好吧，所以我正在制作一个需要UsePass的着色器。我创建了Shader，我将使用UsePassing：
Shader "Unlit/GrabGlow"
{
Properties
{
_MainTex ("Texture", 2D) = "white" {}
threshold ("threshold", Range(0,1)) = 0
}
SubShader
{
Tags { "RenderType"="Opaque" }
LOD 100
Pass
{
Name "MAIN"
CGPROGRAM
#pragma vertex vert
#pragma fragment frag
#include "UnityCG.cginc"
struct appdata
{
float4 vertex : POSITION;
float2 uv : TEXCOORD0;
};
struct v2f
{
float2 uv : TEXCOORD0;
float4 vertex : SV_POSITION;
};
sampler2D _MainTex;
float4 _MainTex_ST;
uniform float threshold = 0.5;
v2f vert (appdata v)
{
v2f o;
o.vertex = mul(UNITY_MATRIX_MVP, v.vertex);
o.uv = TRANSFORM_TEX(v.uv, _MainTex);
return o;
}
fixed4 frag (v2f i) : SV_Target
{
float3 th = float3(threshold,threshold,threshold);
float2 tc = i.uv;
float4 texColor = tex2D(_MainTex, float2(tc.x, tc.y));
if(texColor.r >= th.r && texColor.g >= th.g && texColor.b >= th.b){
return texColor;
}
return float4(0.0, 0.0, 0.0, 0.0);
}
ENDCG
}
}
}
如果我将它放在所需的纹理上，这将完美地运作。
接下来是实际的完整着色器：
Shader "Unlit/CrossFlares"
{
Properties
{
_MainTex ("Texture", 2D) = "white" {}
threshold ("threshold", Range(0,1)) = 0
radius ("radius", Range(0,30)) = 0
resolution ("resolution", float) = 800
}
SubShader
{
Tags { "RenderType" = "Opaque" }
LOD 100
UsePass "Unlit/GRABGLOW/MAIN"
GrabPass
{
"_ScreenTex"
}
//SetTexture [_ScreenTex]
Pass
{
Name "hBlur"
CGPROGRAM
#pragma vertex vert
#pragma fragment frag
#include "UnityCG.cginc"
struct appdata
{
float4 vertex : POSITION;
float2 uv : TEXCOORD0;
};
struct v2f
{
float2 uv : TEXCOORD0;
float4 vertex : SV_POSITION;
};
sampler2D _MainTex;
float4 _MainTex_ST;
uniform float resolution = 800;
uniform float radius = 200;
uniform float threshold = 0.5;
uniform float2 dir = float2(1,1);
v2f vert (appdata v)
{
v2f o;
o.vertex = mul(UNITY_MATRIX_MVP, v.vertex);
o.uv = TRANSFORM_TEX(v.uv, _MainTex);
return o;
}
fixed4 frag (v2f i) : SV_Target
{
float3 th = float3(threshold,threshold,threshold);
float2 tc = i.uv;
float4 texColor = tex2D(_MainTex, float2(tc.x, tc.y));
float4 sum = float4(0.0, 0.0, 0.0, 0.0);
if(texColor.r >= th.r && texColor.g >= th.g && texColor.b >= th.b){
//blur radius in pixels
float blur = radius/resolution/4;
//the direction of our blur
//(1.0, 0.0) -> x-axis blur
//(0.0, 1.0) -> y-axis blur
float hstep = 1;
float vstep = 1;
sum += tex2D(_MainTex, float2(tc.x - 4.0*blur*hstep, tc.y - 4.0*blur*vstep)) * 0.0162162162;
sum += tex2D(_MainTex, float2(tc.x - 3.0*blur*hstep, tc.y - 3.0*blur*vstep)) * 0.0540540541;
sum += tex2D(_MainTex, float2(tc.x - 2.0*blur*hstep, tc.y - 2.0*blur*vstep)) * 0.1216216216;
sum += tex2D(_MainTex, float2(tc.x - 1.0*blur*hstep, tc.y - 1.0*blur*vstep)) * 0.1945945946;
sum += tex2D(_MainTex, float2(tc.x, tc.y)) * 0.2270270270;
sum += tex2D(_MainTex, float2(tc.x + 1.0*blur*hstep, tc.y + 1.0*blur*vstep)) * 0.1945945946;
sum += tex2D(_MainTex, float2(tc.x + 2.0*blur*hstep, tc.y + 2.0*blur*vstep)) * 0.1216216216;
sum += tex2D(_MainTex, float2(tc.x + 3.0*blur*hstep, tc.y + 3.0*blur*vstep)) * 0.0540540541;
sum += tex2D(_MainTex, float2(tc.x + 4.0*blur*hstep, tc.y + 4.0*blur*vstep)) * 0.0162162162;
}
return sum;
}
ENDCG
}
Pass
{
Name "vBlur"
Blend OneMinusDstColor One
CGPROGRAM
#pragma vertex vert
#pragma fragment frag
#include "UnityCG.cginc"
struct appdata
{
float4 vertex : POSITION;
float2 uv : TEXCOORD0;
};
struct v2f
{
float2 uv : TEXCOORD0;
float4 vertex : SV_POSITION;
};
sampler2D _GrabTexture;
sampler2D _MainTex;
float4 _MainTex_ST;
uniform float resolution = 800;
uniform float radius = 200;
uniform float threshold = 0.5;
uniform float2 dir = float2(1,1);
v2f vert (appdata v)
{
v2f o;
o.vertex = mul(UNITY_MATRIX_MVP, v.vertex);
o.uv = TRANSFORM_TEX(v.uv, _MainTex);
return o;
}
fixed4 frag (v2f i) : SV_Target
{
float3 th = float3(threshold,threshold,threshold);
float2 tc = i.uv;
float4 texColor = tex2D(_MainTex, float2(tc.x, tc.y));
float4 sum = float4(0.0, 0.0, 0.0, 0.0);
if(texColor.r >= th.r && texColor.g >= th.g && texColor.b >= th.b){
//blur radius in pixels
float blur = radius/resolution/4;
//the direction of our blur
//(1.0, 0.0) -> x-axis blur
//(0.0, 1.0) -> y-axis blur
float hstep = -1;
float vstep = 1;
sum += tex2D(_MainTex, float2(tc.x - 4.0*blur*hstep, tc.y - 4.0*blur*vstep)) * 0.0162162162;
sum += tex2D(_MainTex, float2(tc.x - 3.0*blur*hstep, tc.y - 3.0*blur*vstep)) * 0.0540540541;
sum += tex2D(_MainTex, float2(tc.x - 2.0*blur*hstep, tc.y - 2.0*blur*vstep)) * 0.1216216216;
sum += tex2D(_MainTex, float2(tc.x - 1.0*blur*hstep, tc.y - 1.0*blur*vstep)) * 0.1945945946;
sum += tex2D(_MainTex, float2(tc.x, tc.y)) * 0.2270270270;
sum += tex2D(_MainTex, float2(tc.x + 1.0*blur*hstep, tc.y + 1.0*blur*vstep)) * 0.1945945946;
sum += tex2D(_MainTex, float2(tc.x + 2.0*blur*hstep, tc.y + 2.0*blur*vstep)) * 0.1216216216;
sum += tex2D(_MainTex, float2(tc.x + 3.0*blur*hstep, tc.y + 3.0*blur*vstep)) * 0.0540540541;
sum += tex2D(_MainTex, float2(tc.x + 4.0*blur*hstep, tc.y + 4.0*blur*vstep)) * 0.0162162162;
}
return sum;
}
ENDCG
}
}
}
只要我将UsePass行注释掉，它也可以正常工作。
但是一旦我添加了UsePass，我就会收到错误： 'Unlit / CrossFlares'中的着色器警告：此GPU不支持着色器（没有子载体/后备适合）
那么为什么我可以自己使用着色器，但是当我尝试UsePass时，它会抛出这个错误？