CODEWITHSUNDEEP
c#unity-game-enginerotationquaternionsraycasting
Kaspie
Kaspie

Reputation: 187

trying to apply z rotation on instantiated prefab not working as expected

I'm proceduraly generating grass quads by raycasting onto a terrain surface, to make them seem more organic i'd like to add a random rotation on Z, but every one of my attempts rotates the grass block completely wildly.

without the random z rotation, the grass blocks are fine on the terrain but are aligned which doesn't feel very organic

    void RaycastItem(ItemChunk itemChunk)
{
    RaycastHit hit;
    Vector3 randPosition = new Vector3(Random.Range(-gridSize/2, gridSize/2), -20, Random.Range(-gridSize/2, gridSize/2)) + itemChunk.coord;

    if (Physics.Raycast(randPosition, Vector3.down, out hit, raycastDistance))
    {
        Quaternion spawnRotation = Quaternion.FromToRotation(Vector3.up, hit.normal);
        Vector3 overlapTestBoxScale = new Vector3(overlapTestBoxSize, overlapTestBoxSize, overlapTestBoxSize);

        Collider[] collidersInsideOverlapBox = new Collider[1];
        int numberOfCollidersFound = Physics.OverlapBoxNonAlloc(hit.point, overlapTestBoxScale, collidersInsideOverlapBox, spawnRotation, spawnedObjectLayer);

        if (numberOfCollidersFound == 0)
        {
            Pick(itemChunk, hit.point, spawnRotation);
        }
    }
}

void Pick(ItemChunk itemChunk, Vector3 positionToSpawn, Quaternion rotationToSpawn)
{
    int randomIndex = Random.Range(0, itemsToPickFrom.Length);
    GameObject item = itemsToPickFrom[randomIndex];
// this is one of the places I tried applying the random rotation
    rotationToSpawn *= Quaternion.Euler(item.transform.rotation.x, item.transform.rotation.y, item.transform.rotation.z + Random.Range(0, 360));

    GameObject clone = Instantiate(item, positionToSpawn, rotationToSpawn);

    clone.transform.parent = itemChunk.transform;
    Debug.Log(clone.transform.localScale);
}

Here is an image of what is going on enter image description here

Is something wrong in my Quaternion Conversions ? Is this particular to Instantiation ? for practical issues I've had to put the Quad inside an Empty to make a prefab, the Quad has 0 rotations/transforms and the Quad has a 90 degree rotation.

Upvotes: 0

Views: 628

Answers (1)

Kale_Surfer_Dude
Kale_Surfer_Dude

Reputation: 914

Try this:

rotationToSpawn = Quaternion.Euler(item.transform.rotation.x, item.transform.rotation.y, item.transform.rotation.z + Random.Range(-15, 15));

If I get what you're doing, you want the grass to have a slight rotation on the z axis. This should do it. If item already has a large z rotation, you can try this:

rotationToSpawn = Quaternion.Euler(item.transform.rotation.x, item.transform.rotation.y, Random.Range(-15, 15));

Upvotes: 1

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