/*
 * face.h - Data structure and handling of one face of a part
 *
 * Written 2010 by Werner Almesberger
 * Copyright 2010 by Werner Almesberger
 *
 * 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 2 of the License, or
 * (at your option) any later version.
 */

#ifndef FACE_H
#define FACE_H

#include <math.h>

#include "array.h"
#include "matrix.h"


struct face {
	struct array *a;
	double x_step, y_step, z_step;
	int sx, sy, sz;	/* size */
	int cx, cy;	/* center */
	int z_ref;
	double fx, fy;	/* inclination factor */
	struct matrix m;
};


static inline double face_z0(const struct face *f, int x, int y)
{
	return f->z_ref+f->fx*(x-f->sx/2)+f->fy*(y-f->sy/2);
}


static inline double z0_scale(const struct face *f)
{
	return f->z_step/f->x_step;
}


static inline double fx_to_angle(const struct face *f)
{
	return atan(f->fx*z0_scale(f))/M_PI*180;
}


static inline double fy_to_angle(const struct face *f)
{
	return atan(f->fy*z0_scale(f))/M_PI*180;
}


static inline void fx_from_angle(struct face *f, double a)
{
	f->fx = tan(a/180*M_PI)/z0_scale(f);
}


static inline void fy_from_angle(struct face *f, double a)
{
	f->fy = tan(a/180*M_PI)/z0_scale(f);
}


struct face *read_face(const char *name);

#endif /* !FACE_H */