// From Real-time Collision Detection, p179.
public void RayCast(out RayCastOutput output, ref RayCastInput input)
{
output = new RayCastOutput();
float tmin = -Settings.b2_FLT_MAX;
float tmax = Settings.b2_FLT_MAX;
output.hit = false;
Vector2 p = input.p1;
Vector2 d = input.p2 - input.p1;
Vector2 absD = MathUtils.Abs(d);
Vector2 normal = Vector2.Zero;
for (int i = 0; i < 2; ++i)
{
float absD_i = i == 0 ? absD.X : absD.Y;
float lowerBound_i = i == 0 ? lowerBound.X : lowerBound.Y;
float upperBound_i = i == 0 ? upperBound.X : upperBound.Y;
float p_i = i == 0 ? p.X : p.Y;
if (absD_i < Settings.b2_FLT_EPSILON)
{
// Parallel.
if (p_i < lowerBound_i || upperBound_i < p_i)
{
return;
}
}
else
{
float d_i = i == 0 ? d.X : d.Y;
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)
{
MathUtils.Swap<float>(ref t1, ref t2);
s = 1.0f;
}
// Push the min up
if (t1 > tmin)
{
if (i == 0)
{
normal.X = s;
}
else
{
normal.Y = s;
}
tmin = t1;
}
// Pull the max down
tmax = 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;
}
// From Real-time Collision Detection, p179.
public void RayCast(out RayCastOutput output, ref RayCastInput input)
{
output = new RayCastOutput();
float tmin = -Settings.b2_FLT_MAX;
float tmax = Settings.b2_FLT_MAX;
output.hit = false;
Vector2 p = input.p1;
Vector2 d = input.p2 - input.p1;
Vector2 absD = MathUtils.Abs(d);
Vector2 normal = Vector2.Zero;
for (int i = 0; i < 2; ++i)
{
float absD_i = i == 0 ? absD.X : absD.Y;
float lowerBound_i = i == 0 ? lowerBound.X : lowerBound.Y;
float upperBound_i = i == 0 ? upperBound.X : upperBound.Y;
float p_i = i == 0 ? p.X : p.Y;
if (absD_i < Settings.b2_FLT_EPSILON)
{
// Parallel.
if (p_i < lowerBound_i || upperBound_i < p_i)
{
return;
}
}
else
{
float d_i = i == 0 ? d.X : d.Y;
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)
{
MathUtils.Swap <float>(ref t1, ref t2);
s = 1.0f;
}
// Push the min up
if (t1 > tmin)
{
if (i == 0)
{
normal.X = s;
}
else
{
normal.Y = s;
}
tmin = t1;
}
// Pull the max down
tmax = 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;
}