glClear函数来自OPENGL,其中它是通过glClear使用红，绿，蓝以及AFA值来清除颜色缓冲区的，并且都被归一化在（0，1）之间的值，其实就是清空当前的所有颜色。

glClearColor

The glClearColor function specifies clear values for the color buffers.

void glClearColor(

GLclampf red,

GLclampf green,

GLclampf blue,

GLclampf alpha

);

Parameters

red, green, blue, alpha

The red, green, blue, and alpha values used when the color buffers are cleared. The default values are all zero.

红，绿，蓝和AFA值是在颜色缓冲区被清除之后使用的，并且缺省值全是0.即（0，0，0，0），其实就是设置颜色

Remarks

The glClearColor function specifies the red, green, blue, and alpha values used by glClear to clear the color buffers. Values specified by glClearColor are clamped to the range [0,1].

The following functions retrieve information related to the glClearColor function:

glGet with argument GL_ACCUM_CLEAR_VALUE

glGet with argument GL_COLOR_CLEAR_VALUE

备注

以下是有关glClearColor函数的信息参考的函数

glGet with argument GL_ACCUM_CLEAR_VALUE

glGet with argument GL_COLOR_CLEAR_VALUE