Ray-cast output data. The ray hits at p1 + fraction * (p2 - p1), where p1 and p2 come from RayCastInput.
 /// <summary>
 /// Cast a ray against this Shape.
 /// </summary>
 /// <param name="output">The ray-cast results.</param>
 /// <param name="input">The ray-cast input parameters.</param>
 /// <param name="childIndex">Index of the child.</param>
 /// <returns></returns>
 public bool RayCast(out RayCastOutput output, ref RayCastInput input, int childIndex)
 {
     return Shape.RayCast(out output, ref input, ref Body.Xf, childIndex);
 }
Beispiel #2
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        // From Real-time Collision Detection, p179.
        public bool RayCast(out RayCastOutput output, ref RayCastInput input)
        {
            output = new RayCastOutput();

            float tmin = -Settings.MaxFloat;
            float tmax = Settings.MaxFloat;

            Vector2 p = input.Point1;
            Vector2 d = input.Point2 - input.Point1;
            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.Epsilon)
                {
                    // Parallel.
                    if (p_i < lowerBound_i || upperBound_i < p_i)
                    {
                        return false;
                    }
                }
                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(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 false;
                    }
                }
            }

            // Does the ray start inside the box?
            // Does the ray intersect beyond the max fraction?
            if (tmin < 0.0f || input.MaxFraction < tmin)
            {
                return false;
            }

            // Intersection.
            output.Fraction = tmin;
            output.Normal = normal;
            return true;
        }