I have some difficulties with my vertex-fragment fog shader in Unity. I have a good visual result but the problem is that the gradient is based on the camera's position, it moves as the camera moves. I don't know how to fix it.
Here is the shader code.
struct v2f {
float4 pos : SV_POSITION;
float4 grabUV : TEXCOORD0;
float2 uv_depth : TEXCOORD1;
float4 interpolatedRay : TEXCOORD2;
float4 screenPos : TEXCOORD3;
};
v2f vert(appdata_base v) {
v2f o;
o.pos = mul(UNITY_MATRIX_MVP, v.vertex);
o.uv_depth = v.texcoord.xy;
o.grabUV = ComputeGrabScreenPos(o.pos);
half index = v.vertex.z;
o.screenPos = ComputeScreenPos(o.pos);
o.interpolatedRay = mul(UNITY_MATRIX_MV, v.vertex);
return o;
}
sampler2D _GrabTexture;
float4 frag(v2f IN) : COLOR {
float3 uv = UNITY_PROJ_COORD(IN.grabUV);
float dpth = UNITY_SAMPLE_DEPTH(tex2Dproj(_CameraDepthTexture, uv));
dpth = LinearEyeDepth(dpth);
float4 wsPos = (IN.screenPos + dpth * IN.interpolatedRay); // Here is the problem but how to fix it
float fogVert = max(0.0, (wsPos.y - _Depth) * (_DepthScale * 0.1f));
fogVert *= fogVert;
fogVert = (exp (-fogVert));
return fogVert;
}