     */
+    virtual void RemoveProjectile(uint32_t id) = 0;
 
     DECLARE_INTERFACE_TYPE(ProjectileManager)
 };

source/simulation2/components/ICmpProjectileManager.cpp

@@ -22 +22 @@
 #include "simulation2/system/InterfaceScripted.h"
 
 BEGIN_INTERFACE_WRAPPER(ProjectileManager)
-DEFINE_INTERFACE_METHOD_4("LaunchProjectileAtEntity", void, ICmpProjectileManager, LaunchProjectileAtEntity, entity_id_t, entity_id_t, fixed, fixed)
-DEFINE_INTERFACE_METHOD_4("LaunchProjectileAtPoint", void, ICmpProjectileManager, LaunchProjectileAtPoint, entity_id_t, CFixedVector3D, fixed, fixed)
+DEFINE_INTERFACE_METHOD_4("LaunchProjectileAtPoint", uint32_t, ICmpProjectileManager, LaunchProjectileAtPoint, entity_id_t, CFixedVector3D, fixed, fixed)
+DEFINE_INTERFACE_METHOD_1("RemoveProjectile", void, ICmpProjectileManager, RemoveProjectile, uint32_t)
 END_INTERFACE_WRAPPER(ProjectileManager)

source/simulation2/components/ICmpPosition.h

@@ -108 +108 @@
      */
     virtual CFixedVector2D GetPosition2D() = 0;
 
+    /** 
+     * Returns the previous turn's x,y,z position (no interpolation). 
+     * Depends on the current terrain heightmap. 
+     * Must not be called unless IsInWorld is true. 
+     */ 
+    virtual CFixedVector3D GetPreviousPosition() = 0; 
+
+    /** 
+     * Returns the previous turn's x,z position (no interpolation). 
+     * Must not be called unless IsInWorld is true. 
+     */ 
+    virtual CFixedVector2D GetPreviousPosition2D() = 0; 
+
     /**
      * Rotate smoothly to the given angle around the upwards axis.
      * @param y clockwise radians from the +Z axis.

source/simulation2/components/ICmpPosition.cpp

@@ -32 +32 @@
 DEFINE_INTERFACE_METHOD_0("IsFloating", bool, ICmpPosition, IsFloating)
 DEFINE_INTERFACE_METHOD_0("GetPosition", CFixedVector3D, ICmpPosition, GetPosition)
 DEFINE_INTERFACE_METHOD_0("GetPosition2D", CFixedVector2D, ICmpPosition, GetPosition2D)
+DEFINE_INTERFACE_METHOD_0("GetPreviousPosition", CFixedVector3D, ICmpPosition, GetPreviousPosition) 
+DEFINE_INTERFACE_METHOD_0("GetPreviousPosition2D", CFixedVector2D, ICmpPosition, GetPreviousPosition2D) 
 DEFINE_INTERFACE_METHOD_1("TurnTo", void, ICmpPosition, TurnTo, entity_angle_t)
 DEFINE_INTERFACE_METHOD_1("SetYRotation", void, ICmpPosition, SetYRotation, entity_angle_t)
 DEFINE_INTERFACE_METHOD_2("SetXZRotation", void, ICmpPosition, SetXZRotation, entity_angle_t, entity_angle_t)

source/simulation2/components/CCmpProjectileManager.cpp

@@ -20 +20 @@
 #include "simulation2/system/Component.h"
 #include "ICmpProjectileManager.h"
 
+#include "ICmpObstruction.h"
+#include "ICmpObstructionManager.h"
 #include "ICmpPosition.h"
 #include "ICmpRangeManager.h"
 #include "ICmpTerrain.h"
@@ -58 +60 @@
     virtual void Init(const CParamNode& UNUSED(paramNode))
     {
         m_ActorSeed = 0;
+        m_Id = 1;
     }
 
     virtual void Deinit()
@@ -86 +89 @@
         case MT_Interpolate:
         {
             const CMessageInterpolate& msgData = static_cast<const CMessageInterpolate&> (msg);
-            Interpolate(msgData.frameTime, msgData.offset);
+            Interpolate(msgData.frameTime);
             break;
         }
         case MT_RenderSubmit:
@@ -98 +101 @@
         }
     }
 
-    virtual void LaunchProjectileAtEntity(entity_id_t source, entity_id_t target, fixed speed, fixed gravity)
+    virtual uint32_t LaunchProjectileAtPoint(entity_id_t source, CFixedVector3D target, fixed speed, fixed gravity)
     {
-        LaunchProjectile(source, CFixedVector3D(), target, speed, gravity);
+        return LaunchProjectile(source, target, speed, gravity);
     }
+    
+    virtual void RemoveProjectile(uint32_t);
 
-    virtual void LaunchProjectileAtPoint(entity_id_t source, CFixedVector3D target, fixed speed, fixed gravity)
-    {
-        LaunchProjectile(source, target, INVALID_ENTITY, speed, gravity);
-    }
-
 private:
     struct Projectile
     {
         CUnit* unit;
         CVector3D pos;
         CVector3D target;
-        entity_id_t targetEnt; // INVALID_ENTITY if the target is just a point
         float timeLeft;
         float speedFactor;
         float gravity;
         bool stopped;
+        uint32_t id;
     };
 
     std::vector<Projectile> m_Projectiles;
 
     uint32_t m_ActorSeed;
+    
+    uint32_t m_Id;
 
-    void LaunchProjectile(entity_id_t source, CFixedVector3D targetPoint, entity_id_t targetEnt, fixed speed, fixed gravity);
+    uint32_t LaunchProjectile(entity_id_t source, CFixedVector3D targetPoint, fixed speed, fixed gravity);
 
-    void AdvanceProjectile(Projectile& projectile, float dt, float frameOffset);
+    void AdvanceProjectile(Projectile& projectile, float dt);
 
-    void Interpolate(float frameTime, float frameOffset);
+    void Interpolate(float frameTime);
 
     void RenderSubmit(SceneCollector& collector, const CFrustum& frustum, bool culling);
 };
 
 REGISTER_COMPONENT_TYPE(ProjectileManager)
 
-void CCmpProjectileManager::LaunchProjectile(entity_id_t source, CFixedVector3D targetPoint, entity_id_t targetEnt, fixed speed, fixed gravity)
+uint32_t CCmpProjectileManager::LaunchProjectile(entity_id_t source, CFixedVector3D targetPoint, fixed speed, fixed gravity)
 {
     if (!GetSimContext().HasUnitManager())
-        return; // do nothing if graphics are disabled
+        return 0; // do nothing if graphics are disabled
 
     CmpPtr<ICmpVisual> cmpSourceVisual(GetSimContext(), source);
     if (!cmpSourceVisual)
-        return;
+        return 0;
 
     std::wstring name = cmpSourceVisual->GetProjectileActor();
     if (name.empty())
@@ -151 +153 @@
         // If the actor was actually loaded, complain that it doesn't have a projectile
         if (!cmpSourceVisual->GetActorShortName().empty())
             LOGERROR(L"Unit with actor '%ls' launched a projectile but has no actor on 'projectile' attachpoint", cmpSourceVisual->GetActorShortName().c_str());
-        return;
+        return 0;
     }
 
     CVector3D sourceVec(cmpSourceVisual->GetProjectileLaunchPoint());
@@ -161 +163 @@
 
         CmpPtr<ICmpPosition> sourcePos(GetSimContext(), source);
         if (!sourcePos)
-            return;
+            return 0;
 
         sourceVec = sourcePos->GetPosition();
         sourceVec.Y += 3.f;
@@ -169 +171 @@
 
     CVector3D targetVec;
 
-    if (targetEnt == INVALID_ENTITY)
-    {
-        targetVec = CVector3D(targetPoint);
-    }
-    else
-    {
-        CmpPtr<ICmpPosition> cmpTargetPosition(GetSimContext(), targetEnt);
-        if (!cmpTargetPosition)
-            return;
+    targetVec = CVector3D(targetPoint);
 
-        targetVec = CVector3D(cmpTargetPosition->GetPosition());
-    }
-
     Projectile projectile;
     std::set<CStr> selections;
     projectile.unit = GetSimContext().GetUnitManager().CreateUnit(name, m_ActorSeed++, selections);
+    projectile.id = m_Id++;
     if (!projectile.unit)
     {
         // The error will have already been logged
-        return;
+        return 0;
     }
 
     projectile.pos = sourceVec;
     projectile.target = targetVec;
-    projectile.targetEnt = targetEnt;
 
     CVector3D offset = projectile.target - projectile.pos;
     float horizDistance = sqrtf(offset.X*offset.X + offset.Z*offset.Z);
@@ -205 +196 @@
     projectile.gravity = gravity.ToFloat();
 
     m_Projectiles.push_back(projectile);
+    
+    return projectile.id;
 }
 
-void CCmpProjectileManager::AdvanceProjectile(Projectile& projectile, float dt, float frameOffset)
+void CCmpProjectileManager::AdvanceProjectile(Projectile& projectile, float dt)
 {
     // Do special processing if we've already reached the target
     if (projectile.timeLeft <= 0)
@@ -223 +216 @@
         // apply a bit of drag to them
         projectile.speedFactor *= powf(1.0f - 0.4f*projectile.speedFactor, dt);
     }
-    else
-    {
-        // Projectile hasn't reached the target yet:
-        // Track the target entity (if there is one, and it's still alive)
-        if (projectile.targetEnt != INVALID_ENTITY)
-        {
-            CmpPtr<ICmpPosition> cmpTargetPosition(GetSimContext(), projectile.targetEnt);
-            if (cmpTargetPosition && cmpTargetPosition->IsInWorld())
-            {
-                CMatrix3D t = cmpTargetPosition->GetInterpolatedTransform(frameOffset, false);
-                projectile.target = t.GetTranslation();
-                projectile.target.Y += 2.f; // TODO: ought to aim towards a random point in the solid body of the target
 
-                // TODO: if the unit is moving, we should probably aim a bit in front of it
-                // so we don't have to curve so much just before reaching it
-            }
-        }
-    }
-
     CVector3D offset = (projectile.target - projectile.pos) * projectile.speedFactor;
 
     // Compute the vertical velocity that's needed so we travel in a ballistic curve and
@@ -296 +271 @@
     projectile.unit->GetModel().SetTransform(transform);
 }
 
-void CCmpProjectileManager::Interpolate(float frameTime, float frameOffset)
+void CCmpProjectileManager::Interpolate(float frameTime)
 {
     for (size_t i = 0; i < m_Projectiles.size(); ++i)
     {
-        AdvanceProjectile(m_Projectiles[i], frameTime, frameOffset);
+        AdvanceProjectile(m_Projectiles[i], frameTime);
     }
 
     // Remove the ones that have reached their target
@@ -310 +285 @@
         // Those hitting the ground stay for a while, because it looks pretty.
         if (m_Projectiles[i].timeLeft <= 0.f)
         {
-            if (m_Projectiles[i].targetEnt == INVALID_ENTITY && m_Projectiles[i].timeLeft > -PROJECTILE_DECAY_TIME)
+            if (m_Projectiles[i].timeLeft > -PROJECTILE_DECAY_TIME)
             {
                 // Keep the projectile until it exceeds the decay time
             }
@@ -328 +303 @@
     }
 }
 
+void CCmpProjectileManager::RemoveProjectile(uint32_t id)
+{
+    // Scan through the projectile list looking for one with the correct id to remove
+    for (size_t i = 0; i < m_Projectiles.size(); i++)
+    {
+        if (m_Projectiles[i].id == id)
+        {
+            // Delete in-place by swapping with the last in the list
+            std::swap(m_Projectiles[i], m_Projectiles.back());
+            GetSimContext().GetUnitManager().DeleteUnit(m_Projectiles.back().unit);
+            m_Projectiles.pop_back();
+            return;
+        }
+    }
+}
+
 void CCmpProjectileManager::RenderSubmit(SceneCollector& collector, const CFrustum& frustum, bool culling)
 {
     CmpPtr<ICmpRangeManager> cmpRangeManager(GetSimContext(), SYSTEM_ENTITY);

source/simulation2/components/CCmpPosition.cpp

@@ -66 +66 @@
     // Dynamic state:
 
     bool m_InWorld;
-    entity_pos_t m_X, m_Z, m_LastX, m_LastZ; // these values contain undefined junk if !InWorld
+    // m_LastX/Z contain the position from the start of the most recent turn
+    // m_PrevX/Z conatain the position from the turn before that
+    entity_pos_t m_X, m_Z, m_LastX, m_LastZ, m_PrevX, m_PrevZ; // these values contain undefined junk if !InWorld
     entity_pos_t m_YOffset;
     bool m_RelativeToGround; // whether m_YOffset is relative to terrain/water plane, or an absolute height
 
@@ -201 +203 @@
         if (!m_InWorld)
         {
             m_InWorld = true;
-            m_LastX = m_X;
-            m_LastZ = m_Z;
+            m_LastX = m_PrevX = m_X;
+            m_LastZ = m_PrevZ = m_Z;
         }
 
         AdvertisePositionChanges();
@@ -210 +212 @@
 
     virtual void JumpTo(entity_pos_t x, entity_pos_t z)
     {
-        m_LastX = m_X = x;
-        m_LastZ = m_Z = z;
+        m_LastX = m_PrevX = m_X = x;
+        m_LastZ = m_PrevZ = m_Z = z;
         m_InWorld = true;
 
         AdvertisePositionChanges();
@@ -278 +280 @@
         return CFixedVector2D(m_X, m_Z);
     }
 
+    virtual CFixedVector3D GetPreviousPosition() 
+    { 
+        if (!m_InWorld) 
+        { 
+            LOGERROR(L"CCmpPosition::GetPreviousPosition called on entity when IsInWorld is false"); 
+            return CFixedVector3D(); 
+        } 
+
+        entity_pos_t baseY; 
+        if (m_RelativeToGround) 
+        { 
+            CmpPtr<ICmpTerrain> cmpTerrain(GetSimContext(), SYSTEM_ENTITY); 
+            if (cmpTerrain) 
+                baseY = cmpTerrain->GetGroundLevel(m_PrevX, m_PrevZ); 
+
+            if (m_Floating) 
+            { 
+                CmpPtr<ICmpWaterManager> cmpWaterMan(GetSimContext(), SYSTEM_ENTITY); 
+                if (cmpWaterMan) 
+                    baseY = std::max(baseY, cmpWaterMan->GetWaterLevel(m_PrevX, m_PrevZ)); 
+            } 
+        } 
+
+        return CFixedVector3D(m_PrevX, baseY + m_YOffset, m_PrevZ); 
+    } 
+
+    virtual CFixedVector2D GetPreviousPosition2D() 
+    { 
+        if (!m_InWorld) 
+        { 
+            LOGERROR(L"CCmpPosition::GetPreviousPosition2D called on entity when IsInWorld is false"); 
+            return CFixedVector2D(); 
+        } 
+
+        return CFixedVector2D(m_PrevX, m_PrevZ); 
+    }
+
     virtual void TurnTo(entity_angle_t y)
     {
         m_RotY = y;
@@ -408 +447 @@
         }
         case MT_TurnStart:
         {
+            // Store the positions from the turn before
+            m_PrevX = m_LastX;
+            m_PrevZ = m_LastZ;
+            
             m_LastX = m_X;
             m_LastZ = m_Z;
 

source/simulation2/components/CCmpObstructionManager.cpp

@@ -927 +927 @@
 
     // Then look for obstructions that cover the target point when expanded by r
     // (i.e. if the target is not inside an object but closer than we can get to it)
+    
+    GetObstructionsInRange(filter, x-r, z-r, x+r, z+r, squares);
+    // Building squares are more important but returned last, so check backwards
+    for (std::vector<ObstructionSquare>::reverse_iterator it = squares.rbegin(); it != squares.rend(); ++it)
+    {
+        CFixedVector2D halfSize(it->hw + r, it->hh + r);
+        if (Geometry::PointIsInSquare(CFixedVector2D(it->x, it->z) - center, it->u, it->v, halfSize))
+        {
+            square = *it;
+            return true;
+        }
+    }
 
-    // TODO: actually do that
-    // (This might matter when you tell a unit to walk too close to the edge of a building)
-
     return false;
 }
 

binaries/data/mods/public/simulation/components/Attack.js

@@ -1 +1 @@
 function Attack() {}
 
+
 var bonusesSchema = 
     "<optional>" +
         "<element name='Bonuses'>" +
@@ -48 +49 @@
             "<PrepareTime>800</PrepareTime>" +
             "<RepeatTime>1600</RepeatTime>" +
             "<ProjectileSpeed>50.0</ProjectileSpeed>" +
+            "<Spread>2.5</Spread>" +
             "<Bonuses>" +
                 "<Bonus1>" +
                     "<Classes>Cavalry</Classes>" +
                     "<Multiplier>2</Multiplier>" +
                 "</Bonus1>" +
             "</Bonuses>" +
+            "<Splash>" +
+                "<Shape>Circular</Shape>" +
+                "<Range>20</Range>" +
+                "<FriendlyFire>false</FriendlyFire>" +
+                "<Hack>0.0</Hack>" +
+                "<Pierce>10.0</Pierce>" +
+                "<Crush>0.0</Crush>" +
+            "</Splash>" +
         "</Ranged>" +
         "<Charge>" +
             "<Hack>10.0</Hack>" +
@@ -94 +104 @@
                 "<element name='ProjectileSpeed' a:help='Speed of projectiles (in metres per second). If unspecified, then it is a melee attack instead'>" +
                     "<ref name='nonNegativeDecimal'/>" +
                 "</element>" +
+                "<optional><element name='Spread' a:help='Radius over which missiles will tend to land. Roughly 2/3 will land inside this radius (in metres)'><ref name='nonNegativeDecimal'/></element></optional>" +
                 bonusesSchema +
+                "<optional>" +
+                    "<element name='Splash'>" +
+                        "<interleave>" +
+                            "<element name='Shape' a:help='Shape of the splash damage, can be circular or linear'><text/></element>" +
+                            "<element name='Range' a:help='Size of the area affected by the splash'><ref name='nonNegativeDecimal'/></element>" +
+                            "<element name='FriendlyFire' a:help='Whether the splash damage can hurt non enemy units'><data type='boolean'/></element>" +
+                            "<element name='Hack' a:help='Hack damage strength'><ref name='nonNegativeDecimal'/></element>" +
+                            "<element name='Pierce' a:help='Pierce damage strength'><ref name='nonNegativeDecimal'/></element>" +
+                            "<element name='Crush' a:help='Crush damage strength'><ref name='nonNegativeDecimal'/></element>" +
+                            bonusesSchema +
+                        "</interleave>" +
+                    "</element>" +
+                "</optional>" +
             "</interleave>" +
         "</element>" +
     "</optional>" +
@@ -143 +167 @@
 
 Attack.prototype.GetAttackStrengths = function(type)
 {
+    var template = this.template[type];
+    if (!template)
+        template = this.template[type.split(".")[0]].Splash;
     // Convert attack values to numbers, default 0 if unspecified
     return {
-        hack: +(this.template[type].Hack || 0),
-        pierce: +(this.template[type].Pierce || 0),
-        crush: +(this.template[type].Crush || 0)
+        hack: +(template.Hack || 0),
+        pierce: +(template.Pierce || 0),
+        crush: +(template.Crush || 0)
     };
 };
 
@@ -162 +189 @@
 Attack.prototype.GetAttackBonus = function(type, target)
 {
     var attackBonus = 1;
-    if (this.template[type].Bonuses)
+    var template = this.template[type];
+    if (!template)
+        template = this.template[type.split(".")[0]].Splash;
+    
+    if (template.Bonuses)
     {
         var cmpIdentity = Engine.QueryInterface(target, IID_Identity);
         if (!cmpIdentity)
             return 1;
         
         // Multiply the bonuses for all matching classes
-        for (var key in this.template[type].Bonuses)
+        for (var key in template.Bonuses)
         {
-            var bonus = this.template[type].Bonuses[key];
+            var bonus = template.Bonuses[key];
             
             var hasClasses = true;
             if (bonus.Classes){
@@ -188 +219 @@
     return attackBonus;
 };
 
+// Returns a 2d random distribution scaled for a spread of scale 1.
+// The current implementation is a 2d gaussian with sigma = 1
+Attack.prototype.GetNormalizedDistribution = function(){
+    
+    // Use the Box-Muller transform to get a gaussian distribution
+    var a = Math.random();
+    var b = Math.random();
+    
+    var c = Math.sqrt(-2*Math.log(a)) * Math.cos(2*Math.PI*b);
+    var d = Math.sqrt(-2*Math.log(a)) * Math.sin(2*Math.PI*b);
+    
+    return [c, d];
+};
+
 /**
  * Attack the target entity. This should only be called after a successful range check,
  * and should only be called after GetTimers().repeat msec has passed since the last
@@ -198 +243 @@
     // If this is a ranged attack, then launch a projectile
     if (type == "Ranged")
     {
-        // To implement (in)accuracy, for arrows and javelins, we want to do the following:
-        //  * Compute an accuracy rating, based on the entity's characteristics and the distance to the target
-        //  * Pick a random point 'close' to the target (based on the accuracy) which is the real target point
-        //  * Pick a real target unit, based on their footprint's proximity to the real target point
-        //  * If there is none, then harmlessly shoot to the real target point instead
-        //  * If the real target unit moves after being targeted, the projectile will follow it and hit it anyway
-        //
-        // In the future this should be extended:
-        //  * If the target unit moves too far, the projectile should 'detach' and not hit it, so that
-        //    players can dodge projectiles. (Or it should pick a new target after detaching, so it can still
-        //    hit somebody.)
+        // In the future this could be extended:
         //  * Obstacles like trees could reduce the probability of the target being hit
         //  * Obstacles like walls should block projectiles entirely
-        //  * There should be more control over the probabilities of hitting enemy units vs friendly units vs missing,
-        //    for gameplay balance tweaks
-        //  * Larger, slower projectiles (catapults etc) shouldn't pick targets first, they should just
-        //    hurt anybody near their landing point
 
         // Get some data about the entity
         var horizSpeed = +this.template[type].ProjectileSpeed;
         var gravity = 9.81; // this affects the shape of the curve; assume it's constant for now
-        var accuracy = 6; // TODO: get from entity template
-
-        //horizSpeed /= 8; gravity /= 8; // slow it down for testing
-
-        // Find the distance to the target
+        var spread = 1.5; //
+        if (this.template.Ranged.Spread !== undefined) // explicit test here because the value might be 0
+            spread = this.template.Ranged.Spread;
+        
+        //horizSpeed /= 2; gravity /= 2; // slow it down for testing
+        
         var selfPosition = Engine.QueryInterface(this.entity, IID_Position).GetPosition();
         var targetPosition = Engine.QueryInterface(target, IID_Position).GetPosition();
-        var horizDistance = Math.sqrt(Math.pow(targetPosition.x - selfPosition.x, 2) + Math.pow(targetPosition.z - selfPosition.z, 2));
+        var relativePosition = {"x": targetPosition.x - selfPosition.x, "z": targetPosition.z - selfPosition.z}
+        var previousTargetPosition = Engine.QueryInterface(target, IID_Position).GetPreviousPosition();
+        
+        var targetVelocity = {"x": (targetPosition.x - previousTargetPosition.x) / this.turnLength, "z": (targetPosition.z - previousTargetPosition.z) / this.turnLength}
+        // the component of the targets velocity radially away from the archer
+        var radialSpeed = this.VectorDot(relativePosition, targetVelocity) / this.VectorLength(relativePosition);
+        
+        var horizDistance = this.VectorDistance(targetPosition, selfPosition);
+        
+        // This is an approximation of the time ot the target, it assumes that the target has a constant radial 
+        // velocity, but since units move in straight lines this is not true.  The exact value would be more 
+        // difficult to calculate and I think this is sufficiently accurate.  (I tested and for cavalry it was 
+        // about 5% of the units radius out in the worst case)
+        var timeToTarget = horizDistance / (horizSpeed - radialSpeed);
+        
+        // Predict where the unit is when the missile lands.
+        var predictedPosition = {"x": targetPosition.x + targetVelocity.x * timeToTarget,
+                                 "z": targetPosition.z + targetVelocity.z * timeToTarget};
+        
+        // Compute the real target point (based on spread and target speed)
+        var randNorm = this.GetNormalizedDistribution();
+        var offsetX = randNorm[0] * spread * (1 + this.VectorLength(targetVelocity) / 20);
+        var offsetZ = randNorm[1] * spread * (1 + this.VectorLength(targetVelocity) / 20);
 
-        // Compute the real target point (based on accuracy)
-        var angle = Math.random() * 2*Math.PI;
-        var r = 1 - Math.sqrt(Math.random()); // triangular distribution [0,1] (cluster around the center)
-        var offset = r * accuracy; // TODO: should be affected by range
-        var offsetX = offset * Math.sin(angle);
-        var offsetZ = offset * Math.cos(angle);
-
-        var realTargetPosition = { "x": targetPosition.x + offsetX, "y": targetPosition.y, "z": targetPosition.z + offsetZ };
-
-        // TODO: what we should really do here is select the unit whose footprint is closest to the realTargetPosition
-        // (and harmlessly hit the ground if there's none), but as a simplification let's just randomly decide whether to
-        // hit the original target or not.
-        var realTargetUnit = undefined;
-        if (Math.random() < 0.5) // TODO: this is yucky and hardcoded
-        {
-            // Hit the original target
-            realTargetUnit = target;
-            realTargetPosition = targetPosition;
-        }
-        else
-        {
-            // Hit the ground
-            // TODO: ought to make sure Y is on the ground
-        }
-
-        // Hurt the target after the appropriate time
-        if (realTargetUnit)
-        {
-            var realHorizDistance = Math.sqrt(Math.pow(realTargetPosition.x - selfPosition.x, 2) + Math.pow(realTargetPosition.z - selfPosition.z, 2));
-            var timeToTarget = realHorizDistance / horizSpeed;
-            var cmpTimer = Engine.QueryInterface(SYSTEM_ENTITY, IID_Timer);
-            cmpTimer.SetTimeout(this.entity, IID_Attack, "CauseDamage", timeToTarget*1000, {"type": type, "target": target});
-        }
-
+        var realTargetPosition = { "x": predictedPosition.x + offsetX, "y": targetPosition.y, "z": predictedPosition.z + offsetZ };
+        
+        // Calculate when the missile will hit the target position
+        var realHorizDistance = this.VectorDistance(realTargetPosition, selfPosition);
+        var timeToTarget = realHorizDistance / horizSpeed;
+        
+        var missileDirection = {"x": (realTargetPosition.x - selfPosition.x) / realHorizDistance, "z": (realTargetPosition.z - selfPosition.z) / realHorizDistance};
+        
         // Launch the graphical projectile
         var cmpProjectileManager = Engine.QueryInterface(SYSTEM_ENTITY, IID_ProjectileManager);
-        if (realTargetUnit)
-            cmpProjectileManager.LaunchProjectileAtEntity(this.entity, realTargetUnit, horizSpeed, gravity);
-        else
-            cmpProjectileManager.LaunchProjectileAtPoint(this.entity, realTargetPosition, horizSpeed, gravity);
+        var id = cmpProjectileManager.LaunchProjectileAtPoint(this.entity, realTargetPosition, horizSpeed, gravity);
+        
+        var cmpTimer = Engine.QueryInterface(SYSTEM_ENTITY, IID_Timer);
+        cmpTimer.SetTimeout(this.entity, IID_Attack, "MissileHit", timeToTarget*1000, {"type": type, "target": target, "position": realTargetPosition, "direction": missileDirection, "projectileId": id});
     }
     else
     {
@@ -295 +323 @@
     }
 };
 
+Attack.prototype.InterpolatedLocation = function(ent, lateness)
+{
+    var targetPositionCmp = Engine.QueryInterface(ent, IID_Position);
+    if (!targetPositionCmp) // TODO: handle dead target properly
+        return undefined;
+    var curPos = targetPositionCmp.GetPosition();
+    var prevPos = targetPositionCmp.GetPreviousPosition();
+    lateness /= 1000;
+    return {"x": (curPos.x * (this.turnLength - lateness) + prevPos.x * lateness) / this.turnLength,
+            "z": (curPos.z * (this.turnLength - lateness) + prevPos.z * lateness) / this.turnLength};
+};
+
+Attack.prototype.VectorDistance = function(p1, p2)
+{
+    return Math.sqrt((p1.x - p2.x)*(p1.x - p2.x) + (p1.z - p2.z)*(p1.z - p2.z));
+};
+
+Attack.prototype.VectorDot = function(p1, p2)
+{
+    return (p1.x * p2.x + p1.z * p2.z);
+};
+
+Attack.prototype.VectorCross = function(p1, p2)
+{
+    return (p1.x * p2.z - p1.z * p2.x);
+};
+
+Attack.prototype.VectorLength = function(p)
+{
+    return Math.sqrt(p.x*p.x + p.z*p.z);
+};
+
+// Tests whether it point is inside of ent's footprint
+Attack.prototype.testCollision = function(ent, point, lateness)
+{
+    var targetPosition = this.InterpolatedLocation(ent, lateness);
+    var targetShape = Engine.QueryInterface(ent, IID_Footprint).GetShape();
+    
+    if (!targetShape || !targetPosition)
+        return false;
+    
+    if (targetShape.type === 'circle')
+    {
+        return (this.VectorDistance(point, targetPosition) < targetShape.radius);
+    }
+    else
+    {
+        var targetRotation = Engine.QueryInterface(ent, IID_Position).GetRotation().y;
+        
+        var dx = point.x - targetPosition.x;
+        var dz = point.z - targetPosition.z;
+        
+        var dxr = Math.cos(targetRotation) * dx - Math.sin(targetRotation) * dz;
+        var dzr = Math.sin(targetRotation) * dx + Math.cos(targetRotation) * dz;
+        
+        return (-targetShape.width <= dxr && dxr < targetShape.width && -targetShape.depth <= dzr && dzr < targetShape.depth);
+    }
+};
+
+Attack.prototype.MissileHit = function(data, lateness)
+{
+    
+    var targetPosition = this.InterpolatedLocation(data.target, lateness);
+    if (!targetPosition)
+        return;
+    
+    if (this.template.Ranged.Splash) // splash damage, do this first in case the direct hit kills the target
+    {
+        var friendlyFire = this.template.Ranged.Splash.FriendlyFire;
+        var splashRadius = this.template.Ranged.Splash.Range;
+        var splashShape = this.template.Ranged.Splash.Shape;
+        
+        var ents = this.GetNearbyEntities(data.target, this.VectorDistance(data.position, targetPosition) * 2 + splashRadius, friendlyFire);
+        ents.push(data.target); // Add the original unit to the list of splash damage targets
+        
+        for (var i = 0; i < ents.length; i++)
+        {
+            var entityPosition = this.InterpolatedLocation(ents[i], lateness);
+            var radius = this.VectorDistance(data.position, entityPosition);
+            
+            if (radius < splashRadius)
+            {
+                var multiplier = 1;
+                if (splashShape == "Circular") // quadratic falloff
+                {
+                    multiplier *= 1 - ((radius * radius) / (splashRadius * splashRadius));
+                }
+                else if (splashShape == "Linear")
+                {
+                    // position of entity relative to where the missile hit
+                    var relPos = {"x": entityPosition.x - data.position.x, "z": entityPosition.z - data.position.z};
+                    
+                    var splashWidth = splashRadius / 5;
+                    var parallelDist = this.VectorDot(relPos, data.direction);
+                    var perpDist = Math.abs(this.VectorCross(relPos, data.direction));
+                    
+                    // Check that the unit is within the distance splashWidth of the line starting at the missile's 
+                    // landing point which extends in the direction of the missile for length splashRadius.
+                    if (parallelDist > -splashWidth && perpDist < splashWidth)
+                    {
+                        // Use a quadratic falloff in both directions
+                        multiplier = (splashRadius*splashRadius - parallelDist*parallelDist) / (splashRadius*splashRadius)
+                                     * (splashWidth*splashWidth - perpDist*perpDist) / (splashWidth*splashWidth);
+                    }
+                    else
+                    {
+                        multiplier = 0;
+                    }
+                }
+                var newData = {"type": data.type + ".Splash", "target": ents[i], "damageMultiplier": multiplier};
+                this.CauseDamage(newData);
+            }
+        }
+    }
+    
+    if (this.testCollision(data.target, data.position, lateness))
+    {
+        // Hit the primary target
+        this.CauseDamage(data);
+        
+        // Remove the projectile
+        var cmpProjectileManager = Engine.QueryInterface(SYSTEM_ENTITY, IID_ProjectileManager);
+        cmpProjectileManager.RemoveProjectile(data.projectileId);
+    }
+    else
+    {
+        // If we didn't hit the main target look for nearby units
+        var ents = this.GetNearbyEntities(data.target, this.VectorDistance(data.position, targetPosition) * 2);
+        
+        for (var i = 0; i < ents.length; i++)
+        {
+            if (this.testCollision(ents[i], data.position, lateness))
+            {
+                var newData = {"type": data.type, "target": ents[i]};
+                this.CauseDamage(newData);
+                
+                // Remove the projectile
+                var cmpProjectileManager = Engine.QueryInterface(SYSTEM_ENTITY, IID_ProjectileManager);
+                cmpProjectileManager.RemoveProjectile(data.projectileId);
+            }
+        }
+    }
+};
+
+Attack.prototype.GetNearbyEntities = function(startEnt, range, friendlyFire)
+{
+    var cmpPlayerManager = Engine.QueryInterface(SYSTEM_ENTITY, IID_PlayerManager);
+    var cmpOwnership = Engine.QueryInterface(this.entity, IID_Ownership);
+    var owner = cmpOwnership.GetOwner();
+    var cmpPlayer = Engine.QueryInterface(cmpPlayerManager.GetPlayerByID(owner), IID_Player);
+    var numPlayers = cmpPlayerManager.GetNumPlayers();
+    var players = [];
+    
+    for (var i = 1; i < numPlayers; ++i)
+    {   
+        // Only target enemies unless friendly fire is on
+        if (cmpPlayer.IsEnemy(i) || friendlyFire)
+            players.push(i);
+    }
+    
+    var rangeManager = Engine.QueryInterface(SYSTEM_ENTITY, IID_RangeManager);
+    return rangeManager.ExecuteQuery(startEnt, 0, range, players, IID_DamageReceiver);
+}
+
 /**
  * Inflict damage on the target
  */
@@ -302 +494 @@
 {
     var strengths = this.GetAttackStrengths(data.type);
     
-    var attackBonus = this.GetAttackBonus(data.type, data.target);
+    var damageMultiplier = this.GetAttackBonus(data.type, data.target);
+    if (data.damageMultiplier !== undefined)
+        damageMultiplier *= data.damageMultiplier;
     
     var cmpDamageReceiver = Engine.QueryInterface(data.target, IID_DamageReceiver);
     if (!cmpDamageReceiver)
         return;
-    var targetState = cmpDamageReceiver.TakeDamage(strengths.hack * attackBonus, strengths.pierce * attackBonus, strengths.crush * attackBonus);
+    var targetState = cmpDamageReceiver.TakeDamage(strengths.hack * damageMultiplier, strengths.pierce * damageMultiplier, strengths.crush * damageMultiplier);
     // if target killed pick up loot and credit experience
     if (targetState.killed == true)
     {
@@ -320 +514 @@
     PlaySound("attack_impact", this.entity);
 };
 
+Attack.prototype.OnUpdate = function(msg)
+{
+    this.turnLength = msg.turnLength;
+}
+
 Engine.RegisterComponentType(IID_Attack, "Attack", Attack);