Use quad intrinsics to compute trochoid normals

Simple algo. Use quad intrinsics to get neighboring pixels' (x & y)
positions in trochoid space. Compute tangent and bitangent from that.
Then normal as cross product. There's some artifacting on diagonal
boundaries.

1 files changed, 2 insertions, 2 deletions

diff --git a/math.cginc b/math.cginc
index 5b33edf..507ca74 100644
--- a/math.cginc
+++ b/math.cginc
@@ -249,8 +249,8 @@ bool solveQuadratic(float a, float b, float c, out float x0, out float x1)
 
 float determinant(float3x3 m)
 {
-  return m[0][0] * (m[1][1] * m[2][2] - m[1][2] * m[2][1])
-            - m[0][1] * (m[1][0] * m[2][2] - m[1][2] * m[2][0])
+  return (m[0][0] * (m[1][1] * m[2][2] - m[1][2] * m[2][1])
+            - m[0][1] * (m[1][0] * m[2][2] - m[1][2] * m[2][0]))
             + m[0][2] * (m[1][0] * m[2][1] - m[1][1] * m[2][0]);
 }