Three things, arranged in order of increasing plant relevance:
The first has no relationship to plants at all, but I include it because 1) I sort of felt like I needed a third thing, and 2) it makes me chuckle every time I look at it: Straw Feminists in the Closet, from Hark! A Vagrant. (Specifically, I usually lose it when I reach the frame where the dad is swatting at the feminists with the broom.)
I'm still spending quite a bit of time with Sims 3. Because objects in Sims 3 are rendered as a mass of polygons, with a texture painted over it, complicated branchy objects like trees and shrubs would be really difficult to render well if they tried to be realistic -- even if you rendered a leaf as being completely flat, a tree with hundreds of leaves would exhaust the computer's ability to process them all as individual objects. So what they do instead is, some plants are rendered as a few flat polygons, and then transparent sections get cut out after the polygon is painted, like so:
Ordinarily, this all happens fast enough that you don't really notice, though when I'm really pushing the limits of my computer, occasionally everything appears in gray like this and then sloooooooowly gets colored-in, one object at a time.
A lot of medium-sized plants like shrubs just don't get rendered at all until you're up pretty close, which is . . . tough to get used to, actually. You're just out, you know, running around like you do, and then all of a sudden, FWOOM, these shrubs suddenly appear. And I say FWOOM rather than BAM or POP because they don't just blink into existence; they start out tiny and then get larger as you get nearer. But not the usual way that things get larger as you get nearer. They actually get larger relative to the other things near them. I'm not describing it well. I couldn't make it happen when I tried to get screencaps, or I would have pictures. (I suspect the issue must be specific to certain graphics settings.) You can kind of get the gist of what I'm talking about from looking at these two shots of a dandelion:
First, you see from the bottom photo that most of the foliage is in three vertical planes which intersect in the center of the plant, and then the leaflike shapes get cut out of those planes and colored in to look like leaves and Bob's your uncle. But the flowers themselves are a flat image that rotates to face you, regardless of the viewing angle. (Notice how it's the same five flowers, in the same positions relative to one another, even though the top picture is being viewed from the side, and the bottom picture is being viewed from overhead.) This is, I'm pretty sure, known in computer graphics nerdery as a sprite or billboard.
Shrubs and trees both are mostly made by pasting a bunch of copies of the same sprites together, and then rocking them back and forth independently to make it look like the leaves and branches are moving in the breeze. It can be a pretty convincing illusion if you don't look too closely at it, though it does get kind of disorienting to spin 180 degrees around a hydrangea and find yourself looking at the exact same flowers the whole time you're rotating.
Game designers can also just let you paint the image of something vaguely plantlike onto the terrain without even trying to be three-dimensional about it, which saves the most processing power of all:
That works pretty well from far away, when a large area of terrain is painted. Up close, like in the photo, it looks kinda silly.
For a lot more of this sort of thing, there's a tumblr devoted specifically to video game foliage (there's a tumblr devoted specifically to everything), which is called, appropriately enough, Video Game Foliage. Even if you really don't care about the gaming, some of the art is really neat, and it's plant-focused.
Finally and most importantly, Joseph Tychonievich has a podcast, Grow ALL the plants!, and the first episode is up. The guests this week are Rick Schoellhorn, former new products director for Proven Winners, and Julia Hofley, formerly a garden center manager and buyer. This particular episode is about the process of finding new plant varieties, and how they get from the breeders to the store.
It's more interesting than I'm making it sound. Plus it's short (~20 min.), and you'll finally find out how to pronounce Tychonievich. (We've all wondered. You're not alone.)
It's also worth keeping an eye on the site because there's a really, really high chance you'll know one of the guests on the next episode, which will publish Saturday the 22nd.
Actually you might know several of the guests, I suppose: I don't know how connected you are in the whole plant-writing/-blogging universe. But there's one guest in particular.