src/geometry.c


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#include "fracture.h"

int edge_to_verts(unsigned int width, bool periodic, unsigned int edge,
									bool index) {
	assert(edge < pow(width, 2));

	int x = edge / width + 1;
	int y = edge % width + 1;

	if (periodic) {
		return (((index ^ (x % 2)) + 2 * ((y + (index ^ (!(x % 2)))) / 2) - 1) %
								width +
						(x - index) * width) /
					 2;
	} else {
		return ((index ^ (x % 2)) + 2 * ((y + (index ^ (!(x % 2)))) / 2) +
						(x - index) * (width + 1) - 1) /
					 2;
	}
}

int dual_edge_to_verts(unsigned int width, bool periodic, unsigned int edge,
											 bool index) {
	assert(edge < pow(width, 2));

	int x = edge / width + 1;
	int y = edge % width + 1;

	if (periodic) {
		return (((index ^ (!(x % 2))) + 2 * ((y + (index ^ (x % 2))) / 2) - 1) %
								width +
						(x - index) * width) /
					 2;
	} else {
		return ((index ^ (!(x % 2))) + 2 * ((y + (index ^ (x % 2))) / 2) +
						(x - index) * (width + 1) - 1) /
					 2;
	}
}

double dual_vert_to_coord(unsigned int width, bool periodic, unsigned int vert,
													bool index) {
	if (periodic) {
		if (index)
			return vert % (width / 2) + (vert / (width / 2)) % 2;
		else
			return vert / (width / 2);
	} else {
		if (index)
			return (2 * vert) % (width + 1);
		else
			return (2 * vert) / (width + 1);
	}
}