Terrain.load can't be used from server side nodejs simulation

[derickson]

Terrain.load can't be used from server side nodejs simulation

[derickson]

workaround: when the model is server side, use https://github.com/lukeapage/pngjs to load the PNG as data and copy the data to the terrain in the terrain init

var fs = require('fs'),
PNG = require('pngjs').PNG;

then the main. call back is necessary as the png io needs to finish before initializing the model

// Loads map resource from object in serial event async nodejs style
fs.createReadStream(model_params.map)
  .pipe(new PNG({filterType: 4}))
  .on("parsed", function () {
      //save the terrain image data into globalThis scope
      globalThis.terrainImage = this;
      
      // now start the simulation
      model.setup();
      run();
  });

then in the setup

  // load the terrain image to the Terrain object
  // works differently for browser vs nodejs
  if(globalThis.isBrowser) {
    modelStuff.terrain.load(model_params.map);
  } else {
    modelStuff.terrain.init((x,y) => {
      var idx = ((width * y) + x) << 2;
      var rv = globalThis.terrainImage.data[idx];
      var gv = globalThis.terrainImage.data[idx + 1];
      var bv = globalThis.terrainImage.data[idx + 2];
      modelStuff.terrain.set(x,y,{r:rv,g:gv,b:bv,a:255});
    });
  }

[scottpdo]

Hi @derickson pardon my slow reply. While Flocc does attempt to be equally useful in both server and browser contexts, the visualization components really are more browser-focused. It seems like your workaround using pngjs works nicely! One goal of Flocc is to be dependency-free, so I'd want to do a little more work on the Node side to remove that as a dependency, but it seems like that approach would work well.

[derickson]

no worries on slow reply, just trying to be a good open source community member. we are in the middle our our hackathon powered by flocc right now. really appreciate you making this project available.