Version: 2021.3+
This example demonstrates how to use the MeshThe main graphics primitive of Unity. Meshes make up a large part of your 3D worlds. Unity supports triangulated or Quadrangulated polygon meshes. Nurbs, Nurms, Subdiv surfaces must be converted to polygons. More info
See in Glossary API to draw visual content onto a visual elementA node of a visual tree that instantiates or derives from the C# VisualElement
class. You can style the look, define the behaviour, and display it on screen as part of the UI. More info
See in Glossary.
Note: The Mesh API is a tool for advanced users. In version 2022.1 and later, if you only want to generate simple geometry, use the Vector API instead. For more information, see Use Vector API to create a radial progress indicator.
This example creates a custom control that displays progress, as an alternative to a loading bar. The progress indicator displays a progress value in a partially filled ring around a label that displays the percentage. It supports a value between 0 and 100, which determines how much of the ring is filled.
You can find the completed files that this example creates in this GitHub repository.
This guide is for developers familiar with the Unity Editor, UI(User Interface) Allows a user to interact with your application. Unity currently supports three UI systems. More info
See in Glossary Toolkit, and C# scripting. Before you start, get familiar with the following:
Create two C# files with one defining the RadialProgress
class and another defining the custom mesh. In the C# file that defines the RadialProgress
class, create a Factory class to expose the control to UXML and UI Builder.
Create a Unity project with any template.
Create a folder named radial-progress
to store your files.
In the radial-progress
folder, create a C# scrip named RadialProgress.cs
with the following content:
using Unity.Collections;
using UnityEngine;
using UnityEngine.UIElements;
namespace MyUILibrary
{
// An element that displays progress inside a partially filled circle
public class RadialProgress : VisualElement
{
public new class UxmlTraits : VisualElement.UxmlTraits
{
// The progress property is exposed to UXML.
UxmlFloatAttributeDescription m_ProgressAttribute = new UxmlFloatAttributeDescription()
{
name = "progress"
};
// Use the Init method to assign the value of the progress UXML attribute to the C# progress property.
public override void Init(VisualElement ve, IUxmlAttributes bag, CreationContext cc)
{
base.Init(ve, bag, cc);
(ve as RadialProgress).progress = m_ProgressAttribute.GetValueFromBag(bag, cc);
}
}
// Define a factory class to expose this control to UXML.
public new class UxmlFactory : UxmlFactory<RadialProgress, UxmlTraits> { }
// These are USS class names for the control overall and the label.
public static readonly string ussClassName = "radial-progress";
public static readonly string ussLabelClassName = "radial-progress__label";
// These objects allow C# code to access custom USS properties.
static CustomStyleProperty<Color> s_TrackColor = new CustomStyleProperty<Color>("--track-color");
static CustomStyleProperty<Color> s_ProgressColor = new CustomStyleProperty<Color>("--progress-color");
// These are the meshes this control uses.
EllipseMesh m_TrackMesh;
EllipseMesh m_ProgressMesh;
// This is the label that displays the percentage.
Label m_Label;
// This is the number of outer vertices to generate the circle.
const int k_NumSteps = 200;
// This is the number that the Label displays as a percentage.
float m_Progress;
// A value between 0 and 100
public float progress
{
// The progress property is exposed in C#.
get => m_Progress;
set
{
// Whenever the progress property changes, MarkDirtyRepaint() is named. This causes a call to the
// generateVisualContents callback.
m_Progress = value;
m_Label.text = Mathf.Clamp(Mathf.Round(value), 0, 100) + "%";
MarkDirtyRepaint();
}
}
// This default constructor is RadialProgress's only constructor.
public RadialProgress()
{
// Create a Label, add a USS class name, and add it to this visual tree.
m_Label = new Label();
m_Label.AddToClassList(ussLabelClassName);
Add(m_Label);
// Create meshes for the track and the progress.
m_ProgressMesh = new EllipseMesh(k_NumSteps);
m_TrackMesh = new EllipseMesh(k_NumSteps);
// Add the USS class name for the overall control.
AddToClassList(ussClassName);
// Register a callback after custom style resolution.
RegisterCallback<CustomStyleResolvedEvent>(evt => CustomStylesResolved(evt));
// Register a callback to generate the visual content of the control.
generateVisualContent += context => GenerateVisualContent(context);
progress = 0.0f;
}
static void CustomStylesResolved(CustomStyleResolvedEvent evt)
{
RadialProgress element = (RadialProgress)evt.currentTarget;
element.UpdateCustomStyles();
}
// After the custom colors are resolved, this method uses them to color the meshes and (if necessary) repaint
// the control.
void UpdateCustomStyles()
{
if (customStyle.TryGetValue(s_ProgressColor, out var progressColor))
{
m_ProgressMesh.color = progressColor;
}
if (customStyle.TryGetValue(s_TrackColor, out var trackColor))
{
m_TrackMesh.color = trackColor;
}
if (m_ProgressMesh.isDirty || m_TrackMesh.isDirty)
MarkDirtyRepaint();
}
// The GenerateVisualContent() callback method calls DrawMeshes().
static void GenerateVisualContent(MeshGenerationContext context)
{
RadialProgress element = (RadialProgress)context.visualElement;
element.DrawMeshes(context);
}
// DrawMeshes() uses the EllipseMesh utility class to generate an array of vertices and indices, for both the
// "track" ring (in grey) and the progress ring (in green). It then passes the geometry to the MeshWriteData
// object, as returned by the MeshGenerationContext.Allocate() method. For the "progress" mesh, only a slice of
// the index arrays is used to progressively reveal parts of the mesh.
void DrawMeshes(MeshGenerationContext context)
{
float halfWidth = contentRect.width * 0.5f;
float halfHeight = contentRect.height * 0.5f;
if (halfWidth < 2.0f || halfHeight < 2.0f)
return;
m_ProgressMesh.width = halfWidth;
m_ProgressMesh.height = halfHeight;
m_ProgressMesh.borderSize = 10;
m_ProgressMesh.UpdateMesh();
m_TrackMesh.width = halfWidth;
m_TrackMesh.height = halfHeight;
m_TrackMesh.borderSize = 10;
m_TrackMesh.UpdateMesh();
// Draw track mesh first
var trackMeshWriteData = context.Allocate(m_TrackMesh.vertices.Length, m_TrackMesh.indices.Length);
trackMeshWriteData.SetAllVertices(m_TrackMesh.vertices);
trackMeshWriteData.SetAllIndices(m_TrackMesh.indices);
// Keep progress between 0 and 100
float clampedProgress = Mathf.Clamp(m_Progress, 0.0f, 100.0f);
// Determine how many triangles are used to depending on progress, to achieve a partially filled circle
int sliceSize = Mathf.FloorToInt((k_NumSteps * clampedProgress) / 100.0f);
if (sliceSize == 0)
return;
// Every step is 6 indices in the corresponding array
sliceSize *= 6;
var progressMeshWriteData = context.Allocate(m_ProgressMesh.vertices.Length, sliceSize);
progressMeshWriteData.SetAllVertices(m_ProgressMesh.vertices);
var tempIndicesArray = new NativeArray<ushort>(m_ProgressMesh.indices, Allocator.Temp);
progressMeshWriteData.SetAllIndices(tempIndicesArray.Slice(0, sliceSize));
tempIndicesArray.Dispose();
}
}
}
Create a C# script named EllipseMesh.cs
with the following content:
using UnityEngine;
using UnityEngine.UIElements;
namespace MyUILibrary
{
public class EllipseMesh
{
int m_NumSteps;
float m_Width;
float m_Height;
Color m_Color;
float m_BorderSize;
bool m_IsDirty;
public Vertex[] vertices { get; private set; }
public ushort[] indices { get; private set; }
public EllipseMesh(int numSteps)
{
m_NumSteps = numSteps;
m_IsDirty = true;
}
public void UpdateMesh()
{
if (!m_IsDirty)
return;
int numVertices = numSteps * 2;
int numIndices = numVertices * 6;
if (vertices == null || vertices.Length != numVertices)
vertices = new Vertex[numVertices];
if (indices == null || indices.Length != numIndices)
indices = new ushort[numIndices];
float stepSize = 360.0f / (float)numSteps;
float angle = -180.0f;
for (int i = 0; i < numSteps; ++i)
{
angle -= stepSize;
float radians = Mathf.Deg2Rad * angle;
float outerX = Mathf.Sin(radians) * width;
float outerY = Mathf.Cos(radians) * height;
Vertex outerVertex = new Vertex();
outerVertex.position = new Vector3(width + outerX, height + outerY, Vertex.nearZ);
outerVertex.tint = color;
vertices[i * 2] = outerVertex;
float innerX = Mathf.Sin(radians) * (width - borderSize);
float innerY = Mathf.Cos(radians) * (height - borderSize);
Vertex innerVertex = new Vertex();
innerVertex.position = new Vector3(width + innerX, height + innerY, Vertex.nearZ);
innerVertex.tint = color;
vertices[i * 2 + 1] = innerVertex;
indices[i * 6] = (ushort)((i == 0) ? vertices.Length - 2 : (i - 1) * 2); // previous outer vertex
indices[i * 6 + 1] = (ushort)(i * 2); // current outer vertex
indices[i * 6 + 2] = (ushort)(i * 2 + 1); // current inner vertex
indices[i * 6 + 3] = (ushort)((i == 0) ? vertices.Length - 2 : (i - 1) * 2); // previous outer vertex
indices[i * 6 + 4] = (ushort)(i * 2 + 1); // current inner vertex
indices[i * 6 + 5] = (ushort)((i == 0) ? vertices.Length - 1 : (i - 1) * 2 + 1); // previous inner vertex
}
m_IsDirty = false;
}
public bool isDirty => m_IsDirty;
void CompareAndWrite(ref float field, float newValue)
{
if (Mathf.Abs(field - newValue) > float.Epsilon)
{
m_IsDirty = true;
field = newValue;
}
}
public int numSteps
{
get => m_NumSteps;
set
{
m_IsDirty = value != m_NumSteps;
m_NumSteps = value;
}
}
public float width
{
get => m_Width;
set => CompareAndWrite(ref m_Width, value);
}
public float height
{
get => m_Height;
set => CompareAndWrite(ref m_Height, value);
}
public Color color
{
get => m_Color;
set
{
m_IsDirty = value != m_Color;
m_Color = value;
}
}
public float borderSize
{
get => m_BorderSize;
set => CompareAndWrite(ref m_BorderSize, value);
}
}
}
Create a USS file to style the radial progress indicator custom control. Use UI Builder to add the control and apply the USS stylesheet. Test the control with different Progress
values.
Create a USS file named RadialProgress.uss
with the following content:
.radial-progress {
min-width: 26px;
min-height: 20px;
--track-color: rgb(130, 130, 130);
--progress-color: rgb(46, 132, 24);
--percentage-color: white;
margin-left: 5px;
margin-right: 5px;
margin-top: 5px;
margin-bottom: 5px;
flex-direction: row;
justify-content: center;
width: 100px;
height: 100px;
}
.radial-progress__label {
-unity-text-align: middle-left;
color: var(--percentage-color);
}
Create a UI Document named RadialProgressExample.uxml
.
Double-click RadialProgressExample.uxml
to open it in the UI Builder.
In the Library window, select Project > Custom Controls > MyUILibrary.
Drag RadialProgress to the Hierarchy window.
In the StyleSheets section of the UI Builder, add RadialProgress.uss
as existing USS.
In the Hierarchy window, select RadialProgress.
In the InspectorA Unity window that displays information about the currently selected GameObject, asset or project settings, allowing you to inspect and edit the values. More info
See in Glossary window, enter radial-progress
in the Name box.
In the Inspector window, enter different values in the Progress box. The percentage in the ViewportThe user’s visible area of an app on their screen.
See in Glossary changes, and the green progress ring resizes.
Use the UI Document in a sceneA Scene contains the environments and menus of your game. Think of each unique Scene file as a unique level. In each Scene, you place your environments, obstacles, and decorations, essentially designing and building your game in pieces. More info
See in Glossary, and create a C# MonoBehaviour script to update the Progress
property of the control with dynamic values for demo purposes.
In the radial-progress
folder, create a C# script named RadialProgressComponent.cs
with the following content:
using System.Collections;
using System.Collections.Generic;
using UnityEngine;
using UnityEngine.UIElements;
using MyUILibrary;
[RequireComponent(typeof(UIDocument))]
public class RadialProgressComponent : MonoBehaviour
{
RadialProgress m_RadialProgress;
void Start()
{
var root = GetComponent<UIDocument>().rootVisualElement;
m_RadialProgress = new RadialProgress() {
style = {
position = Position.Absolute,
left = 20, top = 20, width = 200, height = 200
}
};
root.Add(m_RadialProgress);
}
void Update()
{
// For demo purpose, give the progress property dynamic values.
m_RadialProgress.progress = ((Mathf.Sin(Time.time) + 1.0f) / 2.0f) * 60.0f + 10.0f;
}
}
In Unity, select GameObject > UI Toolkit > UI Document.
Select the UIDocument in the Hierarchy window.
Add RadialProgressComponent.cs as a component of the UIDocument GameObjectThe fundamental object in Unity scenes, which can represent characters, props, scenery, cameras, waypoints, and more. A GameObject’s functionality is defined by the Components attached to it. More info
See in Glossary.
Enter play mode. The progress indicator appears in the scene, and the progress ring and value change dynamically.
When you visit any website, it may store or retrieve information on your browser, mostly in the form of cookies. This information might be about you, your preferences or your device and is mostly used to make the site work as you expect it to. The information does not usually directly identify you, but it can give you a more personalized web experience. Because we respect your right to privacy, you can choose not to allow some types of cookies. Click on the different category headings to find out more and change our default settings. However, blocking some types of cookies may impact your experience of the site and the services we are able to offer.
More information
These cookies enable the website to provide enhanced functionality and personalisation. They may be set by us or by third party providers whose services we have added to our pages. If you do not allow these cookies then some or all of these services may not function properly.
These cookies allow us to count visits and traffic sources so we can measure and improve the performance of our site. They help us to know which pages are the most and least popular and see how visitors move around the site. All information these cookies collect is aggregated and therefore anonymous. If you do not allow these cookies we will not know when you have visited our site, and will not be able to monitor its performance.
These cookies may be set through our site by our advertising partners. They may be used by those companies to build a profile of your interests and show you relevant adverts on other sites. They do not store directly personal information, but are based on uniquely identifying your browser and internet device. If you do not allow these cookies, you will experience less targeted advertising. Some 3rd party video providers do not allow video views without targeting cookies. If you are experiencing difficulty viewing a video, you will need to set your cookie preferences for targeting to yes if you wish to view videos from these providers. Unity does not control this.
These cookies are necessary for the website to function and cannot be switched off in our systems. They are usually only set in response to actions made by you which amount to a request for services, such as setting your privacy preferences, logging in or filling in forms. You can set your browser to block or alert you about these cookies, but some parts of the site will not then work. These cookies do not store any personally identifiable information.