Develop Reference

Meshes created from code don't have a position unity

So, I tried to create a grid so that I can instantiate objects on it. I check for the position of said hit object (one of the squares I created) and then set the instantiated object to that position. Problem is, the squares I created with code don't have a position and are all set to 0, 0, 0.
{
GameObject tileObject = new GameObject(string.Format("{0}, {1}", x, y));
tileObject.transform.parent = transform;
Mesh mesh = new Mesh();
tileObject.AddComponent<MeshFilter>().mesh = mesh;
tileObject.AddComponent<MeshRenderer>().material = tileMaterial;
Vector3[] vertices = new Vector3[4];
vertices[0] = new Vector3(x * tileSize, 0, y * tileSize);
vertices[1] = new Vector3(x * tileSize, 0, (y +1) * tileSize);
vertices[2] = new Vector3((x +1) * tileSize, 0, y * tileSize);
vertices[3] = new Vector3((x +1) * tileSize, 0, (y +1) * tileSize);
int[] tris = new int[] { 0, 1, 2, 1, 3, 2 };
mesh.vertices = vertices;
mesh.triangles = tris;
mesh.RecalculateNormals();
tileObject.layer = LayerMask.NameToLayer("Tile");
tileObject.AddComponent<BoxCollider>();
//var xPos = Mathf.Round(x);
//var yPos = Mathf.Round(y);
//tileObject.gameObject.transform.position = new Vector3(xPos , 0f, yPos);
return tileObject;
}```

As said your issue is that you leave all tiles on the position 0,0,0 and only set their vertices to the desired world space positions.
You would rather want to keep your vertices local like e.g.
// I would use the offset of -0.5f so the mesh is centered at the transform pivot
// Also no need to recreate the arrays everytime, you can simply reference the same ones
private readonly Vector3[] vertices = new Vector3[4]
{
new Vector3(-0.5f, 0, -0.5f);
new Vector3(-0.5f, 0, 0.5f);
new Vector3(0.5f, 0, -0.5f);
new Vector3(0.5f, 0, 0.5f);
};
private readonly int[] tris = new int[] { 0, 1, 2, 1, 3, 2 };
and then in your method do
GameObject tileObject = new GameObject($"{x},{y}");
tileObject.transform.parent = transform;
tileObject.localScale = new Vector3 (tileSize, 1, tileSize);
tileObject.localPosition = new Vector3(x * tileSize, 0, y * tileSize);
The latter depends of course on your needs. Actually I would prefer to have the tiles also centered around the grid object so something like e.g.
// The "-0.5f" is for centering the tile itself correctly
// The "-gridWith/2f" makes the entire grid centered around the parent
tileObject.localPosition = new Vector3((x - 0.5f - gridWidth/2f) * tileSize, 0, (y - 0.5f - gridHeight/2f) * tileSize);
In order to later find out which tile you are standing on (e.g. via raycasts, collisions, etc) I would then rather use a dedicated component and simply tell it it's coordinates like e.g.
// Note that Tile is a built-in type so you would want to avoid confusion
public class MyTile : MonoBehaviour
{
public Vector2Int GridPosition;
}
and then while generating your grid you would simply add
var tile = tileObject.AddComponent<MyTile>();
tile.GridPosition = new Vector2Int(x,y);
while you can still also access its transform.position to get the actual world space center of the tiles

Rotating cubes to face the origin using Quaternions

I'm in the process of setting up a relatively simple voxel-based world for a game. The high level idea is to first generate voxel locations following a fibonacci grid, then rotate the cubes such that the outer surface of the fibonacci grid resembles a sphere, and finally size the cubes such that they roughly cover the surface of the sphere (overlap is fine). See below the code for generating the voxels along the fibonacci grid:
public static Voxel[] CreateInitialVoxels(int numberOfPoints, int radius)
{
float goldenRatio = (1 + Mathf.Sqrt(5)) / 2;
Voxel[] voxels = new Voxel[numberOfPoints];
for (int i = 0; i < numberOfPoints; i++)
{
float n = i - numberOfPoints / 2; // Center at zero
float theta = 2 * Mathf.PI * n / goldenRatio;
float phi = (Mathf.PI / 2) + Mathf.Asin(2 * n / numberOfPoints);
voxels[i] = new Voxel(new Location(theta, phi, radius));
}
return voxels;
}
This generates a sphere that looks roughly like a staircase
So, my current approach to get this looking a bit more spherical is to basically rotate each cube in each pair of axes, then combine all of the rotations:
private void DrawVoxel(Voxel voxel, GameObject voxelContainer)
{
GameObject voxelObject = Instantiate<GameObject>(GetVoxelPrefab());
voxelObject.transform.position = voxel.location.cartesianCoordinates;
voxelObject.transform.parent = voxelContainer.transform;
Vector3 norm = voxel.location.cartesianCoordinates.normalized;
float xyRotationDegree = Mathf.Atan(norm.y / norm.x) * (180 / Mathf.PI);
float zxRotationDegree = Mathf.Atan(norm.z / norm.x) * (180 / Mathf.PI);
float yzRotationDegree = Mathf.Atan(norm.z / norm.y) * (180 / Mathf.PI);
Quaternion xyRotation = Quaternion.AngleAxis(xyRotationDegree, new Vector3(0, 0, 1));
Quaternion zxRotation = Quaternion.AngleAxis(zxRotationDegree, new Vector3(0, 1, 0));
Quaternion yzRotation = Quaternion.AngleAxis(yzRotationDegree, new Vector3(1, 0, 0));
voxelObject.transform.rotation = zxRotation * yzRotation * xyRotation;
}
The primary thing that I am getting caught on is that each of these rotations seems to work fine for me in isolation, but when combining them things tend to go a bit haywire (pictures below) I'm not sure exactly what the issue is. My best guess is that I've made some sign/rotation mismatch in my rotations so they don't combine right. I can get two working, but never all three together.
Above are the pictures of one and two successful rotations, followed by the error mode when I attempt to combine them. Any help either on telling me that the approach I'm following is too convoluted, or helping me understand what the right way to combine these rotations would be would be very helpful. Cartesian coordinate conversion below for reference.
[System.Serializable]
public struct Location
{
public float theta, phi, r;
public Vector3 polarCoordinates;
public float x, y, z;
public Vector3 cartesianCoordinates;
public Location(float theta, float phi, float r)
{
this.theta = theta;
this.phi = phi;
this.r= r;
this.polarCoordinates = new Vector3(theta, phi, r);
this.x = r * Mathf.Sin(phi) * Mathf.Cos(theta);
this.y = r * Mathf.Sin(phi) * Mathf.Sin(theta);
this.z = r * Mathf.Cos(phi);
this.cartesianCoordinates = new Vector3(x, y, z);
}
}

I managed to find a solution to this problem, though it's still not clear to me what the issue with the above code is.
Unity has an extremely handy function called Quaternion.FromToRotation that will generate the appropriate rotation if you simply pass in the appropriate destination vector.
In my case I was able to just do:
voxelObject.transform.rotation = Quaternion.FromToRotation(new Vector3(0, 0, 1), voxel.location.cartesianCoordinates);

Unity - Determining UVs for a circular plane mesh generated by code

I'm trying to generate a circular mesh made up of triangles with a common center at the center of the circle.
The mesh is generated properly, but the UVs are not and I am having some trouble understanding how to add them.
I assumed I would just copy the vertexes' pattern, but it didn't work out.
Here is the function:
private void _MakeMesh(int sides, float radius = 0.5f)
{
m_LiquidMesh.Clear();
float angleStep = 360.0f / (float) sides;
List<Vector3> vertexes = new List<Vector3>();
List<int> triangles = new List<int>();
List<Vector2> uvs = new List<Vector2>();
Quaternion rotation = Quaternion.Euler(0.0f, angleStep, 0.0f);
// Make first triangle.
vertexes.Add(new Vector3(0.0f, 0.0f, 0.0f));
vertexes.Add(new Vector3(radius, 0.0f, 0.0f));
vertexes.Add(rotation * vertexes[1]);
// First UV ??
uvs.Add(new Vector2(0, 0));
uvs.Add(new Vector2(1, 0));
uvs.Add(rotation * uvs[1]);
// Add triangle indices.
triangles.Add(0);
triangles.Add(1);
triangles.Add(2);
for (int i = 0; i < sides - 1; i++)
{
triangles.Add(0);
triangles.Add(vertexes.Count - 1);
triangles.Add(vertexes.Count);
// UV ??
vertexes.Add(rotation * vertexes[vertexes.Count - 1]);
}
m_LiquidMesh.vertices = vertexes.ToArray();
m_LiquidMesh.triangles = triangles.ToArray();
m_LiquidMesh.uv = uvs.ToArray();
m_LiquidMesh.RecalculateNormals();
m_LiquidMesh.RecalculateBounds();
Debug.Log("<color=yellow>Liquid mesh created</color>");
}
How does mapping UV work in a case like this?
Edit: I'm trying to use this circle as an effect of something flowing outwards from the center (think: liquid mesh for a brewing pot)

This is an old post, but maybe someone else will benefit from my solution.
So basically I gave my center point the center of the uv (0.5, 0.5) and then used the used circle formula to give every other point the uv coordinate. But of course I had to remap the cos and sin results from -1..1 to 0..1 and everything is working great.
Vector2[] uv = new Vector2[vertices.Length];
uv[uv.Length - 1] = new Vector2(0.5f, 0.5f);
for (int i = 0; i < uv.Length - 1; i++)
{
float radians = (float) i / (uv.Length - 1) * 2 * Mathf.PI;
uv[i] = new Vector2(Mathf.Cos(radians).Remap(-1f, 1f, 0f, 1f), Mathf.Sin(radians).Remap(-1f, 1f, 0f, 1f));
}
mesh.uv = uv;
Where the remap is an extension like this and it basically take a value in a range and remaps it to another range (in this case from -1..1 to 0..1):
public static float Remap(this float value, float from1, float to1, float from2, float to2) {
return (value - from1) / (to1 - from1) * (to2 - from2) + from2;
}

How to check if device has been rotated on all axis in Unity

I want to check in Unity if the device has been rotated on all of it's axis.
So, I am reading the rotation of all the axis.
What should I do in order to validate for example that the user has "flipped" his device over the X-axis? I need to check the value, and see that they contain 0, 90, 180 and 270 degrees in a loop.
Here is part of my code:
void Update () {
float X = Input.acceleration.x;
float Y = Input.acceleration.y;
float Z = Input.acceleration.z;
xText.text = ((Mathf.Atan2(Y, Z) * 180 / Mathf.PI)+180).ToString();
yText.text = ((Mathf.Atan2(X, Z) * 180 / Mathf.PI)+180).ToString();
zText.text = ((Mathf.Atan2(X, Y) * 180 / Mathf.PI)+180).ToString();
}

The accelerometer only tells you if the acceleration of the device changes. So you will have values if the device started moving, or stopped moving. You can't retrieve its orientation from that.
Instead you need to use the gyroscope of the device. Most device have one nowadays.
Fortunately, Unity supports the gyroscope through the Gyroscope class
Simply using
Input.gyro.attitude
Will give you the orientation of the device in space, in the form of a quaternion.
To check the angles, use the eulerAngles function, for instance, is the device flipped in the x axis:
Vector3 angles = Input.gyro.attitude.eulerAngles;
bool xFlipped = angles.x > 180;
Be careful, you might have to invert some values if you want to apply the rotation in Unity (because it depend which orientation the devices uses for positive values, left or right)
// The Gyroscope is right-handed. Unity is left handed.
// Make the necessary change to the camera.
private static Quaternion GyroToUnity(Quaternion q)
{
return new Quaternion(q.x, q.y, -q.z, -q.w);
}
Here is the full example from the doc (Unity version 2017.3), in case the link above is broken. It shows how to read value from the gyroscope, and apply them to an object in Unity.
// Create a cube with camera vector names on the faces.
// Allow the device to show named faces as it is oriented.
using UnityEngine;
public class ExampleScript : MonoBehaviour
{
// Faces for 6 sides of the cube
private GameObject[] quads = new GameObject[6];
// Textures for each quad, should be +X, +Y etc
// with appropriate colors, red, green, blue, etc
public Texture[] labels;
void Start()
{
// make camera solid colour and based at the origin
GetComponent<Camera>().backgroundColor = new Color(49.0f / 255.0f, 77.0f / 255.0f, 121.0f / 255.0f);
GetComponent<Camera>().transform.position = new Vector3(0, 0, 0);
GetComponent<Camera>().clearFlags = CameraClearFlags.SolidColor;
// create the six quads forming the sides of a cube
GameObject quad = GameObject.CreatePrimitive(PrimitiveType.Quad);
quads[0] = createQuad(quad, new Vector3(1, 0, 0), new Vector3(0, 90, 0), "plus x",
new Color(0.90f, 0.10f, 0.10f, 1), labels[0]);
quads[1] = createQuad(quad, new Vector3(0, 1, 0), new Vector3(-90, 0, 0), "plus y",
new Color(0.10f, 0.90f, 0.10f, 1), labels[1]);
quads[2] = createQuad(quad, new Vector3(0, 0, 1), new Vector3(0, 0, 0), "plus z",
new Color(0.10f, 0.10f, 0.90f, 1), labels[2]);
quads[3] = createQuad(quad, new Vector3(-1, 0, 0), new Vector3(0, -90, 0), "neg x",
new Color(0.90f, 0.50f, 0.50f, 1), labels[3]);
quads[4] = createQuad(quad, new Vector3(0, -1, 0), new Vector3(90, 0, 0), "neg y",
new Color(0.50f, 0.90f, 0.50f, 1), labels[4]);
quads[5] = createQuad(quad, new Vector3(0, 0, -1), new Vector3(0, 180, 0), "neg z",
new Color(0.50f, 0.50f, 0.90f, 1), labels[5]);
GameObject.Destroy(quad);
}
// make a quad for one side of the cube
GameObject createQuad(GameObject quad, Vector3 pos, Vector3 rot, string name, Color col, Texture t)
{
Quaternion quat = Quaternion.Euler(rot);
GameObject GO = Instantiate(quad, pos, quat);
GO.name = name;
GO.GetComponent<Renderer>().material.color = col;
GO.GetComponent<Renderer>().material.mainTexture = t;
GO.transform.localScale += new Vector3(0.25f, 0.25f, 0.25f);
return GO;
}
protected void Update()
{
GyroModifyCamera();
}
protected void OnGUI()
{
GUI.skin.label.fontSize = Screen.width / 40;
GUILayout.Label("Orientation: " + Screen.orientation);
GUILayout.Label("input.gyro.attitude: " + Input.gyro.attitude);
GUILayout.Label("iphone width/font: " + Screen.width + " : " + GUI.skin.label.fontSize);
}
/********************************************/
// The Gyroscope is right-handed. Unity is left handed.
// Make the necessary change to the camera.
void GyroModifyCamera()
{
transform.rotation = GyroToUnity(Input.gyro.attitude);
}
private static Quaternion GyroToUnity(Quaternion q)
{
return new Quaternion(q.x, q.y, -q.z, -q.w);
}
}

if statement glitching

It appears that my if statement is not working; it is, from what I gather with debug messageboxes that I placed earlier throughout the code to report variables etc., simply not modifying the variable "pos" in the if block, but the if block is definitely being executed. It's hard to explain.
I'm building a little game with cars on a street, and here, I try to spawn new cars and assign them a starting position (or modify their position) based on the lane of the street they're in. This is not production code, it's just me roughing out the basic idea.
for (int i = 0; i < carlane.Count; i++)
{
float lane = carlane.ElementAt(i);
if (lane == 1)
{
if (carpos.Count <= i)
{
pos = new Vector2(screenWidth - 20, (screenHeight / 2) - (8 * screenHeight / 200));
}
else
{
pos = new Vector2(carpos[i].X - 2, carpos[i].Y);
}
rotation = 1.5f * (float)Math.PI;
}
else if (lane == 2)
{
if (carpos.Count <= i)
{
pos = new Vector2(screenWidth - 20, (screenHeight / 2) - (8 * screenHeight / 200));
}
else
{
pos = new Vector2(carpos[i].X - 2, carpos[i].Y);
}
rotation = 1.5f * (float)Math.PI;
}
}
spriteBatch.Draw(car, pos, null, Color.White, rotation, origin, (lane - 1) * (float)Math.PI * 0.5f, SpriteEffects.None, 0f);
if (carpos.Count > i)
{
carpos[i] = (pos);
}
else
{
carpos.Add(pos);
}
And so, when lane is set to 1, nothing happens. Cars spawn, but don't appear. When lane is set to 2, I purposefully used the same code within the if-block as when lane is equal to 1, and the cars spawn and drive along the lane correctly. Something is wrong with the code, when lane = 1, and I don't know what it is.
My computer runs Windows 7 Home Premium 64 bit, and I'm using C# 2010 express edition with XNA game studio 4.0.
Please help?

When lane equals 1, the scale (lane - 1) * (float)Math.PI * 0.5f equals 0, which means that car is scaled to nothing - thus nothing appears on the screen.

When lane is zero, (lane - 1) * (float)Math.PI * 0.5f is zero. You're Drawing with scale argument zero, which draws nothing.
The documentation:
public void Draw (
Texture2D texture,
Vector2 position,
Nullable<Rectangle> sourceRectangle,
Color color,
float rotation,
Vector2 origin,
float scale,
SpriteEffects effects,
float layerDepth
)
Your code:
spriteBatch.Draw(
car,
pos,
null,
Color.White,
rotation,
origin,
(lane - 1) * (float)Math.PI * 0.5f,
SpriteEffects.None,
0f
);
Looks like the scale to me.

You should only change the pos variable depending on the lane, not the size of the sprite (you were changing the scale of the sprite, just set that to 1.0f).
spriteBatch.Draw(car, pos, null, Color.White, rotation,
origin, 1.0f, SpriteEffects.None, 0f);