Continue fucking with trochoid normals

Seems like the determinant of the jacobian is ~0, meaning it's not
invertible. That means the normals look fucked up.

1 files changed, 34 insertions, 22 deletions

diff --git a/tooner_lighting.cginc b/tooner_lighting.cginc
index adf7890..69b19a4 100644
--- a/tooner_lighting.cginc
+++ b/tooner_lighting.cginc
@@ -138,7 +138,40 @@ v2f vert(appdata v)
 #if defined(_TROCHOID)
   {
     o.objPos_pre_trochoid = v.vertex.xyz;
+//#define TROCHOID_DECOMPOSE
+#if defined(TROCHOID_DECOMPOSE)
     v.vertex.xyz = cyl2_to_troch_map(cyl_to_cyl2_map(cart_to_cyl_map(v.vertex.xyz)));
+#else
+    v.vertex.xyz = cart_to_troch_map(v.vertex.xyz);
+#endif
+  }
+#endif
+
+#if defined(_TROCHOID)
+  {
+#if defined(TROCHOID_DECOMPOSE)
+    // Let h(v) be the trochoid of the cartesian coordinates v.
+    // We evaluate h(v) by first mapping it to cylindrical coordinates, then applying a trochoid function defined on those coordinates:
+    //   h(v) = h_cyl(g(v))
+    // g(v) maps v to cylindrical coordinates.
+    // h_cyl(v) evaluates the trochoid function on cylindrical coordinates.
+    // We want to compute h'(v), i.e. its Jacobian.
+    // By the chain rule:
+    //   h'(v) = h_cyl'(g(v)) * g'(v)
+    // The reality is a little more complex: we also apply a distortion to the cylindrical coordinates:
+    //   h(v) = h_cyl(f(g(v)))
+    // where f(v) is that distortion.
+    // Again, by the chain rule:
+    //   h'(v) = h_cyl'(f(g(v))) * f'(g(v)) * g'(v)
+    float3x3 j0 = cart_to_cyl_jacobian(o.objPos_pre_trochoid);
+    float3x3 j1 = cyl_to_cyl2_jacobian(cart_to_cyl_map(o.objPos_pre_trochoid));
+    float3x3 j2 = cyl2_to_troch_jacobian(cyl_to_cyl2_map(cart_to_cyl_map(o.objPos_pre_trochoid)));
+    float3x3 vector_mover = transpose(invert(mul(mul(j2, j1), j0)));
+#else
+    float3x3 vector_mover = transpose(invert(cart_to_troch_jacobian(o.objPos_pre_trochoid)));
+#endif
+    v.normal = mul(vector_mover, v.normal);
+    v.tangent.xyz = mul(vector_mover, v.tangent.xyz);
   }
 #endif
 #if defined(_FACE_ME_WORLD_Y)
@@ -1595,28 +1628,6 @@ float4 effect(inout v2f i, out float depth)
   i.tangent.xyz = normalize(i.tangent.xyz - i.normal * dot(i.tangent.xyz, i.normal));
   //i.tangent.xyz = normalize(i.tangent.xyz);
 
-#if defined(_TROCHOID)
-  {
-    // Let h(v) be the trochoid of the cartesian coordinates v.
-    // We evaluate h(v) by first mapping it to cylindrical coordinates, then applying a trochoid function defined on those coordinates:
-    //   h(v) = h_cyl(g(v))
-    // g(v) maps v to cylindrical coordinates.
-    // h_cyl(v) evaluates the trochoid function on cylindrical coordinates.
-    // We want to compute h'(v), i.e. its Jacobian.
-    // By the chain rule:
-    //   h'(v) = h_cyl'(g(v)) * g'(v)
-    // The reality is a little more complex: we also apply a distortion to the cylindrical coordinates:
-    //   h(v) = h_cyl(f(g(v)))
-    // where f(v) is that distortion.
-    // Again, by the chain rule:
-    //   h'(v) = h_cyl'(f(g(v))) * f'(g(v)) * g'(v)
-    float3x3 j0 = cart_to_cyl_jacobian(i.objPos_pre_trochoid);
-    float3x3 j1 = cyl_to_cyl2_jacobian(cart_to_cyl_map(i.objPos_pre_trochoid));
-    float3x3 j2 = cyl2_to_troch_jacobian(cyl_to_cyl2_map(cart_to_cyl_map(i.objPos_pre_trochoid)));
-    i.normal = normalize(mul(transpose(invert(mul(j0, mul(j1, j2)))), i.normal));
-  }
-#endif
-
 #if defined(_UVSCROLL)
   float2 orig_uv = i.uv0;
   float uv_scroll_mask = round(_UVScroll_Mask.SampleBias(linear_repeat_s, i.uv0, _Global_Sample_Bias));
@@ -2896,6 +2907,7 @@ fixed4 frag(v2f i
   UNITY_APPLY_DITHER_CROSSFADE(i.pos.xy);
   UNITY_SETUP_INSTANCE_ID(i);
   UNITY_SETUP_STEREO_EYE_INDEX_POST_VERTEX(i);
+
   return effect(i, depth);
 }