ofMesh & ofApp::generateIndices(ofMesh & mesh, int width, int height) {
	int steps = 1;
	vector<glm::vec3> &vertices = mesh.getVertices();

	for (int i = 0; i < width - steps; i += steps) {
		for (int j = 0; j < height - steps; j += steps) {
			auto topLeft = width * j + i;
			auto topRight = topLeft + steps;
			auto bottomLeft = topLeft + width * steps;
			auto bottomRight = bottomLeft + steps;

			const ofVec3f & vTL = vertices[topLeft];
			const ofVec3f & vTR = vertices[topRight];
			const ofVec3f & vBL = vertices[bottomLeft];
			const ofVec3f & vBR = vertices[bottomRight];

			//upper left triangle
			if (vTL.z > 0 && vTR.z > 0 && vBL.z > 0
				&& abs(vTL.z - vTR.z) < opts.facesMaxLength
				&& abs(vTL.z - vBL.z) < opts.facesMaxLength) {
				const ofIndexType indices[3] = { topLeft, bottomLeft, topRight };
				mesh.addIndices(indices, 3);
			}

			//bottom right triangle
			if (vBR.z > 0 && vTR.z > 0 && vBL.z > 0
				&& abs(vBR.z - vTR.z) < opts.facesMaxLength
				&& abs(vBR.z - vBL.z) < opts.facesMaxLength) {
				const ofIndexType indices[3] = { topRight, bottomRight, bottomLeft };
				mesh.addIndices(indices, 3);
			}
		}
	}

	return mesh;
}