examples: improve the pendulum simulation, with several modes and diagrams (#13446)

examples/pendulum-simulation/animation.v

@@ -0,0 +1,37 @@
+module main
+
+import benchmark
+import sim
+import sim.anim
+import sim.args as simargs
+
+fn main() {
+	args := simargs.parse_args(extra_workers: 1) ? as simargs.ParallelArgs
+
+	mut app := anim.new_app(args)
+	mut workers := []thread{cap: args.workers}
+
+	mut bmark := benchmark.start()
+
+	defer {
+		app.request_chan.close()
+		sim.log('Waiting for workers to finish')
+		workers.wait()
+		app.result_chan.close()
+		sim.log('Workers finished!')
+		bmark.measure(@FN)
+		sim.log('Done!')
+	}
+
+	for id in 0 .. args.workers {
+		workers << go sim.sim_worker(id, app.request_chan, [app.result_chan])
+	}
+
+	handle_request := fn [app] (request &sim.SimRequest) ? {
+		app.request_chan <- request
+	}
+
+	go app.gg.run()
+
+	sim.run(args.params, grid: args.grid, on_request: sim.SimRequestHandler(handle_request))
+}