c++ - 将 float 作为指向矩阵的指针传递

Question

老实说，我想不出这个问题的更好标题，因为我遇到了 2 个问题，而且我不知道原因。

我遇到的第一个问题是这个

//global declaration
float g_posX = 0.0f;
.............


//if keydown happens
g_posX += 0.03f;


&m_mtxView._41 = g_posX;

我收到这个错误

cannot convert from 'float' to 'float *'

所以我假设矩阵只接受指针。所以我把变量改成这个....

//global declaration
float *g_posX = 0.0f;
.............


//if keydown happens
g_posX += 0.03f;


&m_mtxView._41 = &g_posX;

我得到了这个错误

cannot convert from 'float' to 'float *'

这几乎是在说我不能将 g_posX 声明为指针。

老实说，我不知道该怎么办。

Answer 1

1.)

m_mtxView._41 = g_posX;

2.)

Update: this piece of code is quite unnecessary, although it shows how to use a pointer allocated on the heap.

float* g_posX = new float; // declare a pointer to the address of a new float
*g_posX = 0.0f; // set the value of what it points to, to 0.0This
m_mtxView._41 = *g_posX; // set the value of m_mtxView._41 to the value of g_posX
delete g_posX; // free the memory that posX allocates.

提示:将“*****”读作“的值”，将“&”读作“的地址”