Pointcloud 2D Grid driven by Heightmap

[blaxxun]

Hello,

Iam using "IFX Read Image" to drive a 2D pointcloud grid with a terrain heightmap.
It works actually very nice as long as i use as many particles as the image resolution has pixels (2048x2048).

If i change the particle resolution, the displacement starts to get inaccurat.

I guess the pixel information in the array gets repeated.

My question is now, how do i only pick the correct ID in the array according to the pointcloud resolution?
Or how do i even select every Nth value in the array and feed the Y displacement ?

Iam still a total noob when it comes to something more complicated like arrays etc.

Every help is welcome
Thanks!

[rray]

This tree takes advantage of that fact that the point ids have the same pixel order as the 4-million-colors-array (for example first row, pixels left to right, second row etc.)

So in theory if you multiply the GetPointID output by 2, you could use half the resolution horizontally. Or *4 and 1/4th of the horizontal resolution.

If you need to reduce the vertical resolution too, you'll have to do some modulo computation with the point id (skip every second row)

[blaxxun]

Hello, thanks for the tips.
I was already fidling around with Modulo, but couldnt really figure out how to use it.

I was able to create a second array which holds the calculated numbers 0,2,4,6,8... when i use half the grid resolution and so on.
Unfortunatly i can not connect the output of this second array into the PointID of the first array which holds the color information.

If you need to reduce the vertical resolution too, you'll have to do some modulo computation with the point id (skip every second row)

How would one do this?

[rray]

It's a difficult to describe written down, here's the ICE tree.
Width and height of the image (and probably grid resolution) should be a power of 2

[blaxxun]

Wow, thanks a lot man!
It works like a charm!

I post the whole ICE tree if someone is interested.

My goal is actually to load in tiles from Worldmachine which should be LOD based.
Maybe its possible to build something like a small terrain engine which is based on tiled terrain heightmaps and diffusemaps.

Worldmachines displacement works only on flat grids but not on low/high poly geometry.

So i thought if i can (with some help) build a distance based (camera/terrain) terrain engine it would be really cool.
I dont know yet exactly which approach would work best (meshing of pointclouds or building geometry from scratch based on camera LOD) but i try to find out.

Every help is welcome!