Version: 2023.2+
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 a C# script to define the RadialProgress
class, and expose the control to UXML and UI Builder.
radial-progress
to store your files.radial-progress
folder, create a C# scrip named RadialProgress.cs
with the following content:using Unity.Collections; using UnityEngine; using UnityEngine.UIElements; namespace MyUILibrary { /// <summary> /// An element that displays progress inside a partially filled circle /// </summary> [UxmlElement] public partial class RadialProgress : VisualElement { // 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; /// <summary> /// A value between 0 and 100 /// </summary> [UxmlAttribute] 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__The 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](comp-MeshGroup.html)<span class="tooltipGlossaryLink">See in [Glossary](Glossary.html#Mesh)</span>, 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 triangle 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 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); }
Use UI Builder to add the control and apply the USS stylesheet. Test the control with different Progress
values.
RadialProgressExample.uxml
.RadialProgressExample.uxml
to open it in the UI Builder.RadialProgress.uss
as the existing USS.radial-progress
in the Name box.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# MonoBehaviour named RadialProgressComponent.cs
with the following content:
using MyUILibrary; using UnityEngine; using UnityEngine.UIElements; [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() { m_RadialProgress.progress = ((Mathf.Sin(Time.time) + 1.0f) / 2.0f) * 60.0f + 10.0f; } }
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