devel(makefile): helping development (#36)

* devel(makefile): helping development

see `makefile` header for more information

* fix(makefile): improve `stop` target compatibility

now should work for `make>=4.2.1`

makefile

@@ -0,0 +1,42 @@
+# makefile
+# --------
+# makefile for development, rules:
+#  + `animation` - create simple gif animation, useful to create
+#                  rustracer usage examples (`ffmpeg` needed)
+#  + `docs`      - preview `rustracer` documentation locally
+#  + `ccov`      - preview `rustracer` code-coverage html report locally
+
+animation: examples/demo
+
+examples/demo:
+	@printf "[info] create demo gif animation ... "
+	@mkdir -p $@/frames
+	@for a in `seq 0 359`; do \
+		rustracer demo --width 320 --height 240 --angle-deg $$a $@/frames/frame-`printf '%03d' $$a`.png; done;
+	@ffmpeg -loglevel panic -f image2 -framerate 25 -i $@/frames/frame-%03d.png $@/demo.gif
+	@printf "done\n"
+
+docs: docs.pid
+ccov: ccov.pid
+
+docs.pid:
+	@for f in `ls -1 target/doc/rustracer`; do ln -sf rustracer/$$f target/doc/$$f; done;
+	@printf "starting http.server ... "
+	@{ python3 -m http.server -b 127.0.0.1 -d target/doc/ 8080 >/dev/null 2>&1 \
+		& echo $$! >$@; }
+	@printf "done\n"
+	@printf "docs url: http://localhost:8080/\n"
+
+ccov.pid:
+	@printf "starting http.server ... "
+	@{ python3 -m http.server -b 127.0.0.1 -d target/llvm-cov/html 8081 >/dev/null 2>&1 \
+		& echo $$! >$@; }
+	@printf "done\n"
+	@printf "ccov url: http://localhost:8081/\n"
+
+stop: *.pid
+	@printf "stopping http.server ... "
+	@pkill -F docs.pid 2>/dev/null || exit 0
+	@pkill -F ccov.pid 2>/dev/null || exit 0
+	@rm $^
+	@printf "done\n"