balls

1 files changed, 4 insertions, 4 deletions

diff --git a/vertex_deformation.slang b/vertex_deformation.slang
index 1af5ec9..36d09fb 100644
--- a/vertex_deformation.slang
+++ b/vertex_deformation.slang
@@ -93,11 +93,11 @@ public float3 plane_to_tube(float3 xyz, no_diff float t) {
   float z0 = xyz.z;
 
   float theta = x0 * PI;
-  float radius = ((1.0f - z0) / (dabs(t) + 1e-4f)) * sign(t);
+  float phi   = z0 * PI;
+  float radius = 1.0f / (dabs(t) + 1e-4f) * sign(t);
 
-  float x = sin(theta / radius) * radius * PI_RCP;
-  // The z0 term here is required to make the jacobian invertible.
-  float z = z0 + (1.0f - cos(theta / radius)) * radius * PI_RCP;
+  float x = sin(theta / radius) * (radius * PI_RCP - z0);
+  float z = (1.0f - cos(theta / radius)) * (radius * PI_RCP) + cos(theta / radius) * z0;
 
   return float3(x, y0, z);
 }