Add glitter normal map override option

1 files changed, 8 insertions, 0 deletions

diff --git a/math.cginc b/math.cginc
index 0692440..270ca15 100755
--- a/math.cginc
+++ b/math.cginc
@@ -334,4 +334,12 @@ float3 srgb_to_linear(float3 srgb_color) {
   return lerp(lo, hi, step(0.04045f, srgb_color));
 }
 
+float3x3 tbn_from_normal_tangent(float3 normal, float4 tangent) {
+  float3 n = normal;
+  float3 t = tangent.xyz;
+  t = normalize(t - n * dot(n, t));  // Gram-Schmidt to avoid skew
+  float3 b = normalize(cross(n, t)) * tangent.w;
+  return float3x3(t, b, n);
+}
+
 #endif  // __MATH_INC