Axiom.Core.Frustum.ProjectSphere C# (CSharp) Method

		public virtual bool ProjectSphere( Sphere sphere, out float left, out float top, out float right, out float bottom )
		{
			// initialise
			left = bottom = -1.0f;
			right = top = 1.0f;

			// Transform light position into camera space
			Vector3 eyeSpacePos = this.ViewMatrix.TransformAffine( sphere.Center );

			if ( eyeSpacePos.z < 0 )
			{
				float r = sphere.Radius;
				// early-exit
				if ( eyeSpacePos.LengthSquared <= r * r )
					return false;

				Vector3 screenSpacePos = this.ProjectionMatrix * eyeSpacePos;

				// perspective attenuate
				Vector3 spheresize = new Vector3( r, r, eyeSpacePos.z );
				spheresize = this.ProjectionMatrixRSDepth * spheresize;

				float possLeft = screenSpacePos.x - spheresize.x;
				float possRight = screenSpacePos.x + spheresize.x;
				float possTop = screenSpacePos.y + spheresize.y;
				float possBottom = screenSpacePos.y - spheresize.y;

				left = Utility.Max( -1.0f, possLeft );
				right = Utility.Min( 1.0f, possRight );
				top = Utility.Min( 1.0f, possTop );
				bottom = Utility.Max( -1.0f, possBottom );
			}

			return ( left != -1.0f ) || ( top != 1.0f ) || ( right != 1.0f ) || ( bottom != -1.0f );
		}