protected float? SenseGround()
{
var r = new Rect(x + vx, y + vy + Height, Width, SLOPE_THRESHHOLD);
var x1 = x + vx;
var x2 = x1 + Width;
var bestIntercept = float.MaxValue;
groundHeight = null;
Action<Line> cb = (line) => {
/*
* I think what we want here is to track, for each direction,
* the surface that penetrates the entity's hotspot the most.
*/
var intercept = float.MaxValue;
if ((x1 > line.A.X || x1 > line.B.X) &&
(x1 < line.A.X || x1 < line.B.X)
) {
var ay1 = line.atX(x1);
intercept = ay1;
}
var ay2 = line.atX(x2);
if ((x2 > line.A.X || x2 > line.B.X) &&
(x2 < line.A.X || x2 < line.B.X) &&
ay2 < intercept
) {
intercept = ay2;
}
if (intercept < bestIntercept) {
bestIntercept = intercept;
}
};
engine.obstructionTiles.Test(r, cb);
if (bestIntercept < float.MaxValue) {
groundHeight = bestIntercept;
}
return groundHeight;
}
protected void DoCollision()
{
var limit = 4;
do {
var r = new Rect(x + vx, y + vy, Width, Height);
var cr = engine.obstructionTiles.TestSAT(r);
if (!cr.HasValue) {
break;
}
var mtv = cr.Value.mtv;
var velocity = new Vector2(vx, vy);
velocity += mtv;
vx = velocity.X;
vy = velocity.Y;
--limit;
} while (limit > 0);
var count = 4 - limit;
if (count > 1) {
Console.WriteLine("Resolved in {0} steps", count);
}
}