D3DMXMatrixLookAtLH

A version of this page is also available for

Windows Embedded CE 6.0 R3

4/8/2010

This function builds a left-handed, look-at matrix in floating point format.

Syntax

D3DMXMATRIX* WINAPI D3DMXMatrixLookAtLH(
  D3DMXMATRIX*        pOut,
  CONST D3DMXVECTOR3* pEye,
  CONST D3DMXVECTOR3* pAt,
  CONST D3DMXVECTOR3* pUp
);

Parameters

• pOut
  [in, out] Pointer to the D3DMXMATRIX structure that is the result of the operation.

• pEye
  [in] Pointer to the D3DMXVECTOR3 structure that defines the eye point. This value is used in translation.

• pAt
  [in] Pointer to the D3DXVECTOR3 structure that defines the camera look-at target.

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

Return Value

Pointer to a D3DMXMATRIX 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

See Also

Reference

D3DMX Functions
D3DMXMATRIX
D3DMXVECTOR3
D3DMXMatrixLookAtLHFxd