Texture 纹理贴图

基础贴图Shader：只有纹理

1. 在属性中声明纹理贴图： _MainTex ("Texture", 2D) = "white" {}

2. 在Pass中声明变量： sampler2D _MainTex; float4 _MainTex_ST; 这个是成对出现，_MainTex_ST 用与计算坐标偏移offset

3. 在Vertex Function函数中进行纹理坐标采样： o.tex = v.texcoord;

4. 在Fragment Function 函数中采样纹理，并输出： float4 tex = tex2D(_MainTex,i.tex.xy*_MainTex_ST.xy+_MainTex_ST.zw); return float4(tex);

源代码：

Shader "Unlit/Textures_Base"
{
    Properties
    {
        _MainTex ("Texture", 2D) = "white" {}
    }
    SubShader
    {
        Pass
        {
            CGPROGRAM
            #pragma vertex vert
            #pragma fragment frag

            #include "UnityCG.cginc"

            sampler2D _MainTex;
            float4 _MainTex_ST;

            //输入结构体
            struct vertexInput{
                float4 vertex:POSITION;
                float4 texcoord:TEXCOORD0;
            };

            //输出结构体
            struct vertexOutput{
                float4 pos:SV_POSITION;
                float4 tex:TEXCOORD0;
            };

            vertexOutput vert (vertexInput v)
            {
                vertexOutput o;

                o.pos = mul(UNITY_MATRIX_MVP, v.vertex);
                o.tex = v.texcoord;

                return o;
            }

            fixed4 frag (vertexOutput i) : COLOR
            {
                //Texture Map
                float4 tex  = tex2D(_MainTex,i.tex.xy*_MainTex_ST.xy+_MainTex_ST.zw);
                return float4(tex);
            }
            ENDCG
        }
    }
}

纹理（Texture）+高光（Specular）+边缘光（Rim）+漫反射（diffuse）+环境光（ambient）+多光源（Lighting）（1个平行光，1个点光源）：

源代码：

Shader "JQM/Textures"
{
    Properties
    {
        _Color("Color", color) = (1.0,1.0,1.0,1.0)
        _MainTex ("Texture", 2D) = "white" {}
        _SpecColor("Specular Color", color) = (1.0,1.0,1.0,1.0)
        _Shininess("Shininess",float) =
        _RimColor("Rim Coloe Color", color) = (1.0,1.0,1.0,1.0)
        _RimPower("Rim Power",Range(0.1,10.0)) = 3.0
    }

    SubShader
    {

        Pass
        {
            Tags { "LightMode"="ForwardBase" }

            CGPROGRAM
            #pragma vertex vert
            #pragma fragment frag
            //#pragma exclude_renderers flash //给指定平台编译

            #include "UnityCG.cginc"

            //使用自定义变量
            sampler2D _MainTex;
            float4 _MainTex_ST;
            uniform float4 _Color;
            uniform float4 _SpecColor;
            uniform float4 _RimColor;
            uniform float _Shininess;
            uniform float _RimPower;

            //使用Unity定义的变量
            uniform float4 _LightColor0;

            //输入结构体
            struct vertexInput{
                float4 vertex:POSITION;
                float3 normal:NORMAL;
                float4 texcoord:TEXCOORD0;
            };

            //输出结构体
            struct vertexOutput{
                float4 pos:SV_POSITION;
                float4 tex:TEXCOORD0;
                float4 posWorld:TEXCOORD1;
                float3 normalDir:TEXCOORD2;
            };

            vertexOutput vert (vertexInput v)
            {
                vertexOutput o;

                o.posWorld = mul(_Object2World, v.vertex);
                o.normalDir =  normalize( mul(float4(v.normal,0.0),_World2Object).xyz);
                o.pos = mul(UNITY_MATRIX_MVP, v.vertex);
                o.tex = v.texcoord;

                return o;
            }

            fixed4 frag (vertexOutput i) : COLOR
            {
                float3 normalDirection = i.normalDir;
                float3 viewDirection = normalize(_WorldSpaceCameraPos.xyz- i.posWorld.xyz);
                float3 lightDirection;
                float atten;

                if(_WorldSpaceLightPos0.w==0.0)//平行光
                {
                    atten = 1.0;
                    lightDirection = normalize(_WorldSpaceLightPos0.xyz);
                }
                else
                {
                    float3 fragmentToLightSource = _WorldSpaceLightPos0.xyz -i.posWorld.xyz;
                    float distance = length(fragmentToLightSource);
                    atten  = 1.0/distance;
                    lightDirection = normalize(fragmentToLightSource);
                }

                //灯光
                float3 diffuseReflection = atten * _LightColor0.xyz *  saturate( dot(normalDirection,lightDirection));
                float3 specularReflection = atten * _LightColor0.xyz * _SpecColor.rgb*saturate( dot(normalDirection,lightDirection))*pow(saturate(dot(reflect(-lightDirection,normalDirection),viewDirection)),_Shininess);

                //Rim Light
                float rim= -dot(normalize(viewDirection),normalDirection);
                float3 rimLighting = atten * _LightColor0.xyz * _RimColor.rgb*saturate(dot(normalDirection,lightDirection))*pow(rim,_RimPower);

                float3 lightFinal = rimLighting + diffuseReflection+specularReflection+UNITY_LIGHTMODEL_AMBIENT.xyz;

                //Texture Map
                float4 tex  = tex2D(_MainTex,i.tex.xy*_MainTex_ST.xy+_MainTex_ST.zw);
                return float4(tex*lightFinal*_Color.xyz,1.0);

            }
            ENDCG
        }

        Pass
        {
            Tags { "LightMode"="ForwardAdd" }
            Blend One One

            CGPROGRAM
            #pragma vertex vert
            #pragma fragment frag
            //#pragma exclude_renderers flash //给指定平台编译

            #include "UnityCG.cginc"

            //使用自定义变量
            sampler2D _MainTex;
            float4 _MainTex_ST;
            uniform float4 _Color;
            uniform float4 _SpecColor;
            uniform float4 _RimColor;
            uniform float _Shininess;
            uniform float _RimPower;

            //使用Unity定义的变量
            uniform float4 _LightColor0;

            //输入结构体
            struct vertexInput{
                float4 vertex:POSITION;
                float3 normal:NORMAL;
                float4 texcoord:TEXCOORD0;
            };

            //输出结构体
            struct vertexOutput{
                float4 pos:SV_POSITION;
                float4 tex:TEXCOORD0;
                float4 posWorld:TEXCOORD1;
                float3 normalDir:TEXCOORD2;
            };

            vertexOutput vert (vertexInput v)
            {
                vertexOutput o;

                o.posWorld = mul(_Object2World, v.vertex);
                o.normalDir =  normalize( mul(float4(v.normal,0.0),_World2Object).xyz);
                o.pos = mul(UNITY_MATRIX_MVP, v.vertex);
                o.tex = v.texcoord;

                return o;
            }

            fixed4 frag (vertexOutput i) : COLOR
            {
                float3 normalDirection = i.normalDir;
                float3 viewDirection = normalize(_WorldSpaceCameraPos.xyz- i.posWorld.xyz);
                float3 lightDirection;
                float atten;

                if(_WorldSpaceLightPos0.w==0.0)//平行光
                {
                    atten = 1.0;
                    lightDirection = normalize(_WorldSpaceLightPos0.xyz);
                }
                else
                {
                    float3 fragmentToLightSource = _WorldSpaceLightPos0.xyz -i.posWorld.xyz;
                    float distance = length(fragmentToLightSource);
                    atten  = 1.0/distance;
                    lightDirection = normalize(fragmentToLightSource);
                }

                //灯光
                float3 diffuseReflection = atten * _LightColor0.xyz *  saturate( dot(normalDirection,lightDirection));
                float3 specularReflection = atten * _LightColor0.xyz * _SpecColor.rgb*saturate( dot(normalDirection,lightDirection))*pow(saturate(dot(reflect(-lightDirection,normalDirection),viewDirection)),_Shininess);

                //Rim Light
                float rim= -dot(normalize(viewDirection),normalDirection);
                float3 rimLighting = atten * _LightColor0.xyz * _RimColor.rgb*saturate(dot(normalDirection,lightDirection))*pow(rim,_RimPower);

                float3 lightFinal = rimLighting + diffuseReflection+specularReflection+UNITY_LIGHTMODEL_AMBIENT.xyz;

                //Texture Map
                float4 tex  = tex2D(_MainTex,i.tex.xy*_MainTex_ST.xy+_MainTex_ST.zw);
                return float4(tex*lightFinal*_Color.xyz,1.0);

            }
            ENDCG
        }
    }
}