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Message List

Messages now have a simple structure which can be thought of similarly for any of the protocol variants provided by zstar. Examples here will be given in text mode for clarity.

We have introduced the concept of a loadable message handler written in java, and we think that this will allow application writing to be much easier. We will, of course, still need a way of messaging the client, and so these messages stand. We have added one message, 'loadJar', which loads and runs some java code. The client will be able to implement any type of message handler using java code.

Client Messages

Message Name: controlDef
Format: ssiiii

string -- Control proper name (e.g. generic.turn.x)
string -- Control description
integer -- Control integer id
integer -- Control min value
integer -- Control max value
integer -- Control type, currently 0 is one shot, and 1 is continuous. One shots are useful for cannons and other such, and continuous controls are good for turning, throttles, etc.

Purpose: Define a control. If the client has a user action bound to this control (by name) then that action will cause the client to send the indicated control message.

Message Name: textureSet
Format: si

string -- Texture image URL
integer -- Texture id in the client

Purpose: Associate the indicated texture with an ID in the client when the texture is loaded.
Note: The controlling party assigns the id as in the X-Window System.

Message Name: objectDef
Format: si

string -- Mesh file URL
integer -- Mesh id as used by objects

Purpose: Associate the indicated mesh with an ID in the client when the mesh is loaded.

Message Name: primary
Format: s

string -- Primary server URL.

Purpose: Hyperlink the client to a new primary server. Upon receiving this message, the client redirects control messages to the indicated server and sends a hello.

Message Name: contact
Format: s

string -- Server address as above

Purpose: This message tells the client to send an olleh to the indicated server. This mechanism may be used by servers to distribute world updates across multiple originators. This does not affect the client's view of the primary server.

Message Name: decontact
Format: #
Purpose: Cause the client to send termination messages (bye) to servers contacted because of a contact message. This is needed when the client hyperlinks to properly terminate connections to foreign servers.

Message Name: next
Format: #
Purpose: Cause the client to commit changes to the universe and redraw the frame.

Message Name: config
Format: s

string -- Configuration string.

Purpose: Send a configuration string to the client. This feature may be used for feature negotiation at some later time.

Message Name: chatMSG
Format: si

string -- The chat message
integer -- Recipient ID

Purpose: Cause the client to display a chat message in the message scroll. Note: ID must be sent zero and is not yet used.

Message Name: systemMSG
Format: si

string -- A message generated by the server
integer -- Severity level

Purpose: Cause the client to display a system message in the message scroll. The message may be distinguished from a normal chat message in some way.
Note: Severity is not currently used and must be zero.

Message Name: camera
Format: [nf

float array -- Six parameters of the camera are currently specified:
- x,y,z -- World position of the camera
- p,r,s -- World rotation of the camera in degrees

Purpose: Cause the client to move the camera.
Note: Extra parameters might be used later. Do not send more than six elements in this array. It is acceptable to send less than six, however.

Message Name: object
Format: ii[nf

integer -- Object id to change
integer -- Mesh id to bind to the object
float array -- Six parameters of the object are currently specified:
- x,y,z -- World position of the object
- p,r,s -- World rotation of the object in degrees

Purpose: Cause the client to move the indicated object, and bind it to a new mesh. These messages are ganged, because it is likely that objects will be animated by cycling a set of meshes over them. If the object is to have its mesh changed, a zero-element floating array may be used.

Message Name: light
Format: ii[nf

integer -- Light id to change
integer -- Light type
float array -- Three parameters are specified currently:
- x,y,z -- World position of the light

Purpose: Cause the client to move the indicated light.

Message Name: fog
Format: iiff

integer -- Color as RGB triple (24 bits)
integer -- Type:
- 0 -- Linear
- 1 -- 1/e
- 2 -- 1/e^2
float -- Fog in distance.
float -- Fog out distance.

Purpose: Cause the client to enable a fog effect for distance cues.

Message Name: meshPTS
Format: ii[nf

integer -- Mesh ID to change
integer -- First vertex to change
float array -- Vertices specified as triplets

Purpose: The specified vertices will overwrite those currently in the indicated mesh starting from the indicated start point. The mesh will be expanded if necessary.

Message Name: meshTRI
Format: ii[ni

integer -- Mesh ID to change
integer -- First triangle to change
integer array -- Triangles specified as triplets. Each value is a pointer into the mesh's vertex array.

Purpose: The specified triangles will overwrite those currently in the indicated mesh starting from the indicated start point. The mesh will be expanded if necessary.

Message Name: rm
Format: si

string -- Name domain to delete from:
- light
- mesh
- obj
- tex
integer -- The ID of the object to remove.

Purpose: Removes the indicated object from the client's data set.

Message Name: cp
Format: sii

string -- Name domain as above.
integer -- Object ID to copy from.
integer -- Object ID to copy to.

Purpose: Copies the indicated object to a new ID. The two copies are completely independent, but are identical directly after the copy is made.

Message Name: mv
Format: sii

string -- Name domain as above.
integer -- Object ID to move from.
integer -- Object ID to move to.

Purpose: Changes the ID of the indicated object to the new ID. The object occupying the new ID before the mv command if any is deleted.

Message Name: clear
Format: #
Purpose: Erases all objects and lights from the scene. Provides a completely clean slate for client redraws.

Message Name: hold
Format: #
Purpose: Prevens client redraws until the next next command is processed. Useful at the beginning of a long refresh.

Message Name: meshVRML
Format: si
Purpose: Creates a mesh object from a VRML file read at the url given in argument 1 and assigns it to the mesh number given in argument 2. Objects bearing this mesh number are drawn as the VRML scene. The entire VRML scene will be transformed by the object position and orientation last given by the object command for that object.

Message Name: loadScript
Format: s
Purpose: Loads and executes a TCL script from the URL given by it's argument. Any procs encountered, after effects, etc. go into effect directly after this command is processed. It is useful for loading scripts into the client and then later invoking them with tclcmd.

Message Name: tclcmd
Format: s
Purpose: Executes a TCL "one-liner" script. This is useful for invoking commands stored in the client by the loadScript command. This makes it easy for most environments to load complex effects into the client and start them working with a single message passed, reducing server load.

Message Name: sndload
Format: sii

s -- URL of sound file to load.
i -- Type of sound (1 == clip, 0 == mod song)
i -- Sound ID

Purpose: Load the clip from the url given, as either a clip or a MOD, and store it in the given ID. The sound may be manipulated later by its ID.

Message Name: sndplay
Format: i
Purpose: Play the sound at the given ID.

Message Name: sndstop
Format: i
Purpose: Stop playing the sound at the given ID.

Message Name: sndpause
Format: i
Purpose: Pause the sound at the given ID. It can be resumed with sndres.

Message Name: sndres
Format: i
Purpose: Resume the sound at the given ID.

Message Name: sndloop
Format: i
Purpose: Loop the sound at the given ID until some other action is taken on that ID.

Message Name: loadJar
Format: ss

s -- URL to a 'jar' file to load. All contained classes will be loaded.
s -- Name of 'main' class. This class's public static void init() method will be called, allowing it to create threads, register services, etc.

Purpose: This message is similar to the applet tag in HTML, in that it causes the indicated java 'jar' file to be loaded and some contained method to be executed. Classes can register currently for two types of messages, frame messages, which transfer control to java before a frame is rendered, and protocol messages, which relay unfamiliar network messages to java classes for interpretation. This allows a game designer to create new types of messages (such as compressed updates, abbreviated motion updates, etc).