第10讲摄像机漫游

1、摄像机漫游设置观察矩阵代码：/建立并设置观察矩阵D3DXVECTOR3 vEyePt( 0.0f,0.0f,-15.0f );D3DXVECTOR3 vLookatPt( 0.0f, 0.0f, 0.0f );D3DXVECTOR3 vUpVec( 0.0f, 1.0f, 0.0f );D3DXMATRIX matView;D3DXMatrixLookAtLH( &matView, &vEyePt, &vLookatPt, &vUpVec );g_pd3dDevice-SetTransform( D3DTS_VIEW, &matView );观察变换-摄像机属性通常用四个分量来确定一个摄像机相

2、对于世界坐标系的位置和朝向：左分量、上分量、观察分量和位置分量。在世界坐标系中，这几个分量都通过向量表示，并且实际上它们为摄像机定义了一个局部坐标系，需要将世界坐标系中的物体随着摄像机一起进行变换，以便让摄像机的坐标系与世界坐标系完全重合摄像机变换 1沿各分量平移由于摄像机包含向右、向上、观察三个分量，因此可以控制摄像机分别沿这三个分量进行平移。其中，沿右分量的平移称作扫视，沿上分量的平移称作升降，而沿观察分量的平移称作平动，如图所示 2绕各分量旋转摄像机的另一种变换是分别绕上分量、右分量和观察分量进行旋转。其中，绕上分量的旋转称作偏航，绕右分量的旋转称作俯仰，而绕观察分量的旋转称作滚动，如图

3、所示 3绕观察点旋转摄像机的平移和旋转已经能够满足简单的应用，但是有时候还需要将观察点固定，并控制摄像机围绕该点做圆周运动，以便能够从不同角度观察同一物体。因此，还需要让摄像机绕某个点进行旋转，如图所示以摄像机在y方向上绕点l=(lx,ly,lz)旋转为例，假设当前摄像机位于p点（观察点l与p点同在y平面内），那么当摄像机按逆时针方向旋转a 角度后应该位于p点，如图所示。/摄像机绕Y轴旋转fAngle角度VOID CCamera:CircleRotationY(FLOAT fAngle) D3DXMATRIX R; D3DXMatrixRotationAxis(&R, &m_vUpVec, f

4、Angle); D3DXVec3TransformCoord(&m_vRightVec, &m_vRightVec, &R); D3DXVec3TransformCoord(&m_vLookVec, &m_vLookVec, &R); float dx = m_vPosition.x - m_vLookat.x; float dz = m_vPosition.z - m_vLookat.z; m_vPosition.x = m_vLookat.x + dx * cosf(fAngle) - dz * sinf(fAngle); m_vPosition.z = m_vLookat.z + dx

5、* sinf(fAngle) + dz * cosf(fAngle); ResetLookatPos(&m_vLookat);根据上面介绍的内容，可以定义一个具有九个自由度的摄像机CCamera类，其中可以沿三个分量平移、绕三个分量旋转，以及在三个坐标方向上绕观察点旋转。4CCamera类定义#pragma once#include #include /-/ Name: class CCamera/ Desc: 虚拟摄像机平移、旋转/-class CCameraprivate: D3DXVECTOR3 m_vRightVec; / 摄像机右侧向量 D3DXVECTOR3 m_vUpVec; /

6、 摄像机上方向量 D3DXVECTOR3 m_vLookVec; /摄像机视线方向 D3DXVECTOR3 m_vPosition; / 摄像机当前位置 D3DXMATRIX m_matView; / 摄像机矩阵 D3DXMATRIX m_matProj; / 投影矩阵 D3DXVECTOR3 m_vLookat; /摄像机视线位置 LPDIRECT3DDEVICE9 m_pd3dDevice;public: CCamera(IDirect3DDevice9 *pd3dDevice); virtual CCamera(void);public: VOID GetViewMatrix(D3DXM

7、ATRIX *pMatrix);/获取摄像机矩阵 VOID GetProjMatrix(D3DXMATRIX *pMatrix) *pMatrix = m_matProj; VOID GetCameraPos(D3DXVECTOR3 *pVector) *pVector = m_vPosition; VOID GetLookVector(D3DXVECTOR3 *pVector) *pVector = m_vLookVec; VOID ResetLookatPos(D3DXVECTOR3 *pLookat = NULL);/设置视线位置 VOID ResetCameraPos(D3DXVECT

8、OR3 *pVector = NULL);/设置摄像机位置 VOID ResetViewMatrix(D3DXMATRIX *pMatrix = NULL);/设置摄像机(观察)矩阵 VOID ResetProjMatrix(D3DXMATRIX *pMatrix = NULL);/设置投影矩阵public: / 沿各分量平移 VOID MoveAlongRightVec(FLOAT fUnits); / 沿right向量移动 VOID MoveAlongUpVec(FLOAT fUnits); / 沿up向量移动 VOID MoveAlongLookVec(FLOAT fUnits); /

9、沿look向量移动 / 绕各分量旋转 VOID RotationRightVec(FLOAT fAngle); / 绕right向量选择 VOID RotationUpVec(FLOAT fAngle); / 绕up向量旋转 VOID RotationLookVec(FLOAT fAngle); / 绕look向量旋转 / 绕空间点旋转 VOID CircleRotationX(FLOAT fAngle); / 在X方向上绕观察点旋转 VOID CircleRotationY(FLOAT fAngle); / 在Y方向上绕观察点旋转 VOID CircleRotationZ(FLOAT fAn

10、gle); / 在Z方向上绕观察点旋转;5、摄像机类CCamera类的实现#include Camera.h#include CCamera:CCamera(IDirect3DDevice9 *pd3dDevice) m_pd3dDevice = pd3dDevice; m_vRightVec = D3DXVECTOR3(1.0f, 0.0f, 0.0f); / 默认右向量与X正半轴重合 m_vUpVec = D3DXVECTOR3(0.0f, 1.0f, 0.0f); / 默认上向量与Y正半轴重合 m_vLookVec = D3DXVECTOR3(0.0f, 0.0f, 1.0f); / 默

11、认观察向量与Z正半轴重合 m_vPosition = D3DXVECTOR3(0.0f, 0.0f, 0.0f); / 默认摄像机的位置为原点 m_vLookat = D3DXVECTOR3(0.0f, 0.0f, 0.0f); GetViewMatrix(&m_matView); / 取得取景变换矩阵 D3DXMatrixPerspectiveFovLH(&m_matProj, D3DX_PI / 4.0f, 1.0f, 1.0f, 2000.0f); / 投影变换矩阵CCamera:CCamera(void)VOID CCamera:GetViewMatrix(D3DXMATRIX *pM

12、atrix) / 使各分量相互垂直 D3DXVec3Normalize(&m_vLookVec, &m_vLookVec); D3DXVec3Cross(&m_vUpVec, &m_vLookVec, &m_vRightVec); / 上向量与观察向量垂直 D3DXVec3Normalize(&m_vUpVec, &m_vUpVec); / 规格化上向量 D3DXVec3Cross(&m_vRightVec, &m_vUpVec, &m_vLookVec); / 右向量与上向量垂直/你能通过左手法则确定叉积返回的向量。按照第一个向量指向第二个向量弯曲你的左手，/这时拇指所指的方向就是叉积向量所

13、指的方向。 D3DXVec3Normalize(&m_vRightVec, &m_vRightVec); / 规格化右向量 / 创建取景变换矩阵 pMatrix-_11 = m_vRightVec.x; / Rx pMatrix-_12 = m_vUpVec.x; / Ux pMatrix-_13 = m_vLookVec.x; / Lx pMatrix-_14 = 0.0f; pMatrix-_21 = m_vRightVec.y; / Ry pMatrix-_22 = m_vUpVec.y; / Uy pMatrix-_23 = m_vLookVec.y; / Ly pMatrix-_24

14、 = 0.0f; pMatrix-_31 = m_vRightVec.z; / Rz pMatrix-_32 = m_vUpVec.z; / Uz pMatrix-_33 = m_vLookVec.z; / Lz pMatrix-_34 = 0.0f; pMatrix-_41 = -D3DXVec3Dot(&m_vRightVec, &m_vPosition); / -P*R pMatrix-_42 = -D3DXVec3Dot(&m_vUpVec, &m_vPosition); / -P*U pMatrix-_43 = -D3DXVec3Dot(&m_vLookVec, &m_vPositi

15、on); / -P*L pMatrix-_44 = 1.0f;VOID CCamera:ResetLookatPos(D3DXVECTOR3 *pLookat) if (pLookat != NULL) m_vLookat = (*pLookat); else m_vLookat = D3DXVECTOR3(0.0f, 0.0f, 1.0f); m_vLookVec = m_vLookat - m_vPosition; D3DXVec3Normalize(&m_vLookVec, &m_vLookVec); D3DXVec3Cross(&m_vUpVec, &m_vLookVec, &m_vR

16、ightVec); D3DXVec3Normalize(&m_vUpVec, &m_vUpVec); D3DXVec3Cross(&m_vRightVec, &m_vUpVec, &m_vLookVec); D3DXVec3Normalize(&m_vRightVec, &m_vRightVec);VOID CCamera:ResetCameraPos(D3DXVECTOR3 *pVector) D3DXVECTOR3 V = D3DXVECTOR3(0.0f, 0.0f, 0.0f); m_vPosition = pVector ? (*pVector) : V;VOID CCamera:R

17、esetViewMatrix(D3DXMATRIX *pMatrix) if (pMatrix) m_matView = *pMatrix; else GetViewMatrix(&m_matView); m_pd3dDevice-SetTransform(D3DTS_VIEW, &m_matView); m_vRightVec = D3DXVECTOR3(m_matView._11, m_matView._12, m_matView._13); m_vUpVec = D3DXVECTOR3(m_matView._21, m_matView._22, m_matView._23); m_vLo

18、okVec = D3DXVECTOR3(m_matView._31, m_matView._32, m_matView._33);VOID CCamera:ResetProjMatrix(D3DXMATRIX *pMatrix) if (pMatrix != NULL) m_matProj = *pMatrix; else D3DXMatrixPerspectiveFovLH(&m_matProj, D3DX_PI / 4.0f, 1.0f, 1.0f, 1000.0f); m_pd3dDevice-SetTransform(D3DTS_PROJECTION, &m_matProj);/ 沿右

19、向量平移fUnits个单位VOID CCamera:MoveAlongRightVec(FLOAT fUnits) m_vPosition += m_vRightVec * fUnits; m_vLookat += m_vRightVec * fUnits;/ 沿上向量平移fUnits个单位VOID CCamera:MoveAlongUpVec(FLOAT fUnits) m_vPosition += m_vUpVec * fUnits; m_vLookat += m_vUpVec * fUnits;/ 沿观察向量平移fUnits个单位VOID CCamera:MoveAlongLookVec

20、(FLOAT fUnits) m_vPosition += m_vLookVec * fUnits; m_vLookat += m_vLookVec * fUnits;/旋转使用D3DXMatrixRotationAxis函数实现，绕rightuplook方向旋转的实现方法：VOID CCamera:RotationRightVec(FLOAT fAngle) D3DXMATRIX R; D3DXMatrixRotationAxis(&R, &m_vRightVec, fAngle); D3DXVec3TransformCoord(&m_vUpVec, &m_vPosition, &R); D

21、3DXVec3TransformCoord(&m_vLookVec, &m_vLookVec, &R); m_vLookat = m_vLookVec * D3DXVec3Length(&m_vPosition);/*D3DXVec3TransformCoord用矩阵变换3-D向量，并且用w = 1投影结果。定义：D3DXVECTOR3*WINAPID3DXVec3TransformCoord(D3DXVECTOR3*pOut,CONST D3DXVECTOR3*pV,CONST D3DXMATRIX*pM);ParameterspOut: in, out指向D3DXVECTOR3结构的操作结

22、果。pV: in指向D3DXVECTOR3结构的向量。pM: in指向D3DXMATRIX结构的变换矩阵。Return Value指向D3DXVECTOR3结构的变换后的向量。说明：这个函数用矩阵pM变换3-D向量pV(x, y, z, 1)，并且用w = 1投影结果。函数返回值跟pOut 参数返回值是一样的。这样可以让函数D3DXVec3TransformCoord作为其它函数的参数使用。*/VOID CCamera:RotationUpVec(FLOAT fAngle) D3DXMATRIX R; D3DXMatrixRotationAxis(&R, &m_vUpVec, fAngle);

23、 D3DXVec3TransformCoord(&m_vRightVec, &m_vRightVec, &R); D3DXVec3TransformCoord(&m_vLookVec, &m_vLookVec, &R); m_vLookat = m_vLookVec * D3DXVec3Length(&m_vPosition); D3DXVECTOR3 vNormal; D3DXVec3Normalize(&vNormal, &m_vLookat);VOID CCamera:RotationLookVec(FLOAT fAngle) D3DXMATRIX R; D3DXMatrixRotati

24、onAxis(&R, &m_vLookVec, fAngle); D3DXVec3TransformCoord(&m_vRightVec, &m_vRightVec, &R); D3DXVec3TransformCoord(&m_vUpVec, &m_vUpVec, &R); m_vLookat = m_vLookVec * D3DXVec3Length(&m_vPosition);/摄像机绕X轴旋转fAngle角度VOID CCamera:CircleRotationX(FLOAT fAngle) D3DXMATRIX R; D3DXMatrixRotationAxis(&R, &m_vRi

25、ghtVec, fAngle); D3DXVec3TransformCoord(&m_vUpVec, &m_vUpVec, &R); D3DXVec3TransformCoord(&m_vLookVec, &m_vLookVec, &R); float dy = m_vPosition.y - m_vLookat.y; float dz = m_vPosition.z - m_vLookat.z; m_vPosition.y = m_vLookat.y + dy * cosf(fAngle) - dz * sinf(fAngle); m_vPosition.z = m_vLookat.z + dy * sinf(fAngle) + dz * cosf(fAngle); ResetLookatPos(&m_vLookat);/摄像机绕Y轴旋转fAngle角度VOID CCamera:CircleRotationY(FLOAT fAngle) D3DXMATRIX R; D3DXMatrix