UGUI描边

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原创 2022-10-30 21:01:46 949 阅读 AI 写同款· GEO 优化 ›

Unity UGUI的Outl通用化的推荐能力ine(描边)组件的介绍及使用新增数据源阅读详情

实现描边

采样坐标用圆的参数方程计算

fixed SampleAlpha(int pIndex, v2f IN)
{
    const fixed sinArray[12] = { 0, 0.5, 0.866, 1, 0.866, 0.5, 0, -0.5, -0.866, -1, -0.866, -0.5 };
	const fixed cosArray[12] = { 1, 0.866, 0.5, 0, -0.5, -0.866, -1, -0.866, -0.5, 0, 0.5, 0.866 };
    float2 pos = IN.texcoord + _MainTex_TexelSize.xy * float2(cosArray[pIndex], sinArray[pIndex]) * _OutlineWidth;
    return (tex2D(_MainTex, pos) + _TextureSampleAdd).w * _OutlineColor.w;
}

像素着色器

fixed4 frag(v2f IN) : SV_Target
{
    fixed4 color = (tex2D(_MainTex, IN.texcoord) + _TextureSampleAdd) * IN.color;
 
    half4 val = half4(_OutlineColor.x, _OutlineColor.y, _OutlineColor.z, 0);
	// 注意：这里为了简化代码用了循环
	// 尽量不要在Shader中使用循环，多复制几次代码都行
	for (int i = 0; i < 12; i++)
	{
		val.w += SampleAlpha(i, IN);
	}
	color = (val * (1.0 - color.a)) + (color * color.a);
 
	return color;
}

超出图片范围的部分被裁减掉了，我们需要对图片的区域进行调整，保证描边的部分也被包含在区域内。

在C#层进行区域扩展

要扩展区域，就得修改顶点。Unity提供了BaseMeshEffect类供开发者对UI组件的顶点进行修改。

获取顶点

获取到所有的顶点信息

public class OutlineEx : BaseMeshEffect
{
    public Color OutlineColor = Color.white;
    [Range(0, 6)]
    public int OutlineWidth = 0;
 
    private static List<UIVertex> m_VetexList = new List<UIVertex>();
 
 
    protected override void Awake()
    {
        base.Awake();
 
        var shader = Shader.Find("TSF Shaders/UI/OutlineEx");
        base.graphic.material = new Material(shader);
 
        var v1 = base.graphic.canvas.additionalShaderChannels;
        var v2 = AdditionalCanvasShaderChannels.Tangent;
        if ((v1 & v2) != v2)
        {
            base.graphic.canvas.additionalShaderChannels |= v2;
        }
        this._Refresh();
    }
 
 
#if UNITY_EDITOR
    protected override void OnValidate()
    {
        base.OnValidate();
 
        if (base.graphic.material != null)
        {
            this._Refresh();
        }
    }
#endif
 
 
    private void _Refresh()
    {
        base.graphic.material.SetColor("_OutlineColor", this.OutlineColor);
        base.graphic.material.SetInt("_OutlineWidth", this.OutlineWidth);
        base.graphic.SetVerticesDirty();
    }
 
 
    public override void ModifyMesh(VertexHelper vh)
    {
        vh.GetUIVertexStream(m_VetexList);
 
        this._ProcessVertices();
 
        vh.Clear();
        vh.AddUIVertexTriangleStream(m_VetexList);
    }
 
 
    private void _ProcessVertices()
    {
        // TODO: 处理顶点
    }
}

进行外扩

private void _ProcessVertices()
{
    for (int i = 0, count = m_VetexList.Count - 3; i <= count; i += 3)
    {
        var v1 = m_VetexList[i];
        var v2 = m_VetexList[i + 1];
        var v3 = m_VetexList[i + 2];
        // 计算原顶点坐标中心点
        //
        var minX = _Min(v1.position.x, v2.position.x, v3.position.x);
        var minY = _Min(v1.position.y, v2.position.y, v3.position.y);
        var maxX = _Max(v1.position.x, v2.position.x, v3.position.x);
        var maxY = _Max(v1.position.y, v2.position.y, v3.position.y);
        var posCenter = new Vector2(minX + maxX, minY + maxY) * 0.5f;
        // 计算原始顶点坐标和UV的方向
        //
        Vector2 triX, triY, uvX, uvY;
        Vector2 pos1 = v1.position;
        Vector2 pos2 = v2.position;
        Vector2 pos3 = v3.position;
        if (Mathf.Abs(Vector2.Dot((pos2 - pos1).normalized, Vector2.right))
            > Mathf.Abs(Vector2.Dot((pos3 - pos2).normalized, Vector2.right)))
        {
            triX = pos2 - pos1;
            triY = pos3 - pos2;
            uvX = v2.uv0 - v1.uv0;
            uvY = v3.uv0 - v2.uv0;
        }
        else
        {
            triX = pos3 - pos2;
            triY = pos2 - pos1;
            uvX = v3.uv0 - v2.uv0;
            uvY = v2.uv0 - v1.uv0;
        }
        // 为每个顶点设置新的Position和UV
        //
        v1 = _SetNewPosAndUV(v1, this.OutlineWidth, posCenter, triX, triY, uvX, uvY);
        v2 = _SetNewPosAndUV(v2, this.OutlineWidth, posCenter, triX, triY, uvX, uvY);
        v3 = _SetNewPosAndUV(v3, this.OutlineWidth, posCenter, triX, triY, uvX, uvY);
        // 应用设置后的UIVertex
        //
        m_VetexList[i] = v1;
        m_VetexList[i + 1] = v2;
        m_VetexList[i + 2] = v3;
    }
}
 
 
private static UIVertex _SetNewPosAndUV(UIVertex pVertex, int pOutLineWidth,
    Vector2 pPosCenter,
    Vector2 pTriangleX, Vector2 pTriangleY,
    Vector2 pUVX, Vector2 pUVY)
{
    // Position
    var pos = pVertex.position;
    var posXOffset = pos.x > pPosCenter.x ? pOutLineWidth : -pOutLineWidth;
    var posYOffset = pos.y > pPosCenter.y ? pOutLineWidth : -pOutLineWidth;
    pos.x += posXOffset;
    pos.y += posYOffset;
    pVertex.position = pos;
    // UV
    var uv = pVertex.uv0;
    uv += pUVX / pTriangleX.magnitude * posXOffset * (Vector2.Dot(pTriangleX, Vector2.right) > 0 ? 1 : -1);
    uv += pUVY / pTriangleY.magnitude * posYOffset * (Vector2.Dot(pTriangleY, Vector2.up) > 0 ? 1 : -1);
    pVertex.uv0 = uv;
 
    return pVertex;
}
 
 
private static float _Min(float pA, float pB, float pC)
{
    return Mathf.Min(Mathf.Min(pA, pB), pC);
}
 
 
private static float _Max(float pA, float pB, float pC)
{
    return Mathf.Max(Mathf.Max(pA, pB), pC);
}

在这里插入图片描述

UV裁剪，排除不需要的像素

UV裁剪框就相当于图集中每个小图的范围。直接扩大必然会包含到小图邻接的图的像素。所以这一步我们需要对最终绘制出的图进行裁剪，保证这些不要的像素不被画出来。
裁剪的逻辑也很简单。如果该像素处于被扩大前的UV范围外，则设置它的alpha为0

UIVertex结构体

public struct UIVertex
{
    public static UIVertex simpleVert;
    public Vector3 position;
    public Vector3 normal;
    public Color32 color;
    public Vector2 uv0;
    public Vector2 uv1;
    public Vector2 uv2;
    public Vector2 uv3;
    public Vector4 tangent;
}

将原始UV框赋值给uv1和uv2成员

var uvMin = _Min(v1.uv0, v2.uv0, v3.uv0);
var uvMax = _Max(v1.uv0, v2.uv0, v3.uv0);
vertex.uv1 = new Vector2(pUVOrigin.x, pUVOrigin.y);
vertex.uv2 = new Vector2(pUVOrigin.z, pUVOrigin.w);
 
private static Vector2 _Min(Vector2 pA, Vector2 pB, Vector2 pC)
{
    return new Vector2(_Min(pA.x, pB.x, pC.x), _Min(pA.y, pB.y, pC.y));
}
 
 
private static Vector2 _Max(Vector2 pA, Vector2 pB, Vector2 pC)
{
    return new Vector2(_Max(pA.x, pB.x, pC.x), _Max(pA.y, pB.y, pC.y));
}

在这里插入图片描述

最终代码

using UnityEngine;
using UnityEngine.UI;
using System.Collections.Generic;
 
 
namespace TooSimpleFramework.UI
{
    /// <summary>
    /// UGUI描边
    /// </summary>
    public class OutlineEx : BaseMeshEffect
    {
        public Color OutlineColor = Color.white;
        [Range(0, 6)]
        public int OutlineWidth = 0;
 
        private static List<UIVertex> m_VetexList = new List<UIVertex>();
 
 
        protected override void Start()
        {
            base.Start();
 
            var shader = Shader.Find("TSF Shaders/UI/OutlineEx");
            base.graphic.material = new Material(shader);
 
            var v1 = base.graphic.canvas.additionalShaderChannels;
            var v2 = AdditionalCanvasShaderChannels.TexCoord1;
            if ((v1 & v2) != v2)
            {
                base.graphic.canvas.additionalShaderChannels |= v2;
            }
            v2 = AdditionalCanvasShaderChannels.TexCoord2;
            if ((v1 & v2) != v2)
            {
                base.graphic.canvas.additionalShaderChannels |= v2;
            }
 
            this._Refresh();
        }
 
 
#if UNITY_EDITOR
        protected override void OnValidate()
        {
            base.OnValidate();
 
            if (base.graphic.material != null)
            {
                this._Refresh();
            }
        }
#endif
 
 
        private void _Refresh()
        {
            base.graphic.material.SetColor("_OutlineColor", this.OutlineColor);
            base.graphic.material.SetInt("_OutlineWidth", this.OutlineWidth);
            base.graphic.SetVerticesDirty();
        }
 
 
        public override void ModifyMesh(VertexHelper vh)
        {
            vh.GetUIVertexStream(m_VetexList);
 
            this._ProcessVertices();
 
            vh.Clear();
            vh.AddUIVertexTriangleStream(m_VetexList);
        }
 
 
        private void _ProcessVertices()
        {
            for (int i = 0, count = m_VetexList.Count - 3; i <= count; i += 3)
            {
                var v1 = m_VetexList[i];
                var v2 = m_VetexList[i + 1];
                var v3 = m_VetexList[i + 2];
                // 计算原顶点坐标中心点
                //
                var minX = _Min(v1.position.x, v2.position.x, v3.position.x);
                var minY = _Min(v1.position.y, v2.position.y, v3.position.y);
                var maxX = _Max(v1.position.x, v2.position.x, v3.position.x);
                var maxY = _Max(v1.position.y, v2.position.y, v3.position.y);
                var posCenter = new Vector2(minX + maxX, minY + maxY) * 0.5f;
                // 计算原始顶点坐标和UV的方向
                //
                Vector2 triX, triY, uvX, uvY;
                Vector2 pos1 = v1.position;
                Vector2 pos2 = v2.position;
                Vector2 pos3 = v3.position;
                if (Mathf.Abs(Vector2.Dot((pos2 - pos1).normalized, Vector2.right))
                    > Mathf.Abs(Vector2.Dot((pos3 - pos2).normalized, Vector2.right)))
                {
                    triX = pos2 - pos1;
                    triY = pos3 - pos2;
                    uvX = v2.uv0 - v1.uv0;
                    uvY = v3.uv0 - v2.uv0;
                }
                else
                {
                    triX = pos3 - pos2;
                    triY = pos2 - pos1;
                    uvX = v3.uv0 - v2.uv0;
                    uvY = v2.uv0 - v1.uv0;
                }
                // 计算原始UV框
                //
                var uvMin = _Min(v1.uv0, v2.uv0, v3.uv0);
                var uvMax = _Max(v1.uv0, v2.uv0, v3.uv0);
                var uvOrigin = new Vector4(uvMin.x, uvMin.y, uvMax.x, uvMax.y);
                // 为每个顶点设置新的Position和UV，并传入原始UV框
                //
                v1 = _SetNewPosAndUV(v1, this.OutlineWidth, posCenter, triX, triY, uvX, uvY, uvOrigin);
                v2 = _SetNewPosAndUV(v2, this.OutlineWidth, posCenter, triX, triY, uvX, uvY, uvOrigin);
                v3 = _SetNewPosAndUV(v3, this.OutlineWidth, posCenter, triX, triY, uvX, uvY, uvOrigin);
                // 应用设置后的UIVertex
                //
                m_VetexList[i] = v1;
                m_VetexList[i + 1] = v2;
                m_VetexList[i + 2] = v3;
            }
        }
 
 
        private static UIVertex _SetNewPosAndUV(UIVertex pVertex, int pOutLineWidth,
            Vector2 pPosCenter,
            Vector2 pTriangleX, Vector2 pTriangleY,
            Vector2 pUVX, Vector2 pUVY,
            Vector4 pUVOrigin)
        {
            // Position
            var pos = pVertex.position;
            var posXOffset = pos.x > pPosCenter.x ? pOutLineWidth : -pOutLineWidth;
            var posYOffset = pos.y > pPosCenter.y ? pOutLineWidth : -pOutLineWidth;
            pos.x += posXOffset;
            pos.y += posYOffset;
            pVertex.position = pos;
            // UV
            var uv = pVertex.uv0;
            uv += pUVX / pTriangleX.magnitude * posXOffset * (Vector2.Dot(pTriangleX, Vector2.right) > 0 ? 1 : -1);
            uv += pUVY / pTriangleY.magnitude * posYOffset * (Vector2.Dot(pTriangleY, Vector2.up) > 0 ? 1 : -1);
            pVertex.uv0 = uv;
            // 原始UV框
            pVertex.uv1 = new Vector2(pUVOrigin.x, pUVOrigin.y);
            pVertex.uv2 = new Vector2(pUVOrigin.z, pUVOrigin.w);
 
            return pVertex;
        }
 
 
        private static float _Min(float pA, float pB, float pC)
        {
            return Mathf.Min(Mathf.Min(pA, pB), pC);
        }
 
 
        private static float _Max(float pA, float pB, float pC)
        {
            return Mathf.Max(Mathf.Max(pA, pB), pC);
        }
 
 
        private static Vector2 _Min(Vector2 pA, Vector2 pB, Vector2 pC)
        {
            return new Vector2(_Min(pA.x, pB.x, pC.x), _Min(pA.y, pB.y, pC.y));
        }
 
 
        private static Vector2 _Max(Vector2 pA, Vector2 pB, Vector2 pC)
        {
            return new Vector2(_Max(pA.x, pB.x, pC.x), _Max(pA.y, pB.y, pC.y));
        }
    }
}

Shader

Shader "TSF Shaders/UI/OutlineEx" 
{
    Properties
    {
        _MainTex ("Main Texture", 2D) = "white" {}
        _Color ("Tint", Color) = (1, 1, 1, 1)
        _OutlineColor ("Outline Color", Color) = (1, 1, 1, 1)
        _OutlineWidth ("Outline Width", Int) = 1
 
        _StencilComp ("Stencil Comparison", Float) = 8
        _Stencil ("Stencil ID", Float) = 0
        _StencilOp ("Stencil Operation", Float) = 0
        _StencilWriteMask ("Stencil Write Mask", Float) = 255
        _StencilReadMask ("Stencil Read Mask", Float) = 255
 
        _ColorMask ("Color Mask", Float) = 15
 
        [Toggle(UNITY_UI_ALPHACLIP)] _UseUIAlphaClip ("Use Alpha Clip", Float) = 0
    }
 
    SubShader
    {
        Tags
        { 
            "Queue"="Transparent" 
            "IgnoreProjector"="True" 
            "RenderType"="Transparent" 
            "PreviewType"="Plane"
            "CanUseSpriteAtlas"="True"
        }
        
        Stencil
        {
            Ref [_Stencil]
            Comp [_StencilComp]
            Pass [_StencilOp] 
            ReadMask [_StencilReadMask]
            WriteMask [_StencilWriteMask]
        }
 
        Cull Off
        Lighting Off
        ZWrite Off
        ZTest [unity_GUIZTestMode]
        Blend SrcAlpha OneMinusSrcAlpha
        ColorMask [_ColorMask]
 
        Pass
        {
			Name "OUTLINE"
 
            CGPROGRAM
            #pragma vertex vert
            #pragma fragment frag
 
			sampler2D _MainTex;
			fixed4 _Color;
			fixed4 _TextureSampleAdd;
			float4 _MainTex_TexelSize;
 
			float4 _OutlineColor;
			int _OutlineWidth;
 
			struct appdata
			{
				float4 vertex : POSITION;
				float2 texcoord : TEXCOORD0;
                float2 texcoord1 : TEXCOORD1;
                float2 texcoord2 : TEXCOORD2;
				fixed4 color : COLOR;
			};
 
			struct v2f
			{
				float4 vertex : SV_POSITION;
				float2 texcoord : TEXCOORD0;
                float2 uvOriginXY : TEXCOORD1;
                float2 uvOriginZW : TEXCOORD2;
				fixed4 color : COLOR;
			};
 
			v2f vert(appdata IN)
			{
				v2f o;
 
				o.vertex = UnityObjectToClipPos(IN.vertex);
				o.texcoord = IN.texcoord;
                o.uvOriginXY = IN.texcoord1;
                o.uvOriginZW = IN.texcoord2;
				o.color = IN.color * _Color;
 
				return o;
			}
 
			fixed IsInRect(float2 pPos, float2 pClipRectXY, float2 pClipRectZW)
			{
				pPos = step(pClipRectXY, pPos) * step(pPos, pClipRectZW);
				return pPos.x * pPos.y;
			}
 
            fixed SampleAlpha(int pIndex, v2f IN)
            {
                const fixed sinArray[12] = { 0, 0.5, 0.866, 1, 0.866, 0.5, 0, -0.5, -0.866, -1, -0.866, -0.5 };
                const fixed cosArray[12] = { 1, 0.866, 0.5, 0, -0.5, -0.866, -1, -0.866, -0.5, 0, 0.5, 0.866 };
                float2 pos = IN.texcoord + _MainTex_TexelSize.xy * float2(cosArray[pIndex], sinArray[pIndex]) * _OutlineWidth;
				return IsInRect(pos, IN.uvOriginXY, IN.uvOriginZW) * (tex2D(_MainTex, pos) + _TextureSampleAdd).w * _OutlineColor.w;
            }
 
            fixed4 frag(v2f IN) : SV_Target
            {
                fixed4 color = (tex2D(_MainTex, IN.texcoord) + _TextureSampleAdd) * IN.color;
                if (_OutlineWidth > 0) 
                {
                    color.w *= IsInRect(IN.texcoord, IN.uvOriginXY, IN.uvOriginZW);
                    half4 val = half4(_OutlineColor.x, _OutlineColor.y, _OutlineColor.z, 0);
 
                    val.w += SampleAlpha(0, IN);
                    val.w += SampleAlpha(1, IN);
                    val.w += SampleAlpha(2, IN);
                    val.w += SampleAlpha(3, IN);
                    val.w += SampleAlpha(4, IN);
                    val.w += SampleAlpha(5, IN);
                    val.w += SampleAlpha(6, IN);
                    val.w += SampleAlpha(7, IN);
                    val.w += SampleAlpha(8, IN);
                    val.w += SampleAlpha(9, IN);
                    val.w += SampleAlpha(10, IN);
                    val.w += SampleAlpha(11, IN);
 
                    val.w = clamp(val.w, 0, 1);
                    color = (val * (1.0 - color.a)) + (color * color.a);
                }
                return color;
            }
            ENDCG
        }
    }
}

在这里插入图片描述

优化

仔细观察上面最终效果的Ass，可以发现它们的字符本身被后一个字符的描边覆盖了一部分。使用两个Pass可以解决，一个只绘制描边，另一个只绘制本身
Pass1

fixed4 frag(v2f IN) : SV_Target
{
    // 省略
    val.w = clamp(val.w, 0, 1);
    return val;
}

Pass2

fixed4 frag(v2f IN) : SV_Target
{
    fixed4 color = (tex2D(_MainTex, IN.texcoord) + _TextureSampleAdd) * IN.color;
    color.w *= IsInRect(IN.texcoord, IN.uvOriginXY, IN.uvOriginZW);
    return color;
}

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