Terrain Heigthdata dimensions

Hi Forum!
How can examine the of the container’s dimensions what Terrain::GetHeightData () give?

(Spoiler: you want this urho3d.github.io/documentation/1 … ea3e1efca4)

Good question. Couldn’t really find anything better but you can get the image and from that the dimensions: urho3d.github.io/documentation/1 … 98b5493628

    Image* i=terrain->GetHeightMap();
    int w=i->GetWidth();
    int h=i->GetHeight();

You can also manipulate the image data to manipulate the heights (call terrain->ApplyHeightMap(); when done).

Oh I just looked at the source code (Urho3D/Graphics/Terrain.cpp):
GetHeightData() contains the height of the vertices. The size is calculated as:

numVertices_ = IntVector2(numPatches_.x_ * patchSize_ + 1, numPatches_.y_ * patchSize_ + 1);
unsigned newDataSize = (unsigned)(numVertices_.x_ * numVertices_.y_);

Oh there’s actually a handy function to query the vertice number: urho3d.github.io/documentation/1 … ea3e1efca4
So thats the function you are looking for.
That documentation could be way better.

Thank you very mutch gawag!
I not found that function, maybe I’m blind! :smiley:
I have trouble if I manipulate the terrain over an Image. This is why I would direct the Heightdata set.
GetHeightData just give a pointer.
So thx again!
Arpi

Oh I think the GetHeightData can’t be used to manipulate the terrain. Just to read height values.
It would be good if one could manipulate the vertice in a more direct way besides editing the source code or editing the heightmap but I think that’s not possible?
I actually had once a project years ago (with Ogre (a 3D engine)) where I needed editable terrain. I changed the terrain library I used (ETM) to be editable faster as it was really slow. Maybe I should look into the Urho terrain more and see what it can do and how good…

So long:
To edit terrain the heightmap can be changed:

    // moves 10x10 pixel under the camera up by 10%
    IntVector2 v=terrain->WorldToHeightMap(cameraNode_->GetWorldPosition());
    Image* i=terrain->GetHeightMap();
    for(int x=-10;x<10;x++)
        for(int y=-10;y<10;y++)
            i->SetPixel(v.x_+x,v.y_+y,i->GetPixel(v.x_+x,v.y_+y)+Color(0.1,0.1,0.1));
    terrain->ApplyHeightMap();

To edit the splatting map of a terrain:

    // sets 10x10 pixels under the camera to a relatively dark red (first splatting texture blended a bit with the other two)
    IntVector2 v=terrain->WorldToHeightMap(cameraNode_->GetWorldPosition());
    Texture2D* t=(Texture2D*)terrain->GetMaterial()->GetTexture(TU_DIFFUSE);  // TU_DIFFUSE is defined to be 0, as in "the first texture" which is the splatting map in the default terrain
    uint32_t c=Color(1,0.1,0.1).ToUInt();
    for(int x=-10;x<10;x++)
        for(int y=-10;y<10;y++)
            t->SetData(0,v.x_+x,v.y_+y,1,1,&c);
    terrain->GetMaterial()->SetTexture(TU_DIFFUSE,t);

Edit: fixed splatting manipulation code and started a new wiki article as I’m just testing terrain stuff anyway: github.com/urho3d/Urho3D/wiki/Terrain

You can edit the pixels of the heightmap image and call ApplyHeightMap(). More direct modification support than that isn’t coded into Terrain for these reasons:

  • There is a number of processes that need to run when the heightmap is edited, error estimation, possible smoothing (if enabled) and updating of individual patches’ vertex buffers.
  • For ease of serialization the heightmap image is thought as the authoritative source. If the heightmap data could be changed outside of that, then the Terrain component would have to support serializing the full height data grid, which would be a massive blob of data in the scene file.

Naturally, you’re free to create your own better modifiable terrain system using your own components, perhaps basing it on Urho’s original terrain; there isn’t anything magical about it and it works just like any Drawable subclasses.

Ah, I see.

I just ran some experiments (and fixed my pasted code which was wrong). The issue that I had with this ETM years ago was that changing just a bit of the terrain took quite a while as it was updating the whole terrain. The Urho terrain engine is super fast when changing the height map or splatting map.
I was thinking about special needs in regard of only changing single chunks to be faster but Urho’s heightmap approach seems fast enough.

(The heightmap and splatting map editing approach feels odd. Got an idea on how to make terrain editing way easier and more elegant… maybe I try to implement that…)

I hope you had a chance to review my post, Terran Editor.
I had zero experience working with a terrain editor when I wrote it, but I had the need for it and decided to write one. You are more than welcome to enhance it and make it more elegant as I’m sure you have more expertise in the area.

Thanks the reply guys!
I droped this approach( the direct modify ). I working with SRTM datas. I my code, at first I made an Image, then set all the Pixels, then I resize the Image, then add this Image to Terrain class. The Terrain looks strange a bit after the resize. I think because the 16 value divided to red and green componets, everywhere arond 256 m, the terrain have a deep canyon( and 512, and 768 …). This is not the Image class mistake of course! External resizing give the same problem.
This is why I would acces direct the Heightfield datas.

@cadaver, I noticed what you detalied above. I trust the code and would not modifing.
@Lumak, I will review your Terrain Editor. Its look very interesting!

BTW: this Engine is great!
Arpi