// ProjectileEntity.cpp
// Implements the cProjectileEntity class representing the common base class for projectiles, as well as individual projectile types
#include "Globals.h"
#include "../Bindings/PluginManager.h"
#include "ProjectileEntity.h"
#include "../ClientHandle.h"
#include "../LineBlockTracer.h"
#include "../BoundingBox.h"
#include "../ChunkMap.h"
#include "../Chunk.h"
#include "ArrowEntity.h"
#include "ThrownEggEntity.h"
#include "ThrownEnderPearlEntity.h"
#include "ExpBottleEntity.h"
#include "ThrownSnowballEntity.h"
#include "FireChargeEntity.h"
#include "FireworkEntity.h"
#include "GhastFireballEntity.h"
#include "WitherSkullEntity.h"
#include "SplashPotionEntity.h"
#include "Player.h"
/// Converts an angle in radians into a byte representation used by the network protocol
#define ANGLE_TO_PROTO(X) (Byte)(X * 255 / 360)
////////////////////////////////////////////////////////////////////////////////
// cProjectileTracerCallback:
class cProjectileTracerCallback :
public cBlockTracer::cCallbacks
{
public:
cProjectileTracerCallback(cProjectileEntity * a_Projectile) :
m_Projectile(a_Projectile),
m_SlowdownCoeff(0.99) // Default slowdown when not in water
{
}
double GetSlowdownCoeff(void) const { return m_SlowdownCoeff; }
protected:
cProjectileEntity * m_Projectile;
double m_SlowdownCoeff;
// cCallbacks overrides:
virtual bool OnNextBlock(int a_BlockX, int a_BlockY, int a_BlockZ, BLOCKTYPE a_BlockType, NIBBLETYPE a_BlockMeta, char a_EntryFace) override
{
/*
// DEBUG:
LOGD("Hit block %d:%d at {%d, %d, %d} face %d, %s (%s)",
a_BlockType, a_BlockMeta,
a_BlockX, a_BlockY, a_BlockZ, a_EntryFace,
cBlockInfo::IsSolid(a_BlockType) ? "solid" : "non-solid",
ItemToString(cItem(a_BlockType, 1, a_BlockMeta)).c_str()
);
*/
if (cBlockInfo::IsSolid(a_BlockType))
{
// The projectile hit a solid block, calculate the exact hit coords:
cBoundingBox bb(a_BlockX, a_BlockX + 1, a_BlockY, a_BlockY + 1, a_BlockZ, a_BlockZ + 1); // Bounding box of the block hit
const Vector3d LineStart = m_Projectile->GetPosition(); // Start point for the imaginary line that goes through the block hit
const Vector3d LineEnd = LineStart + m_Projectile->GetSpeed(); // End point for the imaginary line that goes through the block hit
double LineCoeff = 0; // Used to calculate where along the line an intersection with the bounding box occurs
eBlockFace Face; // Face hit
if (bb.CalcLineIntersection(LineStart, LineEnd, LineCoeff, Face))
{
Vector3d Intersection = LineStart + m_Projectile->GetSpeed() * LineCoeff; // Point where projectile goes into the hit block
if (cPluginManager::Get()->CallHookProjectileHitBlock(*m_Projectile, a_BlockX, a_BlockY, a_BlockZ, Face, &Intersection))
{
return false;
}
m_Projectile->OnHitSolidBlock(Intersection, Face);
return true;
}
else
{
LOGD("WEIRD! block tracer reports a hit, but BBox tracer doesn't. Ignoring the hit.");
}
}
// Convey some special effects from special blocks:
switch (a_BlockType)
{
case E_BLOCK_LAVA:
case E_BLOCK_STATIONARY_LAVA:
{
m_Projectile->StartBurning(30);
m_SlowdownCoeff = std::min(m_SlowdownCoeff, 0.9); // Slow down to 0.9* the speed each tick when moving through lava
break;
}
case E_BLOCK_WATER:
case E_BLOCK_STATIONARY_WATER:
{
m_Projectile->StopBurning();
m_SlowdownCoeff = std::min(m_SlowdownCoeff, 0.8); // Slow down to 0.8* the speed each tick when moving through water
break;
}
} // switch (a_BlockType)
// Continue tracing
return false;
}
} ;
////////////////////////////////////////////////////////////////////////////////
// cProjectileEntityCollisionCallback:
class cProjectileEntityCollisionCallback :
public cEntityCallback
{
public:
cProjectileEntityCollisionCallback(cProjectileEntity * a_Projectile, const Vector3d & a_Pos, const Vector3d & a_NextPos) :
m_Projectile(a_Projectile),
m_Pos(a_Pos),
m_NextPos(a_NextPos),
m_MinCoeff(1),
m_HitEntity(nullptr)
{
}
virtual bool Item(cEntity * a_Entity) override
{
if (
(a_Entity == m_Projectile) || // Do not check collisions with self
(a_Entity->GetUniqueID() == m_Projectile->GetCreatorUniqueID()) // Do not check whoever shot the projectile
)
{
// Don't check creator only for the first 5 ticks so that projectiles can collide with the creator
if (m_Projectile->GetTicksAlive() <= 5)
{
return false;
}
}
cBoundingBox EntBox(a_Entity->GetPosition(), a_Entity->GetWidth() / 2, a_Entity->GetHeight());
// Instead of colliding the bounding box with another bounding box in motion, we collide an enlarged bounding box with a hairline.
// The results should be good enough for our purposes
double LineCoeff;
eBlockFace Face;
EntBox.Expand(m_Projectile->GetWidth() / 2, m_Projectile->GetHeight() / 2, m_Projectile->GetWidth() / 2);
if (!EntBox.CalcLineIntersection(m_Pos, m_NextPos, LineCoeff, Face))
{
// No intersection whatsoever
return false;
}
if (!a_Entity->IsMob() && !a_Entity->IsMinecart() && !a_Entity->IsPlayer() && !a_Entity->IsBoat())
{
// Not an entity that interacts with a projectile
return false;
}
if (cPluginManager::Get()->CallHookProjectileHitEntity(*m_Projectile, *a_Entity))
{
// A plugin disagreed.
return false;
}
if (LineCoeff < m_MinCoeff)
{
// The entity is closer than anything we've stored so far, replace it as the potential victim
m_MinCoeff = LineCoeff;
m_HitEntity = a_Entity;
}
// Don't break the enumeration, we want all the entities
return false;
}
/// Returns the nearest entity that was hit, after the enumeration has been completed
cEntity * GetHitEntity(void) const { return m_HitEntity; }
/// Returns the line coeff where the hit was encountered, after the enumeration has been completed
double GetMinCoeff(void) const { return m_MinCoeff; }
/// Returns true if the callback has encountered a true hit
bool HasHit(void) const { return (m_MinCoeff < 1); }
protected:
cProjectileEntity * m_Projectile;
const Vector3d & m_Pos;
const Vector3d & m_NextPos;
double m_MinCoeff; // The coefficient of the nearest hit on the Pos line
// Although it's bad(tm) to store entity ptrs from a callback, we can afford it here, because the entire callback
// is processed inside the tick thread, so the entities won't be removed in between the calls and the final processing
cEntity * m_HitEntity; // The nearest hit entity
} ;
////////////////////////////////////////////////////////////////////////////////
// cProjectileEntity:
cProjectileEntity::cProjectileEntity(eKind a_Kind, cEntity * a_Creator, double a_X, double a_Y, double a_Z, double a_Width, double a_Height) :
super(etProjectile, a_X, a_Y, a_Z, a_Width, a_Height),
m_ProjectileKind(a_Kind),
m_CreatorData(
((a_Creator != nullptr) ? a_Creator->GetUniqueID() : cEntity::INVALID_ID),
((a_Creator != nullptr) ? (a_Creator->IsPlayer() ? ((cPlayer *)a_Creator)->GetName() : "") : ""),
((a_Creator != nullptr) ? a_Creator->GetEquippedWeapon().m_Enchantments : cEnchantments())
),
m_IsInGround(false)
{
}
cProjectileEntity::cProjectileEntity(eKind a_Kind, cEntity * a_Creator, const Vector3d & a_Pos, const Vector3d & a_Speed, double a_Width, double a_Height) :
super(etProjectile, a_Pos.x, a_Pos.y, a_Pos.z, a_Width, a_Height),
m_ProjectileKind(a_Kind),
m_CreatorData(a_Creator->GetUniqueID(), a_Creator->IsPlayer() ? ((cPlayer *)a_Creator)->GetName() : "", a_Creator->GetEquippedWeapon().m_Enchantments),
m_IsInGround(false)
{
SetSpeed(a_Speed);
SetYawFromSpeed();
SetPitchFromSpeed();
}
cProjectileEntity * cProjectileEntity::Create(eKind a_Kind, cEntity * a_Creator, double a_X, double a_Y, double a_Z, const cItem * a_Item, const Vector3d * a_Speed)
{
Vector3d Speed;
if (a_Speed != nullptr)
{
Speed = *a_Speed;
}
switch (a_Kind)
{
case pkArrow: return new cArrowEntity (a_Creator, a_X, a_Y, a_Z, Speed);
case pkEgg: return new cThrownEggEntity (a_Creator, a_X, a_Y, a_Z, Speed);
case pkEnderPearl: return new cThrownEnderPearlEntity(a_Creator, a_X, a_Y, a_Z, Speed);
case pkSnowball: return new cThrownSnowballEntity (a_Creator, a_X, a_Y, a_Z, Speed);
case pkGhastFireball: return new cGhastFireballEntity (a_Creator, a_X, a_Y, a_Z, Speed);
case pkFireCharge: return new cFireChargeEntity (a_Creator, a_X, a_Y, a_Z, Speed);
case pkExpBottle: return new cExpBottleEntity (a_Creator, a_X, a_Y, a_Z, Speed);
case pkSplashPotion: return new cSplashPotionEntity (a_Creator, a_X, a_Y, a_Z, Speed, *a_Item);
case pkWitherSkull: return new cWitherSkullEntity (a_Creator, a_X, a_Y, a_Z, Speed);
case pkFirework:
{
ASSERT(a_Item != nullptr);
if (a_Item->m_FireworkItem.m_Colours.empty())
{
return nullptr;
}
return new cFireworkEntity(a_Creator, a_X, a_Y, a_Z, *a_Item);
}
}
LOGWARNING("%s: Unknown projectile kind: %d", __FUNCTION__, a_Kind);
return nullptr;
}
void cProjectileEntity::OnHitSolidBlock(const Vector3d & a_HitPos, eBlockFace a_HitFace)
{
// Set the position based on what face was hit:
SetPosition(a_HitPos);
SetSpeed(0, 0, 0);
// DEBUG:
LOGD("Projectile %d: pos {%.02f, %.02f, %.02f}, hit solid block at face %d",
m_UniqueID,
a_HitPos.x, a_HitPos.y, a_HitPos.z,
a_HitFace
);
m_IsInGround = true;
}
AString cProjectileEntity::GetMCAClassName(void) const
{
switch (m_ProjectileKind)
{
case pkArrow: return "Arrow";
case pkSnowball: return "Snowball";
case pkEgg: return "Egg";
case pkGhastFireball: return "Fireball";
case pkFireCharge: return "SmallFireball";
case pkEnderPearl: return "ThrownEnderpearl";
case pkExpBottle: return "ThrownExpBottle";
case pkSplashPotion: return "SplashPotion";
case pkWitherSkull: return "WitherSkull";
case pkFirework: return "Firework";
case pkFishingFloat: return ""; // Unknown, perhaps MC doesn't save this?
}
ASSERT(!"Unhandled projectile entity kind!");
return "";
}
void cProjectileEntity::Tick(std::chrono::milliseconds a_Dt, cChunk & a_Chunk)
{
super::Tick(a_Dt, a_Chunk);
BroadcastMovementUpdate();
}
void cProjectileEntity::HandlePhysics(std::chrono::milliseconds a_Dt, cChunk & a_Chunk)
{
if (m_IsInGround)
{
// Already-grounded projectiles don't move at all
return;
}
const Vector3d PerTickSpeed = GetSpeed() / 20;
const Vector3d Pos = GetPosition();
const Vector3d NextPos = Pos + PerTickSpeed;
// Test for entity collisions:
cProjectileEntityCollisionCallback EntityCollisionCallback(this, Pos, NextPos);
a_Chunk.ForEachEntity(EntityCollisionCallback);
if (EntityCollisionCallback.HasHit())
{
// An entity was hit:
Vector3d HitPos = Pos + (NextPos - Pos) * EntityCollisionCallback.GetMinCoeff();
// DEBUG:
LOGD("Projectile %d has hit an entity %d (%s) at {%.02f, %.02f, %.02f} (coeff %.03f)",
m_UniqueID,
EntityCollisionCallback.GetHitEntity()->GetUniqueID(),
EntityCollisionCallback.GetHitEntity()->GetClass(),
HitPos.x, HitPos.y, HitPos.z,
EntityCollisionCallback.GetMinCoeff()
);
OnHitEntity(*(EntityCollisionCallback.GetHitEntity()), HitPos);
}
// TODO: Test the entities in the neighboring chunks, too
// Trace the tick's worth of movement as a line:
cProjectileTracerCallback TracerCallback(this);
if (!cLineBlockTracer::Trace(*m_World, TracerCallback, Pos, NextPos))
{
// Something has been hit, abort all other processing
return;
}
// The tracer also checks the blocks for slowdown blocks - water and lava - and stores it for later in its SlowdownCoeff
// Update the position:
SetPosition(NextPos);
// Add slowdown and gravity effect to the speed:
Vector3d NewSpeed(GetSpeed());
NewSpeed.y += m_Gravity / 20;
NewSpeed *= TracerCallback.GetSlowdownCoeff();
SetSpeed(NewSpeed);
SetYawFromSpeed();
SetPitchFromSpeed();
/*
LOGD("Projectile %d: pos {%.02f, %.02f, %.02f}, speed {%.02f, %.02f, %.02f}, rot {%.02f, %.02f}",
m_UniqueID,
GetPosX(), GetPosY(), GetPosZ(),
GetSpeedX(), GetSpeedY(), GetSpeedZ(),
GetYaw(), GetPitch()
);
*/
}
void cProjectileEntity::SpawnOn(cClientHandle & a_Client)
{
// Default spawning - use the projectile kind to spawn an object:
a_Client.SendSpawnObject(*this, m_ProjectileKind, 12, ANGLE_TO_PROTO(GetYaw()), ANGLE_TO_PROTO(GetPitch()));
a_Client.SendEntityMetadata(*this);
}
void cProjectileEntity::CollectedBy(cPlayer & a_Dest)
{
// Overriden in arrow
UNUSED(a_Dest);
}
