Straighten out hilbert and quadkey encoding

clip.cpp

@@ -10,6 +10,7 @@
 #include "evaluator.hpp"
 #include "serial.hpp"
 #include "attribute.hpp"
+#include "projection.hpp"
 
 static std::vector<std::pair<double, double>> clip_poly1(std::vector<std::pair<double, double>> &geom,
 							 long long minx, long long miny, long long maxx, long long maxy,

geometry.cpp

@@ -497,7 +497,7 @@ drawvec simplify_lines(drawvec &geom, int z, int tx, int ty, int detail, bool ma
 
 				// to quadkey
 				struct node n;
-				n.index = encode_quadkey((unsigned) d.x, (unsigned) d.y);
+				n.index = encode_quadkey(coordinate_to_encodable(d.x), coordinate_to_encodable(d.y));
 
 				if (bsearch(&n, shared_nodes_map, nodepos / sizeof(node), sizeof(node), nodecmp) != NULL) {
 					geom[i].necessary = true;
@@ -578,8 +578,8 @@ drawvec reorder_lines(const drawvec &geom) {
 	// instead of down and to the right
 	// so that it will coalesce better
 
-	unsigned long long l1 = encode_index(geom[0].x, geom[0].y);
+	unsigned long long l1 = encode_index(coordinate_to_encodable(geom[0].x), coordinate_to_encodable(geom[0].y));
-	unsigned long long l2 = encode_index(geom[geom.size() - 1].x, geom[geom.size() - 1].y);
+	unsigned long long l2 = encode_index(coordinate_to_encodable(geom[geom.size() - 1].x), coordinate_to_encodable(geom[geom.size() - 1].y));
 
 	if (l1 > l2) {
 		drawvec out;
@@ -1302,6 +1302,9 @@ drawvec checkerboard_anchors(drawvec const &geom, int tx, int ty, int z, unsigne
 	unsigned wx, wy;
 	decode_index(label_point, &wx, &wy);
 
+	long long wwx = decoded_to_coordinate(wx);
+	long long wwy = decoded_to_coordinate(wy);
+
 	// upper left of tile in world coordinates
 	long long tx1 = 0, ty1 = 0;
 	// lower right of tile in world coordinates;
@@ -1340,16 +1343,16 @@ drawvec checkerboard_anchors(drawvec const &geom, int tx, int ty, int z, unsigne
 
 	const long long label_spacing = spiral_dist * (tx2 - tx1);
 
-	long long x1 = floor(std::min(bx1 - wx, bx2 - wx) / label_spacing);
+	long long x1 = floor(std::min(bx1 - wwx, bx2 - wwx) / label_spacing);
-	long long x2 = ceil(std::max(bx1 - wx, bx2 - wx) / label_spacing);
+	long long x2 = ceil(std::max(bx1 - wwx, bx2 - wwx) / label_spacing);
 
-	long long y1 = floor(std::min(by1 - wy, by2 - wy) / label_spacing - 0.5);
+	long long y1 = floor(std::min(by1 - wwy, by2 - wwy) / label_spacing - 0.5);
-	long long y2 = ceil(std::max(by1 - wy, by2 - wy) / label_spacing);
+	long long y2 = ceil(std::max(by1 - wwy, by2 - wwy) / label_spacing);
 
 	for (long long lx = x1; lx <= x2; lx++) {
 		for (long long ly = y1; ly <= y2; ly++) {
-			long long x = lx * label_spacing + wx;
+			long long x = lx * label_spacing + wwx;
-			long long y = ly * label_spacing + wy;
+			long long y = ly * label_spacing + wwy;
 
 			if (((unsigned long long) lx & 1) == 1) {
 				y += label_spacing / 2;

geometry.hpp

@@ -20,8 +20,6 @@
 #define VT_LINETO 2
 #define VT_CLOSEPATH 7
 
-#define GLOBAL_DETAIL 32
-
 // The bitfield is to make sizeof(draw) be 16 instead of 24
 // at the cost, apparently, of a 0.7% increase in running time
 // for packing and unpacking.

main.cpp

@@ -2069,7 +2069,7 @@ std::pair<int, metadata> read_input(std::vector<source> &sources, char *fname, i
 #endif
 
 				struct node n;
-				n.index = encode_quadkey((unsigned) x, (unsigned) y);
+				n.index = encode_quadkey(coordinate_to_encodable(x), coordinate_to_encodable(y));
 
 				fwrite_check((char *) &n, sizeof(struct node), 1, readers[0].nodefile, &readers[0].nodepos, "vertices");
 			}
@@ -2152,7 +2152,7 @@ std::pair<int, metadata> read_input(std::vector<source> &sources, char *fname, i
 				unsigned wx, wy;
 				decode_quadkey(here.index, &wx, &wy);
 				double lon, lat;
-				tile2lonlat(wx, wy, 32, &lon, &lat);
+				tile2lonlat(decoded_to_coordinate(wx), decoded_to_coordinate(wy), GLOBAL_DETAIL, &lon, &lat);
 				printf("{\"type\":\"Feature\", \"properties\":{}, \"geometry\":{\"type\":\"Point\", \"coordinates\":[%f,%f]}}\n", lon, lat);
 #endif
 			}
@@ -2505,6 +2505,9 @@ std::pair<int, metadata> read_input(std::vector<source> &sources, char *fname, i
 			unsigned xx, yy;
 			decode_index(map[ip].ix, &xx, &yy);
 
+			long long gxx = decoded_to_coordinate(xx);
+			long long gyy = decoded_to_coordinate(yy);
+
 			long long nprogress = 100 * ip / indices;
 			if (nprogress != progress) {
 				progress = nprogress;
@@ -2520,8 +2523,8 @@ std::pair<int, metadata> read_input(std::vector<source> &sources, char *fname, i
 				if (z != 0) {
 					// These are tile numbers, not pixels,
 					// so shift, not round
-					xxx = xx >> (32 - z);
+					xxx = gxx >> (GLOBAL_DETAIL - z);
-					yyy = yy >> (32 - z);
+					yyy = gyy >> (GLOBAL_DETAIL - z);
 				}
 
 				double scale = (double) (1LL << (64 - 2 * (z + 8)));

projection.cpp

@@ -200,6 +200,14 @@ void decode_quadkey(unsigned long long index, unsigned *wx, unsigned *wy) {
 	}
 }
 
+unsigned coordinate_to_encodable(long long coord) {
+	return (unsigned) (coord / (1LL << (GLOBAL_DETAIL - 32)));
+}
+
+long long decoded_to_coordinate(unsigned coord) {
+	return ((long long) coord) * (1LL << (GLOBAL_DETAIL - 32));
+}
+
 void set_projection_or_exit(const char *optarg) {
 	struct projection *p;
 	for (p = projections; p->name != NULL; p++) {

projection.hpp

@@ -1,6 +1,8 @@
 #ifndef PROJECTION_HPP
 #define PROJECTION_HPP
 
+#define GLOBAL_DETAIL 32
+
 void lonlat2tile(double lon, double lat, int zoom, long long *x, long long *y);
 void epsg3857totile(double ix, double iy, int zoom, long long *x, long long *y);
 void tile2lonlat(long long x, long long y, int zoom, double *lon, double *lat);
@@ -26,4 +28,7 @@ void decode_quadkey(unsigned long long index, unsigned *wx, unsigned *wy);
 unsigned long long encode_hilbert(unsigned int wx, unsigned int wy);
 void decode_hilbert(unsigned long long index, unsigned *wx, unsigned *wy);
 
+unsigned coordinate_to_encodable(long long coord);
+long long decoded_to_coordinate(unsigned coord);
+
 #endif

serial.cpp

@@ -409,7 +409,7 @@ static void add_scaled_node(struct reader *r, serialization_state *sst, draw g)
 	long long y = SHIFT_LEFT(g.y);
 
 	struct node n;
-	n.index = encode_quadkey((unsigned) x, (unsigned) y);
+	n.index = encode_quadkey(coordinate_to_encodable(x), coordinate_to_encodable(y));
 
 	fwrite_check((char *) &n, sizeof(struct node), 1, r->nodefile, &r->nodepos, sst->fname);
 }
@@ -704,14 +704,15 @@ int serialize_feature(struct serialization_state *sst, serial_feature &sf, std::
 		midy = SHIFT_LEFT(scaled_geometry[ix].y) & ((1LL << GLOBAL_DETAIL) - 1);
 	}
 
-	bbox_index = encode_index(midx, midy);
+	bbox_index = encode_index(coordinate_to_encodable(midx), coordinate_to_encodable(midy));
 
 	if (sf.t == VT_POLYGON && additional[A_GENERATE_POLYGON_LABEL_POINTS]) {
 		drawvec dv = polygon_to_anchor(scaled_geometry);
 		if (dv.size() > 0) {
 			dv[0].x = SHIFT_LEFT(dv[0].x) & ((1LL << GLOBAL_DETAIL) - 1);
 			dv[0].y = SHIFT_LEFT(dv[0].y) & ((1LL << GLOBAL_DETAIL) - 1);
-			sf.label_point = encode_index(dv[0].x, dv[0].y);
+			// this could just be serialized as numbers instead of encoding and decoding
+			sf.label_point = encode_index(coordinate_to_encodable(dv[0].x), coordinate_to_encodable(dv[0].y));
 		}
 	}