Frustum.cpp
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Frustum.cpp
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	/*
	-----------------------------------------------------------------------------
	This source file is part of OGRE
	(Object-oriented Graphics Rendering Engine)
	For the latest info, see http://www.ogre3d.org

	Copyright (c) 2000-2009 Torus Knot Software Ltd

	Permission is hereby granted, free of charge, to any person obtaining a copy
	of this software and associated documentation files (the "Software"), to deal
	in the Software without restriction, including without limitation the rights
	to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
	copies of the Software, and to permit persons to whom the Software is
	furnished to do so, subject to the following conditions:

	The above copyright notice and this permission notice shall be included in
	all copies or substantial portions of the Software.

	THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
	IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
	FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
	AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
	LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
	OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
	THE SOFTWARE.
	-----------------------------------------------------------------------------
	*/
	#include <echo/Graphics/Frustum.h>
	#include <echo/Maths/EchoMaths.h>
	#include <echo/Maths/Matrix3.h>
	#include <echo/Maths/Sphere.h>

	namespace Echo
	{
	const f32 Frustum::INFINITE_FAR_PLANE_ADJUST = 0.00001f;
	//-----------------------------------------------------------------------
	Frustum::Frustum() :
	mProjType(ProjectionTypes::PERSPECTIVE),
	mFOVy(f32(Maths::PI/4.0f)),
	mFarDist(10000.0f),
	mNearDist(1.0f),
	mAspect(1.33333333333333f),
	mOrthoHeight(1000),
	mFrustumOffset(Vector2::ZERO),
	mFocalLength(1.0f),
	mLastParentOrientation(Quaternion::IDENTITY),
	mLastParentPosition(Vector3::ZERO),
	mRecalcFrustum(true),
	mRecalcView(true),
	mRecalcFrustumPlanes(true),
	mRecalcWorldSpaceCorners(true),
	mRecalcVertexData(true),
	mCustomViewMatrix(false),
	mCustomProjMatrix(false),
	mFrustumExtentsManuallySet(false),
	mOrientationMode(OrientationModes::DEGREE_0),
	mReflect(false),
	mObliqueDepthProjection(false)
	{
	mLastLinkedReflectionPlane.normal = Vector3::ZERO;
	mLastLinkedObliqueProjPlane.normal = Vector3::ZERO;

	UpdateView();
	UpdateFrustum();
	}

	//-----------------------------------------------------------------------
	Frustum::~Frustum()
	{
	// Do nothing
	}

	//-----------------------------------------------------------------------
	void Frustum::SetFOVy(const Radian& fov)
	{
	mFOVy = fov;
	InvalidateFrustum();
	}

	//-----------------------------------------------------------------------
	const Radian& Frustum::GetFOVy(void) const
	{
	return mFOVy;
	}

	void Frustum::SetFOV(const Radian& fov)
	{
	assert(mAspect>0.f);
	if(mAspect>0.f)
	{
	SetFOVy(fov/mAspect);
	}
	}

	Radian Frustum::GetFOV() const
	{
	return (mFOVy*mAspect);
	}

	//-----------------------------------------------------------------------
	void Frustum::SetFarPlane(f32 farPlane)
	{
	mFarDist = farPlane;
	InvalidateFrustum();
	}

	//-----------------------------------------------------------------------
	f32 Frustum::GetFarPlane(void) const
	{
	return mFarDist;
	}

	//-----------------------------------------------------------------------
	void Frustum::SetNearPlane(f32 nearPlane)
	{
	assert(nearPlane > 0);
	mNearDist = nearPlane;
	InvalidateFrustum();
	}

	//-----------------------------------------------------------------------
	f32 Frustum::GetNearPlane(void) const
	{
	return mNearDist;
	}

	//---------------------------------------------------------------------
	void Frustum::SetFrustumOffset(const Vector2& offset)
	{
	mFrustumOffset = offset;
	InvalidateFrustum();
	}
	//---------------------------------------------------------------------
	void Frustum::SetFrustumOffset(f32 horizontal, f32 vertical)
	{
	SetFrustumOffset(Vector2(horizontal, vertical));
	}
	//---------------------------------------------------------------------
	const Vector2& Frustum::GetFrustumOffset() const
	{
	return mFrustumOffset;
	}
	//---------------------------------------------------------------------
	void Frustum::SetFocalLength(f32 focalLength)
	{
	assert( focalLength > 0);
	mFocalLength = focalLength;
	InvalidateFrustum();
	}
	//---------------------------------------------------------------------
	f32 Frustum::GetFocalLength() const
	{
	return mFocalLength;
	}
	//-----------------------------------------------------------------------
	const Matrix4& Frustum::GetProjectionMatrix(void) const
	{
	UpdateFrustum();
	return mProjMatrix;
	}

	//-----------------------------------------------------------------------
	const Matrix4& Frustum::GetViewMatrix(void) const
	{
	UpdateView();
	return mViewMatrix;
	}

	//-----------------------------------------------------------------------
	const Frustum::FrustumPlaneArray& Frustum::GetFrustumPlanes(void) const
	{
	// Make any pending updates to the calculated frustum planes
	UpdateFrustumPlanes();

	return mFrustumPlanes;
	}

	//-----------------------------------------------------------------------
	const Plane& Frustum::GetFrustumPlane(unsigned short plane) const
	{
	// Make any pending updates to the calculated frustum planes
	UpdateFrustumPlanes();

	return mFrustumPlanes[plane];

	}

	//-----------------------------------------------------------------------
	bool Frustum::IsVisible(const AxisAlignedBox& bound, FrustumPlane* culledBy) const
	{
	// Null boxes always invisible
	if (bound.isNull()) return false;

	// Infinite boxes always visible
	if (bound.isInfinite()) return true;

	// Make any pending updates to the calculated frustum planes
	UpdateFrustumPlanes();

	// Get centre of the box
	Vector3 centre = bound.GetCenter();
	// Get the half-size of the box
	Vector3 halfSize = bound.getHalfSize();

	// For each plane, see if all points are on the negative side
	// If so, object is not visible
	for (int plane = 0; plane < 6; ++plane)
	{
	// Skip far plane if infinite view frustum
	if (plane == FrustumPlanes::FAR && mFarDist == 0)
	continue;

	Plane::Side side = mFrustumPlanes[plane].getSide(centre, halfSize);
	if (side == Plane::NEGATIVE_SIDE)
	{
	// ALL corners on negative side therefore out of view
	if (culledBy)
	*culledBy = (FrustumPlane)plane;
	return false;
	}

	}

	return true;
	}

	//-----------------------------------------------------------------------
	bool Frustum::IsVisible(const Vector3& vert, FrustumPlane* culledBy) const
	{
	// Make any pending updates to the calculated frustum planes
	UpdateFrustumPlanes();

	// For each plane, see if all points are on the negative side
	// If so, object is not visible
	for (int plane = 0; plane < 6; ++plane)
	{
	// Skip far plane if infinite view frustum
	if (plane == FrustumPlanes::FAR && mFarDist == 0)
	continue;

	if (mFrustumPlanes[plane].getSide(vert) == Plane::NEGATIVE_SIDE)
	{
	// ALL corners on negative side therefore out of view
	if (culledBy)
	*culledBy = (FrustumPlane)plane;
	return false;
	}

	}

	return true;
	}
	//-----------------------------------------------------------------------
	bool Frustum::IsVisible(const Sphere& sphere, FrustumPlane* culledBy) const
	{
	// Make any pending updates to the calculated frustum planes
	UpdateFrustumPlanes();

	// For each plane, see if sphere is on negative side
	// If so, object is not visible
	for (int plane = 0; plane < 6; ++plane)
	{
	// Skip far plane if infinite view frustum
	if (plane == FrustumPlanes::FAR && mFarDist == 0)
	continue;

	// If the distance from sphere center to plane is negative, and 'more negative'
	// than the radius of the sphere, sphere is outside frustum
	if (mFrustumPlanes[plane].getDistance(sphere.getCenter()) < -sphere.getRadius())
	{
	// ALL corners on negative side therefore out of view
	if (culledBy)
	*culledBy = (FrustumPlane)plane;
	return false;
	}

	}

	return true;
	}
	//---------------------------------------------------------------------
	//u32 Frustum::getTypeFlags(void) const
	//{
	// return SceneManager::FRUSTUM_TYPE_MASK;
	//}
	//-----------------------------------------------------------------------
	void Frustum::CalcProjectionParameters(f32& left, f32& right, f32& bottom, f32& top) const
	{
	if (mCustomProjMatrix)
	{
	// Convert clipspace corners to camera space
	Matrix4 invProj = mProjMatrix.inverse();
	Vector3 topLeft(-0.5f, 0.5f, 0.0f);
	Vector3 bottomRight(0.5f, -0.5f, 0.0f);

	topLeft = invProj * topLeft;
	bottomRight = invProj * bottomRight;

	left = topLeft.x;
	top = topLeft.y;
	right = bottomRight.x;
	bottom = bottomRight.y;

	}
	else
	{
	if (mFrustumExtentsManuallySet)
	{
	left = mLeft;
	right = mRight;
	top = mTop;
	bottom = mBottom;
	}
	// Calculate general projection parameters
	else if (mProjType == ProjectionTypes::PERSPECTIVE)
	{
	Radian thetaY (mFOVy * 0.5f);
	f32 tanThetaY = Maths::Tan(thetaY);
	f32 tanThetaX = tanThetaY * mAspect;

	f32 nearFocal = mNearDist / mFocalLength;
	f32 nearOffsetX = mFrustumOffset.x * nearFocal;
	f32 nearOffsetY = mFrustumOffset.y * nearFocal;
	f32 half_w = tanThetaX * mNearDist;
	f32 half_h = tanThetaY * mNearDist;

	left = - half_w + nearOffsetX;
	right = + half_w + nearOffsetX;
	bottom = - half_h + nearOffsetY;
	top = + half_h + nearOffsetY;

	mLeft = left;
	mRight = right;
	mTop = top;
	mBottom = bottom;
	}
	else
	{
	// Unknown how to apply frustum offset to orthographic camera, just ignore here
	f32 half_w = GetOrthoWindowWidth() * 0.5f;
	f32 half_h = GetOrthoWindowHeight() * 0.5f;

	left = - half_w;
	right = + half_w;
	bottom = - half_h;
	top = + half_h;

	mLeft = left;
	mRight = right;
	mTop = top;
	mBottom = bottom;
	}

	}
	}
	//-----------------------------------------------------------------------
	void Frustum::UpdateFrustumImpl(void) const
	{
	// Common calcs
	f32 left, right, bottom, top;
	CalcProjectionParameters(left, right, bottom, top);

	if (!mCustomProjMatrix)
	{

	// The code below will dealing with general projection
	// parameters, similar glFrustum and glOrtho.
	// Doesn't optimise manually except division operator, so the
	// code more self-explaining.

	f32 inv_w = 1 / (right - left);
	f32 inv_h = 1 / (top - bottom);
	f32 inv_d = 1 / (mFarDist - mNearDist);

	// Recalc if frustum params changed
	if (mProjType == ProjectionTypes::PERSPECTIVE)
	{
	// Calc matrix elements
	f32 A = 2 * mNearDist * inv_w;
	f32 B = 2 * mNearDist * inv_h;
	f32 C = (right + left) * inv_w;
	f32 D = (top + bottom) * inv_h;
	f32 q, qn;
	if (mFarDist == 0)
	{
	// Infinite far plane
	q = Frustum::INFINITE_FAR_PLANE_ADJUST - 1;
	qn = mNearDist * (Frustum::INFINITE_FAR_PLANE_ADJUST - 2);
	}
	else
	{
	q = - (mFarDist + mNearDist) * inv_d;
	qn = -2 * (mFarDist * mNearDist) * inv_d;
	}

	// NB: This creates 'uniform' perspective projection matrix,
	// which depth range [-1,1], right-handed rules
	//
	// [ A 0 C 0 ]
	// [ 0 B D 0 ]
	// [ 0 0 q qn ]
	// [ 0 0 -1 0 ]
	//
	// A = 2 * near / (right - left)
	// B = 2 * near / (top - bottom)
	// C = (right + left) / (right - left)
	// D = (top + bottom) / (top - bottom)
	// q = - (far + near) / (far - near)
	// qn = - 2 * (far * near) / (far - near)

	mProjMatrix = Matrix4::ZERO;
	mProjMatrix[0][0] = A;
	mProjMatrix[0][2] = C;
	mProjMatrix[1][1] = B;
	mProjMatrix[1][2] = D;
	mProjMatrix[2][2] = q;
	mProjMatrix[2][3] = qn;
	mProjMatrix[3][2] = -1;

	if (mObliqueDepthProjection)
	{
	// Translate the plane into view space

	// Don't use getViewMatrix here, incase overrided by
	// camera and return a cull frustum view matrix
	UpdateView();
	Plane plane = mViewMatrix * mObliqueProjPlane;

	// Thanks to Eric Lenyel for posting this calculation
	// at www.terathon.com

	// Calculate the clip-space corner point opposite the
	// clipping plane
	// as (sgn(clipPlane.x), sgn(clipPlane.y), 1, 1) and
	// transform it into camera space by multiplying it
	// by the inverse of the projection matrix

	/* generalised version
	Vector4 q = matrix.inverse() *
	Vector4(Maths::Sign(plane.normal.x),
	Maths::Sign(plane.normal.y), 1.0f, 1.0f);
	*/
	Vector4 q;
	q.x = (Maths::Sign(plane.normal.x) + mProjMatrix[0][2]) / mProjMatrix[0][0];
	q.y = (Maths::Sign(plane.normal.y) + mProjMatrix[1][2]) / mProjMatrix[1][1];
	q.z = -1;
	q.w = (1 + mProjMatrix[2][2]) / mProjMatrix[2][3];

	// Calculate the scaled plane vector
	Vector4 clipPlane4d(plane.normal.x, plane.normal.y, plane.normal.z, plane.d);
	Vector4 c = clipPlane4d * (2 / (clipPlane4d.dotProduct(q)));

	// Replace the third row of the projection matrix
	mProjMatrix[2][0] = c.x;
	mProjMatrix[2][1] = c.y;
	mProjMatrix[2][2] = c.z + 1;
	mProjMatrix[2][3] = c.w;
	}
	} // perspective
	else if (mProjType == ProjectionTypes::ORTHOGRAPHIC)
	{
	f32 A = 2 * inv_w;
	f32 B = 2 * inv_h;
	f32 C = - (right + left) * inv_w;
	f32 D = - (top + bottom) * inv_h;
	f32 q, qn;
	if (mFarDist == 0)
	{
	// Can not do infinite far plane here, avoid divided zero only
	q = - Frustum::INFINITE_FAR_PLANE_ADJUST / mNearDist;
	qn = - Frustum::INFINITE_FAR_PLANE_ADJUST - 1;
	}
	else
	{
	q = - 2 * inv_d;
	qn = - (mFarDist + mNearDist) * inv_d;
	}

	// NB: This creates 'uniform' orthographic projection matrix,
	// which depth range [-1,1], right-handed rules
	//
	// [ A 0 0 C ]
	// [ 0 B 0 D ]
	// [ 0 0 q qn ]
	// [ 0 0 0 1 ]
	//
	// A = 2 * / (right - left)
	// B = 2 * / (top - bottom)
	// C = - (right + left) / (right - left)
	// D = - (top + bottom) / (top - bottom)
	// q = - 2 / (far - near)
	// qn = - (far + near) / (far - near)

	mProjMatrix = Matrix4::ZERO;
	mProjMatrix[0][0] = A;
	mProjMatrix[0][3] = C;
	mProjMatrix[1][1] = B;
	mProjMatrix[1][3] = D;
	mProjMatrix[2][2] = q;
	mProjMatrix[2][3] = qn;
	mProjMatrix[3][3] = 1;
	} // ortho
	} // !mCustomProjMatrix

	#if OGRE_NO_VIEWPORT_ORIENTATIONMODE == 0
	// Deal with orientation mode
	mProjMatrix = mProjMatrix * Quaternion(Degree(mOrientationMode * 90.f), Vector3::UNIT_Z);
	#endif

	// Calculate bounding box (local)
	// Box is from 0, down -Z, max dimensions as determined from far plane
	// If infinite view frustum just pick a far value
	f32 farDist = (mFarDist == 0) ? 100000 : mFarDist;
	// Near plane bounds
	Vector3 min(left, bottom, -farDist);
	Vector3 max(right, top, 0);

	if (mCustomProjMatrix)
	{
	// Some custom projection matrices can have unusual inverted settings
	// So make sure the AABB is the right way around to start with
	Vector3 tmp = min;
	min.makeFloor(max);
	max.makeCeil(tmp);
	}

	if (mProjType == ProjectionTypes::PERSPECTIVE)
	{
	// Merge with far plane bounds
	f32 radio = farDist / mNearDist;
	min.makeFloor(Vector3(left * radio, bottom * radio, -farDist));
	max.makeCeil(Vector3(right * radio, top * radio, 0));
	}
	mBoundingBox.setExtents(min, max);

	mRecalcFrustum = false;

	// Signal to update frustum clipping planes
	mRecalcFrustumPlanes = true;
	}
	//-----------------------------------------------------------------------
	void Frustum::UpdateFrustum(void) const
	{
	if (IsFrustumOutOfDate())
	{
	UpdateFrustumImpl();
	}
	}

	//-----------------------------------------------------------------------
	//void Frustum::updateVertexData(void) const
	//{
	// if (mRecalcVertexData)
	// {
	// if (mVertexData.vertexBufferBinding->getBufferCount() <= 0)
	// {
	// // Initialise vertex & index data
	// mVertexData.vertexDeclaration->addElement(0, 0, VET_FLOAT3, VES_POSITION);
	// mVertexData.vertexCount = 32;
	// mVertexData.vertexStart = 0;
	// mVertexData.vertexBufferBinding->setBinding( 0,
	// HardwareBufferManager::getSingleton().createVertexBuffer(
	// sizeof(float)*3, 32, HardwareBuffer::HBU_DYNAMIC_WRITE_ONLY) );
	// }

	// // Note: Even though we can dealing with general projection matrix here,
	// // but because it's incompatibly with infinite far plane, thus, we
	// // still need to working with projection parameters.

	// // Calc near plane corners
	// f32 vpLeft, vpRight, vpBottom, vpTop;
	// calcProjectionParameters(vpLeft, vpRight, vpBottom, vpTop);

	// // Treat infinite fardist as some arbitrary far value
	// f32 farDist = (mFarDist == 0) ? 100000 : mFarDist;

	// // Calc far plane corners
	// f32 radio = mProjType == ProjectionTypes::PERSPECTIVE ? farDist / mNearDist : 1;
	// f32 farLeft = vpLeft * radio;
	// f32 farRight = vpRight * radio;
	// f32 farBottom = vpBottom * radio;
	// f32 farTop = vpTop * radio;

	// // Calculate vertex positions (local)
	// // 0 is the origin
	// // 1, 2, 3, 4 are the points on the near plane, top left first, clockwise
	// // 5, 6, 7, 8 are the points on the far plane, top left first, clockwise
	// HardwareVertexBufferSharedPtr vbuf = mVertexData.vertexBufferBinding->getBuffer(0);
	// float* pFloat = static_cast<float*>(vbuf->lock(HardwareBuffer::HBL_DISCARD));

	// // near plane (remember frustum is going in -Z direction)
	// pFloat++ = vpLeft; pFloat++ = vpTop; *pFloat++ = -mNearDist;
	// pFloat++ = vpRight; pFloat++ = vpTop; *pFloat++ = -mNearDist;

	// pFloat++ = vpRight; pFloat++ = vpTop; *pFloat++ = -mNearDist;
	// pFloat++ = vpRight; pFloat++ = vpBottom; *pFloat++ = -mNearDist;

	// pFloat++ = vpRight; pFloat++ = vpBottom; *pFloat++ = -mNearDist;
	// pFloat++ = vpLeft; pFloat++ = vpBottom; *pFloat++ = -mNearDist;

	// pFloat++ = vpLeft; pFloat++ = vpBottom; *pFloat++ = -mNearDist;
	// pFloat++ = vpLeft; pFloat++ = vpTop; *pFloat++ = -mNearDist;

	// // far plane (remember frustum is going in -Z direction)
	// pFloat++ = farLeft; pFloat++ = farTop; *pFloat++ = -farDist;
	// pFloat++ = farRight; pFloat++ = farTop; *pFloat++ = -farDist;

	// pFloat++ = farRight; pFloat++ = farTop; *pFloat++ = -farDist;
	// pFloat++ = farRight; pFloat++ = farBottom; *pFloat++ = -farDist;

	// pFloat++ = farRight; pFloat++ = farBottom; *pFloat++ = -farDist;
	// pFloat++ = farLeft; pFloat++ = farBottom; *pFloat++ = -farDist;

	// pFloat++ = farLeft; pFloat++ = farBottom; *pFloat++ = -farDist;
	// pFloat++ = farLeft; pFloat++ = farTop; *pFloat++ = -farDist;

	// // Sides of the pyramid
	// pFloat++ = 0.0f; pFloat++ = 0.0f; *pFloat++ = 0.0f;
	// pFloat++ = vpLeft; pFloat++ = vpTop; *pFloat++ = -mNearDist;

	// pFloat++ = 0.0f; pFloat++ = 0.0f; *pFloat++ = 0.0f;
	// pFloat++ = vpRight; pFloat++ = vpTop; *pFloat++ = -mNearDist;

	// pFloat++ = 0.0f; pFloat++ = 0.0f; *pFloat++ = 0.0f;
	// pFloat++ = vpRight; pFloat++ = vpBottom; *pFloat++ = -mNearDist;

	// pFloat++ = 0.0f; pFloat++ = 0.0f; *pFloat++ = 0.0f;
	// pFloat++ = vpLeft; pFloat++ = vpBottom; *pFloat++ = -mNearDist;

	// // Sides of the box

	// pFloat++ = vpLeft; pFloat++ = vpTop; *pFloat++ = -mNearDist;
	// pFloat++ = farLeft; pFloat++ = farTop; *pFloat++ = -farDist;

	// pFloat++ = vpRight; pFloat++ = vpTop; *pFloat++ = -mNearDist;
	// pFloat++ = farRight; pFloat++ = farTop; *pFloat++ = -farDist;

	// pFloat++ = vpRight; pFloat++ = vpBottom; *pFloat++ = -mNearDist;
	// pFloat++ = farRight; pFloat++ = farBottom; *pFloat++ = -farDist;

	// pFloat++ = vpLeft; pFloat++ = vpBottom; *pFloat++ = -mNearDist;
	// pFloat++ = farLeft; pFloat++ = farBottom; *pFloat++ = -farDist;


	// vbuf->unlock();

	// mRecalcVertexData = false;
	// }
	//}

	//-----------------------------------------------------------------------
	bool Frustum::IsViewOutOfDate(void) const
	{
	// Attached to node?
	//if (mParentNode)
	//{
	// if (mRecalcView \|\|
	// mParentNode->_getDerivedOrientation() != mLastParentOrientation \|\|
	// mParentNode->_getDerivedPosition() != mLastParentPosition)
	// {
	// // Ok, we're out of date with SceneNode we're attached to
	// mLastParentOrientation = mParentNode->_getDerivedOrientation();
	// mLastParentPosition = mParentNode->_getDerivedPosition();
	// mRecalcView = true;
	// }
	//}
	//// Deriving reflection from linked plane?
	//if (mLinkedReflectPlane &&
	// !(mLastLinkedReflectionPlane == mLinkedReflectPlane->_getDerivedPlane()))
	//{
	// mReflectPlane = mLinkedReflectPlane->_getDerivedPlane();
	// mReflectMatrix = Maths::buildReflectionMatrix(mReflectPlane);
	// mLastLinkedReflectionPlane = mLinkedReflectPlane->_getDerivedPlane();
	// mRecalcView = true;
	//}

	return mRecalcView;
	}

	//-----------------------------------------------------------------------
	bool Frustum::IsFrustumOutOfDate(void) const
	{
	// Deriving custom near plane from linked plane?
	if (mObliqueDepthProjection)
	{
	// Out of date when view out of data since plane needs to be in view space
	if (IsViewOutOfDate())
	{
	mRecalcFrustum = true;
	}
	// Update derived plane
	//if (mLinkedObliqueProjPlane &&
	// !(mLastLinkedObliqueProjPlane == mLinkedObliqueProjPlane->_getDerivedPlane()))
	//{
	// mObliqueProjPlane = mLinkedObliqueProjPlane->_getDerivedPlane();
	// mLastLinkedObliqueProjPlane = mObliqueProjPlane;
	// mRecalcFrustum = true;
	//}
	}

	return mRecalcFrustum;
	}

	//-----------------------------------------------------------------------
	void Frustum::UpdateViewImpl(void) const
	{
	// ----------------------
	// Update the view matrix
	// ----------------------

	// Get orientation from quaternion

	if (!mCustomViewMatrix)
	{
	Matrix3 rot;
	const Quaternion& orientation = GetOrientationForViewUpdate();
	const Vector3& position = GetPositionForViewUpdate();

	mViewMatrix = Maths::makeViewMatrix(position, orientation, mReflect? &mReflectMatrix : 0);
	}

	mRecalcView = false;

	// Signal to update frustum clipping planes
	mRecalcFrustumPlanes = true;
	// Signal to update world space corners
	mRecalcWorldSpaceCorners = true;
	// Signal to update frustum if oblique plane enabled,
	// since plane needs to be in view space
	if (mObliqueDepthProjection)
	{
	mRecalcFrustum = true;
	}
	}
	//---------------------------------------------------------------------
	void Frustum::CalcViewMatrixRelative(const Vector3& relPos, Matrix4& matToUpdate) const
	{
	Matrix4 matTrans = Matrix4::IDENTITY;
	matTrans.setTrans(relPos);
	matToUpdate = GetViewMatrix() * matTrans;

	}
	//-----------------------------------------------------------------------
	void Frustum::UpdateView(void) const
	{
	if (IsViewOutOfDate())
	{
	UpdateViewImpl();
	}
	}

	//-----------------------------------------------------------------------
	void Frustum::UpdateFrustumPlanesImpl(void) const
	{
	// -------------------------
	// Update the frustum planes
	// -------------------------
	Matrix4 combo = mProjMatrix * mViewMatrix;

	mFrustumPlanes[FrustumPlanes::LEFT].normal.x = combo[3][0] + combo[0][0];
	mFrustumPlanes[FrustumPlanes::LEFT].normal.y = combo[3][1] + combo[0][1];
	mFrustumPlanes[FrustumPlanes::LEFT].normal.z = combo[3][2] + combo[0][2];
	mFrustumPlanes[FrustumPlanes::LEFT].d = combo[3][3] + combo[0][3];

	mFrustumPlanes[FrustumPlanes::RIGHT].normal.x = combo[3][0] - combo[0][0];
	mFrustumPlanes[FrustumPlanes::RIGHT].normal.y = combo[3][1] - combo[0][1];
	mFrustumPlanes[FrustumPlanes::RIGHT].normal.z = combo[3][2] - combo[0][2];
	mFrustumPlanes[FrustumPlanes::RIGHT].d = combo[3][3] - combo[0][3];

	mFrustumPlanes[FrustumPlanes::TOP].normal.x = combo[3][0] - combo[1][0];
	mFrustumPlanes[FrustumPlanes::TOP].normal.y = combo[3][1] - combo[1][1];
	mFrustumPlanes[FrustumPlanes::TOP].normal.z = combo[3][2] - combo[1][2];
	mFrustumPlanes[FrustumPlanes::TOP].d = combo[3][3] - combo[1][3];

	mFrustumPlanes[FrustumPlanes::BOTTOM].normal.x = combo[3][0] + combo[1][0];
	mFrustumPlanes[FrustumPlanes::BOTTOM].normal.y = combo[3][1] + combo[1][1];
	mFrustumPlanes[FrustumPlanes::BOTTOM].normal.z = combo[3][2] + combo[1][2];
	mFrustumPlanes[FrustumPlanes::BOTTOM].d = combo[3][3] + combo[1][3];

	mFrustumPlanes[FrustumPlanes::NEAR].normal.x = combo[3][0] + combo[2][0];
	mFrustumPlanes[FrustumPlanes::NEAR].normal.y = combo[3][1] + combo[2][1];
	mFrustumPlanes[FrustumPlanes::NEAR].normal.z = combo[3][2] + combo[2][2];
	mFrustumPlanes[FrustumPlanes::NEAR].d = combo[3][3] + combo[2][3];

	mFrustumPlanes[FrustumPlanes::FAR].normal.x = combo[3][0] - combo[2][0];
	mFrustumPlanes[FrustumPlanes::FAR].normal.y = combo[3][1] - combo[2][1];
	mFrustumPlanes[FrustumPlanes::FAR].normal.z = combo[3][2] - combo[2][2];
	mFrustumPlanes[FrustumPlanes::FAR].d = combo[3][3] - combo[2][3];

	// Renormalise any normals which were not unit length
	for(int i=0; i<6; i++ )
	{
	f32 length = mFrustumPlanes[i].normal.Normalise();
	mFrustumPlanes[i].d /= length;
	}

	mRecalcFrustumPlanes = false;
	}
	//-----------------------------------------------------------------------
	void Frustum::UpdateFrustumPlanes(void) const
	{
	UpdateView();
	UpdateFrustum();

	if (mRecalcFrustumPlanes)
	{
	UpdateFrustumPlanesImpl();
	}
	}
	//-----------------------------------------------------------------------
	void Frustum::UpdateWorldSpaceCornersImpl(void) const
	{
	Matrix4 eyeToWorld = mViewMatrix.inverseAffine();

	// Note: Even though we can dealing with general projection matrix here,
	// but because it's incompatibly with infinite far plane, thus, we
	// still need to working with projection parameters.

	// Calc near plane corners
	f32 nearLeft, nearRight, nearBottom, nearTop;
	CalcProjectionParameters(nearLeft, nearRight, nearBottom, nearTop);

	// Treat infinite fardist as some arbitrary far value
	f32 farDist = (mFarDist == 0) ? 100000 : mFarDist;

	// Calc far palne corners
	f32 radio = mProjType == ProjectionTypes::PERSPECTIVE ? farDist / mNearDist : 1;
	f32 farLeft = nearLeft * radio;
	f32 farRight = nearRight * radio;
	f32 farBottom = nearBottom * radio;
	f32 farTop = nearTop * radio;

	// near
	mWorldSpaceCorners[0] = eyeToWorld.transformAffine(Vector3(nearRight, nearTop, -mNearDist));
	mWorldSpaceCorners[1] = eyeToWorld.transformAffine(Vector3(nearLeft, nearTop, -mNearDist));
	mWorldSpaceCorners[2] = eyeToWorld.transformAffine(Vector3(nearLeft, nearBottom, -mNearDist));
	mWorldSpaceCorners[3] = eyeToWorld.transformAffine(Vector3(nearRight, nearBottom, -mNearDist));
	// far
	mWorldSpaceCorners[4] = eyeToWorld.transformAffine(Vector3(farRight, farTop, -farDist));
	mWorldSpaceCorners[5] = eyeToWorld.transformAffine(Vector3(farLeft, farTop, -farDist));
	mWorldSpaceCorners[6] = eyeToWorld.transformAffine(Vector3(farLeft, farBottom, -farDist));
	mWorldSpaceCorners[7] = eyeToWorld.transformAffine(Vector3(farRight, farBottom, -farDist));


	mRecalcWorldSpaceCorners = false;
	}
	//-----------------------------------------------------------------------
	void Frustum::UpdateWorldSpaceCorners(void) const
	{
	UpdateView();

	if (mRecalcWorldSpaceCorners)
	{
	UpdateWorldSpaceCornersImpl();
	}

	}

	//-----------------------------------------------------------------------
	f32 Frustum::GetAspectRatio(void) const
	{
	return mAspect;
	}

	//-----------------------------------------------------------------------
	void Frustum::SetAspectRatio(f32 r)
	{
	mAspect = r;
	InvalidateFrustum();
	}

	// -------------------------------------------------------------------
	void Frustum::InvalidateFrustum() const
	{
	mRecalcFrustum = true;
	mRecalcFrustumPlanes = true;
	mRecalcWorldSpaceCorners = true;
	mRecalcVertexData = true;
	}
	// -------------------------------------------------------------------
	void Frustum::InvalidateView() const
	{
	mRecalcView = true;
	mRecalcFrustumPlanes = true;
	mRecalcWorldSpaceCorners = true;
	}
	// -------------------------------------------------------------------
	const Frustum::WorldSpaceCorners& Frustum::GetWorldSpaceCorners(void) const
	{
	UpdateWorldSpaceCorners();

	return mWorldSpaceCorners;
	}
	//-----------------------------------------------------------------------
	void Frustum::SetProjectionType(ProjectionType pt)
	{
	mProjType = pt;
	InvalidateFrustum();
	}

	//-----------------------------------------------------------------------
	ProjectionType Frustum::GetProjectionType(void) const
	{
	return mProjType;
	}
	//-----------------------------------------------------------------------
	const Vector3& Frustum::GetPositionForViewUpdate(void) const
	{
	return mLastParentPosition;
	}
	//-----------------------------------------------------------------------
	const Quaternion& Frustum::GetOrientationForViewUpdate(void) const
	{
	return mLastParentOrientation;
	}
	//-----------------------------------------------------------------------
	void Frustum::EnableReflection(const Plane& p)
	{
	mReflect = true;
	mReflectPlane = p;
	//mLinkedReflectPlane = 0;
	mReflectMatrix = Maths::buildReflectionMatrix(p);
	InvalidateView();

	}
	////-----------------------------------------------------------------------
	//void Frustum::enableReflection(const MovablePlane* p)
	//{
	// mReflect = true;
	// mLinkedReflectPlane = p;
	// mReflectPlane = mLinkedReflectPlane->_getDerivedPlane();
	// mReflectMatrix = Maths::buildReflectionMatrix(mReflectPlane);
	// mLastLinkedReflectionPlane = mLinkedReflectPlane->_getDerivedPlane();
	// invalidateView();
	//}
	//-----------------------------------------------------------------------
	void Frustum::DisableReflection(void)
	{
	mReflect = false;
	//mLinkedReflectPlane = 0;
	mLastLinkedReflectionPlane.normal = Vector3::ZERO;
	InvalidateView();
	}
	//---------------------------------------------------------------------
	bool Frustum::ProjectSphere(const Sphere& sphere,
	f32* left, f32* top, f32* right, f32* bottom) const
	{
	// See http://www.gamasutra.com/features/20021011/lengyel_06.htm
	// Transform light position into camera space

	UpdateView();
	Vector3 eyeSpacePos = mViewMatrix.transformAffine(sphere.getCenter());

	// initialise
	left = bottom = -1.0f;
	right = top = 1.0f;

	if (eyeSpacePos.z < 0)
	{
	UpdateFrustum();
	const Matrix4& projMatrix = GetProjectionMatrix();
	f32 r = sphere.getRadius();
	f32 rsq = r * r;

	// early-exit
	if (eyeSpacePos.LengthSquared() <= rsq)
	return false;

	f32 Lxz = Maths::Sqr(eyeSpacePos.x) + Maths::Sqr(eyeSpacePos.z);
	f32 Lyz = Maths::Sqr(eyeSpacePos.y) + Maths::Sqr(eyeSpacePos.z);

	// Find the tangent planes to the sphere
	// XZ first
	// calculate quadratic discriminant: b*b - 4ac
	// x = Nx
	// a = Lx^2 + Lz^2
	// b = -2rLx
	// c = r^2 - Lz^2
	f32 a = Lxz;
	f32 b = -2.0f * r * eyeSpacePos.x;
	f32 c = rsq - Maths::Sqr(eyeSpacePos.z);
	f32 D = bb - 4.0fa*c;

	// two roots?
	if (D > 0)
	{
	f32 sqrootD = Maths::Sqrt(D);
	// solve the quadratic to get the components of the normal
	f32 Nx0 = (-b + sqrootD) / (2 * a);
	f32 Nx1 = (-b - sqrootD) / (2 * a);

	// Derive Z from this
	f32 Nz0 = (r - Nx0 * eyeSpacePos.x) / eyeSpacePos.z;
	f32 Nz1 = (r - Nx1 * eyeSpacePos.x) / eyeSpacePos.z;

	// Get the point of tangency
	// Only consider points of tangency in front of the camera
	f32 Pz0 = (Lxz - rsq) / (eyeSpacePos.z - ((Nz0 / Nx0) * eyeSpacePos.x));
	if (Pz0 < 0)
	{
	// Project point onto near plane in worldspace
	f32 nearx0 = (Nz0 * mNearDist) / Nx0;
	// now we need to map this to viewport coords
	// use projection matrix since that will take into account all factors
	Vector3 relx0 = projMatrix * Vector3(nearx0, 0, -mNearDist);

	// find out whether this is a left side or right side
	f32 Px0 = -(Pz0 * Nz0) / Nx0;
	if (Px0 > eyeSpacePos.x)
	{
	right = std::min(right, relx0.x);
	}
	else
	{
	left = std::max(left, relx0.x);
	}
	}
	f32 Pz1 = (Lxz - rsq) / (eyeSpacePos.z - ((Nz1 / Nx1) * eyeSpacePos.x));
	if (Pz1 < 0)
	{
	// Project point onto near plane in worldspace
	f32 nearx1 = (Nz1 * mNearDist) / Nx1;
	// now we need to map this to viewport coords
	// use projection matrix since that will take into account all factors
	Vector3 relx1 = projMatrix * Vector3(nearx1, 0, -mNearDist);

	// find out whether this is a left side or right side
	f32 Px1 = -(Pz1 * Nz1) / Nx1;
	if (Px1 > eyeSpacePos.x)
	{
	right = std::min(right, relx1.x);
	}
	else
	{
	left = std::max(left, relx1.x);
	}
	}
	}


	// Now YZ
	// calculate quadratic discriminant: b*b - 4ac
	// x = Ny
	// a = Ly^2 + Lz^2
	// b = -2rLy
	// c = r^2 - Lz^2
	a = Lyz;
	b = -2.0f * r * eyeSpacePos.y;
	c = rsq - Maths::Sqr(eyeSpacePos.z);
	D = bb - 4.0fa*c;

	// two roots?
	if (D > 0)
	{
	f32 sqrootD = Maths::Sqrt(D);
	// solve the quadratic to get the components of the normal
	f32 Ny0 = (-b + sqrootD) / (2 * a);
	f32 Ny1 = (-b - sqrootD) / (2 * a);

	// Derive Z from this
	f32 Nz0 = (r - Ny0 * eyeSpacePos.y) / eyeSpacePos.z;
	f32 Nz1 = (r - Ny1 * eyeSpacePos.y) / eyeSpacePos.z;

	// Get the point of tangency
	// Only consider points of tangency in front of the camera
	f32 Pz0 = (Lyz - rsq) / (eyeSpacePos.z - ((Nz0 / Ny0) * eyeSpacePos.y));
	if (Pz0 < 0)
	{
	// Project point onto near plane in worldspace
	f32 neary0 = (Nz0 * mNearDist) / Ny0;
	// now we need to map this to viewport coords
	// use projection matriy since that will take into account all factors
	Vector3 rely0 = projMatrix * Vector3(0, neary0, -mNearDist);

	// find out whether this is a top side or bottom side
	f32 Py0 = -(Pz0 * Nz0) / Ny0;
	if (Py0 > eyeSpacePos.y)
	{
	top = std::min(top, rely0.y);
	}
	else
	{
	bottom = std::max(bottom, rely0.y);
	}
	}
	f32 Pz1 = (Lyz - rsq) / (eyeSpacePos.z - ((Nz1 / Ny1) * eyeSpacePos.y));
	if (Pz1 < 0)
	{
	// Project point onto near plane in worldspace
	f32 neary1 = (Nz1 * mNearDist) / Ny1;
	// now we need to map this to viewport coords
	// use projection matriy since that will take into account all factors
	Vector3 rely1 = projMatrix * Vector3(0, neary1, -mNearDist);

	// find out whether this is a top side or bottom side
	f32 Py1 = -(Pz1 * Nz1) / Ny1;
	if (Py1 > eyeSpacePos.y)
	{
	top = std::min(top, rely1.y);
	}
	else
	{
	bottom = std::max(bottom, rely1.y);
	}
	}
	}
	}

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

	}

	void Frustum::EnableCustomNearClipPlane(const Plane& plane)
	{
	mObliqueDepthProjection = true;
	// mLinkedObliqueProjPlane = 0;
	mObliqueProjPlane = plane;
	InvalidateFrustum();
	}
	//---------------------------------------------------------------------
	void Frustum::DisableCustomNearClipPlane(void)
	{
	mObliqueDepthProjection = false;
	// mLinkedObliqueProjPlane = 0;
	InvalidateFrustum();
	}
	//---------------------------------------------------------------------
	void Frustum::SetCustomViewMatrix(bool enable, const Matrix4& viewMatrix)
	{
	mCustomViewMatrix = enable;
	if (enable)
	{
	assert(viewMatrix.isAffine());
	mViewMatrix = viewMatrix;
	}
	InvalidateView();
	}
	//---------------------------------------------------------------------
	void Frustum::SetCustomProjectionMatrix(bool enable, const Matrix4& projMatrix)
	{
	mCustomProjMatrix = enable;
	if (enable)
	{
	mProjMatrix = projMatrix;
	}
	InvalidateFrustum();
	}
	//---------------------------------------------------------------------
	void Frustum::SetOrthoWindow(f32 w, f32 h)
	{
	mOrthoHeight = h;
	mAspect = w / h;
	InvalidateFrustum();
	}
	//---------------------------------------------------------------------
	void Frustum::SetOrthoWindowHeight(f32 h)
	{
	mOrthoHeight = h;
	InvalidateFrustum();
	}
	//---------------------------------------------------------------------
	void Frustum::SetOrthoWindowWidth(f32 w)
	{
	mOrthoHeight = w / mAspect;
	InvalidateFrustum();
	}
	//---------------------------------------------------------------------
	f32 Frustum::GetOrthoWindowHeight() const
	{
	return mOrthoHeight;
	}
	//---------------------------------------------------------------------
	f32 Frustum::GetOrthoWindowWidth() const
	{
	return mOrthoHeight * mAspect;
	}

	void Frustum::SetFrustumExtents(f32 left, f32 right, f32 top, f32 bottom)
	{
	mFrustumExtentsManuallySet = true;
	mLeft = left;
	mRight = right;
	mTop = top;
	mBottom = bottom;

	InvalidateFrustum();
	}

	void Frustum::ResetFrustumExtents()
	{
	mFrustumExtentsManuallySet = false;
	InvalidateFrustum();
	}
	//---------------------------------------------------------------------
	void Frustum::GetFrustumExtents(f32& outleft, f32& outright, f32& outtop, f32& outbottom) const
	{
	UpdateFrustum();
	outleft = mLeft;
	outright = mRight;
	outtop = mTop;
	outbottom = mBottom;
	}

	void Frustum::SetOrientationMode(OrientationMode orientationMode)
	{
	mOrientationMode = orientationMode;
	InvalidateFrustum();
	}
	//---------------------------------------------------------------------
	OrientationMode Frustum::GetOrientationMode() const
	{
	return mOrientationMode;
	}
	}

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