MeshWriteData.SetNextIndex

参数

描述

分配已分配索引列表的下一个索引的值。

Used to iteratively fill the values of the allocated indices via repeated calls to this function until all values have been provided. This way of filling index data is mutually exclusive with the use of SetAllIndices. After each invocation to this function, the internal counter for the next index is automatically incremented. When this method is called, it is not possible to use SetAllIndices to fill the indices. The index values provided refer directly to the vertices allocated in the same MeshWriteData object. Thus, an index of 0 means the first vertex and index 1 means the second vertex and so on.

using UnityEngine.UIElements;
public class MyVisualElement : VisualElement
{
    void MyGenerateVisualContent(MeshGenerationContext mgc)
    {
        var meshWriteData = mgc.Allocate(4, 6);
        // meshWriteData has been allocated with 6 indices for 2 triangles

        // ... set the vertices

        // Set indices for the first triangle
        meshWriteData.SetNextIndex(0);
        meshWriteData.SetNextIndex(1);
        meshWriteData.SetNextIndex(2);

        // Set indices for the second triangle
        meshWriteData.SetNextIndex(2);
        meshWriteData.SetNextIndex(1);
        meshWriteData.SetNextIndex(3);
    }
}

注意，调用 SetNextIndex 的次数少于分配的索引数将使其余索引具有随机值，因为 MeshGenerationContext.Allocate 不将返回的数据初始化为 0 以避免冗余工作。