Unity手绘Mesh实现颜色渐变

我的接到的需求是这样的

请看最后的效果图

我们开始

简化一下需求就是根据2个点创建宽度为width*2的带有颜色渐变的Mesh

创建一个正方形的Mesh需要四个点，而我这儿的需求是只有两个所以我就将两点看成中心点通过一个Width来得到四个点也就是这儿。

Vector3 pos1 = nextDrawnMesh.transform.position + new Vector3(-width, 0, 0);
Vector3 pos2 = nextDrawnMesh.transform.position + new Vector3(width, 0, 0);
Vector3 pos3 = currentDrawnMesh.transform.position + new Vector3(width, 0, 0);
Vector3 pos4 = currentDrawnMesh.transform.position + new Vector3(-width, 0, 0);

可以看到他她是一个Vector3的所以这个值附在不同的位置会有不同的方向可以自己去测试一下想要的效果

或者说自己定义四个点不用这儿的计算可自行赋值

所以就有方法 addpos他就是用来添加所有的点的 addpos对应添加点了 name就有对应添加颜色 addcolor

currentDrawnMesh.SetShaderColor("_ColorTop", color);
currentDrawnMesh.SetShaderColor("_ColorMid", color);
nextDrawnMesh.SetShaderColor("_ColorBot", color);

这三个东西呢不需要了解是Shader的属性，根须Shader的字段来的这儿踩到个坑哈，这个属性名称不是在Shader代码里属性的名称哈，要设置Shader里属性要仔细看看Shader面板下面的各个属性名称去对应一下，我一开始就拿错了，去Shader里拿代码里面的名称是修改不了的哦!

public class ProtractMeshController : MonoBehaviour
{
    public static ProtractMeshController interest;
    public float width = 0.002f;
    public GameObject MeshPosObj;
    public Color color;
    private void Awake()
    {
        interest = this;
        InitProtractMeshPos();
        widthRecording = width;
    }

    float widthRecording ;

    public void Update()
    {
        if(widthRecording!= width)
        {
            widthRecording = width;
            InitProtractMeshPos();
        }
    }

    public void AddPos(List<GameObject> pos){
 
        for(int  i=0;i< pos.Count; i++)
        {
            GameObject go = GameObject.Instantiate(MeshPosObj, pos[i].transform.position,Quaternion.identity);
            go.transform.parent = this.transform;
        }

        InitProtractMeshPos();
    }

    public void AddColor(List<Color32> colors)
    {
        if (this.transform.childCount <= 0) return;

        for (int i = 0; i < colors.Count; i++)
        {
            if (i + 1 < colors.Count)
            {
                DrawnMesh currentDrawnMesh = transform.GetChild(i).GetComponent<DrawnMesh>();
                DrawnMesh nextDrawnMesh = transform.GetChild(i + 1).GetComponent<DrawnMesh>();
                currentDrawnMesh.SetShaderColor("_ColorTop", colors[i + 1]);
                currentDrawnMesh.SetShaderColor("_ColorMid", colors[i + 1]);
                currentDrawnMesh.SetShaderColor("_ColorBot", colors[i]);
            }
        }
    }

    /// <summary>
    /// 初始化mesh点位
    /// </summary>
    public void InitProtractMeshPos()
    {
        for (int i = 0; i < transform.childCount; i++)
        {
            if (i + 1 < transform.childCount)
            {
                DrawnMesh currentDrawnMesh = transform.GetChild(i).GetComponent<DrawnMesh>();
                DrawnMesh nextDrawnMesh = transform.GetChild(i + 1).GetComponent<DrawnMesh>();
                Vector3 pos1 = nextDrawnMesh.transform.position + new Vector3(-width, 0, 0);
                Vector3 pos2 = nextDrawnMesh.transform.position + new Vector3(width, 0, 0);
                Vector3 pos3 = currentDrawnMesh.transform.position + new Vector3(width, 0, 0);
                Vector3 pos4 = currentDrawnMesh.transform.position + new Vector3(-width, 0, 0);
                currentDrawnMesh.posList = new List<Vector3>() { pos4, pos3, pos2, pos1 };
                currentDrawnMesh.SetMesh();
                currentDrawnMesh.SetShaderColor("_ColorTop", color);
                currentDrawnMesh.SetShaderColor("_ColorMid", color);
                nextDrawnMesh.SetShaderColor("_ColorBot", color);
            }
        }
    }

    public void Clean()
    {
        for(int i = transform.childCount; i> 0; i--)
        {
            GameObject.Destroy(transform.GetChild(i - 1).gameObject);
        }
    }
}

这个就是绘制Mesh啦！要注意自己绘制的mesh要添加好UV不然材质上上去不对哦！

public class DrawnMesh : MonoBehaviour
{
    public float proportion = 1f;
    public List<Vector3> posList = new List<Vector3>();//赋值顺序为顺时针或者逆时针(为世界坐标位置)
    public MeshRenderer meshRenderer;


    public GameObject ga;
    void Awake()
    {
        meshRenderer = GetComponent<MeshRenderer>();
    }

    /// <summary>
    /// 设置shader的颜色属性
    /// </summary>
    /// <param name="attributeName"> 三种 "_ColorTop","_ColorMid","_ColorBot" </param>
    /// <param name="color"></param>
    public void SetShaderColor(string attributeName, Color color)
    {
        meshRenderer.materials[0].SetColor(attributeName, color);
    }

    public void SetMiddle(float value)
    {
        meshRenderer.materials[0].SetFloat("_Middle", value);
    }

    public void SetMesh()
    {
        List<Vector3> vertices = new List<Vector3>();
        for (int i = 0; i < posList.Count; i++)
        {
            Vector3 pos = (posList[i] - transform.position) * proportion;
            vertices.Add(pos);
        }

        DrawPentagon(vertices);
    }

    void DrawPentagon(List<Vector3> vertices)
    {
        Mesh mesh = new Mesh();
        mesh.name = gameObject.name;
        int triangleAmount = vertices.Count - 2;
        int[] triangles = new int[3 * triangleAmount];

        //根据三角形的个数，来计算绘制三角形的顶点顺序（索引）  
        //顺序必须为顺时针或者逆时针  
        for (int i = 0; i < triangleAmount; i++)
        {
            triangles[3 * i] = 0;
            triangles[3 * i + 1] = i + 1;
            triangles[3 * i + 2] = i + 2;
        }

        Vector2[] baseUVs = new Vector2[] { new Vector2(0, 0), new Vector2(1, 0), new Vector2(1, 1), new Vector2(0, 1), };

        mesh.vertices = vertices.ToArray();
        mesh.uv = baseUVs;
        mesh.triangles = triangles;

        GetComponent<MeshFilter>().mesh = mesh;
    }
}

这个就是颜色对撞的shader了

Shader "Unlit/Gradient"
{
	Properties
	{
		[PerRendererData] _MainTex("Sprite Texture", 2D) = "white" {}
		_ColorTop("Top Color", Color) = (1, 1, 1, 1)
		_ColorMid("Mid Color", Color) = (1, 1, 1, 1)
		_ColorBot("Bot Color", Color) = (1, 1, 1, 1)
		_Middle("Middle", Range(0.001, 0.999)) = 1
		_test("Test", Range(0.001, 0.999)) = 1
	}
		SubShader
		{
		Tags {"Queue" = "Background"  "IgnoreProjector" = "True"}
		LOD 100
		ZWrite On
		Pass
		{
		CGPROGRAM
#pragma vertex vert  
#pragma fragment frag
#include "UnityCG.cginc"
		fixed4 _ColorTop;
	fixed4 _ColorMid;
	fixed4 _ColorBot;
	float  _Middle;
	float _test;
	struct v2f
	{
		float4 pos : SV_POSITION;
		float4 texcoord : TEXCOORD0;
	};
	v2f vert(appdata_full v)
	{
		v2f o;
		if (v.vertex.y > _test)
		{
			v.vertex.y = _test;
	}
		o.pos = UnityObjectToClipPos(v.vertex);
	o.texcoord = v.texcoord;
	return o;
	}
		fixed4 frag(v2f i) : COLOR
	{
		fixed4 c = lerp(_ColorBot, _ColorMid, i.texcoord.y / _Middle) * step(i.texcoord.y, _Middle);
	c += lerp(_ColorMid, _ColorTop, (i.texcoord.y - _Middle) / (1 - _Middle)) * step(_Middle, i.texcoord.y);
	c.a = 1;
	return c;
	}
		ENDCG
		}
		}
}

Unity手绘Mesh实现颜色渐变

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