Fresnel in fragment not surface

Unity Engine
1

I’ve been struggling for a while but failed to do a fresnel falloff in a fragment shader.
The examples I found are all applied to a surface. I tried to use Strumpy’s fresnel
to see how it’s done but it’s broken.

Here is what I’m at:

			struct vertexToFragment
			{
				float4 vertex : POSITION;
				float4 color : COLOR;
				float2 texcoord : TEXCOORD0;
				float2 texcoord1 : TEXCOORD1;
				float3 viewDir : TEXCOORD2;
				float3 normal : TEXCOORD3;
			};

			vertexToFragment vert (appdata_full v)
			{
				vertexToFragment o;

				o.vertex = mul(UNITY_MATRIX_MVP, v.vertex);
				o.color = v.color;
				o.texcoord = TRANSFORM_TEX(v.texcoord,_MainTexture);
				o.texcoord1 = TRANSFORM_TEX(v.texcoord1,_MainTexture);
				float3 binormal = cross( v.normal, v.tangent.xyz ) * v.tangent.w;
				float3x3 rotation = float3x3( v.tangent.xyz, binormal, v.normal );
				o.viewDir = mul (rotation, ObjSpaceViewDir(v.vertex));
				o.normal = v.normal;

				return o;
			}

			fixed4 frag (vertexToFragment i) : COLOR
			{
				fixed4 debug = fixed4(1.0, 0.5, 0.0, 1.0);
				fixed4 finalColor = fixed4(1.0,1.0,1.0,1.0);

				finalColor.rgb = clamp(abs(dot(i.normal, i.viewDir)), 0, 1);
				return finalColor;
			}

I’d appreciate if someone could show me a working example.

2

Essentially you want to get the dot product of the viewDir and the normal, saturated and one minus.

fixed3 normal = UnpackNormal(_BumpMap, i.texcoord);
float fresnel = 1.0 - saturate(dot(i.viewDir, normal));

Currently you’re getting the dot product of the viewDir that’s in tangent space and the vertex normal that’s in object space. You’ll need to dot product either the object space view dir and the vertex normal, or the tangent space view dir and a normal map.

3

Thank you, I got it working.

o.viewDir = normalize(ObjSpaceViewDir(v.vertex));