Add half_edge.c for operations on half edge structures

src/Makefile

@@ -16,7 +16,7 @@ endif
 
 TARGET = drow-engine
 HEADERS = err.h parser.h common.h print.h filereader.h gl_draw.h vector.h half_edge.h
-OBJECTS = main.o parser.o print.o filereader.o gl_draw.o vector.o
+OBJECTS = main.o parser.o print.o filereader.o gl_draw.o vector.o half_edge.o
 INCS = -I.
 
 CFLAGS += $(shell $(PKG_CONFIG) --cflags gl glu glib-2.0)

src/half_edge.c

@@ -0,0 +1,33 @@
+/*
+ * Copyright 2011-2014 hasufell
+ *
+ * This file is part of a hasufell project.
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation version 2 of the License only.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include "half_edge.h"
+
+#include <stdlib.h>
+
+
+/**
+ * Get all edges that emanate from vertice.
+ *
+ * @param vertice the vertice to get the emanating edges of
+ * @return pointer to a NULL-terminated array of half-edges
+ */
+HE_edge **get_all_emanating_edges(HE_vert *vertice)
+{
+	return NULL;
+}