feat: improve POV demos support

- Avoid recreating known entities when they re-enter in the PVS based on the entity serial number
- Detect if the demo is a client demo and use correct props to detect position (local vs non local)
- Add a parser.IsPOV function

Author: akiver

pkg/demoinfocs/net_messages.go

@@ -3,6 +3,7 @@ package demoinfocs
 import (
 	"bytes"
 	"encoding/binary"
+	"fmt"
 
 	"github.com/markus-wa/ice-cipher-go/pkg/ice"
 	"google.golang.org/protobuf/proto"
@@ -19,34 +20,30 @@ func (p *parser) handlePacketEntities(pe *msg.CSVCMsg_PacketEntities) {
 
 	r := bit.NewSmallBitReader(bytes.NewReader(pe.EntityData))
 
-	currentEntity := -1
+	entityIndex := -1
+
 	for i := 0; i < int(pe.GetUpdatedEntries()); i++ {
-		currentEntity += 1 + int(r.ReadUBitInt())
-
-		cmd := r.ReadBitsToByte(2)
-		if cmd&1 == 0 {
-			if cmd&2 != 0 {
-				// Enter PVS
-				if existing := p.gameState.entities[currentEntity]; existing != nil {
-					// Sometimes entities don't get destroyed when they should be
-					// For instance when a player is replaced by a BOT
-					existing.Destroy()
-				}
+		entityIndex += 1 + int(r.ReadUBitInt())
 
-				p.gameState.entities[currentEntity] = p.stParser.ReadEnterPVS(r, currentEntity)
-			} else {
-				// Delta Update
-				if entity := p.gameState.entities[currentEntity]; entity != nil {
-					entity.ApplyUpdate(r)
+		if r.ReadBit() {
+			// FHDR_LEAVEPVS => LeavePVS
+
+			if r.ReadBit() {
+				// FHDR_LEAVEPVS | FHDR_DELETE => LeavePVS with force delete. Should never happen on full update
+				if existingEntity := p.gameState.entities[entityIndex]; existingEntity != nil {
+					existingEntity.Destroy()
+					delete(p.gameState.entities, entityIndex)
 				}
 			}
+		} else if r.ReadBit() {
+			// FHDR_ENTERPVS => EnterPVS
+			p.gameState.entities[entityIndex] = p.stParser.ReadEnterPVS(r, entityIndex, p.gameState.entities, p.recordingPlayerSlot)
 		} else {
-			if cmd&2 != 0 {
-				// Leave PVS
-				if entity := p.gameState.entities[currentEntity]; entity != nil {
-					entity.Destroy()
-					delete(p.gameState.entities, currentEntity)
-				}
+			// Delta update
+			if p.gameState.entities[entityIndex] != nil {
+				p.gameState.entities[entityIndex].ApplyUpdate(r)
+			} else {
+				panic(fmt.Sprintf("Entity with index %d doesn't exist but got an update", entityIndex))
 			}
 		}
 	}

pkg/demoinfocs/parser.go

@@ -64,6 +64,11 @@ type parser struct {
 	err                          error            // Contains a error that occurred during parsing if any
 	errLock                      sync.Mutex       // Used to sync up error mutations between parsing & handling go-routines
 	decryptionKey                []byte           // Stored in `match730_*.dem.info` see MatchInfoDecryptionKey().
+	/**
+	 * Set to the client slot of the recording player.
+	 * Always -1 for GOTV demos.
+	 */
+	recordingPlayerSlot int
 
 	// Additional fields, mainly caching & tracking things
 
@@ -190,6 +195,11 @@ func (p *parser) Progress() float32 {
 	return float32(p.currentFrame) / float32(p.header.PlaybackFrames)
 }
 
+// IsPOV indicates if the demo being parsed is a POV demo.
+func (p *parser) IsPOV() bool {
+	return p.recordingPlayerSlot != -1
+}
+
 /*
 RegisterEventHandler registers a handler for game events.
 
@@ -350,6 +360,7 @@ func NewParserWithConfig(demostream io.Reader, config ParserConfig) Parser {
 	p.bombsiteA.index = -1
 	p.bombsiteB.index = -1
 	p.decryptionKey = config.NetMessageDecryptionKey
+	p.recordingPlayerSlot = -1
 
 	dispatcherCfg := dp.Config{
 		PanicHandler: func(v any) {

pkg/demoinfocs/sendtables/entity.go

@@ -15,11 +15,14 @@ import (
 type entity struct {
 	serverClass *ServerClass
 	id          int
+	serialNum   int
 	props       []property
 
-	onCreateFinished []func()
-	onDestroy        []func()
-	position         func() r3.Vector
+	onCreateFinished   []func()
+	onDestroy          []func()
+	position           func() r3.Vector
+	positionPropNameXY string
+	positionPropNameZ  string
 }
 
 // ServerClass returns the entity's server-class.
@@ -32,6 +35,11 @@ func (e *entity) ID() int {
 	return e.id
 }
 
+// SerialNum returns the entity's serial number.
+func (e *entity) SerialNum() int {
+	return e.serialNum
+}
+
 // Properties returns all properties of the entity.
 func (e *entity) Properties() (out []Property) {
 	for i := range e.props {
@@ -189,25 +197,36 @@ func (e *entity) applyBaseline(baseline map[int]PropertyValue) {
 const (
 	maxCoordInt = 16384
 
-	propCellBits          = "m_cellbits"
-	propCellX             = "m_cellX"
-	propCellY             = "m_cellY"
-	propCellZ             = "m_cellZ"
-	propVecOrigin         = "m_vecOrigin"
-	propVecOriginPlayerXY = "cslocaldata.m_vecOrigin"
-	propVecOriginPlayerZ  = "cslocaldata.m_vecOrigin[2]"
+	propCellBits                  = "m_cellbits"
+	propCellX                     = "m_cellX"
+	propCellY                     = "m_cellY"
+	propCellZ                     = "m_cellZ"
+	propVecOrigin                 = "m_vecOrigin"
+	propVecOriginPlayerXY         = "cslocaldata.m_vecOrigin"
+	propVecOriginPlayerZ          = "cslocaldata.m_vecOrigin[2]"
+	nonLocalPropVecOriginPlayerXY = "csnonlocaldata.m_vecOrigin"
+	nonLocalPropVecOriginPlayerZ  = "csnonlocaldata.m_vecOrigin[2]"
 
 	serverClassPlayer = "CCSPlayer"
 )
 
 // Sets up the entity.Position() function
 // Necessary because Property() is fairly slow
 // This way we only need to find the necessary properties once
-func (e *entity) initialize() {
+func (e *entity) initialize(recordingPlayerSlot int) {
 	// Player positions are calculated differently
 	if e.isPlayer() {
-		xyProp := e.Property(propVecOriginPlayerXY)
-		zProp := e.Property(propVecOriginPlayerZ)
+		isGOTV := recordingPlayerSlot == -1
+		isRecording := recordingPlayerSlot == e.id-1
+		if isGOTV || isRecording {
+			e.positionPropNameXY = propVecOriginPlayerXY
+			e.positionPropNameZ = propVecOriginPlayerZ
+		} else {
+			e.positionPropNameXY = nonLocalPropVecOriginPlayerXY
+			e.positionPropNameZ = nonLocalPropVecOriginPlayerZ
+		}
+		xyProp := e.Property(e.positionPropNameXY)
+		zProp := e.Property(e.positionPropNameZ)
 
 		e.position = func() r3.Vector {
 			xy := xyProp.Value().VectorVal
@@ -266,8 +285,8 @@ func (e *entity) OnPositionUpdate(h func(pos r3.Vector)) {
 	}
 
 	if e.isPlayer() {
-		e.Property(propVecOriginPlayerXY).OnUpdate(firePosUpdate)
-		e.Property(propVecOriginPlayerZ).OnUpdate(firePosUpdate)
+		e.Property(e.positionPropNameXY).OnUpdate(firePosUpdate)
+		e.Property(e.positionPropNameZ).OnUpdate(firePosUpdate)
 	} else {
 		e.Property(propCellX).OnUpdate(firePosUpdate)
 		e.Property(propCellY).OnUpdate(firePosUpdate)
@@ -366,6 +385,7 @@ func (pe *property) firePropertyUpdate() {
 Bind binds a property's value to a pointer.
 
 Example:
+
 	var i int
 	property.Bind(&i, ValTypeInt)
 

pkg/demoinfocs/sendtables/entity_interface.go

@@ -14,6 +14,8 @@ type Entity interface {
 	ServerClass() *ServerClass
 	// ID returns the entity's ID.
 	ID() int
+	// SerialNum returns the entity's serial number.
+	SerialNum() int
 	// Properties returns all properties of the entity.
 	Properties() (out []Property)
 	// Property finds a property on the entity by name.

pkg/demoinfocs/sendtables/fake/entity.go

@@ -39,6 +39,11 @@ func (e *Entity) ID() int {
 	return e.Called().Int(0)
 }
 
+// SerialNum is a mock-implementation of Entity.SerialNum().
+func (e *Entity) SerialNum() int {
+	return e.Called().Int(0)
+}
+
 // Properties is a mock-implementation of Entity.Properties().
 func (e *Entity) Properties() []st.Property {
 	return e.Called().Get(0).([]st.Property)

pkg/demoinfocs/sendtables/sendtables.go

@@ -120,16 +120,16 @@ func (sc *ServerClass) PropertyEntryDefinitions() []PropertyEntry {
 	return res
 }
 
-func (sc *ServerClass) newEntity(entityDataReader *bit.BitReader, entityID int) *entity {
+func (sc *ServerClass) newEntity(entityDataReader *bit.BitReader, entityID int, classID int, serialNum int, recordingPlayerSlot int) *entity {
 	props := make([]property, len(sc.flattenedProps))
 
 	for i := range sc.flattenedProps {
 		props[i] = property{entry: &sc.flattenedProps[i]}
 	}
 
-	entity := &entity{serverClass: sc, id: entityID, props: props}
+	entity := &entity{serverClass: sc, id: entityID, serialNum: serialNum, props: props}
 
-	entity.initialize()
+	entity.initialize(recordingPlayerSlot)
 
 	if sc.preprocessedBaseline != nil {
 		entity.applyBaseline(sc.preprocessedBaseline)

pkg/demoinfocs/sendtables/st_parser.go

@@ -306,12 +306,23 @@ func (p *SendTableParser) SetInstanceBaseline(scID int, data []byte) {
 // ReadEnterPVS reads an entity entering the PVS (potentially visible system).
 //
 // Intended for internal use only.
-func (p *SendTableParser) ReadEnterPVS(r *bit.BitReader, entityID int) Entity {
-	scID := int(r.ReadInt(p.classBits()))
+func (p *SendTableParser) ReadEnterPVS(r *bit.BitReader, entityID int, existingEntities map[int]Entity, recordingPlayerSlot int) Entity {
+	classID := int(r.ReadInt(p.classBits()))
+	serialNum := int(r.ReadInt(constants.EntityHandleSerialNumberBits))
+	existingEntity := existingEntities[entityID]
+
+	if existingEntity != nil && existingEntity.SerialNum() == serialNum {
+		existingEntity.ApplyUpdate(r)
+		return existingEntity
+	}
 
-	r.Skip(constants.EntityHandleSerialNumberBits) // Serial Number
+	// Serial numbers are different, delete the entity
+	if existingEntity != nil {
+		existingEntity.Destroy()
+		delete(existingEntities, entityID)
+	}
 
-	return p.serverClasses[scID].newEntity(r, entityID)
+	return p.serverClasses[classID].newEntity(r, entityID, classID, serialNum, recordingPlayerSlot)
 }
 
 // classBits seems to calculate how many bits must be read for the server-class ID.

pkg/demoinfocs/stringtables.go

@@ -239,6 +239,10 @@ func (p *parser) processStringTable(tab *msg.CSVCMsg_CreateStringTable) {
 		case stNameUserInfo:
 			player := parsePlayerInfo(bytes.NewReader(userdata))
 
+			if p.header.ClientName == player.Name {
+				p.recordingPlayerSlot = entryIndex
+			}
+
 			p.setRawPlayer(entryIndex, player)
 
 		case stNameInstanceBaseline: