/// <summary>
/// Gets the index of the most visible texture on the terrain at the specified point in world space.
/// These texture indexes are assigned in the "paint textures" tab of the terrain inspector.
/// If the supplied position is outside the bounds of the terrain, this function will return -1.
/// </summary>
public int GetDominantTextureIndexAt(Vector3 worldPosition)
{
Vector3Int alphamapCoordinates = ConvertToAlphamapCoordinates(worldPosition);
if (!CachedTerrainAlphamapData.ContainsIndex(alphamapCoordinates.x, dimension: 1))
{
return(-1);
}
if (!CachedTerrainAlphamapData.ContainsIndex(alphamapCoordinates.z, dimension: 0))
{
return(-1);
}
int mostDominantTextureIndex = 0;
float greatestTextureWeight = float.MinValue;
int textureCount = CachedTerrainAlphamapData.GetLength(2);
for (int textureIndex = 0; textureIndex < textureCount; textureIndex++)
{
// I am really not sure why the x and z coordinates are out of order here, I think it's just Unity being lame and weird
float textureWeight = CachedTerrainAlphamapData[alphamapCoordinates.z, alphamapCoordinates.x, textureIndex];
if (textureWeight > greatestTextureWeight)
{
greatestTextureWeight = textureWeight;
mostDominantTextureIndex = textureIndex;
}
}
return(mostDominantTextureIndex);
Vector3Int ConvertToAlphamapCoordinates(Vector3 _worldPosition)
{
Vector3 relativePosition = _worldPosition - transform.position;
// Important note: terrains cannot be rotated, so we don't have to worry about rotation
return(new Vector3Int
(
x: Mathf.RoundToInt((relativePosition.x / ThisTerrainData.size.x) * ThisTerrainData.alphamapWidth),
y: 0,
z: Mathf.RoundToInt((relativePosition.z / ThisTerrainData.size.z) * ThisTerrainData.alphamapHeight)
));
}
}
