The GL stores both a current single-valued color index
and a current four-valued RGBA color.
GL.glColor sets a new four-valued RGBA color.
GL.glColor has two major variants:
glColor3 and glColor4.
glColor3 variants specify new red,
green,
and blue values explicitly
and set the current alpha value to 1.0 (full intensity) implicitly.
glColor4 variants specify all four color components explicitly.
GL.glColor, GL.glColor,
GL.glColor, GL.glColor, GL.glColor, and GL.glColor take
three or four signed byte, short, or long integers as arguments.
When v is appended to the name,
the color commands can take a pointer to an array of such values.
Current color values are stored in floating-point format,
with unspecified mantissa and exponent sizes.
Unsigned integer color components,
when specified,
are linearly mapped to floating-point values such that the largest
representable value maps to 1.0 (full intensity),
and 0 maps to 0.0 (zero intensity).
Signed integer color components,
when specified,
are linearly mapped to floating-point values such that the most positive
representable value maps to 1.0,
and the most negative representable value maps to -1.0. (Note that
this mapping does not convert 0 precisely to 0.0.)
Floating-point values are mapped directly.
Neither floating-point nor signed integer values are clamped
to the range [0,1] before the current color is updated.
However,
color components are clamped to this range before they are interpolated
or written into a color buffer.
GL.glClearStencil()