Rendering Waves, Part I

For the past couple of weeks I've been testing several different algorithms for water rendering. I've limited myself in terms of technology a bit because of the age of my video card (7+ years old) and to keep the user base somewhat broad...therefore...no pixel shaders or any effects like that. Yes, I can go out and buy a shiny new high-end graphics card, but again, it would ultimately limit the user base down the road because of my tendency to want to push my graphics hardware as far as I can. :-)

I started out by building a basic mesh class (jMesh), and then running various functions across the mesh data. One of the most peculiar algorithms I came across "averages" the four surrounding points to calculate the current point's height on every pass:

y0 = (y1 + y2 + y3 + y4) / 4

I'm not sure who to credit for coming up with that, but I thought I'd give it a run and see what happened.

I was surprised to see that when I randomly dropped raindrops onto the mesh, little wavelets spread out from each drop and then faded out. Soon, though, I ran into some limitations of this concept because I wanted my waves to propagate out further and (hopefully) reflect off some walls I'd set up at the edge of the mesh.

Today, however, I spent some time paging through a 1960's physics book and came across a diagram of something called a "wave machine". That, along with the explanatory text beneath the photo, gave me some new ideas. The text described the wave machine and how it worked. As a result, I changed course on my own algorithm tests and added an "angle" value each point on the mesh. Also, I let the x coordinate and y coordinate of each mesh point be controlled by output of a sine and a cosine function.

The result?

What is difficult to see in this screenshot is that the entire mesh is in motion, and it looks pretty close to what a storm-tossed sea would look like. With a little bit of coloring, and some mountains thrown in, it looks like this:

Maybe I should post a movie at some point. Anyway, this new algorithm is a cross between the sine/cosine functions my own "averaging" type function that has damping and a whole bunch of other variables to play around with.

One key design point I want to make here is that because I've generalized all this into a generic "mesh" class, it opens up a lot of new possibilities such as basic cloth simulation, erosion-generated terrains, etc. I suppose you could also use some of it for creating landscapes altered by earthquakes. One other thing I plan on testing down the road is whether this could be morphed into a semi-realistic cloud mesh for cloud banks.

3-D Dialog Boxes, Part II

Things are moving along pretty well with the game engine...and there have been some recent updates to the 3-D dialog/GUI functionality. So far, the dialog box library can render buttons, picture boxes, text, etc. I'll be adding textboxes soon, too. Again, every GUI that is created with this library is fully 3-D (capable of being rotated, scaled, etc.) and has alpha-blending capabilities.

As usual...here are some screenshots...

Electric Maze

I threw this together in an about an hour or so. Just another test to see how fast I could create a playing field...in this case, a Tron-like 3-D maze.

Mountains

Here are a couple of screenshots demonstrating a basic mountain range made with the contour map tool. This was a basic test not only for the map tool but for the engine itself.

Several engine features are at work here, including terrain rendering, tile map rendering (brown ground tiles) and the skydome (along with a sunset). It probably took me less than an hour to create the tile map, the mountain range (using contours), and the mountain/ground textures. This scene can be viewed from any angle or elevation, by the way.

 

 

I have yet to perfect the sunset/sky coloring yet (or clouds for that matter), although the algorithm I created for it is up and working properly. Now it is just a matter of adjusting some color tables I've created for the skydome to make it look a bit more realistic.