We can use the same basic framework to map both Land and Ocean. There are some differences:
- The texture of the Ocean does not change with every square. You can use essentially the same texture for the entire ocean. But you must also take care to avoid the appearance of "tiling".
- The surface of the ocean moves dynamically.
We have tried many approaches to creating waves. Here are collections of many of these examples:
- Waves - A general collection showing examples of ocean waves.
- Pirates - Dioramas illustrating animated ocean waves with a Pirate Ship.
Here are some flying examples:
- Flight Demo - An aircraft flying over animated ocean waves.
- Flight Simulation Demo - The FM2 flying over reflective animated ocean waves.
The routine for changing wave heights is currently implemented as a normal subroutine, which uses the CPU. Presumably, this could be improved by using a shader, which uses the GPU. We could also use a shader to change wave color, but we may need to use textures to hide slight variations between squares.
Several years ago, we took a cruise from San Francisco to Hawaii and then to Tahiti. I took full advantage of this opportunity to observe, and to take pictures of, the Pacific Ocean. After a few days, you realize that you are surrounded by the color blue at almost all times. So if blue is not a favorite color, you might wish for some variety.
The color of water varies depending on a variety of factors. A small glass container of pure water appears to have no color. However, when a large volume of water is viewed in sunlight, the water appears blue. This is because water reflects back only the blue components of the spectrum and absorbs the rest. Thus, when viewed from space, the basic color of the deep oceans is blue. This blue tint is relatively light but becomes noticeable when looking through 15 feet or more of water. Near the shore, where the ocean is shallow, the color will be a colorful blend of blue tint and the underlying sand or coral. However, both transparency and tint can be affected by particles in the water. For example, most rivers and lakes contain a lot of mud, which reduces transparency and gives the water a brown tint. And waves near the shore are filled with sand that reduces transparency.
Another factor affecting the color of water, especially at lower viewing angles, is reflectivity. Still water can reflect objects like a mirror. Thus, when viewed from a low angle, the natural blue color of water is overridden by the color of the sky or reflected objects. However, a calm ocean is relatively rare - in most cases, the ocean is covered with waves. In this case, the ocean will reflect the general color, but not the shape, of reflected objects. Stormy seas will appear opaque, almost like frosted glass. This is partly due to sea foam, but largely because - while the water is still reflecting the color of the sky and clouds, the reflection is perturbed.
The combination of light and shadows make the waves visible. Looking away from the sun, the waves will creates bright reflections. Looking towards the sun, the waves will create dark shadows.
Throughout the trip, I was surprised by the apparent absence of haze. From ship level, the demarcation between sea and sky always seemed sharp, even in the relatively calm seas. However, when we climbed to the top of an island and looked out over the ocean, the haze was there. The apparent reason for this difference was that, at ship level, our range of visibility was probably quite low - likely less than 10 miles.