struct Matrix4x4{// The elements of the 4x4 matrix are stored in// row-major order.float _11, _12, _13, _14;float _21, _22, _23, _24;float _31, _32, _33, _34;float _41, _42, _43, _44;};void ExtractPlanesD3D(Plane * p_planes,const Matrix4x4 & comboMatrix,bool normalize){// Left clipping planep_planes[0].a = comboMatrix._14 + comboMatrix._11;p_planes[0].b = comboMatrix._24 + comboMatrix._21;p_planes[0].c = comboMatrix._34 + comboMatrix._31;p_planes[0].d = comboMatrix._44 + comboMatrix._41;// Right clipping planep_planes[1].a = comboMatrix._14 - comboMatrix._11;p_planes[1].b = comboMatrix._24 - comboMatrix._21;p_planes[1].c = comboMatrix._34 - comboMatrix._31;p_planes[1].d = comboMatrix._44 - comboMatrix._41;// Top clipping planep_planes[2].a = comboMatrix._14 - comboMatrix._12;p_planes[2].b = comboMatrix._24 - comboMatrix._22;p_planes[2].c = comboMatrix._34 - comboMatrix._32;p_planes[2].d = comboMatrix._44 - comboMatrix._42;// Bottom clipping planep_planes[3].a = comboMatrix._14 + comboMatrix._12;p_planes[3].b = comboMatrix._24 + comboMatrix._22;p_planes[3].c = comboMatrix._34 + comboMatrix._32;p_planes[3].d = comboMatrix._44 + comboMatrix._42;// Near clipping planep_planes[4].a = comboMatrix._13;p_planes[4].b = comboMatrix._23;p_planes[4].c = comboMatrix._33;p_planes[4].d = comboMatrix._43;// Far clipping planep_planes[5].a = comboMatrix._14 - comboMatrix._13;p_planes[5].b = comboMatrix._24 - comboMatrix._23;p_planes[5].c = comboMatrix._34 - comboMatrix._33;p_planes[5].d = comboMatrix._44 - comboMatrix._43;// Normalize the plane equations, if requestedif (normalize == true){NormalizePlane(p_planes[0]);NormalizePlane(p_planes[1]);NormalizePlane(p_planes[2]);NormalizePlane(p_planes[3]);NormalizePlane(p_planes[4]);NormalizePlane(p_planes[5]);}}

        Public Sub ExtractFrustumPlanes(Optional ByVal Normalize As Boolean = True)            Dim comboMatrix As Matrix = Matrix.Multiply(ccCore.Device.Transform.View, ccCore.Device.Transform.Projection)            'Left clipping plane            ccFrustum(0).A = comboMatrix.M14+ comboMatrix.M11            ccFrustum(0).B = -(comboMatrix.M24+ comboMatrix.M21)            ccFrustum(0).C = -(comboMatrix.M34+ comboMatrix.M31)            ccFrustum(0).D = -(comboMatrix.M44+ comboMatrix.M41)            'Right clipping plane            ccFrustum(1).A = -(comboMatrix.M14- comboMatrix.M11)            ccFrustum(1).B = -(comboMatrix.M24- comboMatrix.M21)            ccFrustum(1).C = -(comboMatrix.M34- comboMatrix.M31)            ccFrustum(1).D = -(comboMatrix.M44- comboMatrix.M41)            'Top clipping plane            ccFrustum(2).A = -(comboMatrix.M14- comboMatrix.M12)            ccFrustum(2).B = -(comboMatrix.M24- comboMatrix.M22)            ccFrustum(2).C = -(comboMatrix.M34- comboMatrix.M32)            ccFrustum(2).D = -(comboMatrix.M44- comboMatrix.M42)            'Bottom clipping plane            ccFrustum(3).A = -(comboMatrix.M14+ comboMatrix.M12)            ccFrustum(3).B = -(comboMatrix.M24+ comboMatrix.M22)            ccFrustum(3).C = -(comboMatrix.M34+ comboMatrix.M32)            ccFrustum(3).D = -(comboMatrix.M44+ comboMatrix.M42)            'Near clipping plane            ccFrustum(4).A = -(comboMatrix.M14+ comboMatrix.M13)            ccFrustum(4).B = -(comboMatrix.M24+ comboMatrix.M23)            ccFrustum(4).C = -(comboMatrix.M34+ comboMatrix.M33)            ccFrustum(4).D = -(comboMatrix.M44+ comboMatrix.M43)            'Far clipping plane            ccFrustum(5).A = -(comboMatrix.M14- comboMatrix.M13)            ccFrustum(5).B = -(comboMatrix.M24- comboMatrix.M23)            ccFrustum(5).C = -(comboMatrix.M34- comboMatrix.M33)            ccFrustum(5).D = -(comboMatrix.M44- comboMatrix.M43)            If Normalize Then                For I As Integer = 0 To 5                     ccFrustum(I).Normalize()                    'NormalizePlane(ccFrustum(I))                Next            End If        End Sub

        Public Function FrustumTestSphere(ByVal vCenter As m3dVector3D, ByVal Radius As Single) As Boolean            Dim Distance As Single            Dim tCenter As Vector3            tCenter = vCenter.ToVector3            tCenter.TransformCoordinate(ccCore.Device.Transform.World)            For I As Integer = 0 To 5                 Distance = Plane.DotNormal(ccFrustum(I), tCenter)                Debug.WriteLine(Distance)                If Distance < -Radius Then                    Return False                End If            Next            Return True        End Function

void CFrustum::Calculate(const D3DXMATRIX *matView,const D3DXMATRIX *matProj,		const D3DXVECTOR3 &position,const D3DXVECTOR3 &look,float fov,unsigned int screenWidth,unsigned int screenHeight)	{		// Get combined matrix		D3DXMATRIXA16 matComb;		D3DXMatrixMultiply(&matComb, matView, matProj);			// Left clipping plane			m_frustumPlanes[0].m_normal.x = matComb._14 + matComb._11; 		m_frustumPlanes[0].m_normal.y = matComb._24 + matComb._21; 		m_frustumPlanes[0].m_normal.z = matComb._34 + matComb._31; 		m_frustumPlanes[0].m_distance = matComb._44 + matComb._41;		// Right clipping plane 		m_frustumPlanes[1].m_normal.x = matComb._14 - matComb._11; 		m_frustumPlanes[1].m_normal.y = matComb._24 - matComb._21; 		m_frustumPlanes[1].m_normal.z = matComb._34 - matComb._31; 		m_frustumPlanes[1].m_distance = matComb._44 - matComb._41;		// Top clipping plane 		m_frustumPlanes[2].m_normal.x = matComb._14 - matComb._12; 		m_frustumPlanes[2].m_normal.y = matComb._24 - matComb._22; 		m_frustumPlanes[2].m_normal.z = matComb._34 - matComb._32; 		m_frustumPlanes[2].m_distance = matComb._44 - matComb._42;		// Bottom clipping plane 		m_frustumPlanes[3].m_normal.x = matComb._14 + matComb._12; 		m_frustumPlanes[3].m_normal.y = matComb._24 + matComb._22; 		m_frustumPlanes[3].m_normal.z = matComb._34 + matComb._32; 		m_frustumPlanes[3].m_distance = matComb._44 + matComb._42;		// Near clipping plane 		m_frustumPlanes[4].m_normal.x = matComb._13; 		m_frustumPlanes[4].m_normal.y = matComb._23; 		m_frustumPlanes[4].m_normal.z = matComb._33; 		m_frustumPlanes[4].m_distance = matComb._43;		// Far clipping plane 		m_frustumPlanes[5].m_normal.x = matComb._14 - matComb._13; 		m_frustumPlanes[5].m_normal.y = matComb._24 - matComb._23; 		m_frustumPlanes[5].m_normal.z = matComb._34 - matComb._33; 		m_frustumPlanes[5].m_distance = matComb._44 - matComb._43; 		// Normalise them - only needed if later calcs require an accurate distance		for (int i=0;i<6;i++)			m_frustumPlanes.Normalise();			// Calc frustum AABB		// Create some points relative in clip space then transform them on to the far plane		D3DXVECTOR3 p[8];		p[0]=D3DXVECTOR3(-1.0f,1.0f,1.0f);		p[1]=D3DXVECTOR3(-1.0f,-1.0f,1.0f);		p[2]=D3DXVECTOR3(1.0f,-1.0f,1.0f);		p[3]=D3DXVECTOR3(1.0f,1.0f,1.0f);		p[4]=D3DXVECTOR3(-1.0f,1.0f,0.0f);		p[5]=D3DXVECTOR3(-1.0f,-1.0f,0.0f);		p[6]=D3DXVECTOR3(1.0f,-1.0f,0.0f);		p[7]=D3DXVECTOR3(1.0f,1.0f,0.0f);		D3DXMATRIX cameraWorldMatrix;		CMaths::MakeMatrixFor3d(&cameraWorldMatrix,position,D3DXVECTOR3(0,0,0));	   		// Transform to far plane using the inverse combined matrix of proj, view and world		D3DXMATRIXA16 projView;		D3DXMatrixMultiply(&projView, matView, matProj);		D3DXMATRIXA16 projViewWorld;		D3DXMatrixMultiply(&projViewWorld, &projView, &cameraWorldMatrix);						D3DXMATRIXA16 invProjViewWorld;		D3DXMatrixInverse(&invProjViewWorld,NULL,&invProjViewWorld);		D3DXMATRIXA16 invProjView;		D3DXMatrixInverse(&invProjView,NULL,&projView);		D3DXMATRIXA16 final=invProjView;		D3DXVECTOR3 planePnts[8];		for (i=0;i<8;i++)			D3DXVec3TransformCoord(&planePnts, &p, &final);		D3DXVECTOR3 min=position; // defaults		D3DXVECTOR3 max=position;		for (i=0;i<8;i++)		{			min.x=min(min.x,planePnts.x);			min.y=min(min.y,planePnts.y);			min.z=min(min.z,planePnts.z);			max.x=max(max.x,planePnts.x);			max.y=max(max.y,planePnts.y);			max.z=max(max.z,planePnts.z);		}		m_frustumAABB->SetMinimum(min);		m_frustumAABB->SetMaximum(max);		// Calculate bounding sphere - needs to be in centre of frustum with radius that goes to the far corner		// on the far plane		// Centre of sphere is half way between near and far clipping planes along the view vector of the camera		// starting at the camera position		// Calculate the radius of the frustum sphere		float frustumLength=m_frustumPlanes[FAR_CP].m_distance-m_frustumPlanes[NEAR_CP].m_distance;		// Calculate the height of the frustum at that distance, use some trig		// Its a half angle of course		float frustumFarHeight=frustumLength*tan(fov*0.5f);		float frustumFarWidth=frustumFarHeight; // correct when aspect ratio is 1		// Centre point in frustum is half way from near plane along length		D3DXVECTOR3 centre(0.0f,0.0f,m_frustumPlanes[NEAR_CP].m_distance+frustumLength*0.5f);		// Far corner point (top right)		D3DXVECTOR3 farCorner(frustumFarWidth,frustumFarHeight,frustumLength);		// Vector between the far corner and the centre:		D3DXVECTOR3 v=centre-farCorner;		// Radius is length of this vector		float radius=D3DXVec3Length(&v);		// Now get centre of sphere in world space		D3DXVECTOR3 sphereCentre=position+look* ((frustumLength*0.5f)+m_frustumPlanes[NEAR_CP].m_distance);		//_frusSphere.Center() = m_vCameraPosition + (vLookVector * (fViewLen * 0.5f) + m_fNearPlane);		m_frustumSphere->SetCentre(sphereCentre);		m_frustumSphere->SetRadius(radius);		// Calculate the bounding cone		// Its position is simply the position of the camera and its direction is the look		m_frustumCone->SetPosition(position);		m_frustumCone->SetFacing(look);		// The angle is a bit more tricky, if we set it to the same as FOV then the cone will be inside the frustum		// Instead we need it to encompass the corners of the frustum and not just the sides, use trig		// We use the screen sizes to get the angle between the centre of the viewport to the corner of it						float halfScreenHeight=(0.5f*screenHeight);		float halfScreenWidth=(0.5f*screenWidth);		// calculate the length of the fov triangle		float depth  = halfScreenHeight / tan(fov * 0.5f);// calculate the corner of the screen		float corner = sqrt(halfScreenWidth * halfScreenWidth + halfScreenHeight * halfScreenHeight);// now calculate the new fov		float coneFov = atan(corner / depth);		m_frustumCone->SetSpreadAngle(coneFov);	}