To show the time of day in the 2D iso clients one can apply rgb offsets to all the graphics on the screen. For instance as it gets later in the day you could give all the graphics negative offsets in r, g, and b to make them all darker. Then at brighter times of the day you could give them all positive offsets.

Shadows are implemented by shrinking and shearing the character pixels and converting them to black. Functions for NE and NW shadows are implemented in tkclient at the moment. Karsten has mentioned seperating the character and shadow animations so that shadows can be seen when flying. The distance between shadow and anim would indicate height.

For seasons it would be a little trickier. You could test to see if a graphic has some kind of foliage (tree, grass, bush) by what cvs directory they came from. Then make them greener (apply positive g offsets) for spring, or some graphics randomly redder, oranger, or yellower for fall and whiter to depict snow in winter. Of course the trunks of the trees shouldn't become too red for fall or too white for winter, so you might want to do conditional offsets. For instance if a pixel is in the green range make it redder, but not if it is in any other range.

A weird thing to consider would be to invert all the colors of the graphics, maybe for a dream-like state or when dealing with something supernatural or when dead. Other type filters are also possible. For example the imaging library in tkclient supports the following image filters:

  • BLUR
  • As well as continous values for color, brightness, contrast, and sharpness as might be found on a TV set as knobs. Keeping these possibilities in mind when creating 2d iso graphics (and speaking up to developers to set standards for these types of effects in file formats) could save a lot of work and hard drive space.

    -- Unknown Author

    Here are some additional illustrations, the oak from Acorn going through seasonal and life cycles.
    Seasonal cycle of the oak Life cycle animation of the oak

    The oak is divided up in different layers that can be drawn on top of each other to create the final picture. The oak has one layer for the trunk with branches, a few for the leaves and one for the snow and ice. In the animation above the leaf layers change hue in spring and autumn.

    This way it is easy to produce nice autumn colored leaves without changing the color of the trunk. For a really smooth transition between seasons, the leaf layers could be faded in and out slowly (so that the first leaf layer appears faintly transparent in spring, solidifying towards late spring. I'm not sure how good this would look, however. It is probably better to just have more leaf layers (currently I'm using about six)).

    The snow and ice are also a separate layers, so that they can be turned on when the first frost and winter comes.

    --zzorn, 2000-11-11