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D3DXMatrixLookAtLH function

Builds a left-handed, look-at matrix.

Syntax


D3DXMATRIX* D3DXMatrixLookAtLH(
  _Inout_  D3DXMATRIX *pOut,
  _In_     const D3DXVECTOR3 *pEye,
  _In_     const D3DXVECTOR3 *pAt,
  _In_     const D3DXVECTOR3 *pUp
);

Parameters

pOut [in, out]

Type: D3DXMATRIX*

Pointer to the D3DXMATRIX structure that is the result of the operation.

pEye [in]

Type: const D3DXVECTOR3*

Pointer to the D3DXVECTOR3 structure that defines the eye point. This value is used in translation.

pAt [in]

Type: const D3DXVECTOR3*

Pointer to the D3DXVECTOR3 structure that defines the camera look-at target.

pUp [in]

Type: const D3DXVECTOR3*

Pointer to the D3DXVECTOR3 structure that defines the current world's up, usually [0, 1, 0].

Return value

Type: D3DXMATRIX*

Pointer to a D3DXMATRIX structure that is a left-handed, look-at matrix.

Remarks

The return value for this function is the same value returned in the pOut parameter. In this way, the D3DXMatrixLookAtLH function can be used as a parameter for another function.

This function uses the following formula to compute the returned matrix.



zaxis = normal(At - Eye)
xaxis = normal(cross(Up, zaxis))
yaxis = cross(zaxis, xaxis)
    
 xaxis.x           yaxis.x           zaxis.x          0
 xaxis.y           yaxis.y           zaxis.y          0
 xaxis.z           yaxis.z           zaxis.z          0
-dot(xaxis, eye)  -dot(yaxis, eye)  -dot(zaxis, eye)  1


Requirements

Header

D3dx9math.h

Library

D3dx9.lib

See also

D3DXMatrixLookAtRH

 

 

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