koobas.hobune.stream
Random Instantiate onto Planet
Hi Everyone! I've been working on a First Person Planet Exploration game for the past month or so and I have run into a problem. I'm trying to randomly place trees onto a mesh of a planet but all I can do is place them at the vertices of the planet. Is there a way to find random points on the planet that aren't on top of a vertex? Any help would be great! Here is a picture of my planet and the script that I am using.(BTW the planet was modeled in Blender).
var tree:GameObject;
var offset:Vector3;
var verticies:int;
function Start () {
offset=transform.position;
AddTrees();
}
function AddTrees(){
var baseVertices : Vector3[];
var mesh : Mesh = GetComponent(MeshFilter).mesh;
if (baseVertices == null){
baseVertices = mesh.vertices;
}
var vertices = new Vector3[baseVertices.Length];
verticies=vertices.Length;
for(var i=0; i<(vertices.Length);i++){
var vertex = baseVertices[i];
Instantiate (tree, vertex, Quaternion.identity);
}
}
[1]: /storage/temp/31830-unity++tree+problem.png
Were you the person who then in the future launched No $$anonymous$$an's Sky?
Nah but i am working on something in relation if you want my planetary source code its up for grabs for the first 5 people who send a request to my email(of course you have your copy guaranteed @lluvensanger ) why ? ...i want indie space exploration games to soar .. even at the cost of my source so yes only 5 people can claim this source, abiding you do not sell or send this to any other person (please?). Email : jordankmuguluma@gmail.com.
Not sure of your requirements. I can think of two approaches. First, instead of generating a random vertex, generate a random triangle from the Mesh.triangles array. The triangle will give you three vertices forming the triangle. You can then generate a random position on the triangle. See Andeeee's answer here:
http://forum.unity3d.com/threads/random-instantiate-on-surface-of-mesh.11153/
The second methods is to generate a position well beyond the planed, and do a Collider.Raycast() back to the planet. Some untested code:
var dir = -Random.onUnitSphere;
var pos = planet.position - dir * someLargerDistance;
var ray = new Ray(pos, dir);
var hit : RaycastHit;
collider.Raycast(ray, hit, someLargerDistance);
'someLargerDistance' is some distance guaranteed to be beyond the planet when measured from planet pivot. 'hit.point' will be the random position.
Thanks so much! For anyone who's curious about this, here is the now the working code and a picture to go with it!
var tree:GameObject;
var pointa:Vector3=Vector3.zero;
var pointb:Vector3=Vector3.zero;
var pointc:Vector3=Vector3.zero;
function Start () {
RandomAdd();
}
function RandomAdd () {
var baseVertices : Vector3[];
var mesh : Mesh = GetComponent(MeshFilter).mesh;
for(var i:int= 0; i < mesh.triangles.Length; i += 3){
var rndA = Random.value;
var rndB = Random.value;
var rndC = Random.value;
pointa = mesh.vertices[mesh.triangles[i + 0]];
pointb = mesh.vertices[mesh.triangles[i + 1]];
pointc = mesh.vertices[mesh.triangles[i + 2]];
var rndTriPoint = (rndA pointa + rndB pointb + rndC * pointc) / (rndA + rndB + rndC);
Instantiate (tree, rndTriPoint, Quaternion.identity);
}
}
[1]: /storage/temp/31864-unity+tree+solved.png
Hey, great code, thanks for sharing.
Can you clarify this part:
var rndTriPoint = (rndA pointa + rndB pointb + rndC * pointc) / (rndA + rndB + rndC);
It throws an error.
I change the code, but the trees don't spawn on the mesh.
Thanks!
First off, be advised that I have not tried this and it is coming right off the top of my head. Now, there is a function called GetTopology listed in the Mesh API page. It claims to get points (as well as other things) from a sub-mesh and use those to render the mesh. My thinking is perhaps you can use such a function and mix it with an array and a random number generator and maybe be left with an array to Instantiate your trees?
Here is the MeshTopology Page: http://docs.unity3d.com/ScriptReference/MeshTopology.html
I've not tried this before, so hopefully it's a good place to start from.
HERE you are maybe late but better than never var tree:GameObject; var pointa:Vector3=Vector3.zero; var pointb:Vector3=Vector3.zero; var pointc:Vector3=Vector3.zero;
function Start () { RandomAdd(); }
function RandomAdd () { var baseVertices : Vector3[]; var mesh : Mesh = GetComponent(MeshFilter).mesh; for(var i:int= 0; i < mesh.triangles.Length; i += 3){ var rndA = Random.value; var rndB = Random.value; var rndC = Random.value; var rndTriPoint = (rndA pointa + rndB pointb + rndC * pointc) / (rndA + rndB + rndC);
pointa = mesh.vertices[mesh.triangles[i + 0]];
pointb = mesh.vertices[mesh.triangles[i + 1]];
pointc = mesh.vertices[mesh.triangles[i + 2]];
Instantiate (tree, rndTriPoint, Quaternion.identity);
}
}
