Unity编辑器 - 使用GL绘制控件

Unity编辑器 - 使用GL绘制控件

控件较为复杂时，可能造成界面卡顿，在EditorGUI中也可以灵活使用GL绘制来提升性能。
以绘制线段为例：

using UnityEngine;
using UnityEditor;

public class EditorGL {
    private static Material _sLineMat;

    static EditorGL() {
        Shader shader = Shader.Find("Hidden/Internal-Colored");
        _sLineMat = new Material(shader);
        _sLineMat.hideFlags = HideFlags.HideAndDontSave;
        _sLineMat.SetInt("_SrcBlend", (int)UnityEngine.Rendering.BlendMode.SrcAlpha);
        _sLineMat.SetInt("_DstBlend", (int)UnityEngine.Rendering.BlendMode.OneMinusSrcAlpha);
        _sLineMat.SetInt("_Cull", (int)UnityEngine.Rendering.CullMode.Off);
        _sLineMat.SetInt("_ZWrite", 0);
    }

    public static void DrawVerticalLine(float x, float minY, float maxY, Color color) {
        if (Event.current.type == EventType.Repaint) {
            Color color2 = Handles.color;
            _sLineMat.SetPass(0);
            if (Application.platform == RuntimePlatform.WindowsEditor) {
                GL.Begin(7);
            }
            else {
                GL.Begin(1);
            }
            DrawVerticalLineFast(x, minY, maxY, color);
            GL.End();
            Handles.color = color2;
        }
    }

    private static void DrawVerticalLineFast(float x, float minY, float maxY, Color color) {
        if (Application.platform == RuntimePlatform.WindowsEditor) {
            GL.Color(color);
            GL.Vertex(new Vector3(x - 0.5f, minY, 0f));
            GL.Vertex(new Vector3(x + 0.5f, minY, 0f));
            GL.Vertex(new Vector3(x + 0.5f, maxY, 0f));
            GL.Vertex(new Vector3(x - 0.5f, maxY, 0f));
        }
        else {
            GL.Color(color);
            GL.Vertex(new Vector3(x, minY, 0f));
            GL.Vertex(new Vector3(x, maxY, 0f));
        }
    }
}