Symptoms
- I would like to add a bit of seasonal flare to my trees added via the Terrain paint widget. The trees are not placed as GameObjects in the hierarchy.
Cause
There is not a function to swap between tree prefabs.
Resolution
Unity Terrain exposes the Tree instances using the array Terrain.treeInstances. Every Tree instance included in this array has a property that stores the tree Prefab configured in the Terrain settings (prototypeIndex).
The tree Prefab is updated automatically by changing this value.
TreeInstance[] currentTreeList;
TerrainData terrain;
int springTreeIndex;
int fallTreeIndex;
bool season;
void ChangeSeasons ()
{
// The currentTreeList array must be at least terrain.treeInstances.Length in size
System.Array.Copy (terrain.treeInstances, currentTreeList, terrain.treeInstances.Length);
if (terrain.treeInstances.Length == currentTreeList.Length)
{
for (int tcnt=0; tcnt < currentTreeList.Length; tcnt++)
{
if (season)
{
if (currentTreeList [tcnt].prototypeIndex == springTreeIndex)
currentTreeList [tcnt].prototypeIndex = fallTreeIndex;
}
else
{
if (currentTreeList [tcnt].prototypeIndex == fallTreeIndex)
currentTreeList [tcnt].prototypeIndex = springTreeIndex;
}
}
terrain.treeInstances = currentTreeList;
season = !season;
}
}
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