begin work on "un-tube" feature

essentially the inverse of the sheet -> tube transform.

7 files changed, 206 insertions, 3 deletions

diff --git a/3ner.shader b/3ner.shader
index 609bac2..1334699 100644
--- a/3ner.shader
+++ b/3ner.shader
@@ -183,6 +183,27 @@ Shader "yum_food/3ner"
           [HideInInspector] m_start_Vertex_Deformation_Tubes("Tubes", Float) = 0
             [ThryToggle(_VERTEX_DEFORMATION_TUBES)] _Vertex_Deformation_Tubes_Enabled("Enable", Float) = 0
 
+            //ifex _Vertex_Deformation_XZ_Untube_Enabled==0
+            [HideInInspector] m_start_Vertex_Deformation_XZ_Untube("XZ Untube", Float) = 0
+              [ThryToggle(_VERTEX_DEFORMATION_XZ_UNTUBE)] _Vertex_Deformation_XZ_Untube_Enabled("Enable", Float) = 0
+              _Vertex_Deformation_XZ_Untube_t("t", Range(-1,1)) = 0
+            [HideInInspector] m_end_Vertex_Deformation_XZ_Untube("XZ Untube", Float) = 0
+            //endex
+
+            //ifex _Vertex_Deformation_YZ_Untube_Enabled==0
+            [HideInInspector] m_start_Vertex_Deformation_YZ_Untube("YZ Untube", Float) = 0
+              [ThryToggle(_VERTEX_DEFORMATION_YZ_UNTUBE)] _Vertex_Deformation_YZ_Untube_Enabled("Enable", Float) = 0
+              _Vertex_Deformation_YZ_Untube_t("t", Range(-1,1)) = 0
+            [HideInInspector] m_end_Vertex_Deformation_YZ_Untube("YZ Untube", Float) = 0
+            //endex
+
+            //ifex _Vertex_Deformation_XY_Untube_Enabled==0
+            [HideInInspector] m_start_Vertex_Deformation_XY_Untube("XY Untube", Float) = 0
+              [ThryToggle(_VERTEX_DEFORMATION_XY_UNTUBE)] _Vertex_Deformation_XY_Untube_Enabled("Enable", Float) = 0
+              _Vertex_Deformation_XY_Untube_t("t", Range(-1,1)) = 0
+            [HideInInspector] m_end_Vertex_Deformation_XY_Untube("XY Untube", Float) = 0
+            //endex
+
             //ifex _Vertex_Deformation_XZ_Tube_Enabled==0
             [HideInInspector] m_start_Vertex_Deformation_XZ_Tube("XZ Tube", Float) = 0
               [ThryToggle(_VERTEX_DEFORMATION_XZ_TUBE)] _Vertex_Deformation_XZ_Tube_Enabled("Enable", Float) = 0
diff --git a/Images/plane_tube_deformation_derivation.png b/Images/plane_tube_deformation_derivation.png
index 4ce0130..9103ca7 100644
--- a/Images/plane_tube_deformation_derivation.png
+++ b/Images/plane_tube_deformation_derivation.png
diff --git a/LUTS/dfg_cloth.exr.meta b/LUTS/dfg_cloth.exr.meta
index 2dc43e3..450e377 100644
--- a/LUTS/dfg_cloth.exr.meta
+++ b/LUTS/dfg_cloth.exr.meta
@@ -22,7 +22,7 @@ TextureImporter:
     normalMapFilter: 0
     flipGreenChannel: 0
   isReadable: 0
-  streamingMipmaps: 0
+  streamingMipmaps: 1
   streamingMipmapsPriority: 0
   vTOnly: 0
   ignoreMipmapLimit: 0
diff --git a/features.cginc b/features.cginc
index 08d8e3f..af52b18 100644
--- a/features.cginc
+++ b/features.cginc
@@ -39,6 +39,9 @@
 
 //ifex _Vertex_Deformation_Tubes_Enabled==0
 #pragma shader_feature_local _VERTEX_DEFORMATION_TUBES
+#pragma shader_feature_local _VERTEX_DEFORMATION_XZ_UNTUBE
+#pragma shader_feature_local _VERTEX_DEFORMATION_YZ_UNTUBE
+#pragma shader_feature_local _VERTEX_DEFORMATION_XY_UNTUBE
 #pragma shader_feature_local _VERTEX_DEFORMATION_XZ_TUBE
 #pragma shader_feature_local _VERTEX_DEFORMATION_YZ_TUBE
 #pragma shader_feature_local _VERTEX_DEFORMATION_XY_TUBE
diff --git a/globals.cginc b/globals.cginc
index 56d9e49..4e03e0b 100644
--- a/globals.cginc
+++ b/globals.cginc
@@ -78,6 +78,15 @@ texture2D _Cloth_Sheen_DFG_LUT;
 #if defined(_VERTEX_DEFORMATION_XY_TUBE)
 float _Vertex_Deformation_XY_Tube_t;
 #endif  // _VERTEX_DEFORMATION_XY_TUBE
+#if defined(_VERTEX_DEFORMATION_XY_UNTUBE)
+float _Vertex_Deformation_XY_Untube_t;
+#endif  // _VERTEX_DEFORMATION_XY_UNTUBE
+#if defined(_VERTEX_DEFORMATION_XZ_UNTUBE)
+float _Vertex_Deformation_XZ_Untube_t;
+#endif  // _VERTEX_DEFORMATION_XZ_UNTUBE
+#if defined(_VERTEX_DEFORMATION_YZ_UNTUBE)
+float _Vertex_Deformation_YZ_Untube_t;
+#endif  // _VERTEX_DEFORMATION_YZ_UNTUBE
 #if defined(_VERTEX_DEFORMATION_XZ_TUBE)
 float _Vertex_Deformation_XZ_Tube_t;
 #endif  // _VERTEX_DEFORMATION_XZ_TUBE
diff --git a/vertex.cginc b/vertex.cginc
index 9cdbead..f82fad6 100644
--- a/vertex.cginc
+++ b/vertex.cginc
@@ -6,6 +6,59 @@
 
 #define FOO(x) (x)
 
+#if defined(_VERTEX_DEFORMATION_XZ_UNTUBE)
+#define VERTEX_DEFORM_XZ_UNTUBE_PREAMBLE                    \
+  float t = _Vertex_Deformation_XZ_Untube_t
+#define VERTEX_DEFORM_XZ_UNTUBE_POS                         \
+  objPos = tube_to_plane(objPos.xyz, t)
+#define VERTEX_DEFORM_XZ_UNTUBE_NORM                        \
+  tube_to_plane_normal(objPos, objNorm, objTan, t)
+#else
+#define VERTEX_DEFORM_XZ_UNTUBE_PREAMBLE
+#define VERTEX_DEFORM_XZ_UNTUBE_POS
+#define VERTEX_DEFORM_XZ_UNTUBE_NORM
+#endif  // VERTEX_DEFORMATION_XZ_UNTUBE
+
+#if defined(_VERTEX_DEFORMATION_YZ_UNTUBE)
+#define VERTEX_DEFORM_YZ_UNTUBE_PREAMBLE                    \
+  float t = _Vertex_Deformation_YZ_Untube_t
+#define VERTEX_DEFORM_YZ_UNTUBE_POS                         \
+  objPos = tube_to_plane(objPos.yxz, t);                    \
+  objPos = objPos.yxz
+#define VERTEX_DEFORM_YZ_UNTUBE_NORM                        \
+  float3 yzPos = objPos.yxz;                                \
+  float3 yzNorm = objNorm.yxz;                              \
+  float3 yzTan = objTan.yxz;                                \
+  tube_to_plane_normal(yzPos, yzNorm, yzTan, t);            \
+  objPos = yzPos.yxz;                                       \
+  objNorm = yzNorm.yxz;                                     \
+  objTan = yzTan.yxz
+#else
+#define VERTEX_DEFORM_YZ_UNTUBE_PREAMBLE
+#define VERTEX_DEFORM_YZ_UNTUBE_POS
+#define VERTEX_DEFORM_YZ_UNTUBE_NORM
+#endif  // VERTEX_DEFORMATION_YZ_UNTUBE
+
+#if defined(_VERTEX_DEFORMATION_XY_UNTUBE)
+#define VERTEX_DEFORM_XY_UNTUBE_PREAMBLE                    \
+  float t = _Vertex_Deformation_XY_Untube_t
+#define VERTEX_DEFORM_XY_UNTUBE_POS                         \
+  objPos = tube_to_plane(objPos.xzy, t);                    \
+  objPos = objPos.xzy
+#define VERTEX_DEFORM_XY_UNTUBE_NORM                        \
+  float3 xyPos = objPos.xzy;                                \
+  float3 xyNorm = objNorm.xzy;                              \
+  float3 xyTan = objTan.xzy;                                \
+  tube_to_plane_normal(xyPos, xyNorm, xyTan, t);            \
+  objPos = xyPos.xzy;                                       \
+  objNorm = xyNorm.xzy;                                     \
+  objTan = xyTan.xzy
+#else
+#define VERTEX_DEFORM_XY_UNTUBE_PREAMBLE
+#define VERTEX_DEFORM_XY_UNTUBE_POS
+#define VERTEX_DEFORM_XY_UNTUBE_NORM
+#endif  // VERTEX_DEFORMATION_XY_UNTUBE
+
 #if defined(_VERTEX_DEFORMATION_XZ_TUBE)
 #define VERTEX_DEFORM_XZ_TUBE_PREAMBLE                    \
   float t = _Vertex_Deformation_XZ_Tube_t
@@ -128,6 +181,18 @@
 void deform(inout float3 objPos) {
   const float t = getTime();
   {
+    VERTEX_DEFORM_XZ_UNTUBE_PREAMBLE;
+    VERTEX_DEFORM_XZ_UNTUBE_POS;
+  }
+  {
+    VERTEX_DEFORM_YZ_UNTUBE_PREAMBLE;
+    VERTEX_DEFORM_YZ_UNTUBE_POS;
+  }
+  {
+    VERTEX_DEFORM_XY_UNTUBE_PREAMBLE;
+    VERTEX_DEFORM_XY_UNTUBE_POS;
+  }
+  {
     VERTEX_DEFORM_XZ_TUBE_PREAMBLE;
     VERTEX_DEFORM_XZ_TUBE_POS;
   }
@@ -160,6 +225,18 @@ void deform(inout float3 objPos) {
 void deform_normal(inout float3 objPos, inout float3 objNorm, inout float3 objTan) {
   const float t = getTime();
   {
+    VERTEX_DEFORM_XZ_UNTUBE_PREAMBLE;
+    VERTEX_DEFORM_XZ_UNTUBE_NORM;
+  }
+  {
+    VERTEX_DEFORM_YZ_UNTUBE_PREAMBLE;
+    VERTEX_DEFORM_YZ_UNTUBE_NORM;
+  }
+  {
+    VERTEX_DEFORM_XY_UNTUBE_PREAMBLE;
+    VERTEX_DEFORM_XY_UNTUBE_NORM;
+  }
+  {
     VERTEX_DEFORM_XZ_TUBE_PREAMBLE;
     VERTEX_DEFORM_XZ_TUBE_NORM;
   }
@@ -209,6 +286,27 @@ void undeform_normal(inout float3 objPos, inout float3 objNorm, inout float3 obj
   int posCount = 0;
   posHistory[posCount++] = objPos;
 
+#if defined(_VERTEX_DEFORMATION_XZ_UNTUBE)
+  {
+    VERTEX_DEFORM_XZ_UNTUBE_PREAMBLE;
+    VERTEX_DEFORM_XZ_UNTUBE_POS;
+    posHistory[posCount++] = objPos;
+  }
+#endif
+#if defined(_VERTEX_DEFORMATION_YZ_UNTUBE)
+  {
+    VERTEX_DEFORM_YZ_UNTUBE_PREAMBLE;
+    VERTEX_DEFORM_YZ_UNTUBE_POS;
+    posHistory[posCount++] = objPos;
+  }
+#endif
+#if defined(_VERTEX_DEFORMATION_XY_UNTUBE)
+  {
+    VERTEX_DEFORM_XY_UNTUBE_PREAMBLE;
+    VERTEX_DEFORM_XY_UNTUBE_POS;
+    posHistory[posCount++] = objPos;
+  }
+#endif
 #if defined(_VERTEX_DEFORMATION_XZ_TUBE)
   {
     VERTEX_DEFORM_XZ_TUBE_PREAMBLE;
@@ -338,6 +436,43 @@ void undeform_normal(inout float3 objPos, inout float3 objNorm, inout float3 obj
     cursor -= 1;
   }
 #endif
+#if defined(_VERTEX_DEFORMATION_XY_UNTUBE)
+  if (cursor > 0) {
+    VERTEX_DEFORM_XY_UNTUBE_PREAMBLE;
+    float3 stageInput = posHistory[cursor - 1];
+    float3 xyPos = stageInput.xzy;
+    float3 xyNorm = objNorm.xzy;
+    float3 xyTan = objTan.xzy;
+    tube_to_plane_undeform_normal(xyPos, xyNorm, xyTan, t);
+    objNorm = xyNorm.xzy;
+    objTan = xyTan.xzy;
+    objPos = stageInput;
+    cursor -= 1;
+  }
+#endif
+#if defined(_VERTEX_DEFORMATION_YZ_UNTUBE)
+  if (cursor > 0) {
+    VERTEX_DEFORM_YZ_UNTUBE_PREAMBLE;
+    float3 stageInput = posHistory[cursor - 1];
+    float3 yzPos = stageInput.yxz;
+    float3 yzNorm = objNorm.yxz;
+    float3 yzTan = objTan.yxz;
+    tube_to_plane_undeform_normal(yzPos, yzNorm, yzTan, t);
+    objNorm = yzNorm.yxz;
+    objTan = yzTan.yxz;
+    objPos = stageInput;
+    cursor -= 1;
+  }
+#endif
+#if defined(_VERTEX_DEFORMATION_XZ_UNTUBE)
+  if (cursor > 0) {
+    VERTEX_DEFORM_XZ_UNTUBE_PREAMBLE;
+    float3 stageInput = posHistory[cursor - 1];
+    tube_to_plane_undeform_normal(stageInput, objNorm, objTan, t);
+    objPos = stageInput;
+    cursor -= 1;
+  }
+#endif
 
   objPos = objPos_deformed;
 }
diff --git a/vertex_deformation.slang b/vertex_deformation.slang
index 047f7d7..577b0d2 100644
--- a/vertex_deformation.slang
+++ b/vertex_deformation.slang
@@ -84,7 +84,7 @@ float3x3 inverse(float3x3 m, float det) {
   return inv;
 }
 
-// Takes map a 2x2 quad on the xy plane to a tube. The circular cross section
+// Maps a 2x2 quad on the xy plane to a tube. The circular cross section
 // is on the xz plane.
 [Differentiable]
 public float3 plane_to_tube(float3 xyz, no_diff float t) {
@@ -93,7 +93,8 @@ public float3 plane_to_tube(float3 xyz, no_diff float t) {
   float z0 = xyz.z;
 
   float theta = x0 * PI;
-  float phi   = z0 * PI;
+
+  // Equivalent to (1 / (|t| + eps)) * sign(t)
   float radius = 1.0f / (dabs(t) + 1e-4f) * sign(t);
 
   float x = sin(theta / radius) * (radius * PI_RCP - z0);
@@ -114,6 +115,40 @@ public void plane_to_tube_undeform_normal(float3 xyz, inout float3 normal,
   R3R3_UNDEFORM_NORMAL_AND_TANGENT(normal, tangent);
 }
 
+// Maps a tube with circular cross section on the xz plane to a quad on the xy
+// plane.
+[Differentiable]
+public float3 tube_to_plane(float3 xyz, no_diff float t) {
+  float x0 = xyz.x;
+  float y0 = xyz.y;
+  float z0 = xyz.z;
+
+  float theta = atan2(z0, x0) - PI;
+  float r = length(float2(x0, z0));
+  x0 = r * cos(theta);
+  z0 = r * sin(theta);
+
+  // Equivalent to (1 / (|t| + eps)) * sign(t)
+  float radius = 1.0f / (dabs(t) + 1e-4f) * sign(t);
+
+  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);
+}
+
+public void tube_to_plane_normal(inout float3 xyz, inout float3 normal,
+    inout float3 tangent, float t) {
+  R3R3_NORMALS(xyz, normal, tangent, tube_to_plane, t);
+}
+
+public void tube_to_plane_undeform_normal(float3 xyz, inout float3 normal,
+    inout float3 tangent, float t) {
+  R3R3_DECLARE_BASIS_VECTORS(xyz);
+  R3R3_AUTODIFF_BASIS_VECTORS(tube_to_plane, t);
+  R3R3_UNDEFORM_NORMAL_AND_TANGENT(normal, tangent);
+}
+
 [Differentiable]
 public float3 seal(float3 xyz, no_diff float A, no_diff float k, no_diff float t) {
   float x = xyz.x;