[Solved] How to get the splatmap width and height that applied to a terrain?

Scripting
#1

Hi, I am experimenting with Terrain splatmap to spawn specific particles after Raycasting from player gun to the terrain. So far, I have created a terrain with only 1 patch, with 16 chunks, each chunk size = 63 (that makes the patch width = height = 25,200 world unit). I also have upto 5 terrain layers, that make the terrain use 2 splatmaps from my understanding.

Currently, here what I did to get a pointer to an array of splatmap:

    private Terrain _terrain;

    public override void OnStart()
       {
            _terrain = Actor.As<Terrain>();
            Int2 patchCoord = new Int2(0, 0); // Assuming that only one patch located at coord: (0,0)
            
            Task.Run(() =>
            {
                unsafe
                {
                    // Get the first splatmap containing layer 0 to layer 3
                    Color32* splatMapPtr = TerrainTools.GetSplatMapData(_terrain, ref patchCoord, 0);
                    for (int i = 0; i < 65536; i++)
                    {
                        var data = splatMapPtr[i];
                        Debug.Log(data.ToString()); // Print out in format: R, G, B, A
                    }
                }
            });
        }

I choose the number 65,536 after looking into the SceneData folder and find a splatmap there with the width and height dimension: 256x256.
I’m wondering is this the right appoach because I also tested printing the array at 999999, it still able to print out (0,0,0,0), perhaps it is storing the default values?;

Thanks!

#2

Hi guys, I have found the solution after a few days, here something I found worth noting:

  • The terrain size (width equals height) can be calculated using: _terrain.ChunkSize * Terrain.PatchEdgeChunksCount * 100 (This will be the world unit, in centimeter)
  • The splatmap size can be calculated similarly: _terrain.ChunkSize * Terrain.PatchEdgeChunksCount + 1

I have a sample code here for future references: TerrainWeightViewer/TerrainUtils.cs at main · NilesGameDev/TerrainWeightViewer · GitHub

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