GameplayKit path-finding in iOS 9 with Xamarin.iOS

Easy-peasy, lemon-squeazy:

[code lang=”csharp”]
var a = GKGraphNode2D.FromPoint (new Vector2 (0, 5));
var b = GKGraphNode2D.FromPoint (new Vector2 (3, 0));
var c = GKGraphNode2D.FromPoint (new Vector2 (2, 6));
var d = GKGraphNode2D.FromPoint (new Vector2 (4, 6));
var e = GKGraphNode2D.FromPoint (new Vector2 (6, 5));
var f = GKGraphNode2D.FromPoint (new Vector2 (6, 0));

a.AddConnections (new [] { b, c }, false);
b.AddConnections (new [] { e, f }, false);
c.AddConnections (new [] { d }, false);
d.AddConnections (new [] { e, f }, false);

var graph = GKGraph.FromNodes(new [] { a, b, c, d, e, f });

var a2e = graph.FindPath (a, e); // [ a, c, d, e ]
var a2f = graph.FindPath (a, f); // [ a, b, f ]
[/code]

GKPathFindPath

FizzBuzz with iOS 9 GameplayKit Expert System in C# with Xam.iOS

OK, so this is silly, but:

[code lang=”csharp”]
var clearRule = GKRule.FromPredicate ((rules) => reset, rules => {
output = "";
reset = false;
});
clearRule.Salience = 1;

var fizzRule = GKRule.FromPredicate (mod (3), rules => {
output += "fizz";
});
fizzRule.Salience = 2;
var buzzRule = GKRule.FromPredicate (mod (5), rules => {
output += "buzz";
});
buzzRule.Salience = 2;

var outputRule = GKRule.FromPredicate (rules => true, rules => {
System.Console.WriteLine(output == "" ? input.ToString() : output);
reset = true;
});
outputRule.Salience = 3;

var rs = new GKRuleSystem ();
rs.AddRules (new [] {
clearRule,
fizzRule,
buzzRule,
outputRule
});

for (input = 1; input < 16; input++) {
rs.Evaluate ();
rs.Reset ();
}
[/code]

Output:

[code]
2015-08-04 13:08:47.164 GameplayKit0[46277:18357203] 1
2015-08-04 13:08:47.164 GameplayKit0[46277:18357203] 2
2015-08-04 13:08:50.338 GameplayKit0[46277:18357203] fizz
2015-08-04 13:08:50.338 GameplayKit0[46277:18357203] 4
2015-08-04 13:08:51.089 GameplayKit0[46277:18357203] buzz
2015-08-04 13:08:51.934 GameplayKit0[46277:18357203] fizz
2015-08-04 13:08:51.934 GameplayKit0[46277:18357203] 7
2015-08-04 13:08:51.935 GameplayKit0[46277:18357203] 8
2015-08-04 13:08:52.589 GameplayKit0[46277:18357203] fizz
2015-08-04 13:08:53.256 GameplayKit0[46277:18357203] buzz
2015-08-04 13:08:53.256 GameplayKit0[46277:18357203] 11
2015-08-04 13:08:53.872 GameplayKit0[46277:18357203] fizz
2015-08-04 13:08:53.873 GameplayKit0[46277:18357203] 13
2015-08-04 13:08:53.873 GameplayKit0[46277:18357203] 14
2015-08-04 13:08:55.005 GameplayKit0[46277:18357203] buzzfizz
[/code]

The important thing I learned is that you have to call GKRuleSystem.Reset() if you want evaluated GKRules to be re-evaluated.