glClearColor - specify clear values for the color buffers
void glClearColor( GLclampf red, GLclampf green, GLclampf blue, GLclampf alpha )
red, green, blue, alpha Specify the red, green, blue, and alpha values used when the color buffers are cleared. The default values are all zero.
glClearColor 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].
GL_INVALID_OPERATION is generated if glClearColor is executed between the execution of glBegin and the corresponding execution of glEnd.
glGet with argument GL_COLOR_CLEAR_VALUE
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Fri Dec 6 11:18:03 EST 1996
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