Reviving multi-source-tile overzoom: the clip.cpp side

clip.cpp

@@ -755,24 +755,36 @@ static std::vector<std::pair<double, double>> clip_poly1(std::vector<std::pair<d
 	return out;
 }
 
-std::string overzoom(const std::string &s, int oz, int ox, int oy, int nz, int nx, int ny,
+std::string overzoom(std::vector<input_tile> const &tiles, int nz, int nx, int ny,
 		     int detail, int buffer, std::set<std::string> const &keep, bool do_compress,
 		     std::vector<std::pair<unsigned, unsigned>> *next_overzoomed_tiles,
 		     bool demultiply, json_object *filter, bool preserve_input_order, std::unordered_map<std::string, attribute_op> const &attribute_accum, std::vector<std::string> const &unidecode_data) {
+	std::vector<source_tile> decoded;
+
+	for (auto const &t : tiles) {
 		mvt_tile tile;
 
 		try {
 			bool was_compressed;
-		if (!tile.decode(s, was_compressed)) {
+			if (!tile.decode(t.tile, was_compressed)) {
-			fprintf(stderr, "Couldn't parse tile %d/%u/%u\n", oz, ox, oy);
+				fprintf(stderr, "Couldn't parse tile %d/%u/%u\n", t.z, t.x, t.y);
 				exit(EXIT_MVT);
 			}
 		} catch (std::exception const &e) {
-		fprintf(stderr, "PBF decoding error in tile %d/%u/%u\n", oz, ox, oy);
+			fprintf(stderr, "PBF decoding error in tile %d/%u/%u\n", t.z, t.x, t.y);
 			exit(EXIT_PROTOBUF);
 		}
 
-	return overzoom(tile, oz, ox, oy, nz, nx, ny, detail, buffer, keep, do_compress, next_overzoomed_tiles, demultiply, filter, preserve_input_order, attribute_accum, unidecode_data);
+		source_tile out;
+		out.tile = tile;
+		out.z = t.z;
+		out.x = t.x;
+		out.y = t.y;
+
+		decoded.push_back(out);
+	}
+
+	return overzoom(decoded, nz, nx, ny, detail, buffer, keep, do_compress, next_overzoomed_tiles, demultiply, filter, preserve_input_order, attribute_accum, unidecode_data);
 }
 
 struct tile_feature {
@@ -870,24 +882,38 @@ static struct preservecmp {
 	}
 } preservecmp;
 
-std::string overzoom(const mvt_tile &tile, int oz, int ox, int oy, int nz, int nx, int ny,
+std::string overzoom(std::vector<source_tile> const &tiles, int nz, int nx, int ny,
 		     int detail, int buffer, std::set<std::string> const &keep, bool do_compress,
 		     std::vector<std::pair<unsigned, unsigned>> *next_overzoomed_tiles,
 		     bool demultiply, json_object *filter, bool preserve_input_order, std::unordered_map<std::string, attribute_op> const &attribute_accum, std::vector<std::string> const &unidecode_data) {
 	mvt_tile outtile;
 	std::shared_ptr<std::string> tile_stringpool = std::make_shared<std::string>();
 
-	for (auto const &layer : tile.layers) {
+	for (auto const &tile : tiles) {
-		mvt_layer outlayer = mvt_layer();
+		for (auto const &layer : tile.tile.layers) {
+			mvt_layer *outlayer = NULL;
 
 			int det = detail;
 			if (det <= 0) {
 				det = std::round(log(layer.extent) / log(2));
 			}
 
-		outlayer.name = layer.name;
+			for (size_t i = 0; i < outtile.layers.size(); i++) {
-		outlayer.version = layer.version;
+				if (outtile.layers[i].name == layer.name) {
-		outlayer.extent = 1LL << det;
+					outlayer = &outtile.layers[i];
+				}
+			}
+
+			if (outlayer == NULL) {
+				mvt_layer newlayer = mvt_layer();
+
+				newlayer.name = layer.name;
+				newlayer.version = layer.version;
+				newlayer.extent = 1LL << det;
+
+				outtile.layers.push_back(newlayer);
+				outlayer = &outtile.layers.back();
+			}
 
 			std::vector<tile_feature> pending_tile_features;
 
@@ -916,7 +942,7 @@ std::string overzoom(const mvt_tile &tile, int oz, int ox, int oy, int nz, int n
 
 				if (flush_multiplier_cluster) {
 					if (pending_tile_features.size() > 0) {
-					feature_out(pending_tile_features, outlayer, keep, attribute_accum, tile_stringpool);
+						feature_out(pending_tile_features, *outlayer, keep, attribute_accum, tile_stringpool);
 						pending_tile_features.clear();
 					}
 				}
@@ -931,18 +957,17 @@ std::string overzoom(const mvt_tile &tile, int oz, int ox, int oy, int nz, int n
 
 				// Convert feature geometry to world coordinates
 
-			long long tilesize = 1LL << (32 - oz);	// source tile size in world coordinates
+				long long tilesize = 1LL << (32 - tile.z);  // source tile size in world coordinates
 				draw ring_closure(0, 0, 0);
-			bool sametile = (nz == oz && nx == ox && ny == oy && outlayer.extent >= layer.extent);
+				bool sametile = (nz == tile.z && nx == tile.x && ny == tile.y && outlayer->extent >= layer.extent);
 
 				for (auto const &g : feature.geometry) {
 					if (g.op == mvt_closepath) {
 						geom.push_back(ring_closure);
 					} else {
 						geom.emplace_back(g.op,
-							  g.x * tilesize / layer.extent + ox * tilesize,
+								  g.x * tilesize / layer.extent + tile.x * tilesize,
-							  g.y * tilesize / layer.extent + oy * tilesize);
+								  g.y * tilesize / layer.extent + tile.y * tilesize);
-
 						if (g.op == mvt_moveto) {
 							ring_closure = geom.back();
 							ring_closure.op = mvt_lineto;
@@ -1019,16 +1044,13 @@ std::string overzoom(const mvt_tile &tile, int oz, int ox, int oy, int nz, int n
 			}
 
 			if (pending_tile_features.size() > 0) {
-			feature_out(pending_tile_features, outlayer, keep, attribute_accum, tile_stringpool);
+				feature_out(pending_tile_features, *outlayer, keep, attribute_accum, tile_stringpool);
 				pending_tile_features.clear();
 			}
 
 			if (preserve_input_order) {
-			std::stable_sort(outlayer.features.begin(), outlayer.features.end(), preservecmp);
+				std::stable_sort(outlayer->features.begin(), outlayer->features.end(), preservecmp);
 			}
-
-		if (outlayer.features.size() > 0) {
-			outtile.layers.push_back(std::move(outlayer));
 		}
 	}
 
@@ -1043,7 +1065,16 @@ std::string overzoom(const mvt_tile &tile, int oz, int ox, int oy, int nz, int n
 		if (outtile.layers.size() > 0) {
 			for (size_t x = 0; x < 2; x++) {
 				for (size_t y = 0; y < 2; y++) {
-					std::string child = overzoom(outtile, nz, nx, ny,
+					source_tile st;
+					st.tile = outtile;
+					st.z = nz;
+					st.x = nx;
+					st.y = ny;
+
+					std::vector<source_tile> sts;
+					sts.push_back(st);
+
+					std::string child = overzoom(sts,
 								     nz + 1, nx * 2 + x, ny * 2 + y,
 								     detail, buffer, keep, false, NULL,
 								     demultiply, filter, preserve_input_order, attribute_accum, unidecode_data);
@@ -1055,6 +1086,12 @@ std::string overzoom(const mvt_tile &tile, int oz, int ox, int oy, int nz, int n
 		}
 	}
 
+	for (ssize_t i = outtile.layers.size() - 1; i >= 0; i--) {
+		if (outtile.layers[i].features.size() == 0) {
+			outtile.layers.erase(outtile.layers.begin() + i);
+		}
+	}
+
 	if (outtile.layers.size() > 0) {
 		std::string pbf = outtile.encode();
 

geometry.hpp

@@ -100,14 +100,28 @@ void visvalingam(drawvec &ls, size_t start, size_t end, double threshold, size_t
 int pnpoly(const drawvec &vert, size_t start, size_t nvert, long long testx, long long testy);
 double distance_from_line(long long point_x, long long point_y, long long segA_x, long long segA_y, long long segB_x, long long segB_y);
 
-std::string overzoom(const mvt_tile &tile, int oz, int ox, int oy, int nz, int nx, int ny,
+struct input_tile {
+	std::string tile;
+	int z;
+	int x;
+	int y;
+};
+
+struct source_tile {
+	mvt_tile tile;
+	int z;
+	int x;
+	int y;
+};
+
+std::string overzoom(std::vector<source_tile> const &tiles, int nz, int nx, int ny,
 		     int detail, int buffer, std::set<std::string> const &keep, bool do_compress,
 		     std::vector<std::pair<unsigned, unsigned>> *next_overzoomed_tiles,
 		     bool demultiply, json_object *filter, bool preserve_input_order,
 		     std::unordered_map<std::string, attribute_op> const &attribute_accum,
 		     std::vector<std::string> const &unidecode_data);
 
-std::string overzoom(const std::string &s, int oz, int ox, int oy, int nz, int nx, int ny,
+std::string overzoom(std::vector<input_tile> const &tiles, int nz, int nx, int ny,
 		     int detail, int buffer, std::set<std::string> const &keep, bool do_compress,
 		     std::vector<std::pair<unsigned, unsigned>> *next_overzoomed_tiles,
 		     bool demultiply, json_object *filter, bool preserve_input_order,

overzoom.cpp

@@ -125,33 +125,45 @@ int main(int argc, char **argv) {
 		usage(argv);
 	}
 
-	std::string tile;
-	char buf[1000];
-	int len;
-
-	FILE *f = fopen(infile, "rb");
-	if (f == NULL) {
-		perror(infile);
-		exit(EXIT_FAILURE);
-	}
-
-	while ((len = fread(buf, sizeof(char), 1000, f)) > 0) {
-		tile.append(std::string(buf, len));
-	}
-	fclose(f);
-
-	f = fopen(outfile, "wb");
-	if (f == NULL) {
-		perror(outfile);
-		exit(EXIT_FAILURE);
-	}
-
 	json_object *json_filter = NULL;
 	if (filter.size() > 0) {
 		json_filter = parse_filter(filter.c_str());
 	}
 
-	std::string out = overzoom(tile, oz, ox, oy, nz, nx, ny, detail, buffer, keep, true, NULL, demultiply, json_filter, preserve_input_order, attribute_accum, unidecode_data);
+	std::string out;
+	{
+		FILE *fi = fopen(infile, "rb");
+		if (fi == NULL) {
+			perror(infile);
+			exit(EXIT_FAILURE);
+		}
+
+		std::string tile;
+		char buf[1000];
+		int len;
+
+		while ((len = fread(buf, sizeof(char), 1000, fi)) > 0) {
+			tile.append(std::string(buf, len));
+		}
+		fclose(fi);
+
+		std::vector<input_tile> tv;
+		input_tile t;
+		t.tile = std::move(tile);
+		t.z = oz;
+		t.x = ox;
+		t.y = oy;
+		tv.push_back(std::move(t));
+
+		out = overzoom(tv, nz, nx, ny, detail, buffer, keep, true, NULL, demultiply, json_filter, preserve_input_order, attribute_accum, unidecode_data);
+	}
+
+	FILE *f = fopen(outfile, "wb");
+	if (f == NULL) {
+		perror(outfile);
+		exit(EXIT_FAILURE);
+	}
+
 	fwrite(out.c_str(), sizeof(char), out.size(), f);
 	fclose(f);
 

tile-join.cpp

@@ -704,7 +704,15 @@ struct tileset_reader {
 		}
 
 		if (source.layers.size() != 0) {
-			std::string ret = overzoom(source, parent_tile.z, parent_tile.x, parent_tile.y, tile.z, tile.x, tile.y, -1, buffer, std::set<std::string>(), false, &next_overzoomed_tiles, false, NULL, false, std::unordered_map<std::string, attribute_op>(), unidecode_data);
+			std::vector<source_tile> tv;
+			source_tile t;
+			t.tile = std::move(source);
+			t.z = parent_tile.z;
+			t.x = parent_tile.x;
+			t.y = parent_tile.y;
+			tv.push_back(std::move(t));
+
+			std::string ret = overzoom(tv, tile.z, tile.x, tile.y, -1, buffer, std::set<std::string>(), false, &next_overzoomed_tiles, false, NULL, false, std::unordered_map<std::string, attribute_op>(), unidecode_data);
 			return ret;
 		}