PolyPathGCodeTools.js

/*
    Copyright 2013 Google Inc

    Licensed under the Apache License, Version 2.0 (the "License");
    you may not use this file except in compliance with the License.
    You may obtain a copy of the License at

      http://www.apache.org/licenses/LICENSE-2.0

    Unless required by applicable law or agreed to in writing, software
    distributed under the License is distributed on an "AS IS" BASIS,
    WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    See the License for the specific language governing permissions and
    limitations under the License.
*/
exports.PolyPathGCodeTools = {};
var PolyPathGCodeTools = exports.PolyPathGCodeTools;

//similar to drawPolyPath() but generates a gcode program
exports.PolyPathGCodeTools.gcodeFromPolyPath = function(polyPath) {
    var gcode = '';

    function appendLine(str) {
        gcode += str + '\n';
    }

    function appendComment(str) {
        appendLine('( ' + str + ' )');
    }

    function appendCommand(args) {
        var cmdStr = args.cmd;
        for (var n in args) {
            if (n != 'cmd') {
                cmdStr += ' ' + n;
                if (Math.round(args[n]).toString() == args[n].toString())
                    cmdStr += (n + '.0');
                else
                    cmdStr += n.toString();
            }
        }
    }

    var xOffset = 0; - 1 * (ConfigParams.CAM_X / 2);
    var yOffset = 0; - 1 * (ConfigParams.CAM_Y / 2);

    appendComment('Generated by robotcontrol');
    appendComment('');

    var fDrawing = 900; // feed rate while drawing
    var fTraveling = 3000; // feed rate while traveling

    var zDrawing = 0; // Z axis for drawing moves (mm)
    var zTraveling = 100; // Z axis for travel moves (mm)

    var eDrawing = 1; // (e)xtruder setting while drawing
    var eTraveling = 0; // (e)xtruder setting while traveling

    // preamble
    appendComment('prepare machine state');

    appendCommand({
        cmd: 'G92',
        e: 0
    }); // reset extruder
    appendCommand({
        cmd: 'G90'
    }); // absolute coordinate system
    appendCommand({
        cmd: 'M82'
    }); // absolute mode for extruder, too
    appendCommand({
        cmd: 'G21'
    }); // units are mm
    appendCommand({
        cmd: 'G92',
        e: 0.0
    }); // reset extruder again... not sure why this is needed, but most gcode does this

    appendComment('beginning of drawing');
    for (var i = 0; i < polyPath.length; i++) {
        appendComment('beginning of line segment ' + i + ' of ' + polyPath.length);
        var path = polyPath[i];
        appendCommand({
            cmd: 'G1',
            z: zTraveling,
            f: fTraveling
        });
        var point = null;
        for (var j = 0; j < path.length; j++) {
            point = path[j];

            if (j == 0) {
                //first point on a new path, so move the tool above the drawing point but above the workpiece
                appendCommand({
                    cmd: 'G1',
                    x: (point.x + xOffset),
                    y: (point.y + yOffset),
                    z: zTraveling,
                    f: fTraveling
                });
            }
            appendCommand({
                cmd: 'G1',
                x: (point.x + xOffset),
                y: (point.y + yOffset),
                z: zDrawing,
                f: fDrawing
            });
        }
        if (point != null) {
            //end of line, raise the tool
            appendCommand({
                cmd: 'G1',
                x: (point.x + xOffset),
                y: (point.y + yOffset),
                z: zTraveling,
                f: fTraveling
            });
        }
        appendComment('end of line segment ' + i + ' of ' + polyPath.length);
    }
    appendComment('end of drawing');
    return gcode;
};