PxSys Server

Server-side rendering for Blockland.

Lets you create a screen of any size and send pixel data over to clients via TCP. Mostly used to create dynamic screens out of bricks, since JavaScript is exponentially faster than TorqueScript.

It's also optimized to only send over the values that were changed.

Usage

Here is a bare-bones server setup example:

const { createPxSys } = require ('PxSys');

// Create a PxSys object with a screen width of 320 and a height of 240
const pxObject = createPxSys (320, 240);
// Start a PxSysServer listening on 127.0.0.1:23
pxObject.createServer (23, '127.0.0.1');

// Handle a new socket connection
pxObject.onServer ('connection', socket =>
{
	// Send the screen's width and height to the socket
	pxObject.sendScreenData (socket);
	// Send all current pixel data to the socket
	pxObject.sendPixelData (socket);
});

Each pixel contains various key-value pairs that store data for various fields, like colorID, printID, colorPrintID (more on this in Additional Information), etc. By default they only have a colorID field that's 0 by default.

To set a specific field for a specific pixel, use pxObject.setScreenPixel (x, y, key, value);

When you're done, call pxObject.sendChangedPixels (); to send only the pixels and only the fields in those pixels that were changed.

If you want to send all pixel data regardless of whether they were changed or not, use pxObject.sendPixelData ();

API

createPxSys (width, height[, defaultValues]);

Creates a PxSys instance with an internal PxSysScreen instance attached to it.

| Argument | Description | | ----------- | ----------- | | width | The width of the internal PxSysScreen object. | | height | The height of the internal PxSysScreen object. | | defaultValues | An object containing the default values for pixels in the internal PxSysScreen object. Default object is { colorID: 0 } |

PxSys::createServer (port, address[, callbacks]);

Starts up an internal PxSysServer instance for handling connections.

| Argument | Description | | ----------- | ----------- | | port | The port to listen to. | | address | The address to listen on. | | callbacks | An object containing callbacks for the server. Supported callbacks are onStart and onEnd |

PxSys::destroyServer ([callback]);

Destroys the internal server with an optional callback for when it's done.

PxSys::onServer (event, callback);

Adds a callback to the internal TCP server. Uses the default net server so it supports all callbacks for that.

PxSys::offServer (event, callback);

Removes a callback from the internal TCP server.

PxSys::onPacket (packetCommand, callback);

Adds a callback for handling a specific client command. The first argument for the callback is always the sender's Socket instance.

PxSys::offPacket (packetCommand, callback);

Removes a callback for handling a specific client command.

PxSys::sendCommand (socket, command[, ...args]);

Sends a command to a specific client with whatever arguments.

PxSys::sendError (socket, errorCommand, errorCode[, errorMessage, data]);

Sends an error to a specific client with an optional error message and whatever additional data.

PxSys::sendCommandToAll (command[, ...args]);

Sends a command to all clients with whatever arguments.

PxSys::sendErrorToAll (errorCommand, errorCode[, errorMessage, data]);

Sends an error to all clients with an optional error message and whatever additional data.

PxSys::sendScreenData ([socket]);

Sends screen width and height (SV_SCREEN_SIZE) to a specific client, or to all of them if socket is not specified.

PxSys::setScreenPixel (x, y, key, value);

Sets a pixel field value for the internal PxSysScreen instance.

| Argument | Description | | ----------- | ----------- | | x | The x position of the pixel data. | | y | The y position of the pixel data. | | key | Each pixel contains an object with various key-value pairs. This specifies which field we're setting/modifying. | | value | Each pixel contains an object with various key-value pairs. This specifies what value we're setting the field to. |

PxSys::sendChangedPixels ([socket]);

Sends only the pixel fields that were changed (SV_PIXEL_DATA), either to a specific client, or to all clients if socket is not specified.

PxSys::sendPixelData ([socket]);

Sends all pixel fields regardless of whether they were changed or not (SV_PIXEL_DATA), either to a specific client, or to all clients if socket is not specified.

PxSys::delete ([onServerClose]);

"Deletes" the PxSys object by "deleting" all internal instances, shutting down the TCP server, and dereferencing all properties. Optional onServerClose callback for when the internal TCP server is shut down.

Commands and Errors

This package uses some internal commands already using a simple format: PREFIX_NAME

There are three prefixes:

• SV - This is a command specifically to be sent from the server to the client.
• CL - This is a command specifically to be sent from the client to the server.
• CS - This is a command that can be sent by both.

Example: SV_PIXEL_DATA

You can send your own commands using the PxSys::sendCommand method (see API).

Sending errors works in a similar way. The difference is that there are both error commands and error codes.

Error commands are only one of these three:

• SV_ERROR - The server is at fault.
• CL_ERROR - The client is at fault.
• CS_ERROR - Nobody is at fault! It's just an unfortunate error.

Error codes are just strings without the prefix. Example: MALFORMED_PACKET

You can send your own commands using the PxSys::sendError method (see API).

Obviously none of your own commands or errors have to use this format, just like you don't have to recycle or tip your waiter or thank your bus driver... it's just a good idea to do it.

Additional Information

This package is best used in conjunction with Server_PxSys. You can of course use your own client though.

You may have noticed I mentioned the colorPrintID field. This is a special field for setting a brick's print to a PxSys color. This allows for much sharper pixel changes since changing a brick's print doesn't fade like changing its color does. Here is the default pack of colors.

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