Beispiel #1
0
		/// <summary>
		/// Determines whether there is an intersection between a <see cref="SharpDX.Ray"/> and a <see cref="SharpDX.BoundingSphere"/>. 
		/// </summary>
		/// <param name="ray">The ray to test.</param>
		/// <param name="sphere">The sphere to test.</param>
		/// <param name="point">When the method completes, contains the point of intersection,
		/// or <see cref="SharpDX.Vector3.Zero"/> if there was no intersection.</param>
		/// <returns>Whether the two objects intersected.</returns>
		public static bool Intersect(ref Ray ray, ref Vector3 centerSphere,float radius,ref Matrix4 matrix, out Vector3 point)
		{
			float distance;
			if (!Intersect(ref ray, ref centerSphere, radius,ref matrix, out distance))
			{
				point = Vector3.Zero;
				return false;
			}

			point = ray.origin + (ray.direction * distance);
			return true;
		}
Beispiel #2
0
		public bool Intersect(ref Ray ray, ref Matrix4 matrix)
		{
			var max=Vector3.TransformPosition(Max,matrix);
			var min=Vector3.TransformPosition(Min,matrix);
			//first test if start in box
			if (ray.origin.X >= min.X
				&& ray.origin.X <= max.X
				&& ray.origin.Y >= min.Y
				&& ray.origin.Y <= max.Y
				&& ray.origin.Z >= min.Z
				&& ray.origin.Z <= max.Z)
				return true;// here we concidere cube is full and origine is in cube so intersect at origine


			//Second we check each face
			Vector3 maxT = new Vector3(-1.0f);
			//Vector3 minT = new Vector3(-1.0f);
			//calcul intersection with each faces
			if (ray.origin.X < min.X && ray.direction.X != 0.0f)
				maxT.X = (min.X - ray.origin.X) / ray.direction.X;
			else if (ray.origin.X > max.X && ray.direction.X != 0.0f)
				maxT.X = (max.X - ray.origin.X) / ray.direction.X;
			if (ray.origin.Y < min.Y && ray.direction.Y != 0.0f)
				maxT.Y = (min.Y - ray.origin.Y) / ray.direction.Y;
			else if (ray.origin.Y > max.Y && ray.direction.Y != 0.0f)
				maxT.Y = (max.Y - ray.origin.Y) / ray.direction.Y;
			if (ray.origin.Z < min.Z && ray.direction.Z != 0.0f)
				maxT.Z = (min.Z - ray.origin.Z) / ray.direction.Z;
			else if (ray.origin.Z > max.Z && ray.direction.Z != 0.0f)
				maxT.Z = (max.Z - ray.origin.Z) / ray.direction.Z;


			//get the maximum maxT
			if (maxT.X > maxT.Y && maxT.X > maxT.Z)
			{
				if (maxT.X < 0.0f)
					return false;// ray go on opposite of face
				//coordonate of hit point of face of cube
				float coord = ray.origin.Z + maxT.X * ray.direction.Z;
				// if hit point coord ( intersect face with ray) is out of other plane coord it miss 
				if (coord < min.Z || coord > max.Z)
					return false;
				coord = ray.origin.Y + maxT.X *ray.direction.Y;
				if (coord < min.Y || coord > max.Y)
					return false;
				return true;
			}
			if (maxT.Y > maxT.X && maxT.Y > maxT.Z)
			{
				if (maxT.Y < 0.0f)
					return false;// ray go on opposite of face
				//coordonate of hit point of face of cube
				float coord = ray.origin.Z + maxT.Y * ray.direction.Z;
				// if hit point coord ( intersect face with ray) is out of other plane coord it miss 
				if (coord < min.Z || coord > max.Z)
					return false;
				coord =ray.origin.X + maxT.Y * ray.direction.X;
				if (coord < min.X || coord > max.X)
					return false;
				return true;
			}
			else //Z
			{
				if (maxT.Z < 0.0f)
					return false;// ray go on opposite of face
				//coordonate of hit point of face of cube
				float coord =ray.origin.X + maxT.Z * ray.direction.X;
				// if hit point coord ( intersect face with ray) is out of other plane coord it miss 
				if (coord < min.X || coord > max.X)
					return false;
				coord = ray.origin.Y + maxT.Z * ray.direction.Y;
				if (coord < min.Y || coord > max.Y)
					return false;
				return true;
			}
		}
Beispiel #3
0
		/// <summary>
		/// Determines whether there is an intersection between a <see cref="SharpDX.Ray"/> and a <see cref="SharpDX.BoundingSphere"/>.
		/// </summary>
		/// <param name="ray">The ray to test.</param>
		/// <param name="sphere">The sphere to test.</param>
		/// <param name="distance">When the method completes, contains the distance of the intersection,
		/// or 0 if there was no intersection.</param>
		/// <returns>Whether the two objects intersected.</returns>
		public static bool Intersect(ref Ray ray, ref Vector3 centerSphere,float radius,ref Matrix4 matrix, out float distance)
		{
			//Source: Real-Time Collision Detection by Christer Ericson
			//Reference: Page 177
			var center=Vector3.TransformPosition(centerSphere,matrix);
			Vector3 m=ray.origin-center;

			float b = Vector3.Dot(m, ray.direction);
			float c = Vector3.Dot(m, m) - (radius * radius);

			if (c > 0f && b > 0f)
			{
				distance = 0f;
				return false;
			}

			float discriminant = b * b - c;

			if (discriminant < 0f)
			{
				distance = 0f;
				return false;
			}

			distance = -b - (float)Math.Sqrt(discriminant);

			if (distance < 0f)
				distance = 0f;

			return true;
		}