# generateVisualContent

> Delegate function to generate the visual content of a visual element.

## Definition

* **Type:** Property
* **Namespace:** [UnityEngine.UIElements](/engine/6000.0/script-reference/unityengine/uielements.md)
* **Assembly:** UnityEngine.UIElementsModule

```csharp
public Action<MeshGenerationContext> generateVisualContent { get; set; }
```

### Remarks

Use this delegate to generate custom geometry in the content region of the [VisualElement](/engine/6000.0/script-reference/unityengine/uielements/visualelement.md).

This delegate is called during the initial creation of the [VisualElement](/engine/6000.0/script-reference/unityengine/uielements/visualelement.md) and whenever a repaint is needed. This delegate isn't called on every frame refresh. To force a repaint, call [VisualElement.MarkDirtyRepaint](/engine/6000.0/script-reference/unityengine/uielements/visualelement/markdirtyrepaint.md).

**Note**: When you execute code in a handler to this delegate, don't update any property of the [VisualElement](/engine/6000.0/script-reference/unityengine/uielements/visualelement.md), as this can alter the generated content and cause unwanted side effects, such as lagging or missed updates. To avoid this, treat the [VisualElement](/engine/6000.0/script-reference/unityengine/uielements/visualelement.md) as read-only within the delegate.

Additional Resources: [MeshGenerationContext](/engine/6000.0/script-reference/unityengine/uielements/meshgenerationcontext.md)

### Examples

```csharp
//This example creates a custom element that dynamically renders a textured rectangle 
//based on the element’s size. 

using UnityEngine;
using UnityEngine.UIElements;

public class TexturedElement : VisualElement
{
    static readonly Vertex[] k_Vertices = new Vertex[4];
    static readonly ushort[] k_Indices = { 0, 1, 2, 2, 3, 0 };

    static TexturedElement()
    {
        k_Vertices[0].tint = Color.white;
        k_Vertices[1].tint = Color.white;
        k_Vertices[2].tint = Color.white;
        k_Vertices[3].tint = Color.white;

        k_Vertices[0].uv = new Vector2(0, 0);
        k_Vertices[1].uv = new Vector2(0, 1);
        k_Vertices[2].uv = new Vector2(1, 1);
        k_Vertices[3].uv = new Vector2(1, 0);
    }

    Texture2D m_Texture;

    public TexturedElement()
    {
        //This element grows to fill the available space.
        style.flexGrow = 1.0f;

        //Subscribes the OnGenerateVisualContent method to the generateVisualContent delegate.
        generateVisualContent += OnGenerateVisualContent;

        //Create a simple 2x2 checkerboard texture.
        m_Texture = new Texture2D(2, 2);
        m_Texture.SetPixels(new Color[] {
            Color.white, Color.black,
            Color.black, Color.white
        });
        m_Texture.Apply();

        //You can also load a texture from a file.
        //m_Texture = AssetDatabase.LoadAssetAtPath<Texture2D>("Assets/tex.png");
    }

    //This method is called when the element needs to render its content.
    void OnGenerateVisualContent(MeshGenerationContext mgc)
    {
        Rect r = contentRect;
        if (r.width < 0.01f || r.height < 0.01f)
            return; // Skip rendering when too small.

        float left = 0;
        float right = r.width;
        float top = 0;
        float bottom = r.height;

        k_Vertices[0].position = new Vector3(left, bottom, Vertex.nearZ);
        k_Vertices[1].position = new Vector3(left, top, Vertex.nearZ);
        k_Vertices[2].position = new Vector3(right, top, Vertex.nearZ);
        k_Vertices[3].position = new Vector3(right, bottom, Vertex.nearZ);

        MeshWriteData mwd = mgc.Allocate(k_Vertices.Length, k_Indices.Length, m_Texture);

        mwd.SetAllVertices(k_Vertices);
        mwd.SetAllIndices(k_Indices);
    }
}
```