buffer is a
2D array of pixels that are set during rendering. The
colour buffer typically resides on the graphics card (server).
colour buffer is specified using the pixel format descriptor (Lecture 1). A typical format is 32 bits (8 bits each for
R, G, B, A).
rendering a frame, the colour buffer is first cleared using
pixels in the buffer are set to the colour specified by
g, b, a);
that values in the colour buffer are clamped. For example, using floating point colours,
each r, g, b, a value is limited to the range [0, 1].