No need for line clipping to have its own source file

Makefile

@@ -42,7 +42,7 @@ C = $(shell find . '(' -name '*.c' -o -name '*.cpp' ')')
 INCLUDES = -I/usr/local/include -I.
 LIBS = -L/usr/local/lib
 
-tippecanoe: geojson.o jsonpull.o tile.o clip.o pool.o mbtiles.o geometry.o projection.o memfile.o clipper/clipper.o mvt.o
+tippecanoe: geojson.o jsonpull.o tile.o pool.o mbtiles.o geometry.o projection.o memfile.o clipper.o mvt.o
 	$(CXX) $(PG) $(LIBS) $(FINAL_FLAGS) $(CXXFLAGS) -o $@ $^ $(LDFLAGS) -lm -lz -lsqlite3 -lpthread
 
 tippecanoe-enumerate: enumerate.o
@@ -64,14 +64,15 @@ libjsonpull.a: jsonpull.o
 %.o: %.cpp $(H)
 	$(CXX) $(PG) $(INCLUDES) $(FINAL_FLAGS) $(CXXFLAGS) -c $<
 
+clipper.o: clipper/clipper.cpp $(H)
+	$(CXX) $(PG) $(INCLUDES) $(FINAL_FLAGS) $(CXXFLAGS) -c $<
+
 clean:
 	rm -f tippecanoe *.o
 
 indent:
 	clang-format -i -style="{BasedOnStyle: Google, IndentWidth: 8, UseTab: Always, AllowShortIfStatementsOnASingleLine: false, ColumnLimit: 0, ContinuationIndentWidth: 8, SpaceAfterCStyleCast: true, IndentCaseLabels: false, AllowShortBlocksOnASingleLine: false, AllowShortFunctionsOnASingleLine: false}" $(C) $(H)
 
-geometry.o: clipper/clipper.hpp
-
 TESTS = $(wildcard tests/*/out/*.json)
 SPACE = $(NULL) $(NULL)
 

clip.c

@@ -1,84 +0,0 @@
-#include "clip.h"
-
-#define INSIDE 0
-#define LEFT 1
-#define RIGHT 2
-#define BOTTOM 4
-#define TOP 8
-
-static int computeOutCode(double x, double y, double xmin, double ymin, double xmax, double ymax) {
-	int code = INSIDE;
-
-	if (x < xmin) {
-		code |= LEFT;
-	} else if (x > xmax) {
-		code |= RIGHT;
-	}
-
-	if (y < ymin) {
-		code |= BOTTOM;
-	} else if (y > ymax) {
-		code |= TOP;
-	}
-
-	return code;
-}
-
-int clip(double *x0, double *y0, double *x1, double *y1, double xmin, double ymin, double xmax, double ymax) {
-	int outcode0 = computeOutCode(*x0, *y0, xmin, ymin, xmax, ymax);
-	int outcode1 = computeOutCode(*x1, *y1, xmin, ymin, xmax, ymax);
-	int accept = 0;
-	int changed = 0;
-
-	while (1) {
-		if (!(outcode0 | outcode1)) {  // Bitwise OR is 0. Trivially accept and get out of loop
-			accept = 1;
-			break;
-		} else if (outcode0 & outcode1) {  // Bitwise AND is not 0. Trivially reject and get out of loop
-			break;
-		} else {
-			// failed both tests, so calculate the line segment to clip
-			// from an outside point to an intersection with clip edge
-			double x = *x0, y = *y0;
-
-			// At least one endpoint is outside the clip rectangle; pick it.
-			int outcodeOut = outcode0 ? outcode0 : outcode1;
-
-			// Now find the intersection point;
-			// use formulas y = y0 + slope * (x - x0), x = x0 + (1 / slope) * (y - y0)
-			if (outcodeOut & TOP) {  // point is above the clip rectangle
-				x = *x0 + (*x1 - *x0) * (ymax - *y0) / (*y1 - *y0);
-				y = ymax;
-			} else if (outcodeOut & BOTTOM) {  // point is below the clip rectangle
-				x = *x0 + (*x1 - *x0) * (ymin - *y0) / (*y1 - *y0);
-				y = ymin;
-			} else if (outcodeOut & RIGHT) {  // point is to the right of clip rectangle
-				y = *y0 + (*y1 - *y0) * (xmax - *x0) / (*x1 - *x0);
-				x = xmax;
-			} else if (outcodeOut & LEFT) {  // point is to the left of clip rectangle
-				y = *y0 + (*y1 - *y0) * (xmin - *x0) / (*x1 - *x0);
-				x = xmin;
-			}
-
-			// Now we move outside point to intersection point to clip
-			// and get ready for next pass.
-			if (outcodeOut == outcode0) {
-				*x0 = x;
-				*y0 = y;
-				outcode0 = computeOutCode(*x0, *y0, xmin, ymin, xmax, ymax);
-				changed = 1;
-			} else {
-				*x1 = x;
-				*y1 = y;
-				outcode1 = computeOutCode(*x1, *y1, xmin, ymin, xmax, ymax);
-				changed = 1;
-			}
-		}
-	}
-
-	if (accept == 0) {
-		return 0;
-	} else {
-		return changed + 1;
-	}
-}

clip.h

@@ -1 +0,0 @@
-int clip(double *x0, double *y0, double *x1, double *y1, double xmin, double ymin, double xmax, double ymax);

geometry.cpp

@@ -14,11 +14,11 @@
 extern "C" {
 #include <sqlite3.h>
 #include "tile.h"
-#include "clip.h"
 #include "projection.h"
 }
 
 static int pnpoly(drawvec &vert, size_t start, size_t nvert, long long testx, long long testy);
+static int clip(double *x0, double *y0, double *x1, double *y1, double xmin, double ymin, double xmax, double ymax);
 
 drawvec decode_geometry(FILE *meta, long long *geompos, int z, unsigned tx, unsigned ty, int detail, long long *bbox, unsigned initial_x, unsigned initial_y) {
 	drawvec out;
@@ -1310,3 +1310,86 @@ std::vector<drawvec> chop_polygon(std::vector<drawvec> &geoms) {
 		geoms = out;
 	}
 }
+
+#define INSIDE 0
+#define LEFT 1
+#define RIGHT 2
+#define BOTTOM 4
+#define TOP 8
+
+static int computeOutCode(double x, double y, double xmin, double ymin, double xmax, double ymax) {
+	int code = INSIDE;
+
+	if (x < xmin) {
+		code |= LEFT;
+	} else if (x > xmax) {
+		code |= RIGHT;
+	}
+
+	if (y < ymin) {
+		code |= BOTTOM;
+	} else if (y > ymax) {
+		code |= TOP;
+	}
+
+	return code;
+}
+
+static int clip(double *x0, double *y0, double *x1, double *y1, double xmin, double ymin, double xmax, double ymax) {
+	int outcode0 = computeOutCode(*x0, *y0, xmin, ymin, xmax, ymax);
+	int outcode1 = computeOutCode(*x1, *y1, xmin, ymin, xmax, ymax);
+	int accept = 0;
+	int changed = 0;
+
+	while (1) {
+		if (!(outcode0 | outcode1)) {  // Bitwise OR is 0. Trivially accept and get out of loop
+			accept = 1;
+			break;
+		} else if (outcode0 & outcode1) {  // Bitwise AND is not 0. Trivially reject and get out of loop
+			break;
+		} else {
+			// failed both tests, so calculate the line segment to clip
+			// from an outside point to an intersection with clip edge
+			double x = *x0, y = *y0;
+
+			// At least one endpoint is outside the clip rectangle; pick it.
+			int outcodeOut = outcode0 ? outcode0 : outcode1;
+
+			// Now find the intersection point;
+			// use formulas y = y0 + slope * (x - x0), x = x0 + (1 / slope) * (y - y0)
+			if (outcodeOut & TOP) {  // point is above the clip rectangle
+				x = *x0 + (*x1 - *x0) * (ymax - *y0) / (*y1 - *y0);
+				y = ymax;
+			} else if (outcodeOut & BOTTOM) {  // point is below the clip rectangle
+				x = *x0 + (*x1 - *x0) * (ymin - *y0) / (*y1 - *y0);
+				y = ymin;
+			} else if (outcodeOut & RIGHT) {  // point is to the right of clip rectangle
+				y = *y0 + (*y1 - *y0) * (xmax - *x0) / (*x1 - *x0);
+				x = xmax;
+			} else if (outcodeOut & LEFT) {  // point is to the left of clip rectangle
+				y = *y0 + (*y1 - *y0) * (xmin - *x0) / (*x1 - *x0);
+				x = xmin;
+			}
+
+			// Now we move outside point to intersection point to clip
+			// and get ready for next pass.
+			if (outcodeOut == outcode0) {
+				*x0 = x;
+				*y0 = y;
+				outcode0 = computeOutCode(*x0, *y0, xmin, ymin, xmax, ymax);
+				changed = 1;
+			} else {
+				*x1 = x;
+				*y1 = y;
+				outcode1 = computeOutCode(*x1, *y1, xmin, ymin, xmax, ymax);
+				changed = 1;
+			}
+		}
+	}
+
+	if (accept == 0) {
+		return 0;
+	} else {
+		return changed + 1;
+	}
+}

tile.cpp

@@ -25,7 +25,6 @@
 extern "C" {
 #include "tile.h"
 #include "pool.h"
-#include "clip.h"
 #include "mbtiles.h"
 #include "projection.h"
 }