getAltitudeAt()

[jerome]

continued from : http://www.html5gamedevs.com/topic/15523-getheightatcoordinates-alternative/?p=111175

 

same algo slightly modified for a ribbon : http://www.babylonjs-playground.com/#1QC4YQ#8

[jerome]

Stronger ! with a live morphed ribbon : http://www.babylonjs-playground.com/#1QC4YQ#10

 

obviously, this needs some GC optimizations but it still runs

 

please don't mind about the balls jumping on the edges, I just return altitude == 0 when the balls are out of the ribbon, even if they are above the trough of the wave

 

the same with lower ball velocities to better understand : http://www.babylonjs-playground.com/#1QC4YQ#11

 

note : there are no physics here (so no gravity, no friction, no acceleration, no mass, etc), the ball still roll from an edge to another following the waving surface

[Convergence]

Great work on a staple function of game-making

 

How about a getAngleAt(x, z, rotation) ? to make it work for cubes

[jerome]

quick and dirty GC optimization : http://www.babylonjs-playground.com/#1QC4YQ#12

 

about the angle, I'm thinking about it ... something like getNormalsAt() and/or getSlopeAt()

 

this runs at 58 fps on my laptop : http://www.babylonjs-playground.com/#1QC4YQ#13

as you can see there many subdivisions

this would run faster with far less subdivisions

[jerome]

I reduced the number of subdivisions, now this runs at 60 fps on my laptop with 100 balls : http://www.babylonjs-playground.com/#1QC4YQ#14

[jerome]

500 balls floating on the waving surface at 35 fps on my old laptop : http://www.babylonjs-playground.com/#1QC4YQ#15

not that bad   if I don't care about the erratic movement on the edges

 

 

2000 tiny floating balls : http://www.babylonjs-playground.com/#1QC4YQ#16

still 25 fps in full screen on my pushcart computer ... I love this framework !

[jerome]

up

 

@DK : let me know if you want it as a new function or in replacement of getHeightAtCoordinates

knowing this : 

http://www.html5gamedevs.com/topic/15523-getheightatcoordinates-alternative/?p=110994

[GameMonetize]

As long as this produces the same result, we can use the new algorithm in the previous function

[GameMonetize]

Or perhaps keep the current implementation and hide it under a flag in the function signature (In order to keep it working with tiled grounds)

[jerome]

Actually to get the height of a flat tiled ground is not that pertinent imho ...

 

Ok, what I propose is to keep aside the current implementation within the function code and add a boolean to the tiled ground constructor : isTiled = true

 

If isTiled, the function will do the same as currently (ray intersection)

else :

on first call, it will generate the underlying quad array (if it doesn't already exists)

on each call, it will compute the height from this array

 

Oki doki ? 

Unless you prefer, I just add a flag in the signature of getHeightAtCoordinates() to allow the user to explicitly choose the way he wants (more simple to code for me)

 

 

And I will also provide the almost same for ribbons/grounds/whatever with the same geometry in vanilla JS in UserFunction repository. This version will have an updatable quad array in the render loop, like I did in the PG with the waving ribbon.

[GameMonetize]

oki doki

[jerome]

BTW, as the facet plane equations are pre-computed also in the array, I would like to provide a fast method to get them at will :

 

getFacetNormalAt(x, z) ?  => returns a Vector3, the normal to the map at the coordinates (x, z)

or

getFacetPlaneEquationAt(x, z) ? => returns a Vector4(a, b, c, d) , the plane equation ax + by + cy + d = 0 at the coordinates (x, z) , knowing that (a, b, c) is actually the normal described in getFacetNormaAtl()

Which one do you prefer ?

 

Or any other more pertinent name, let me know ...

 

 

This could be very useful for the users to set mesh orientations/rotations on the map surface.

 

Note : for a tiled ground, this would return (0, 1, 0) for instance, in any case.

[GameMonetize]

For the sake of comprehension I prefer the first one!

[jerome]

mmh.. after reading the code in the class meshBuilder, I can see that the TiledGround is NOT an instance of the class GroundMesh, but only an instance of the class Mesh.

In other terms, the current method getHeightAtCoordinates() is not a method of a TiledGround object : http://doc.babylonjs.com/classes/2.2/TiledGround

 

I should have checked this before !  (that's why it wasn't pertinent)

This means I can simply replace the current code of getHeightAtCoordinates() by the new one

No need for special tips, flags, etc.

[jerome]

PRed

in replacement of the current one

works pretty well on my test scene

[jerome]

BTW, it returns y from x, z in the ground local system as it doesn't really make sense to return an altitude from the ground in the world system

 

but if it's expected in the world system I can fix it as well