Work on supporting H3-style indexing for feature indices

geometry.cpp

@@ -944,12 +944,10 @@ drawvec polygon_to_anchor(const drawvec &geom) {
 	return drawvec();
 }
 
-drawvec checkerboard_anchors(drawvec const &geom, int tx, int ty, int z, unsigned long long label_point) {
+drawvec checkerboard_anchors(drawvec const &geom, int tx, int ty, int z, unsigned wx, unsigned wy) {
 	drawvec out;
 
-	// anchor point in world coordinates
-	unsigned wx, wy;
-	decode_index(label_point, &wx, &wy);
+	// wx,wy is anchor point in world coordinates
 
 	// upper left of tile in world coordinates
 	long long tx1 = 0, ty1 = 0;

geometry.hpp

@@ -89,7 +89,7 @@ void check_polygon(drawvec &geom);
 double get_area(const drawvec &geom, size_t i, size_t j);
 double get_mp_area(drawvec &geom);
 drawvec polygon_to_anchor(const drawvec &geom);
-drawvec checkerboard_anchors(drawvec const &geom, int tx, int ty, int z, unsigned long long label_point);
+drawvec checkerboard_anchors(drawvec const &geom, int tx, int ty, int z, unsigned label_x, unsigned label_y);
 
 drawvec simple_clip_poly(drawvec &geom, int z, int buffer, drawvec &shared_nodes, bool prevent_simplify_shared_nodes);
 drawvec simple_clip_poly(drawvec &geom, long long x1, long long y1, long long x2, long long y2, bool prevent_simplify_shared_nodes);

main.cpp

@@ -94,11 +94,13 @@ unsigned int drop_denser = 0;
 std::map<std::string, serial_val> set_attributes;
 unsigned long long preserve_point_density_threshold = 0;
 unsigned long long preserve_multiplier_density_threshold = 0;
+std::vector<int> preserve_multiplier_density_bits_by_zoom;
 long long extend_zooms_max = 0;
 int retain_points_multiplier = 1;
 std::vector<std::string> unidecode_data;
 size_t maximum_string_attribute_length = 0;
 std::string accumulate_numeric;
+std::string use_h3_index;
 
 std::vector<order_field> order_by;
 bool order_reverse;
@@ -2498,6 +2500,7 @@ std::pair<int, metadata> read_input(std::vector<source> &sources, char *fname, i
 		long long ip;
 		for (ip = 0; ip < indices; ip++) {
 			unsigned xx, yy;
+			// XXX this will behave oddly if the index is actually H3
 			decode_index(map[ip].ix, &xx, &yy);
 
 			long long nprogress = 100 * ip / indices;
@@ -3087,6 +3090,7 @@ int main(int argc, char **argv) {
 		{"cluster-maxzoom", required_argument, 0, 'k'},
 		{"preserve-point-density-threshold", required_argument, 0, '~'},
 		{"preserve-multiplier-density-threshold", required_argument, 0, '~'},
+		{"preserve-multiplier-density-bits-by-zoom", required_argument, 0, '~'},
 
 		{"Dropping or merging a fraction of features to keep under tile size limits", 0, 0, 0},
 		{"drop-densest-as-needed", no_argument, &additional[A_DROP_DENSEST_AS_NEEDED], 1},
@@ -3128,6 +3132,7 @@ int main(int argc, char **argv) {
 		{"coalesce", no_argument, &additional[A_COALESCE], 1},
 		{"reverse", no_argument, &additional[A_REVERSE], 1},
 		{"hilbert", no_argument, &additional[A_HILBERT], 1},
+		{"use-h3-index", required_argument, 0, '~'},
 		{"order-by", required_argument, 0, '~'},
 		{"order-descending-by", required_argument, 0, '~'},
 		{"order-smallest-first", no_argument, 0, '~'},
@@ -3269,6 +3274,8 @@ int main(int argc, char **argv) {
 					fprintf(stderr, "%s: --extra-detail can be at most 30\n", argv[0]);
 					exit(EXIT_ARGS);
 				}
+			} else if (strcmp(opt, "use-h3-index") == 0) {
+				use_h3_index = optarg;
 			} else if (strcmp(opt, "order-by") == 0) {
 				order_by.push_back(order_field(optarg, false));
 			} else if (strcmp(opt, "order-descending-by") == 0) {
@@ -3300,6 +3307,21 @@ int main(int argc, char **argv) {
 				preserve_point_density_threshold = atoll_require(optarg, "Preserve point density threshold");
 			} else if (strcmp(opt, "preserve-multiplier-density-threshold") == 0) {
 				preserve_multiplier_density_threshold = atoll_require(optarg, "Preserve multiplier density threshold");
+			} else if (strcmp(opt, "preserve-multiplier-density-bits-by-zoom") == 0) {
+				const char *cp = optarg;
+				while (*cp != '\0') {
+					if (!isdigit(*cp)) {
+						fprintf(stderr, "%s: unexpected multiplier density bits by zoom %s\n", argv[0], cp);
+						exit(EXIT_ARGS);
+					}
+					preserve_multiplier_density_bits_by_zoom.push_back(atoi(cp));
+					while (isdigit(*cp)) {
+						cp++;
+					}
+					if (*cp == ',') {
+						cp++;
+					}
+				}
 			} else if (strcmp(opt, "extend-zooms-if-still-dropping-maximum") == 0) {
 				extend_zooms_max = atoll_require(optarg, "Maximum number by which to extend zooms");
 			} else if (strcmp(opt, "retain-points-multiplier") == 0) {

main.hpp

@@ -53,7 +53,9 @@ extern long long extend_zooms_max;
 extern int retain_points_multiplier;
 extern size_t maximum_string_attribute_length;
 extern std::string accumulate_numeric;
+extern std::string use_h3_index;
 extern unsigned long long preserve_multiplier_density_threshold;
+extern std::vector<int> preserve_multiplier_density_bits_by_zoom;
 
 struct order_field {
 	std::string name;

serial.cpp

@@ -186,7 +186,7 @@ std::string serialize_feature(serial_feature *sf, long long wx, long long wy) {
 
 	long long layer = 0;
 	layer |= sf->layer << FLAG_LAYER;
-	layer |= (sf->label_point != 0) << FLAG_LABEL_POINT;
+	layer |= ((sf->label_x | sf->label_y) != 0) << FLAG_LABEL_POINT;
 	layer |= (sf->index != 0) << FLAG_INDEX;
 	layer |= (sf->extent != 0) << FLAG_EXTENT;
 	layer |= sf->has_id << FLAG_ID;
@@ -211,10 +211,13 @@ std::string serialize_feature(serial_feature *sf, long long wx, long long wy) {
 
 	if (sf->index != 0) {
 		serialize_ulong_long(s, sf->index);
+		serialize_uint(s, sf->wx);
+		serialize_uint(s, sf->wy);
 		serialize_ulong_long(s, sf->gap);
 	}
-	if (sf->label_point != 0) {
-		serialize_ulong_long(s, sf->label_point);
+	if ((sf->label_x | sf->label_y) != 0) {
+		serialize_uint(s, sf->label_x);
+		serialize_uint(s, sf->label_y);
 	}
 	if (sf->extent != 0) {
 		serialize_long_long(s, sf->extent);
@@ -261,17 +264,21 @@ serial_feature deserialize_feature(std::string const &geoms, unsigned z, unsigne
 
 	sf.index = 0;
 	sf.gap = 0;
-	sf.label_point = 0;
+	sf.label_x = 0;
+	sf.label_y = 0;
 	sf.extent = 0;
 
 	sf.geometry = decode_geometry(&cp, z, tx, ty, sf.bbox, initial_x[sf.segment], initial_y[sf.segment]);
 
 	if (sf.layer & (1 << FLAG_INDEX)) {
 		deserialize_ulong_long(&cp, &sf.index);
+		deserialize_uint(&cp, &sf.wx);
+		deserialize_uint(&cp, &sf.wy);
 		deserialize_ulong_long(&cp, &sf.gap);
 	}
 	if (sf.layer & (1 << FLAG_LABEL_POINT)) {
-		deserialize_ulong_long(&cp, &sf.label_point);
+		deserialize_uint(&cp, &sf.label_x);
+		deserialize_uint(&cp, &sf.label_y);
 	}
 	if (sf.layer & (1 << FLAG_EXTENT)) {
 		deserialize_long_long(&cp, &sf.extent);
@@ -714,6 +721,19 @@ int serialize_feature(struct serialization_state *sst, serial_feature &sf, std::
 	}
 
 	bbox_index = encode_index(midx, midy);
+
+	if (use_h3_index.size() > 0) {
+		for (size_t i = 0; i < sf.full_keys.size(); i++) {
+			if (*(sf.full_keys[i]) == use_h3_index) {
+				unsigned long long h3_index = atoll(sf.full_values[i].s.c_str());
+				// the top 52 bits of the feature index are the H3 index;
+				// the bottom 12 bits are retained from what otherwise would have been the index.
+				bbox_index = ((h3_index & ((1LL << 52) - 1)) << 12) | (bbox_index & ((1 << 12) - 1));
+				break;
+			}
+		}
+	}
+
 	if (additional[A_CALCULATE_INDEX]) {
 		sf.full_keys.push_back(key_pool.pool("tippecanoe:index"));
 
@@ -728,7 +748,8 @@ int serialize_feature(struct serialization_state *sst, serial_feature &sf, std::
 		if (dv.size() > 0) {
 			dv[0].x = SHIFT_LEFT(dv[0].x) & ((1LL << 32) - 1);
 			dv[0].y = SHIFT_LEFT(dv[0].y) & ((1LL << 32) - 1);
-			sf.label_point = encode_index(dv[0].x, dv[0].y);
+			sf.label_x = dv[0].x;
+			sf.label_y = dv[0].y;
 		}
 	}
 
@@ -748,8 +769,12 @@ int serialize_feature(struct serialization_state *sst, serial_feature &sf, std::
 	    preserve_multiplier_density_threshold > 0 ||
 	    cluster_distance != 0) {
 		sf.index = bbox_index;
+		sf.wx = midx;
+		sf.wy = midy;
 	} else {
 		sf.index = 0;
+		sf.wx = 0;
+		sf.wy = 0;
 	}
 
 	if (sst->layermap->count(layername) == 0) {

serial.hpp

@@ -58,6 +58,10 @@ struct serial_val {
 		s = milo::dtoa_milo(val);
 	}
 
+	std::string toString() const {
+		return s;
+	}
+
 	double to_double() const {
 		return atof(s.c_str());
 	}
@@ -118,8 +122,9 @@ struct serial_feature {
 
 	drawvec geometry = drawvec();
 	unsigned long long index = 0;
+	unsigned wx = 0, wy = 0;
 	unsigned long long gap = 0;  // filled in during z0. square of planar distance
-	unsigned long long label_point = 0;
+	unsigned label_x = 0, label_y = 0;
 	long long extent = 0;
 
 	// These fields are not directly serialized, but are used