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KenneyNL/GrassGeometry.shader

Created June 13, 2019 11:48
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GrassGeometry.shader
Shader "Custom/Grass Geometry Shader" {
Properties{
[NoScaleOffset] _MainTex("Grass A", 2D) = "white" {}
[NoScaleOffset] _GrassTwo("Grass B", 2D) = "white" {}
_Splat("Splat", 2D) = "white" {}
_Cutoff("Cutoff", Range(0,1)) = 0.25
_GrassHeight("Grass height", Float) = 0.25
_WindSpeed("Wind speed", Float) = 100
_WindStength("Wind strength", Float) = 0.05
}
SubShader{
Tags{ "Queue" = "AlphaTest" "IgnoreProjector" = "True" "RenderType" = "TransparentCutout" }
LOD 200
Pass{
CULL OFF
CGPROGRAM
#include "UnityCG.cginc"
#pragma vertex vert
#pragma fragment frag
#pragma geometry geom
//#pragma alphatest : _Cutoff
// Use shader model 4.0 target, we need geometry shader support
#pragma target 4.0
sampler2D _MainTex, _GrassTwo, _Splat;
struct v2g{
float4 pos : SV_POSITION;
float3 norm : NORMAL;
float2 uv : TEXCOORD0;
float3 color : TEXCOORD1;
};
struct g2f{
float4 pos : SV_POSITION;
float3 norm : NORMAL;
float2 uv : TEXCOORD0;
float3 diffuseColor : TEXCOORD1;
//float3 specularColor : TEXCOORD2;
};
half _GrassHeight;
half _Cutoff;
half _WindStength;
half _WindSpeed;
v2g vert(appdata_full v){
float3 v0 = v.vertex.xyz;
v2g OUT;
OUT.pos = v.vertex;
OUT.norm = v.normal;
OUT.uv = v.texcoord;
OUT.color = tex2Dlod(_MainTex, v.texcoord).rgb;
return OUT;
}
[maxvertexcount(24)]
void geom(point v2g IN[1], inout TriangleStream<g2f> triStream){
float3 lightPosition = _WorldSpaceLightPos0;
float3 perpendicularAngle = float3(0, 0, 1);
float3 faceNormal = cross(perpendicularAngle, IN[0].norm);
float3 v0 = IN[0].pos.xyz;
float3 v1 = IN[0].pos.xyz + IN[0].norm * _GrassHeight;
float3 wind =
float3(sin(_Time.x * _WindSpeed + v0.x) + sin(_Time.x * _WindSpeed + v0.z * 2) +
sin(_Time.x * _WindSpeed * 0.1 + v0.x), 0,
cos(_Time.x * _WindSpeed + v0.x * 2) + cos(_Time.x * _WindSpeed + v0.z));
v1 += wind * _WindStength;
float3 color = (IN[0].color);
float sin30 = 0.5;
float sin60 = 0.866f;
float cos30 = sin60;
float cos60 = sin30;
g2f OUT;
// Quad 1
OUT.pos = UnityObjectToClipPos(v0 + perpendicularAngle * 0.5 * _GrassHeight);
OUT.norm = faceNormal;
OUT.diffuseColor = color;
OUT.uv = float2(1, 0);
triStream.Append(OUT);
OUT.pos = UnityObjectToClipPos(v1 + perpendicularAngle * 0.5 * _GrassHeight);
OUT.norm = faceNormal;
OUT.diffuseColor = color;
OUT.uv = float2(1, 1);
triStream.Append(OUT);
OUT.pos = UnityObjectToClipPos(v0);
OUT.norm = faceNormal;
OUT.diffuseColor = color;
OUT.uv = float2(0.5, 0);
triStream.Append(OUT);
OUT.pos = UnityObjectToClipPos(v1);
OUT.norm = faceNormal;
OUT.diffuseColor = color;
OUT.uv = float2(0.5, 1);
triStream.Append(OUT);
OUT.pos = UnityObjectToClipPos(v1 - perpendicularAngle * 0.5 * _GrassHeight);
OUT.norm = faceNormal;
OUT.diffuseColor = color;
OUT.uv = float2(0, 1);
triStream.Append(OUT);
OUT.pos = UnityObjectToClipPos(v0 - perpendicularAngle * 0.5 * _GrassHeight);
OUT.norm = faceNormal;
OUT.diffuseColor = color;
OUT.uv = float2(0, 0);
triStream.Append(OUT);
OUT.pos = UnityObjectToClipPos(v0);
OUT.norm = faceNormal;
OUT.diffuseColor = color;
OUT.uv = float2(0.5, 0);
triStream.Append(OUT);
OUT.pos = UnityObjectToClipPos(v1);
OUT.norm = faceNormal;
OUT.diffuseColor = color;
OUT.uv = float2(0.5, 1);
triStream.Append(OUT);
// Quad 2
OUT.pos = UnityObjectToClipPos(v0 + float3(sin60, 0, -cos60) * 0.5 * _GrassHeight);
OUT.norm = faceNormal;
OUT.diffuseColor = color;
OUT.uv = float2(1, 0);
triStream.Append(OUT);
OUT.pos = UnityObjectToClipPos(v1 + float3(sin60, 0, -cos60)* 0.5 * _GrassHeight);
OUT.norm = faceNormal;
OUT.diffuseColor = color;
OUT.uv = float2(1, 1);
triStream.Append(OUT);
OUT.pos = UnityObjectToClipPos(v0);
OUT.norm = faceNormal;
OUT.diffuseColor = color;
OUT.uv = float2(0.5, 0);
triStream.Append(OUT);
OUT.pos = UnityObjectToClipPos(v1);
OUT.norm = faceNormal;
OUT.diffuseColor = color;
OUT.uv = float2(0.5, 1);
triStream.Append(OUT);
OUT.pos = UnityObjectToClipPos(v0 - float3(sin60, 0, -cos60) * 0.5 * _GrassHeight);
OUT.norm = faceNormal;
OUT.diffuseColor = color;
OUT.uv = float2(0, 0);
triStream.Append(OUT);
OUT.pos = UnityObjectToClipPos(v1 - float3(sin60, 0, -cos60) * 0.5 * _GrassHeight);
OUT.norm = faceNormal;
OUT.diffuseColor = color;
OUT.uv = float2(0, 1);
triStream.Append(OUT);
OUT.pos = UnityObjectToClipPos(v0);
OUT.norm = faceNormal;
OUT.diffuseColor = color;
OUT.uv = float2(0.5, 0);
triStream.Append(OUT);
OUT.pos = UnityObjectToClipPos(v1);
OUT.norm = faceNormal;
OUT.diffuseColor = color;
OUT.uv = float2(0.5, 1);
triStream.Append(OUT);
// Quad 3 - Positive
OUT.pos = UnityObjectToClipPos(v0 + float3(sin60, 0, cos60) * 0.5 * _GrassHeight);
OUT.norm = faceNormal;
OUT.diffuseColor = color;
OUT.uv = float2(1, 0);
triStream.Append(OUT);
OUT.pos = UnityObjectToClipPos(v1 + float3(sin60, 0, cos60)* 0.5 * _GrassHeight);
OUT.norm = faceNormal;
OUT.diffuseColor = color;
OUT.uv = float2(1, 1);
triStream.Append(OUT);
OUT.pos = UnityObjectToClipPos(v0);
OUT.norm = faceNormal;
OUT.diffuseColor = color;
OUT.uv = float2(0.5, 0);
triStream.Append(OUT);
OUT.pos = UnityObjectToClipPos(v1);
OUT.norm = faceNormal;
OUT.diffuseColor = color;
OUT.uv = float2(0.5, 1);
triStream.Append(OUT);
// Quad 3 - Negative
OUT.pos = UnityObjectToClipPos(v0 - float3(sin60, 0, cos60) * 0.5 * _GrassHeight);
OUT.norm = faceNormal;
OUT.diffuseColor = color;
OUT.uv = float2(0, 0);
triStream.Append(OUT);
OUT.pos = UnityObjectToClipPos(v1 - float3(sin60, 0, cos60) * 0.5 * _GrassHeight);
OUT.norm = faceNormal;
OUT.diffuseColor = color;
OUT.uv = float2(0, 1);
triStream.Append(OUT);
OUT.pos = UnityObjectToClipPos(v0);
OUT.norm = faceNormal;
OUT.diffuseColor = color;
OUT.uv = float2(0.5, 0);
triStream.Append(OUT);
OUT.pos = UnityObjectToClipPos(v1);
OUT.norm = faceNormal;
OUT.diffuseColor = color;
OUT.uv = float2(0.5, 1);
triStream.Append(OUT);
}
half4 frag(g2f IN) : COLOR{
fixed4 c = tex2D(_MainTex, IN.uv);
clip(c.a - _Cutoff);
return c;
}
ENDCG
}
}
}
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