Message types, payload layouts and value encodings shared by the client and the server (src/Common/Protocol). More...

Classes
struct	rtype::protocol::BigEndian< T >
	Unsigned integer stored as big-endian bytes, with an alignment of 1. More...

struct	rtype::protocol::DisconnectPayload
	Payload of a Disconnect message, 1 byte. More...

struct	rtype::protocol::CreateEntityPayload
	Payload of a CreateEntity message, 16 bytes, sent by the server to spawn an entity on a client. More...

struct	rtype::protocol::DestroyEntityPayload
	Payload of a DestroyEntity message, 9 bytes, sent by the server to remove an entity from a client. More...

struct	rtype::protocol::QueryEntityPayload
	Payload of a QueryEntity message, 4 bytes, sent by a client that received a snapshot for an entity it does not know. More...

struct	rtype::protocol::InputPayload
	Payload of an Input message, 9 bytes, sent by a client every frame with the actions currently held. More...

struct	rtype::protocol::SnapshotHeader
	Fixed part of a Snapshot message, 6 bytes. More...

struct	rtype::protocol::SnapshotEntityState
	State of one entity inside a Snapshot message, 11 bytes. More...

struct	rtype::protocol::SnapshotPayload
	Decoded Snapshot message: a SnapshotHeader followed by `entityCount` SnapshotEntityState records. More...

Typedefs
using	rtype::protocol::be16 = BigEndian<std::uint16_t>
	16-bit unsigned integer stored in big-endian order.

using	rtype::protocol::be32 = BigEndian<std::uint32_t>
	32-bit unsigned integer stored in big-endian order.

using	rtype::protocol::NetworkEntityId = std::uint32_t
	Server assigned identifier of a replicated entity, 0 means no entity.

Enumerations
enum class	rtype::protocol::DisconnectReason : std::uint8_t { DisconnectReason::ClientQuit = 0x01 , DisconnectReason::Timeout = 0x02 , DisconnectReason::ProtocolError = 0x03 , DisconnectReason::ServerShutdown = 0x04 }
	Reason carried by a Disconnect message. More...

enum class	rtype::protocol::DestroyReason : std::uint8_t { DestroyReason::Unknown = 0x00 , DestroyReason::Collision = 0x01 , DestroyReason::OutOfBounds = 0x02 , DestroyReason::PlayerDisconnected = 0x03 , DestroyReason::GameEnded = 0x04 }
	Reason carried by a DestroyEntity message. More...

enum class	rtype::protocol::InputAction : std::uint8_t { InputAction::NoneAction = 0x00 , InputAction::Up = 0x01 , InputAction::Down = 0x02 , InputAction::Left = 0x04 , InputAction::Right = 0x08 , InputAction::Shoot = 0x10 }
	Bit flags of the actions held by a player. More...

enum class	rtype::protocol::MessageType : std::uint16_t { MessageType::Invalid = 0 , MessageType::Input = 0x02 , MessageType::Ping = 0x03 , MessageType::Disconnect = 0x04 , MessageType::QueryEntity = 0x13 , MessageType::Snapshot = 0x83 , MessageType::CreateEntity = 0x84 , MessageType::DestroyEntity = 0x85 , MessageType::Pong = 0x86 }
	Type identifier of every message exchanged on a connection. More...

Functions
constexpr bool	rtype::protocol::isValid (const DisconnectPayload &payload)
	Checks that the reason is a known value.

constexpr bool	rtype::protocol::isValid (const CreateEntityPayload &payload)
	Checks that the entity id is not 0.

constexpr bool	rtype::protocol::isValid (const DestroyEntityPayload &payload)
	Checks the entity id and the destroy reason.

constexpr bool	rtype::protocol::isValid (const QueryEntityPayload &payload)
	Checks that the entity id is not 0.

CreateEntityPayload	rtype::protocol::createEntityPayload (std::uint32_t serverTick, std::uint32_t networkId, std::uint16_t entityType, float x, float y, float rotation=0.0f)
	Builds a CreateEntity payload from world values.

DestroyEntityPayload	rtype::protocol::destroyEntityPayload (std::uint32_t serverTick, std::uint32_t networkId, DestroyReason reason)
	Builds a DestroyEntity payload.

constexpr InputAction	rtype::protocol::operator\| (InputAction left, InputAction right)
	Combines two action sets.

constexpr bool	rtype::protocol::hasAction (InputAction actions, InputAction action)
	Tells whether an action set contains an action.

constexpr std::uint16_t	rtype::protocol::toMessageId (MessageType type)
	Converts a message type to its wire identifier.

template<typename T > requires std::is_trivially_copyable_v<T>
bool	rtype::protocol::writePayload (PacketWriter &writer, const T &payload)
	Appends the raw bytes of a padding free payload struct.

template<typename T > requires std::is_trivially_copyable_v<T>
bool	rtype::protocol::readPayload (PacketReader &reader, T &payload)
	Reads the raw bytes of a padding free payload struct.

be16	rtype::protocol::encodePosition (float position)
	Encodes a position as a 16-bit fixed point value.

float	rtype::protocol::decodePosition (be16 encoded)
	Decodes a position encoded by encodePosition().

be16	rtype::protocol::encodeRotation (float radians)
	Encodes an angle as a fraction of a full turn on 16 bits.

float	rtype::protocol::decodeRotation (be16 encoded)
	Decodes an angle encoded by encodeRotation().

bool	rtype::protocol::writeSnapshot (PacketWriter &writer, const SnapshotPayload &payload)
	Encodes a snapshot.

bool	rtype::protocol::readSnapshot (PacketReader &reader, SnapshotPayload &payload)
	Decodes and validates a snapshot.

Variables
constexpr float	rtype::protocol::POSITION_SCALE = 4.0f
	Number of encoded steps per pixel, giving a 0.25 pixel resolution.

constexpr float	rtype::protocol::POSITION_OFFSET = 8192.0f
	Offset added before encoding so that negative positions fit.

constexpr float	rtype::protocol::MIN_POSITION = -POSITION_OFFSET
	Smallest position that can be encoded, in pixels.

constexpr float	rtype::protocol::MAX_POSITION
	Largest position that can be encoded, in pixels.

constexpr std::size_t	rtype::protocol::SNAPSHOT_MAX_ENTITIES
	Largest number of entity states that fit in one Snapshot message.

Detailed Description

Message types, payload layouts and value encodings shared by the client and the server (src/Common/Protocol).

See Network protocol specification for the full specification.

Enumeration Type Documentation

◆ DisconnectReason

enum class rtype::protocol::DisconnectReason : std::uint8_t

strong

Reason carried by a Disconnect message.

Enumerator
ClientQuit	The player left the game.
Timeout	The peer stopped answering.
ProtocolError	The peer sent invalid data.
ServerShutdown	The server is stopping.

◆ DestroyReason

enum class rtype::protocol::DestroyReason : std::uint8_t

strong

Reason carried by a DestroyEntity message.

Enumerator
Unknown	No specific reason.
Collision	Removed by gameplay, such as a hit.
OutOfBounds	Left the playable area.
PlayerDisconnected	Owner of the ship left the game.
GameEnded	The game is over.

◆ InputAction

enum class rtype::protocol::InputAction : std::uint8_t

strong

Bit flags of the actions held by a player.

Enumerator
NoneAction	No action held.
Up	Move up.
Down	Move down.
Left	Move left.
Right	Move right.
Shoot	Shoot button held.

◆ MessageType

enum class rtype::protocol::MessageType : std::uint16_t

strong

Type identifier of every message exchanged on a connection.

Enumerator
Invalid	Never sent, marks an unset type.
Input	Client to server: actions held by the player.
Ping	Client to server: latency probe.
Disconnect	Client to server: closes the connection.
QueryEntity	Client to server: asks for an unknown entity.
Snapshot	Server to client: positions of the entities.
CreateEntity	Server to client: spawns an entity.
DestroyEntity	Server to client: removes an entity.
Pong	Server to client: answer to a Ping.

Function Documentation

◆ isValid() [1/4]

bool rtype::protocol::isValid ( const DisconnectPayload & payload )

constexpr

Checks that the reason is a known value.

Parameters

payload Decoded payload.

Returns: True if the payload is valid.

◆ isValid() [2/4]

bool rtype::protocol::isValid ( const CreateEntityPayload & payload )

constexpr

Checks that the entity id is not 0.

Parameters

payload Decoded payload.

Returns: True if the payload is valid.

◆ isValid() [3/4]

bool rtype::protocol::isValid ( const DestroyEntityPayload & payload )

constexpr

Checks the entity id and the destroy reason.

Parameters

payload Decoded payload.

Returns: True if the payload is valid.

◆ isValid() [4/4]

bool rtype::protocol::isValid ( const QueryEntityPayload & payload )

constexpr

Checks that the entity id is not 0.

Parameters

payload Decoded payload.

Returns: True if the payload is valid.

◆ createEntityPayload()

CreateEntityPayload rtype::protocol::createEntityPayload	(	std::uint32_t	serverTick,
		std::uint32_t	networkId,
		std::uint16_t	entityType,
		float	x,
		float	y,
		float	rotation = 0.0f )

inline

Builds a CreateEntity payload from world values.

Parameters

serverTick	Current server tick.
networkId	Identifier of the entity.
entityType	Archetype id of the entity blueprint.
x	Horizontal position in pixels.
y	Vertical position in pixels.
rotation	Rotation in radians.

Returns: The encoded payload.

◆ destroyEntityPayload()

DestroyEntityPayload rtype::protocol::destroyEntityPayload	(	std::uint32_t	serverTick,
		std::uint32_t	networkId,
		DestroyReason	reason )

inline

Builds a DestroyEntity payload.

Parameters

serverTick	Current server tick.
networkId	Identifier of the entity.
reason	Why the entity is removed.

Returns: The encoded payload.

◆ operator|()

InputAction rtype::protocol::operator\|	(	InputAction	left,
		InputAction	right )

constexpr

Combines two action sets.

Parameters

left	First action set.
right	Second action set.

Returns: The union of both sets.

◆ hasAction()

bool rtype::protocol::hasAction	(	InputAction	actions,
		InputAction	action )

constexpr

Tells whether an action set contains an action.

Parameters

actions	Action set to test.
action	Action to look for.

Returns: True if the action is set.

◆ toMessageId()

std::uint16_t rtype::protocol::toMessageId ( MessageType type )

constexpr

Converts a message type to its wire identifier.

Parameters

type	Message type.

Returns: The 16-bit identifier written in the message header.

◆ writePayload()

template<typename T >
requires std::is_trivially_copyable_v<T>

bool rtype::protocol::writePayload	(	PacketWriter &	writer,
		const T &	payload )

Appends the raw bytes of a padding free payload struct.

Template Parameters

T	Payload type, made of single bytes and BigEndian fields.

Parameters

writer	Destination buffer.
payload	Payload to write.

Returns: True on success, false if the buffer is full.

◆ readPayload()

template<typename T >
requires std::is_trivially_copyable_v<T>

bool rtype::protocol::readPayload	(	PacketReader &	reader,
		T &	payload )

Reads the raw bytes of a padding free payload struct.

Template Parameters

T	Payload type, made of single bytes and BigEndian fields.

Parameters

reader	Source buffer.
payload	Receives the payload.

Returns: True on success, false if not enough bytes remain.

◆ encodePosition()

be16 rtype::protocol::encodePosition ( float position )

inline

Encodes a position as a 16-bit fixed point value.

Parameters

position Position in pixels, clamped to the encodable range.

Returns: round((position + 8192) * 4), or the encoding of 0 if not finite.

◆ decodePosition()

float rtype::protocol::decodePosition ( be16 encoded )

inline

Decodes a position encoded by encodePosition().

Parameters

encoded Encoded value.

Returns: The position in pixels.

◆ encodeRotation()

be16 rtype::protocol::encodeRotation ( float radians )

inline

Encodes an angle as a fraction of a full turn on 16 bits.

Parameters

radians Angle in radians, any value.

Returns: 0 for 0 radians, 32768 for pi, wrapping at 65536.

◆ decodeRotation()

float rtype::protocol::decodeRotation ( be16 encoded )

inline

Decodes an angle encoded by encodeRotation().

Parameters

encoded Encoded value.

Returns: The angle in radians, in the range [0, 2 pi).

◆ writeSnapshot()

bool rtype::protocol::writeSnapshot	(	PacketWriter &	writer,
		const SnapshotPayload &	payload )

inline

Encodes a snapshot.

Parameters

writer	Destination buffer.
payload	Snapshot with at most SNAPSHOT_MAX_ENTITIES states.

Returns: True on success, false if there are too many states or no room.

◆ readSnapshot()

bool rtype::protocol::readSnapshot	(	PacketReader &	reader,
		SnapshotPayload &	payload )

inline

Decodes and validates a snapshot.

Parameters

reader	Buffer holding exactly one snapshot payload.
payload	Receives the snapshot, left untouched on failure.

Returns: True if the size, count and entity ids are all valid.

Variable Documentation

◆ MAX_POSITION

float rtype::protocol::MAX_POSITION

inlineconstexpr

Initial value:

=
    static_cast<float>(std::numeric_limits<std::uint16_t>::max()) /
        POSITION_SCALE -
    POSITION_OFFSET

Largest position that can be encoded, in pixels.

◆ SNAPSHOT_MAX_ENTITIES

std::size_t rtype::protocol::SNAPSHOT_MAX_ENTITIES

inlineconstexpr

Initial value:

=
    (MAX_MESSAGE_SIZE - MessageHeader::HEADER_SIZE - sizeof(SnapshotHeader)) /
    sizeof(SnapshotEntityState)

Largest number of entity states that fit in one Snapshot message.

Classes

Typedefs

Enumerations

Functions

Variables

Detailed Description

Enumeration Type Documentation

◆ DisconnectReason

◆ DestroyReason

◆ InputAction

◆ MessageType

Function Documentation

◆ isValid() [1/4]

◆ isValid() [2/4]

◆ isValid() [3/4]

◆ isValid() [4/4]

◆ createEntityPayload()

◆ destroyEntityPayload()

◆ operator|()

◆ hasAction()

◆ toMessageId()

◆ writePayload()

◆ readPayload()

◆ encodePosition()

◆ decodePosition()

◆ encodeRotation()

◆ decodeRotation()

◆ writeSnapshot()

◆ readSnapshot()

Variable Documentation

◆ MAX_POSITION

◆ SNAPSHOT_MAX_ENTITIES