D3DXMatrixLookAtLH

D3DXMatrixLookAtLH

Builds a left-handed, look-at matrix.

D3DXMATRIX * D3DXMatrixLookAtLH(

D3DXMATRIX *pOut,

CONST D3DXVECTOR3 *pEye,

CONST D3DXVECTOR3 *pAt,

CONST D3DXVECTOR3 *pUp

);

Parameters

pOut

[in, out] Pointer to the D3DXMATRIX structure that is the result of the operation.

pEye

[in] Pointer to the D3DXVECTOR3 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].

pEye确定眼睛的位置,是一个点

pAt和pEye两点确定一条直线,这里是一个向量,决定了眼睛看向哪个方向,这个方向好比我们围绕自身转一圈有360度

pUp和pEye再次确定一个向量,虽然这是看向那边已经由pAt决定了,但我们可以看天上看地上,这里就是确定我们怎么看,因为眼睛只能看一定高度范围的东西,这里确定到底要看哪个高度范围的东西