add detail map feature

1 files changed, 10 insertions, 0 deletions

diff --git a/math.cginc b/math.cginc
index c37ce07..02d0fe0 100644
--- a/math.cginc
+++ b/math.cginc
@@ -89,5 +89,15 @@ float3 round_hex(float3 hex_coord) {
     return rounded;
 }
 
+// Reoriented normal mapping
+// https://blog.selfshadow.com/publications/blending-in-detail/
+// Inputs are in tangent space.
+float3 blendNormalsHill12(float3 n0, float3 n1) {
+  n0.z += 1.0;
+  n1.xy = -n1.xy;
+  
+  return normalize(n0 * dot(n0, n1) - n1 * n0.z);
+}
+
 #endif  // __MATH_INC