using System.Collections;
using System.Collections.Generic;
using UnityEngine;
using UnityEngine.UI;
[AddComponentMenu("UI/Effects/Gradient")]
public class Gridient : BaseMeshEffect
{
[SerializeField] private Color32 topColor = Color.white;
[SerializeField] private Color32 bottomColor = Color.black;
public override void ModifyMesh(VertexHelper vh)
{
if (!IsActive())
{
return;
}
var vertexList = new List<UIVertex>();
vh.GetUIVertexStream(vertexList);
int count = vertexList.Count;
ApplyGradient(vertexList, 0, count);
vh.Clear();
vh.AddUIVertexTriangleStream(vertexList);
}
private void ApplyGradient(List<UIVertex> vertexList, int start, int end)
{
float bottomY = vertexList[0].position.y-0.2f;
float topY = vertexList[0].position.y;
for (int i = start; i < end; ++i)
{
float y = vertexList[i].position.y;
if (y > topY)
{
topY = y;
}
else if (y < bottomY)
{
bottomY = y;
}
}
float uiElementHeight = topY - bottomY;
for (int i = start; i < end; ++i)
{
UIVertex uiVertex = vertexList[i];
uiVertex.color = Color32.Lerp(bottomColor, topColor, (uiVertex.position.y - bottomY) / uiElementHeight);
vertexList[i] = uiVertex;
}
}
}