Camera.cpp

#include "Camera.h"


Camera::Camera():mPosition(0.0f,0.0f,0.0f),mRight(1.0f,0.0f,0.0f),mUp(0.0f,1.0f,0.0f),mLook(0.0f,0.0f,1.0f)
{
	SetLens(0.25f*MathHelper::Pi,1.0f,1.0f,1000.0f);
}


Camera::~Camera(void)
{
}

XMVECTOR Camera::GetPositionXM()const
{
	return XMLoadFloat3(&mPosition);
}

XMFLOAT3 Camera::GetPosition()const
{
	return mPosition;
}

void Camera::SetPosition(float x, float y, float z)
{
	mPosition = XMFLOAT3(x,y,z);
}

void Camera::SetPosition(const XMFLOAT3&  v)
{
	mPosition = v;
}

XMVECTOR Camera::GetRightXM()const 
{
	return XMLoadFloat3(&mRight);
}

XMVECTOR Camera::GetUpXM()const 
{
	return XMLoadFloat3(&mUp);
}

XMFLOAT3 Camera::GetUp()const
{
	return mUp;
}

XMVECTOR Camera::GetLookXM()const
{
	return XMLoadFloat3(&mLook);
}

XMFLOAT3 Camera::GetLook()const
{
	return mLook;
}

float Camera::GetNearZ()const
{
	return mNearZ;
}

float Camera::GetFarZ()const
{
	return mFarZ;
}

float Camera::GetAspect()const 
{
	return mAspect;
}

float Camera::GetFovY()const
{
	return mFovY;
}

float Camera::GetFovX()const
{
	float halfWidth = 0.5f*GetNearWindowWidth();
	return 2.0f*atan(halfWidth/mNearZ);
}

float Camera::GetNearWindowWidth()const
{
	return mAspect*mNearWindowHeight;
}

float Camera::GetNearWindowHeight()const
{
	return mNearWindowHeight;
}

float Camera::GetFarWindowWidth()const
{
	return mAspect*mFarWindowHeight;
}

float Camera::GetFarWindowHeight()const
{
	return mFarWindowHeight;
}

void Camera::SetLens(float fovY,float aspect,float zn,float zf)
{
	mFovY = fovY;
	mAspect = aspect;
	mNearZ = zn;
	mFarZ = zf;

	mNearWindowHeight = 2.0f*mNearZ*tanf(0.5f*mFovY);
	mFarWindowHeight = 2.0f*mFarZ*tanf(0.5f*mFovY);

	//投影矩阵需要的四个参数
	XMMATRIX P = XMMatrixPerspectiveFovLH(mFovY,mAspect,mNearZ,mFarZ);
	XMStoreFloat4x4(&mProj,P);
}

void Camera::LookAt(FXMVECTOR pos, FXMVECTOR target, FXMVECTOR worldUp)
{
	XMVECTOR L = XMVector3Normalize(XMVectorSubtract(target,pos));
	XMVECTOR R = XMVector3Normalize(XMVector3Cross(worldUp,L));
	XMVECTOR U = XMVector3Cross(L,R);

	XMStoreFloat3(&mPosition,pos);
	XMStoreFloat3(&mLook,L);
	XMStoreFloat3(&mRight,R);
	XMStoreFloat3(&mUp,U);
}

void Camera::LookAt(const XMFLOAT3& pos,const XMFLOAT3& target, const XMFLOAT3& up)
{
	XMVECTOR P = XMLoadFloat3(&pos);
	XMVECTOR T = XMLoadFloat3(&target);
	XMVECTOR U = XMLoadFloat3(&up);

	LookAt(P,T,U);
}

XMMATRIX Camera::View()const
{
	return XMLoadFloat4x4(&mView);
}

XMMATRIX Camera::Proj()const
{
	return XMLoadFloat4x4(&mProj);
}

XMMATRIX Camera::ViewProj()const
{
	return XMMatrixMultiply(View(),Proj());
}

//横向移动镜头
void Camera::Strafe(float d)
{
	// mPosition += d*mRight
	XMVECTOR s = XMVectorReplicate(d);
	XMVECTOR r = XMLoadFloat3(&mRight);
	XMVECTOR p = XMLoadFloat3(&mPosition);

	XMStoreFloat3(&mPosition,XMVectorMultiplyAdd(s,r,p));
}

void Camera::Walk(float d)
{
	// mPosition += d*mLook
	XMVECTOR s = XMVectorReplicate(d);
	XMVECTOR l = XMLoadFloat3(&mLook);
	XMVECTOR p = XMLoadFloat3(&mPosition);
	
	XMStoreFloat3(&mPosition,XMVectorMultiplyAdd(s,l,p));
}

void Camera::Pitch(float angle)
{
	//根据right向量旋转up和look向量
	XMMATRIX R = XMMatrixRotationAxis(XMLoadFloat3(&mRight),angle);

	XMStoreFloat3(&mUp,XMVector3TransformNormal(XMLoadFloat3(&mUp),R));

	XMStoreFloat3(&mLook, XMVector3TransformNormal(XMLoadFloat3(&mLook),R));
}

void Camera::RotateY(float angle)
{
	XMMATRIX R = XMMatrixRotationY(angle);

	XMStoreFloat3(&mRight,XMVector3TransformNormal(XMLoadFloat3(&mRight),R));
	XMStoreFloat3(&mUp,XMVector3TransformNormal(XMLoadFloat3(&mLook),R));
	XMStoreFloat3(&mLook,XMVector3TransformNormal(XMLoadFloat3(&mLook),R));
}

void Camera::UpdateViewMatrix()
{
	XMVECTOR R = XMLoadFloat3(&mRight);
	XMVECTOR U = XMLoadFloat3(&mUp);
	XMVECTOR L = XMLoadFloat3(&mLook);
	XMVECTOR P = XMLoadFloat3(&mPosition);

	//保持镜头的各个轴都垂直，并且是单位长度
	L = XMVector3Normalize(L);
	U = XMVector3Normalize(XMVector3Cross(L,R));

	R = XMVector3Cross(U,L);

	//获得视图矩阵的原点
	float x = -XMVectorGetX(XMVector3Dot(P,R));
	float y = -XMVectorGetX(XMVector3Dot(P,U));
	float z = -XMVectorGetX(XMVector3Dot(P,L));

	XMStoreFloat3(&mRight,R);
	XMStoreFloat3(&mUp,U);
	XMStoreFloat3(&mLook,L);

	mView(0,0) = mRight.x;
	mView(1,0) = mRight.y;
	mView(2,0) = mRight.z;
	mView(3,0) = x;

	mView(0,1) = mUp.x;
	mView(1,1) = mUp.y;
	mView(2,1) = mUp.z;
	mView(3,1) = y;

	mView(0,2) = mLook.x;
	mView(1,2) = mLook.y;
	mView(2,2) = mLook.z;
	mView(3,2) = z;

	mView(0,3) = 0.0f;
	mView(1,3) = 0.0f;
	mView(2,3) = 0.0f;
	mView(3,3) = 1.0f;
}