- Initial Release Date
- June 1, 1993
- Color Palette
- Max Resolution
- License Status
- Shareware © Daniel Baumberger and Ian Greenhoe
- Daniel Baumberger and Ian Greenhoe
Northern Lights renders sets of scintillating, bouncing lines in SVGA resolutions up to 1024x768. It was one of a package of screen savers known as the Over the Edge collection.
Northern Lights is a variation of the classic bouncing lines program. It has a unique feature of having the lines fade in and fade out, like the Northern Lights.
Northern Lights, like many other line bouncers, takes a fairly simplified approach to drawing each set of lines, only drawing 2 lines per update: a black line to erase the line drawn X steps back (50 by default); and a line of the next color. Fading is handled via palette manipulation rather than by rerendering pixels. Since the full set of lines isn't updated each time it performs quickly, but the simple erasure method used overwrites parts of lines not intended for deletion causing subtle black artifacts.
Unlike the other bouncing lines program in the Over the Edge collection, Magic Mirror, Northern Lights is clearly targeted at SVGA displays, not supporting the EGA modes the Magic Mirror does.
Northern Lights supports a variety of options. Some of the less obvious are described below. Refer to the Command Line Reference and Readme in the Documentation section for further details.
The Reflection setting controls the number of sets of lines output and their boundary areas.
- 1, the default, uses a single set of lines that can cover the entire screen.
- 2 overlays a single set of lines that can cover the entire screen along with it's mirror image.
- 3 renders three sets of lines restricted into overlapping screen sections, each half of the screen's width.
- 4 should render a single set of lines that can cover the entire screen mirror image in both directions. However, there seems to a bug that causes one of the lines to be drawn in an incorrect position breaking the mirroring.
- 5 renders five sets of lines restricted into five overlapping quadrants, one in each corner and a fifth in the center of the screen.
The Bounce setting controls what happens when line vertexes reach the edges of their containing block.
- Crazy, the default, chooses a new direction and speed at random.
- True uses a more realistic algorithm based on the reflection of light where the angle of incidence equals the angle of reflection and speed is maintained.
Northern Lights provides 4 color modes.
- Random: Migrates smoothly between random colors.
- Simple: Starts out red and then alternates between purple and green.
- Single: Just white lines.
- Complex: Outputs the full rainbow spectrum.