A little glitchy, but close

earcut.cpp

@@ -75,54 +75,33 @@ drawvec fix_by_triangulation(drawvec const &dv, int z, int detail) {
 	std::vector<N> indices = mapbox::earcut<N>(polygon);
 
 	drawvec out2;
-	bool again = true;
+	for (size_t i = 0; i + 2 < indices.size(); i += 3) {
-	while (again) {
+		std::vector<double> lengths;
-		again = false;
-		for (size_t i = 0; i + 2 < indices.size(); i += 3) {
-			std::vector<double> lengths;
 
-			for (size_t j = 0; j < 3; j++) {
+		for (size_t j = 0; j < 3; j++) {
-				size_t v1 = i + j;
+			size_t v1 = i + j;
-				size_t v2 = i + ((j + 1) % 3);
+			size_t v2 = i + ((j + 1) % 3);
+			size_t v3 = i + ((j + 2) % 3);
 
-				double dx = out[indices[v1]].x - out[indices[v2]].x;
+			long long px, py;
-				double dy = out[indices[v1]].y - out[indices[v2]].y;
-				double d = sqrt(dx * dx + dy * dy);
 
-				lengths.push_back(d);
+			if (distance_from_line(out[indices[v1]].x, out[indices[v1]].y,	// the point
-			}
+					       out[indices[v2]].x, out[indices[v2]].y,	// start of opposite side
+					       out[indices[v3]].x, out[indices[v3]].y,	// end of opposite side
+					       &px, &py) < scale) {
+				// make a new triangle that is not so flat
+				out2.push_back(draw(VT_MOVETO, out[indices[v2]].x, out[indices[v2]].y));
+				out2.push_back(draw(VT_LINETO, out[indices[v3]].x, out[indices[v3]].y));
 
-			std::sort(lengths.begin(), lengths.end());
+				double ang = atan2(out[indices[v1]].y - py, out[indices[v1]].x - px);
-			printf("%f %f\n", lengths[2], lengths[0]);
+				out2.push_back(draw(VT_LINETO, out[indices[v1]].x + scale * cos(ang), out[indices[v1]].y + scale * sin(ang)));
-
+				out2.push_back(draw(VT_LINETO, out[indices[v2]].x, out[indices[v2]].y));
-			if (lengths[2] > 5 * lengths[0]) {
-				for (size_t j = 0; j < 3; j++) {
-					size_t v1 = i + j;
-					size_t v2 = i + ((j + 1) % 3);
-					size_t v3 = i + ((j + 2) % 3);
-
-					if (std::llabs(std::llround(out[indices[v1]].x / scale) - std::llround(out[indices[v2]].x / scale)) < 2 &&
-					    std::llabs(std::llround(out[indices[v1]].y / scale) - std::llround(out[indices[v2]].y / scale)) < 2) {
-						double ang = atan2(out[indices[v2]].y - out[indices[v1]].y, out[indices[v2]].x - out[indices[v1]].x);
-
-						double stretch = 1.5;
-
-						drawvec tri;
-						tri.emplace_back(VT_MOVETO, (long long) out[indices[v3]].x, (long long) out[indices[v3]].y);
-						tri.emplace_back(VT_LINETO, out[indices[v1]].x - scale * cos(ang) * stretch, out[indices[v1]].y - scale * sin(ang) * stretch);
-						tri.emplace_back(VT_LINETO, out[indices[v2]].x + scale * cos(ang) * stretch, out[indices[v2]].y + scale * sin(ang) * stretch);
-						tri.emplace_back(VT_LINETO, (long long) out[indices[v3]].x, (long long) out[indices[v3]].y);
-						printf("%f\n", get_area(tri, 0, tri.size()));
-
-						for (auto const &d : tri) {
-							out2.push_back(d);
-						}
-					}
-				}
 			}
 		}
 	}
 
+	// re-close the rings from which we removed the last points earlier
+
 	for (size_t i = 0; i < out.size(); i++) {
 		if (out[i].op == VT_MOVETO) {
 			size_t j;
@@ -136,7 +115,6 @@ drawvec fix_by_triangulation(drawvec const &dv, int z, int detail) {
 				out2.push_back(out[k]);
 			}
 
-			// re-close the ring
 			out2.push_back(draw(VT_LINETO, out[i].x, out[i].y));
 			i = j - 1;
 		}

geometry.cpp

@@ -334,7 +334,7 @@ bool point_within_tile(long long x, long long y, int z) {
 	return x >= 0 && y >= 0 && x < area && y < area;
 }
 
-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) {
+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, long long *px, long long *py) {
 	long long p2x = segB_x - segA_x;
 	long long p2y = segB_y - segA_y;
 	double something = p2x * p2x + p2y * p2y;
@@ -349,6 +349,13 @@ double distance_from_line(long long point_x, long long point_y, long long segA_x
 	double x = segA_x + u * p2x;
 	double y = segA_y + u * p2y;
 
+	if (px != NULL) {
+		*px = std::round(x);
+	}
+	if (py != NULL) {
+		*py = std::round(y);
+	}
+
 	double dx = x - point_x;
 	double dy = y - point_y;
 
@@ -400,7 +407,7 @@ static void douglas_peucker(drawvec &geom, int start, int n, double e, size_t ke
 		if (geom[start + first] < geom[start + second]) {
 			farthest_element_index = first;
 			for (i = first + 1; i < second; i++) {
-				double temp_dist = distance_from_line(geom[start + i].x, geom[start + i].y, geom[start + first].x, geom[start + first].y, geom[start + second].x, geom[start + second].y);
+				double temp_dist = distance_from_line(geom[start + i].x, geom[start + i].y, geom[start + first].x, geom[start + first].y, geom[start + second].x, geom[start + second].y, NULL, NULL);
 
 				double distance = std::fabs(temp_dist);
 
@@ -412,7 +419,7 @@ static void douglas_peucker(drawvec &geom, int start, int n, double e, size_t ke
 		} else {
 			farthest_element_index = second;
 			for (i = second - 1; i > first; i--) {
-				double temp_dist = distance_from_line(geom[start + i].x, geom[start + i].y, geom[start + second].x, geom[start + second].y, geom[start + first].x, geom[start + first].y);
+				double temp_dist = distance_from_line(geom[start + i].x, geom[start + i].y, geom[start + second].x, geom[start + second].y, geom[start + first].x, geom[start + first].y, NULL, NULL);
 
 				double distance = std::fabs(temp_dist);
 
@@ -1046,7 +1053,7 @@ double label_goodness(const drawvec &dv, long long x, long long y) {
 		}
 
 		if (i > 0 && dv[i].op == VT_LINETO) {
-			dist = distance_from_line(x, y, dv[i - 1].x, dv[i - 1].y, dv[i].x, dv[i].y);
+			dist = distance_from_line(x, y, dv[i - 1].x, dv[i - 1].y, dv[i].x, dv[i].y, NULL, NULL);
 			if (dist < closest) {
 				closest = dist;
 			}

geometry.hpp

@@ -96,7 +96,7 @@ drawvec clip_lines(drawvec &geom, long long x1, long long y1, long long x2, long
 drawvec clip_point(drawvec &geom, long long x1, long long y1, long long x2, long long y2);
 void visvalingam(drawvec &ls, size_t start, size_t end, double threshold, size_t retain);
 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);
+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, long long *px, long long *py);
 
 std::string overzoom(mvt_tile tile, int oz, int ox, int oy, int nz, int nx, int ny,
 		     int detail, int buffer, std::set<std::string> const &keep, bool do_compress);

serial.cpp

@@ -586,7 +586,7 @@ int serialize_feature(struct serialization_state *sst, serial_feature &sf) {
 						for (size_t k = i + 1; k < j - 1; k++) {
 							double d = distance_from_line(scaled_geometry[k].x, scaled_geometry[k].y,
 										      scaled_geometry[i].x, scaled_geometry[i].y,
-										      scaled_geometry[which].x, scaled_geometry[which].y);
+										      scaled_geometry[which].x, scaled_geometry[which].y, NULL, NULL);
 							if ((d > far) ||
 							    ((d == far) && (scaled_geometry[k] < scaled_geometry[which2]))) {
 								far = d;