Leaf color can be set interactively by using an onscreen slider interface to change the various leaf parameters. Nearby trees are updated in realtime, and distant tree billboards are updated using the "T" key to recreate trees. These color parameters also affect grass, which looks a bit odd against the bright green terrain texture. At some point I should probably tune the leaf and grass colors in tiled terrain mode to make them brighter. Right now I'm working on other things, so that will have to wait until later.
Here are some screenshots of how fall trees look in 3DWorld. Click to view larger images.
Here is what the onscreen display looks like. It reminds me of my computer monitor's onscreen display. Since 3DWorld doesn't have any real UI or dialog boxes, everything is done within the main rendering window using hotkeys. Arrow keys move up and down in the list and move the slider positions left and right. The 'X' key switches between menus.
|This image shows the onscreen display used to set tree leaf and grass colors.|
The leaf red, blue, and green colors are actually color biases. They adjust the amount of color for leaves from the default greenish value. It's not possible to set the color exactly because of the way the leaf texture color is modulated with the base color. Leaf color variance sets the amount of random color difference between leaves on the same tree. Tree color variance sets the amount of random color difference between two different trees. These two numbers added together determine the overall color variation for a given leaf. Grass length and width are self-explanatory.
When I say the update is interactive, I mean 3DWorld actually destroys and recreates all of the trees and grass when these parameters change. It's surprisingly fast to regenerate everything, especially when using the GPU and 8 threads on a quad core machine. So the update only generates a slight pause.