public static int DistanceSq(D2D_Point a, D2D_Point b)
{
var x = b.X - a.X;
var y = b.Y - a.Y;
return(x * x + y * y);
}
public void Split(ref D2D_Quad first, ref D2D_Quad second, float irregularity)
{
if (first == null)
{
first = new D2D_Quad();
}
if (second == null)
{
second = new D2D_Quad();
}
var b = D2D_Point.DistanceSq(BL, BR);
var t = D2D_Point.DistanceSq(TL, TR);
var l = D2D_Point.DistanceSq(BL, TL);
var r = D2D_Point.DistanceSq(BR, TR);
// Vertical split
if (b > l || b > t || t > l || t > r)
{
var TS = TL + (TR - TL) * Random.Range(0.5f - irregularity, 0.5f + irregularity);
var BS = BL + (BR - BL) * Random.Range(0.5f - irregularity, 0.5f + irregularity);
first.BL = BL;
first.BR = BS;
first.TL = TL;
first.TR = TS;
first.CalculateSize();
second.BL = BS;
second.BR = BR;
second.TL = TS;
second.TR = TR;
second.CalculateSize();
}
// Horizontal split
else
{
var LS = BL + (TL - BL) * Random.Range(0.5f - irregularity, 0.5f + irregularity);
var RS = BR + (TR - BR) * Random.Range(0.5f - irregularity, 0.5f + irregularity);
first.BL = LS;
first.BR = RS;
first.TL = TL;
first.TR = TR;
first.CalculateSize();
second.BL = BL;
second.BR = BR;
second.TL = LS;
second.TR = RS;
second.CalculateSize();
}
}
public void AddTriangle(D2D_Point a, D2D_Point b, D2D_Point c)
{
if (a.Y != b.Y || a.Y != c.Y)
{
// Make a highest, and c lowest
if (b.Y > a.Y)
{
D2D_Helper.Swap(ref a, ref b);
}
if (c.Y > a.Y)
{
D2D_Helper.Swap(ref c, ref a);
}
if (c.Y > b.Y)
{
D2D_Helper.Swap(ref b, ref c);
}
var fth = a.Y - c.Y; // Full triangle height
var tth = a.Y - b.Y; // Top triangle height
var bth = b.Y - c.Y; // Bottom triangle height
// Find a to c intercept along b plane
var inx = c.X + (a.X - c.X) * D2D_Helper.Divide(bth, fth);
var d = new D2D_Point((int)inx, b.Y);
// Top triangle
var abs = D2D_Helper.Divide(a.X - b.X, tth); // A/B slope
var ads = D2D_Helper.Divide(a.X - d.X, tth); // A/D slope
AddTriangle(b.X, d.X, abs, ads, b.Y, 1, tth);
// Bottom triangle
var cbs = D2D_Helper.Divide(c.X - b.X, bth); // C/B slope
var cds = D2D_Helper.Divide(c.X - d.X, bth); // C/D slope
AddTriangle(b.X, d.X, cbs, cds, b.Y, -1, bth);
}
}
