Game Development Patterns and Best Practices

The horizontal and vertical blank

The display is updated by reading data from the framebuffer and updating in sequence, starting from the left to right and top to bottom. We can think about this exactly as if we were iterating through a 2D array in C or C++. At the end of each scan line, the electron gun is adjusted to point at the start of the next scan line. Another adjustment must be made after the last pixel is lit so the beam can start again at the top.

The time it takes for the electron gun to move from the rightmost pixel of scan line X to the leftmost pixel of scan line X + 1 is called the Horizontal Blank Interval. This is because the electron gun is blanked, meaning that it is outputting zero electrons during this interval. This ...