public static bool PointTriangle(JellyVector2 p, JellyVector2 a, JellyVector2 b, JellyVector2 c)
{
float u, v, w;
Barycentric(a, b, c, p, out u, out v, out w);
return(v >= 0.0 && w >= 0.0 && (v + w) <= 1.0);
}
public static bool SegmentTest(JellyVector2 a, JellyVector2 b, JellyVector2 c, JellyVector2 d)
{
float triaa = SignedTriangleArea(a, b, d);
float triab = SignedTriangleArea(a, b, c);
float triac = 0;
float triad = 0;
if (triaa * triab < 0.0)
{
triac = SignedTriangleArea(c, d, a);
triad = triac + triab - triaa;
if (triac * triad < 0.0)
{
return(true);
}
}
if (triaa + triab + triac + triad == 0.0)
{
JellyVector2 ab = b - a;
float abdab = JellyVector2.Dot(ab, ab);
JellyVector2 ac = c - a;
float abdac = JellyVector2.Dot(ab, ac);
JellyVector2 ad = d - a;
float abdad = JellyVector2.Dot(ab, ad);
float min = System.Math.Min(abdac, abdad);
float max = System.Math.Max(abdac, abdad);
return(min < abdab && max > 0);
}
return(false);
}
public static void ComputeBezierPoint(JellyVector2 begv, JellyVector2 midv, JellyVector2 endv, ref JellyVector2[] ptlist, ref int sind, int maxiter)
{
JellyVector2 vab = midv - begv;
JellyVector2 vbc = endv - midv;
begv = begv + vab * 0.5f;
endv = midv + vbc * 0.5f;
vab = midv - begv;
vbc = endv - midv;
int iter = 0;
float factor = 1.0f / maxiter;
float delta = 0;
while (iter < maxiter)
{
JellyVector2 bab = begv + vab * delta;
JellyVector2 bbc = midv + vbc * delta;
JellyVector2 vbb = bbc - bab;
JellyVector2 be = bab + vbb * delta;
ptlist[sind + iter] = be;
++iter;
delta = factor * iter;
}
sind += iter;
}
public static void Barycentric(JellyVector2 a, JellyVector2 b, JellyVector2 c, JellyVector2 p, out float u, out float v, out float w)
{
JellyVector2 v0 = b - a, v1 = c - a, v2 = p - a;
float d00 = JellyVector2.Dot(v0, v0);
float d01 = JellyVector2.Dot(v0, v1);
float d11 = JellyVector2.Dot(v1, v1);
float d20 = JellyVector2.Dot(v2, v0);
float d21 = JellyVector2.Dot(v2, v1);
float denom = d00 * d11 - d01 * d01;
v = (d11 * d20 - d01 * d21) / denom;
w = (d00 * d21 - d01 * d20) / denom;
u = 1 - v - w;
}
public static JellyVector2 ClosestPointOnSegment(JellyVector2 a, JellyVector2 b, JellyVector2 c)
{
JellyVector2 ab = b - a;
float t = JellyVector2.Dot(c - a, ab) / JellyVector2.Dot(ab, ab);
if (t < 0)
{
return(a);
}
if (t > 1)
{
return(b);
}
return(a + ab * t);
}
public static bool SegmentPolygonTest(JellyVector2 a, JellyVector2 b, JellyVertex[] poly, out int id)
{
id = 0;
while (id < poly.Length - 1)
{
if (SegmentTest(a, b, poly[id].Position, poly[++id].Position))
{
return(true);
}
}
if (SegmentTest(a, b, poly[id].Position, poly[0].Position))
{
return(true);
}
id = int.MaxValue;
return(false);
}
public static bool SegmentPolygonTest(JellyVector2 a, JellyVector2 b, JellyVertex[] poly, out JellyVector2 ins)
{
int c = 0;
while (c < poly.Length - 1)
{
if (SegmentTest(a, b, poly[c].Position, poly[++c].Position, out ins))
{
return(true);
}
}
if (SegmentTest(a, b, poly[c].Position, poly[0].Position, out ins))
{
return(true);
}
ins = JellyVector2.Zero;//it should be null,change in XNA
return(false);
}
public static bool PointInPolygon(JellyVertex[] vs, JellyVector2 pt, JellyVector2 infinity)
{
uint count = 0;
uint i = 0;
while (i < vs.Length - 1)
{
if (SegmentTest(pt, infinity, vs[i].Position, vs[i + 1].Position))
{
++count;
}
++i;
}
if (SegmentTest(pt, infinity, vs[i].Position, vs[0].Position))
{
++count;
}
return((count & 1) == 1);
}
public static bool SegmentPolygonTest(JellyVector2 a, JellyVector2 b, JellyVertex[] poly, out int id, out JellyVector2 ins)
{
int c;
for (c = 0; c < poly.Length - 1; ++c)
{
if (SegmentTest(a, b, poly[c].Position, poly[c + 1].Position, out ins))
{
id = c;
return(true);
}
}
if (SegmentTest(a, b, poly[c].Position, poly[0].Position, out ins))
{
id = c;
return(true);
}
ins = JellyVector2.Zero;//it should be null,change in XNA
id = int.MaxValue;
return(false);
}
public static bool SegmentTest(JellyVector2 a, JellyVector2 b, JellyVector2 c, JellyVector2 d, out JellyVector2 i)
{
float triaa = SignedTriangleArea(a, b, d);
float triab = SignedTriangleArea(a, b, c);
float triac = 0;
float triad = 0;
if (triaa * triab < 0.0)
{
triac = SignedTriangleArea(c, d, a);
triad = triac + triab - triaa;
if (triac * triad < 0.0)
{
float t = triac / (triac - triad);
i = a + (b - a) * t;
return(true);
}
}
if (triaa + triab + triac + triad == 0.0)
{
JellyVector2 ab = b - a;
float abdab = JellyVector2.Dot(ab, ab);
JellyVector2 ac = c - a;
float abdac = JellyVector2.Dot(ab, ac);
JellyVector2 ad = d - a;
float abdad = JellyVector2.Dot(ab, ad);
float min = System.Math.Min(abdac, abdad);
float max = System.Math.Max(abdac, abdad);
if (min < abdab && max > 0)
{
i = (a + b + c + d) * 0.25f;
return(true);
}
}
i = JellyVector2.Zero;//it should be null,change in XNA
return(false);
}
public JellyVector2(JellyVector2 v)
{
this.X = v.X; this.Y = v.Y;
}
public static float Dot(JellyVector2 a, JellyVector2 b)
{
return(a.X * b.X + a.Y * b.Y);
}
public static float Cross(JellyVector2 va, JellyVector2 vb)
{
return(va.X * vb.Y - va.Y * vb.X);
}
public static float SignedTriangleArea(JellyVector2 a, JellyVector2 b, JellyVector2 c)
{
return((a.X - c.X) * (b.Y - c.Y) - (a.Y - c.Y) * (b.X - c.X));
}
