/// <summary>
// From Real-time Collision Detection, p179.
/// </summary>
public void RayCast(out RayCastOutput output, RayCastInput input)
{
float tmin = -Common.Settings.FLT_MAX;
float tmax = Common.Settings.FLT_MAX;
output = new RayCastOutput();
output.Hit = false;
Vector2 p = input.P1;
Vector2 d = input.P2 - input.P1;
Vector2 absD = d.Abs();
Vector2 normal = Vector2.Zero;
for (int i = 0; i < 2; ++i)
{
if (absD.GetByIndex(i) < Common.Settings.FLT_EPSILON)
{
// Parallel.
if (p.GetByIndex(i) < LowerBound.GetByIndex(i) || UpperBound.GetByIndex(i) < p.GetByIndex(i))
{
return;
}
}
else
{
float inv_d = 1.0f / d.GetByIndex(i);
float t1 = (LowerBound.GetByIndex(i) - p.GetByIndex(i)) * inv_d;
float t2 = (UpperBound.GetByIndex(i) - p.GetByIndex(i)) * inv_d;
// Sign of the normal vector.
float s = -1.0f;
if (t1 > t2)
{
Common.Math.Swap(ref t1, ref t2);
s = 1.0f;
}
// Push the min up
if (t1 > tmin)
{
normal = Vector2.Zero;
normal.SetByIndex(i, s);
tmin = t1;
}
// Pull the max down
tmax = Common.Math.Min(tmax, t2);
if (tmin > tmax)
{
return;
}
}
}
// Does the ray start inside the box?
// Does the ray intersect beyond the max fraction?
if (tmin < 0.0f || input.MaxFraction < tmin)
{
return;
}
// Intersection.
output.Fraction = tmin;
output.Normal = normal;
output.Hit = true;
}
/// <summary>
// From Real-time Collision Detection, p179.
/// </summary>
public void RayCast(out RayCastOutput output, RayCastInput input)
{
float tmin = -Common.Settings.FLT_MAX;
float tmax = Common.Settings.FLT_MAX;
output = new RayCastOutput {
Hit = false
};
Vec2 p = input.P1;
Vec2 d = input.P2 - input.P1;
Vec2 absD = Common.MathB2.Abs(d);
Vec2 normal = new Vec2(0);
for (int i = 0; i < 2; ++i)
{
if (absD[i] < Common.Settings.FLT_EPSILON)
{
// Parallel.
if (p[i] < LowerBound[i] || UpperBound[i] < p[i])
{
return;
}
}
else
{
float inv_d = 1.0f / d[i];
float t1 = (LowerBound[i] - p[i]) * inv_d;
float t2 = (UpperBound[i] - p[i]) * inv_d;
// Sign of the normal vector.
float s = -1.0f;
if (t1 > t2)
{
Common.MathB2.Swap(ref t1, ref t2);
s = 1.0f;
}
// Push the min up
if (t1 > tmin)
{
normal.SetZero();
normal[i] = s;
tmin = t1;
}
// Pull the max down
tmax = Common.MathB2.Min(tmax, t2);
if (tmin > tmax)
{
return;
}
}
}
// Does the ray start inside the box?
// Does the ray intersect beyond the max fraction?
if (tmin < 0.0f || input.MaxFraction < tmin)
{
return;
}
// Intersection.
output.Fraction = tmin;
output.Normal = normal;
output.Hit = true;
}
internal bool RayCast(RayCastOutput output, RayCastInput input, XForm xf, int v)
{
Vec2 p1 = MathB2.MulT(xf.R, input.P1 - xf.Position);
Vec2 p2 = MathB2.MulT(xf.R, input.P2 - xf.Position);
Vec2 d = p2 - p1;
Vec2 v1 = _v1;
Vec2 v2 = _v2;
Vec2 e = v2 - v1;
Vec2 normal = new Vec2(e.Y, -e.X);
normal.Normalize();
// q = p1 + t * d
// dot(normal, q - v1) = 0
// dot(normal, p1 - v1) + t * dot(normal, d) = 0
float numerator = MathB2.Dot(normal, v1 - p1);
float denominator = MathB2.Dot(normal, d);
if (denominator == 0.0f)
{
return(false);
}
float t = numerator / denominator;
if (t < 0.0f || input.MaxFraction < t)
{
return(false);
}
Vec2 q = p1 + t * d;
// q = v1 + s * r
// s = dot(q - v1, r) / dot(r, r)
Vec2 r = v2 - v1;
float rr = MathB2.Dot(r, r);
if (rr == 0.0f)
{
return(false);
}
float s = MathB2.Dot(q - v1, r) / rr;
if (s < 0.0f || 1.0f < s)
{
return(false);
}
output.Fraction = t;
if (numerator > 0.0f)
{
output.Normal = -MathB2.Mul(xf.R, normal);
}
else
{
output.Normal = MathB2.Mul(xf.R, normal);
}
return(true);
}