Feed the Plants

Exceptional plant progress

September 05, 2017

• Live demo here: generate some strawberry plants!
• Source code at this point in history

Latest video, plant timelapse:

SO MUCH PROGRESS since the last update!!

Implementation Notes

A few weeks ago, I had been struggling with exactly what data structure to use for the plant. It felt like the NxN grid was the wrong data structure – code was hard to write, the abstraction just didn’t feel quite right, etc. I wanted something that could more properly represent each “node” of plant, and I wanted something that contained pointers to the next node(s) of the plant, and a pointer to the parent node…

And then I realized…

Clearly the right data structure was a TREE!

• The plant is now represented as a 7-ary tree, where each node of the tree maps to a “plant pixel”.
• Every plant pixel can be connected to another pixel in 8 directions, but it’s a 7-ary tree because one of these directions will be the parent pointer, and then 7 child pointers, many of which will be null.
• The PlantNode looks basically like this:

  PlantNode {
    PlantNode[8] nodes;
    int parentIndex;
  }
  
  const TOP_LEFT = 0;
  const TOP_MIDDLE = 1;
  const TOP_RIGHT = 2;
  const MIDDLE_LEFT = 3;
  const MIDDLE_RIGHT = 4;
  const BOTTOM_LEFT = 5;
  const BOTTOM_MIDDLE = 6;
  const BOTTOM_RIGHT = 7;
  

  • nodes is an array of PlantNode references that are connected to the current node. The nodes array is ordered consistently, where the 0th index represents the TOP_LEFT space, the 1st index represents the TOP_MIDDLE space, etc.
  • The parentIndex indicates which of the nodes references is the parent node.
• The canvas is still represented as an NxN grid, and the plant tree checks against the canvas to see where it is possible to grow in that space

Once I got the plant represented as a 7-ary tree (and once I finally got all the bugs out…), the rest of the code was pretty straightforward, though it’s not too pretty.

Things I could (but probably won’t) clean up later:

• Code redundancy between the 4 orientations of strawberry
• Smarten up some of the arbitrary growth heuristics (e.g. when strawberries bloom)

A fun intermediate stage

When I was playing around with plant growth algorithms, I made this happen:

Didn’t stick with this algorithm, but it’s fun to watch!

• (play with it live!)

Console debugging

I was having trouble getting my 7-ary tree working perfectly, and honestly what I should have done was written a unit test for the PlantNode data structure itself. Had I gone that direction from the beginning, I am certain it would have saved me time. But that’s not what I did!

Instead, I mostly suffered through print-statement debugging, until I realized that the tree growth would be easier to “see” with a little bit of color.

So I wrote a debug mode that was kind of cool, where I color-coded each branch of the tree, and matched the console log statements to the color of the branch:

• (see it live - open the console, docked right!)

TODOs for next time

• START MAKING AN ACTUAL GAME! Like watering the plant, trimming the plant, plant growth each day, etc.
• Add roots?
• Add more speckles to strawberries