Work in progress on inverse spatial ordering

main.cpp

@@ -3211,6 +3211,7 @@ int main(int argc, char **argv) {
 		{"order-descending-by", required_argument, 0, '~'},
 		{"order-smallest-first", no_argument, 0, '~'},
 		{"order-largest-first", no_argument, 0, '~'},
+		{"order-spatial-inverse", no_argument, 0, '~'},
 
 		{"Adding calculated attributes", 0, 0, 0},
 		{"calculate-feature-density", no_argument, &additional[A_CALCULATE_FEATURE_DENSITY], 1},
@@ -3357,6 +3358,9 @@ int main(int argc, char **argv) {
 			} else if (strcmp(opt, "order-largest-first") == 0) {
 				order_by.push_back(order_field(ORDER_BY_SIZE, true));
 				order_by_size = true;
+			} else if (strcmp(opt, "order-spatial-inverse") == 0) {
+				order_by.push_back(order_field(ORDER_SPATIAL, false));
+				order_by.push_back(order_field(ORDER_BY_FEATURE_MINZOOM, false));
 			} else if (strcmp(opt, "simplification-at-maximum-zoom") == 0) {
 				maxzoom_simplification = atof_require(optarg, "Mazoom simplification");
 				if (maxzoom_simplification <= 0) {

main.hpp

@@ -79,6 +79,9 @@ extern std::vector<order_field> order_by;
 #define ORDER_BY_SIZE "\200size"
 extern bool order_by_size;
 
+#define ORDER_SPATIAL "\200spatial"
+#define ORDER_BY_FEATURE_MINZOOM "\200feature_minzoom"
+
 int mkstemp_cloexec(char *name);
 FILE *fopen_oflag(const char *name, const char *mode, int oflag);
 bool progress_time();

serial.cpp

@@ -729,11 +729,14 @@ int serialize_feature(struct serialization_state *sst, serial_feature &sf) {
 		}
 	}
 
+#if 0
 	if (additional[A_DROP_DENSEST_AS_NEEDED] || additional[A_COALESCE_DENSEST_AS_NEEDED] || additional[A_CLUSTER_DENSEST_AS_NEEDED] || additional[A_CALCULATE_FEATURE_DENSITY] || additional[A_DROP_SMALLEST_AS_NEEDED] || additional[A_COALESCE_SMALLEST_AS_NEEDED] || additional[A_INCREASE_GAMMA_AS_NEEDED] || additional[A_GENERATE_POLYGON_LABEL_POINTS] || sst->uses_gamma || cluster_distance != 0) {
 		sf.index = bbox_index;
 	} else {
 		sf.index = 0;
 	}
+#endif
+	sf.index = bbox_index;
 
 	if (sst->layermap->count(sf.layername) == 0) {
 		sst->layermap->insert(std::pair<std::string, layermap_entry>(sf.layername, layermap_entry(sst->layermap->size())));

tile.cpp

@@ -100,6 +100,7 @@ struct coalesce {
 	bool has_id = false;
 	unsigned long long id = 0;
 	long long extent = 0;
+	signed char feature_minzoom = 0;
 
 	bool operator<(const coalesce &o) const {
 		int cmp = coalindexcmp(this, &o);
@@ -253,13 +254,34 @@ static int metacmp(const std::vector<long long> &keys1, const std::vector<long l
 	}
 }
 
+static unsigned long long flop(unsigned long long v) {
+	unsigned long long out = 0;
+	for (size_t i = 0; i < 64; i++) {
+		out |= ((v >> i) & 1) << (63 - i);
+	}
+
+	return out;
+}
+
 static mvt_value find_attribute_value(const struct coalesce *c1, std::string key) {
 	if (key == ORDER_BY_SIZE) {
 		mvt_value v;
 		v.type = mvt_double;
 		v.numeric_value.double_value = c1->extent;
 		return v;
 	}
+	if (key == ORDER_SPATIAL) {
+		mvt_value v;
+		v.type = mvt_uint;
+		v.numeric_value.uint_value = flop(c1->index);
+		return v;
+	}
+	if (key == ORDER_BY_FEATURE_MINZOOM) {
+		mvt_value v;
+		v.type = mvt_double;
+		v.numeric_value.double_value = c1->feature_minzoom;
+		return v;
+	}
 
 	const std::vector<long long> &keys1 = c1->keys;
 	const std::vector<long long> &values1 = c1->values;
@@ -467,6 +489,7 @@ struct partial {
 	double spacing = 0;
 	double simplification = 0;
 	signed char t = 0;
+	signed char feature_minzoom = 0;
 	unsigned long long id = 0;
 	bool has_id = 0;
 	ssize_t renamed = 0;
@@ -2266,6 +2289,7 @@ long long write_tile(decompressor *geoms, std::atomic<long long> *geompos_in, ch
 					p.renamed = -1;
 					p.extent = sf.extent;
 					p.clustered = 0;
+					p.feature_minzoom = sf.feature_minzoom;
 
 					if (line_detail == detail && extra_detail >= 0 && z == maxzoom) {
 						p.extra_detail = extra_detail;
@@ -2312,6 +2336,21 @@ long long write_tile(decompressor *geoms, std::atomic<long long> *geompos_in, ch
 		for (size_t i = 0; i < partials.size(); i++) {
 			partial &p = partials[i];
 
+			{
+				std::string layername = (*layer_unmaps)[p.segment][p.layer];
+
+				serial_val sv, sv2;
+				p.full_keys.push_back("inverse_index");
+				sv.type = mvt_double;
+				sv.s = std::to_string(flop(p.index));
+				p.full_values.push_back(sv);
+
+				p.full_keys.push_back("feature_minzoom");
+				sv2.type = mvt_double;
+				sv2.s = std::to_string(p.feature_minzoom);
+				p.full_values.push_back(sv2);
+			}
+
 			if (p.clustered > 0) {
 				std::string layername = (*layer_unmaps)[p.segment][p.layer];
 				serial_val sv, sv2, sv3, sv4;
@@ -2456,6 +2495,7 @@ long long write_tile(decompressor *geoms, std::atomic<long long> *geompos_in, ch
 					c.id = partials[i].id;
 					c.has_id = partials[i].has_id;
 					c.extent = partials[i].extent;
+					c.feature_minzoom = partials[i].feature_minzoom;
 
 					// printf("segment %d layer %lld is %s\n", partials[i].segment, partials[i].layer, (*layer_unmaps)[partials[i].segment][partials[i].layer].c_str());