Well, the short version is that I have a very basic collision detection and response system working.  My test scene has a sphere that I can move left or right.  If the sphere hits a triangle it slides along the surface of the triangle.  I even put two triangles with different slopes next to one another and the sphere slides along one then changes pace slightly as it slides along the other.  I simplified the code from the Faurby paper I was using and there’s probably some stuff I’ll find out later I’m missing, but the basic concept is working.

My next step is to generalize to code to handle meshes instead of individually defined triangles.  This is “narrow phase” collision detection and is relatively expensive to calculate, so I’ll need a broad phase scheme as well.  Fortunately, THREE.js includes a utility to generate an axis aligned bounding box around a mesh and these are pretty easy to use to eliminate most geometry from consideration during the broad phase.

I’m still plugging away at getting a functioning collision detection system built.  So far the collision detection part seems to be working somewhat reliably, but the collision response part is still largely non-existent.  March 1 is still a reasonable timeframe and even though this is slowing things down somewhat it could definitely be time well spent if I can get this working.

I’m going to write a collide-and-slide collision detection system in Javascript with a fully functioning demo using THREE.js.  I’m writing here so I’ll actually do it.  This will take me time.  If I am very lucky and don’t get burned out immediately, I might have it done by March 1.  I’m putting everything else on hold while I work on this.  If I can make a general purpose collision detection system then my primary purpose for using BabylonJS will no longer be valid and I’ll probably rewrite Lyridia base on THREE.js.

After admitting I was stalling by working on putting some grass into the game, I’ve now stalled some more to improve that process.  Now instead of “solid” grass I can make double sided flat grass and it shows up correctly.  As a result, a chunk of grass that looks virtually identical to the solid grass but is actually made of double sided triangles has just 15 faces.  I can pare that down some if I make the grass model a little simpler, so I’ll make some other grass models at some point that are just dead simple.  I used the tags feature in BabylonJS to accomplish this.  Flat geometry can now be tagged as “doublesided” and when the model is loaded its material type will be converted to double sided by turning off backface culling.  Backface culling should remain on for most objects for performance reasons, but the ability to selectively turn it off on objects modeled in Blender is very useful.

I’ve been looking at the controls in BabylonJS and so far I’m not a fan.  The engine does a lot for you, which is good, but it also hides a lot of the details behind poor documentation, which is not good.  There’s a whole action manager system that seems very confusing at the moment.  If I try to just put in a good old fashioned addEventListener for mousedown or mouseup I get very weird results.  It will pick up left mouse clicks if the right mouse is down, but not otherwise, which is frustrating.

So, I’m going to punt.  The controls are good enough for now and I’m going to move onto other things.  Eventually I may not even use BabylonJS.  I would actually much prefer to use THREE but as it’s not a game engine there are some features it just doesn’t have.  Or maybe I’ll eventually figure out BabylonJS well enough to use it correctly, but I have definitely found myself frustrated by things in BabylonJS not working the way I want to and the root cause seems to be hidden from me.  That sounds like some kind of conspiracy, but it’s not that.  The engine just tries to do a lot for you and if you don’t use it correctly it doesn’t throw an error, it just doesn’t do what you want.  I’ll come up with my next steps and post them here soon.

Last night I made a simple, bad run cycle for my test character and put it in the game.  I then updated the game so that the player only “runs” when he is moving.  The animation is still very rudimentary in that it just starts when you move and stops when you stop.  There’s no blending to make it smoothly transition between idle and running or anything fancy like that.  It’s a very basic start, but it’s a start.

My development schedule from back on February 1st hasn’t gone exactly as planned.  I have basic multiplayer in place, and I’ve been improving Penrith Forest here and there, but I’ve done nothing with the camera controls or jumping.  Instead I’ve been working on this animation stuff.  I’ve also reorganized all of the code into a format that’s easier for me to work with.  I don’t really want to mess with the camera controls or jumping since both open a can of worms, but I guess I will since it has to be done eventually.