/* renamed from cc_hole.gcmc for clarity
 *
 * G-code meta compiler
 *
 * Copyright (C) 2014  B. Stultiens
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 *
 * - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
 * Hole milling example
 * --------------------
 * Mill a hole in continuous curvature movements. Not a single straight line is
 * required to mill an arbitrary large hole from any size milling bit.
 * Continuous curvature milling reduces the stress on the mill, bit and object
 * by preventing any jerking.
 *
 * A hole is milled at a given center and depth with a target radius. The
 * milling-bit radius and the cutting step define how many turning cycles are
 * required to finish the hole. The mill is retracted with a helical move back
 * to the center and starting Z-position.
 *
 * @@@--svg-toolwidth 6.0 --svg-opacity 0.2@@@
 */

feedrate(600mm);

function cc_hole(center, targetradius, toolradius, cutstep, cutz)
{
	local mkunitsum = ismodemm() ? 0.0mm : 0.0in;
	local oldz = position()[2];
	if(!isvector(center) || count(center) < 1) {
		error("Center argument must be a vector and must have at least one X or Y coordinate");
		return;
	}
	if(count(center) > 3) {
		error("Center argument has more than 3 axes defined, may cause unforeseen problems");
		return;
	}
	if(count(center) > 2 && !isundef(center[2])) {
		warning("Center argument has a Z-coordinate, ignoring to prevent plowing into object");
		center = head(center, 2);
	}
	if((count(center) == 1 && isundef(center[0])) || (count(center) > 1 && isundef(center[0]) && isundef(center[1]))) {
		warning("Center argument has neither X nor Y coordinate, using current position");
		center = head(position(), 2);
	}
	if(!isscalar(targetradius)) {
		error("Target radius argument must be scalar");
		return;
	}
	if(!isnone(targetradius) && !isdistance(targetradius)) {
		error("Target radius argument must be a distance");
		return;
	}
	targetradius += mkunitsum;	// Make sure we have units
	if(targetradius <= 0.0mm) {
		error("Target radius argument must be larger than zero");
		return;
	}
	if(!isscalar(toolradius)) {
		error("Tool radius argument must be scalar");
		return;
	}
	if(!isnone(toolradius) && !isdistance(toolradius)) {
		error("Tool radius argument must be a distance");
		return;
	}
	toolradius += mkunitsum;	// Make sure we have units
	if(toolradius <= 0.0mm) {
		error("Tool radius argument must be larger than zero");
		return;
	}
	if(targetradius <= toolradius) {
		error("Hole target radius (", targetradius, ") must be larger than tool radius (", toolradius, ")");
		return;
	}
	if(!isscalar(cutstep)) {
		error("Cutting step argument must be scalar");
		return;
	}
	if(!isnone(cutstep) && !isdistance(cutstep)) {
		error("Cutting step must be a distance");
		return;
	}
	cutstep += mkunitsum;	// Make sure we have units
	if(cutstep <= 0.0mm) {
		error("Cutting step argument must be larger than zero");
		return;
	}
	if(!isscalar(cutz)) {
		error("Cutting depth argument must be scalar");
		return;
	}
	if(!isnone(cutz) && !isdistance(cutz)) {
		error("Cutting depth must be a distance");
		return;
	}
	cutz += mkunitsum;	// Make sure we have units
	if(cutstep > 2.0*toolradius) {
		warning("Cutting step is larger than twice the tool radius, not all material will be removed");
	} elif(cutstep == 2.0*toolradius) {
		warning("Cutting step is exactly twice the tool radius, material may be left at the inner edge");
	}

	comment("-- cc_hole center=", center, " targetradius=", targetradius, " toolradius=", toolradius, " cutstep=", cutstep, " cutz=", cutz, " --");

	goto(center);		// Center of the hole
	move([-, -, cutz]);	// Start the initial cut at the center; r = toolradius

	local r = toolradius;	// Keep track how big the hole is
	local n = 1;
	local dir = -1.0;	// Alternating end-point tracking (=> (-1)^n sign shift)
	local p;		// endpoint for new arc into next hole circle

	// We have to circle 1..n times to make the hole
	while(r < targetradius) {
		if(targetradius - r >= cutstep) {
			// Take a full cutting step because space allows
			p = (2*n-1) * cutstep;
			r += cutstep;
		} else {
			// Last cut is under cutstep in size
			p = (2*n-2) * cutstep + targetradius - r;
			r += targetradius - r;
		}
		arc_cw_r([0.0mm, dir * p], p/2.0);	// Arc into the next circle
		circle_cw(center);			// Widen the hole
		n++;
		dir = -dir;				// Arc endpoint alternate
	}

	// Curve _out_ of the hole by helical arc move back to center and oldz
	arc_cw_r([0.0mm, dir * (targetradius - toolradius), oldz-cutz], (targetradius - toolradius)/2.0);

	comment("-- end cc_hole --");
	return;
}

/* -------------------- Main Program -------------------- */

//ngcgui: info: Circular pocket with continuous curvature movements

//ngcgui: umode = 1;          //, units: 1:mm, 0:inch
//ngcgui: xctr = 0;           //, x center
//ngcgui: yctr = 0;           //, y center
//ngcgui: diameter = 10;      //, diameter
//ngcgui: tool_diameter = 2;  //, tool_diameter
//ngcgui: step = 1;           //, step
//ngcgui: cutdepth = -1;      //, cutdepth
//ngcgui: xfinal = 0;          //
//ngcgui: yfinal = 0;          //
//ngcgui: zfinal = 1;          //
//ngcgui: verbose = 0;        //  precede ensure_units
include("ensure_units.gcmc"); //  avoid preamble conflict

if (umode == 1) {
  zero = 0.0mm;
} else {
  zero = 0.0in;
}
// ngcgui entries are unitless so these additions are used
// to ensure 1) floatingpoint and 2) units per umode setting

         xctr = zero + xctr;
         yctr = zero + yctr;
     diameter = zero + diameter;
tool_diameter = zero + tool_diameter;
         step = zero + step;
     cutdepth = zero + cutdepth;
       xfinal = zero + xfinal;
       yfinal = zero + xfinal;
       zfinal = zero + xfinal;


location = [xctr,yctr];
FINALPOS = [xfinal,yfinal,zfinal];
goto(FINALPOS);
if(!issvg()) {
	move(FINALPOS);	// To visualize subsequent rapids in LinuxCNC
}

//      Center    R_hole      R_tool           Step  Cutting-Z
cc_hole(location, diameter/2, tool_diameter/2, step, cutdepth);

goto(FINALPOS);