[UnityShader2]顶点片段着色器实例(六)

1.棋盘效果

cg函数：floor(x)，返回不大于x的最大整数

cg函数：frac(x)，返回x的小数部分

原理：

a.在顶点程序中，uv的范围为(0,_Density)

b.在片段程序中，对uv取整然后除以2，得到的数类似为：0 / 0.5 / 1 / 1.5 / 2 /等，x和y相加取小数，要么0，要么0.5，乘以2后要么0，要么1，即达到要么黑要么白的效果。

Shader "Unlit/Checkerboard"
{
Properties
{
_Density ("Density", Range(2,50)) = 30
}
SubShader
{
Pass
{
CGPROGRAM
#pragma vertex vert
#pragma fragment frag

struct v2f
{
float2 uv : TEXCOORD0;
float4 vertex : SV_POSITION;
};

float _Density;

v2f vert (float4 pos : POSITION, float2 uv : TEXCOORD0)
{
v2f o;
o.vertex = mul(UNITY_MATRIX_MVP, pos);
o.uv = uv * _Density;
return o;
}

fixed4 frag (v2f i) : SV_Target
{
float2 c = i.uv;
c = floor(c) / 2;
float checker = frac(c.x + c.y) * 2;
return checker;
}
ENDCG
}
}
}



2.



Shader "Unlit/Triplanar"
{
Properties
{
_MainTex ("Texture", 2D) = "white" {}
_Tiling ("Tiling", Float) = 1.0
_OcclusionMap("Occlusion", 2D) = "white" {}
}
SubShader
{
Pass
{
CGPROGRAM
#pragma vertex vert
#pragma fragment frag

struct v2f
{
half3 objNormal : TEXCOORD0;
float3 coords : TEXCOORD1;
float2 uv : TEXCOORD2;
float4 pos : SV_POSITION;
};

float _Tiling;

v2f vert (float4 pos : POSITION, float3 normal : NORMAL, float2 uv : TEXCOORD0)
{
v2f o;
o.pos = mul(UNITY_MATRIX_MVP, pos);
o.coords = pos.xyz * _Tiling;
o.objNormal = normal;
o.uv = uv;
return o;
}

sampler2D _MainTex;
sampler2D _OcclusionMap;

fixed4 frag (v2f i) : SV_Target
{
// use absolute value of normal as texture weights
half3 blend = abs(i.objNormal);
// make sure the weights sum up to 1 (divide by sum of x+y+z)
blend /= dot(blend,1.0);
// read the three texture projections, for x,y,z axes
fixed4 cx = tex2D(_MainTex, i.coords.yz);
fixed4 cy = tex2D(_MainTex, i.coords.xz);
fixed4 cz = tex2D(_MainTex, i.coords.xy);
// blend the textures based on weights
fixed4 c = cx * blend.x + cy * blend.y + cz * blend.z;
// modulate by regular occlusion map
c *= tex2D(_OcclusionMap, i.uv);
return c;
}
ENDCG
}
}
}



3.简单的漫反射

a.我们可以通过声明pass中的“LightMode”这个tag，从而告诉unity我们需要什么光照信息。unity默认的渲染管线是正向渲染。

b.[NoScaleOffset] - material inspector will not show texture tiling/offset fields for texture properties with this attribute.

具体计算原理：http://blog.csdn.net/lyh916/article/details/50906272

Shader "Lit/Simple Diffuse"
{
Properties
{
[NoScaleOffset] _MainTex ("Texture", 2D) = "white" {}
}
SubShader
{
Pass
{
// indicate that our pass is the "base" pass in forward
// rendering pipeline. It gets ambient and main directional
// light data set up; light direction in _WorldSpaceLightPos0
// and color in _LightColor0
Tags {"LightMode"="ForwardBase"}

CGPROGRAM
#pragma vertex vert
#pragma fragment frag
#include "UnityCG.cginc" // for UnityObjectToWorldNormal
#include "UnityLightingCommon.cginc" // for _LightColor0

struct v2f
{
float2 uv : TEXCOORD0;
fixed4 diff : COLOR0; // diffuse lighting color
float4 vertex : SV_POSITION;
};

v2f vert (appdata_base v)
{
v2f o;
o.vertex = mul(UNITY_MATRIX_MVP, v.vertex);
o.uv = v.texcoord;
// get vertex normal in world space
half3 worldNormal = UnityObjectToWorldNormal(v.normal);
// dot product between normal and light direction for
// standard diffuse (Lambert) lighting
half nl = max(0, dot(worldNormal, _WorldSpaceLightPos0.xyz));
// factor in the light color
o.diff = nl * _LightColor0;
return o;
}

sampler2D _MainTex;

fixed4 frag (v2f i) : SV_Target
{
// sample texture
fixed4 col = tex2D(_MainTex, i.uv);
// multiply by lighting
col *= i.diff;
return col;
}
ENDCG
}
}
}



4.带环境光的漫反射



Shader "Lit/Diffuse With Ambient"
{
Properties
{
[NoScaleOffset] _MainTex ("Texture", 2D) = "white" {}
}
SubShader
{
Pass
{
Tags {"LightMode"="ForwardBase"}

CGPROGRAM
#pragma vertex vert
#pragma fragment frag
#include "UnityCG.cginc"
#include "UnityLightingCommon.cginc"

struct v2f
{
float2 uv : TEXCOORD0;
fixed4 diff : COLOR0;
float4 vertex : SV_POSITION;
};

v2f vert (appdata_base v)
{
v2f o;
o.vertex = mul(UNITY_MATRIX_MVP, v.vertex);
o.uv = v.texcoord;
half3 worldNormal = UnityObjectToWorldNormal(v.normal);
half nl = max(0, dot(worldNormal, _WorldSpaceLightPos0.xyz));
o.diff = nl * _LightColor0;

// the only difference from previous shader:
// in addition to the diffuse lighting from the main light,
// add illumination from ambient or light probes
// ShadeSH9 function from UnityCG.cginc evaluates it,
// using world space normal
o.diff.rgb += ShadeSH9(half4(worldNormal,1));
return o;
}

sampler2D _MainTex;

fixed4 frag (v2f i) : SV_Target
{
fixed4 col = tex2D(_MainTex, i.uv);
col *= i.diff;
return col;
}
ENDCG
}
}
}