koobas.hobune.stream
Shader with BW gradient mask and cutoff for projector
Hi guys. Shader-noob here, but keen to learn. I'm trying to create a shader to use with a projector on the standard out-of-the-box pipeline. I'm halfway there. I want my projection to be masked/cutoff by the value of a second image which contains a black to white gradient. In this case it is a radial gradient.
Right now the gradient does nothing. I'll post my current code below. But my question is this. How do I take the value of black from the mask image and use it to progressively reveal the decal image above it?
Shader "Projector/Cutout" {
Properties{
_DecalTex( "Decal", 2D ) = "white" {}
_MaskTex( "Mask", 2D ) = "black" {}
_Cutoff ( "Alpha cutoff", Range( 0, 1 ) ) = 0.5
}
Subshader {
Tags {"Queue" = "AlphaTest" "RenderType" = "TransparentCutout"}
Pass {
ZWrite Off
ColorMask RGB
Blend OneMinusSrcAlpha SrcAlpha
Offset -1, -1
CGPROGRAM
#pragma vertex vert
#pragma fragment frag
#pragma multi_compile_fog
#include "UnityCG.cginc"
struct v2f {
float4 uvShadow : TEXCOORD0;
UNITY_FOG_COORDS(2)
float4 pos : SV_POSITION;
};
float4x4 unity_Projector;
float4x4 unity_ProjectorClip;
v2f vert( float4 vertex : POSITION )
{
v2f o;
o.pos = UnityObjectToClipPos( vertex );
o.uvShadow = mul( unity_Projector, vertex );
UNITY_TRANSFER_FOG( o, o.pos );
return o;
}
sampler2D _DecalTex;
sampler2D _MaskTex;
float _Cutoff;
fixed4 frag(v2f i) : SV_Target
{
fixed4 texDecal = tex2Dproj( _DecalTex, UNITY_PROJ_COORD( i.uvShadow ) );
texDecal.a = 1.0 - texDecal.a;
// clip( texDecal.a - ( _Cutoff ) );
// clip( texDecal.a );
clip( texDecal.a - _Cutoff );
UNITY_APPLY_FOG( i.fogCoord, texDecal );
return texDecal;
}
ENDCG
}
}
}
