add l2 -> l infinity norm deformation

7 files changed, 112 insertions, 23 deletions

diff --git a/3ner.shader b/3ner.shader
index 7feb967..e3b9ae9 100644
--- a/3ner.shader
+++ b/3ner.shader
@@ -60,11 +60,18 @@ Shader "yum_food/3ner"
           //ifex _Ray_Marching_Baked_Origins_Enabled==0
           [HideInInspector] m_start_Ray_Marching_Baked_Origins("Baked Origins", Float) = 0
             [ThryToggle(_RAY_MARCHING_BAKED_ORIGINS)] _Ray_Marching_Baked_Origins_Enabled("Enable", Float) = 0
-
             [IntRange] _Baked_Origins_UV_Channel_Index("UV Channel Index", Range(0, 3)) = 1
           [HideInInspector] m_end_Ray_Marching_Baked_Origins("Baked Origins", Float) = 0
           //endex
 
+          //ifex _Ray_Marching_Ball_Grid_Enabled==0
+          [HideInInspector] m_start_Ray_Marching_Ball_Grid("Ball Grid", Float) = 0
+            [ThryToggle(_RAY_MARCHING_BALL_GRID)] _Ray_Marching_Ball_Grid_Enabled("Enable", Float) = 0
+            _Ray_Marching_Ball_Grid_Radius("Radius", Float) = 1
+            _Ray_Marching_Ball_Grid_Count("Count", Range(0,40)) = 5
+          [HideInInspector] m_end_Ray_Marching_Ball_Grid("Ball Grid", Float) = 0
+          //endex
+
         [HideInInspector] m_end_Ray_Marching("Ray Marching", Float) = 0
         //endex
 
@@ -110,6 +117,13 @@ Shader "yum_food/3ner"
           [HideInInspector] m_end_Vertex_Deformation_Tubes("Tubes", Float) = 0
           //endex
 
+          //ifex _Vertex_Deformation_L2_Linf_Enabled==0
+          [HideInInspector] m_start_Vertex_Deformation_L2_Linf("L2 -> L inf", Float) = 0
+            [ThryToggle(_VERTEX_DEFORMATION_L2_LINF)] _Vertex_Deformation_L2_Linf_Enabled("Enable", Float) = 0
+            _Vertex_Deformation_L2_Linf_t("t", Range(0,1)) = 0
+          [HideInInspector] m_end_Vertex_Deformation_L2_Linf("L2 -> L inf", Float) = 0
+          //endex
+
           //ifex _Vertex_Deformation_Seal_Enabled==0
           [HideInInspector] m_start_Vertex_Deformation_Seal("Seal", Float) = 0
             [ThryToggle(_VERTEX_DEFORMATION_SEAL)] _Vertex_Deformation_Seal_Enabled("Enable", Float) = 0
diff --git a/features.cginc b/features.cginc
index b5c7e64..b00c86b 100644
--- a/features.cginc
+++ b/features.cginc
@@ -36,6 +36,10 @@
 #pragma shader_feature_local _VERTEX_DEFORMATION_XY_TUBE
 //endex
 
+//ifex _Vertex_Deformation_L2_Linf_Enabled==0
+#pragma shader_feature_local _VERTEX_DEFORMATION_L2_LINF
+//endex
+
 //ifex _Vertex_Deformation_Seal_Enabled==0
 #pragma shader_feature_local _VERTEX_DEFORMATION_SEAL
 //endex
@@ -76,4 +80,8 @@
 #pragma shader_feature_local _RAY_MARCHING_BAKED_ORIGINS
 //endex
 
+//ifex _Ray_Marching_Ball_Grid_Enabled==0
+#pragma shader_feature_local _RAY_MARCHING_BALL_GRID
+//endex
+
 #endif  // __FEATURES_INC
diff --git a/globals.cginc b/globals.cginc
index f671b73..6513c32 100644
--- a/globals.cginc
+++ b/globals.cginc
@@ -70,6 +70,10 @@ float _Vertex_Deformation_XZ_Tube_t;
 float _Vertex_Deformation_YZ_Tube_t;
 #endif  // _VERTEX_DEFORMATION_YZ_TUBE
 
+#if defined(_VERTEX_DEFORMATION_L2_LINF)
+float _Vertex_Deformation_L2_Linf_t;
+#endif  // _VERTEX_DEFORMATION_L2_LINF
+
 #if defined(_VERTEX_DEFORMATION_SEAL)
 float _Vertex_Deformation_Seal_A;
 float _Vertex_Deformation_Seal_k;
@@ -118,4 +122,9 @@ float getTime() {
 int _Baked_Origins_UV_Channel_Index;
 #endif  // _RAY_MARCHING_BAKED_ORIGINS
 
+#if defined(_RAY_MARCHING_BALL_GRID)
+float _Ray_Marching_Ball_Grid_Radius;
+float _Ray_Marching_Ball_Grid_Count;
+#endif  // _RAY_MARCHING_BALL_GRID
+
 #endif  // __GLOBALS_INC
diff --git a/ray_marching.cginc b/ray_marching.cginc
index 01011c6..513178b 100644
--- a/ray_marching.cginc
+++ b/ray_marching.cginc
@@ -29,12 +29,14 @@ RayMarchResult ray_march(v2f i) {
   GetRoRd(i, ro, rd);
 
 #if defined(_VERTEX_DEFORMATION)
+  float3 rd_perp = i.normal * dot(i.normal, rd);
+  float3 rd_tan  = rd - rd_perp;
   float3 tmp = ro;
-  undeform_normal(tmp, tmp, rd);
-  rd = normalize(rd);
+  undeform_normal(tmp, rd_perp, rd_tan);
+  rd = normalize(rd_perp + rd_tan);
 #endif
 
-  const float kMinDist = 1e-3;
+  const float kMinDist = 1e-4;
   // TODO dial this in & parameterize
   const float kMaxDist = 10;
   // TODO parameterize
@@ -42,7 +44,11 @@ RayMarchResult ray_march(v2f i) {
   float d_acc = 0;
   for (uint ii = 0; ii < kMaxIter; ++ii) {
     float3 p = ro + rd * d_acc;
-    float d_cur = map(p);
+    float d_cur = 1e9;
+#if defined(_RAY_MARCHING_BALL_GRID)
+    float3 count = _Ray_Marching_Ball_Grid_Count;
+    d_cur = min(d_cur, map_ball_grid(p, count));
+#endif
     d_acc += d_cur;
     if (d_cur < kMinDist) {
       break;
@@ -56,7 +62,10 @@ RayMarchResult ray_march(v2f i) {
   float3 lclPos = ro + rd * d_acc;
   float3 lclNorm;
   float3 lclTan;
-  map_normal(lclPos, lclNorm, lclTan);
+#if defined(_RAY_MARCHING_BALL_GRID)
+  float3 count = _Ray_Marching_Ball_Grid_Count;
+  map_ball_grid_normal(count, lclPos, lclNorm, lclTan);
+#endif
 
   RayMarchResult res;
   res.objPos = lclPos;
diff --git a/ray_marching_maps.slang b/ray_marching_maps.slang
index 87481a0..3c83a19 100644
--- a/ray_marching_maps.slang
+++ b/ray_marching_maps.slang
@@ -14,9 +14,9 @@
   DifferentialPair<float3> dp_z = diffPair(xyz, float3(0, 0, 1))
 
 #define R3R1_AUTODIFF_BASIS_VECTORS(fun, ...) \
-  DifferentialPair<float> dp_x_out = fwd_diff(fun)(dp_x, ##__VA_ARGS__); \
-  DifferentialPair<float> dp_y_out = fwd_diff(fun)(dp_y, ##__VA_ARGS__); \
-  DifferentialPair<float> dp_z_out = fwd_diff(fun)(dp_z, ##__VA_ARGS__)
+  DifferentialPair<float> dp_x_out = fwd_diff(fun)(dp_x, __VA_ARGS__); \
+  DifferentialPair<float> dp_y_out = fwd_diff(fun)(dp_y, __VA_ARGS__); \
+  DifferentialPair<float> dp_z_out = fwd_diff(fun)(dp_z, __VA_ARGS__)
 
 #define R3R1_DEFORM_NORMAL_AND_TANGENT(normal, tangent) \
   { \
@@ -29,29 +29,28 @@
 // Syntactic sugar - wraps the previous three macros.
 #define R3R1_RAY_MARCH_NORMALS(xyz, normal, tangent, fun, ...)  \
   R3R1_DECLARE_BASIS_VECTORS(xyz);                              \
-  R3R1_AUTODIFF_BASIS_VECTORS(fun, ##__VA_ARGS__);              \
+  R3R1_AUTODIFF_BASIS_VECTORS(fun, __VA_ARGS__);              \
   R3R1_DEFORM_NORMAL_AND_TANGENT(normal, tangent)
 
 // Just trace a sphere of radius 0.1 for now.
 [Differentiable]
-public float map(float3 p) {
-  float3 count = float3(20,20,1);
-  float3 period = 0.05f;
+public float map_ball_grid(float3 p, no_diff float3 count) {
+  float3 period = 1.0f / count;
+  period *= 2;
   float3 half_period = period*0.5f;
-  float3 which = abs(floor((p + half_period) / period));
-  if (any(abs(which) >= count)) {
+  float3 which = floor((p + half_period) / period);
+  if (any(abs(which) > count/2)) {
     p = 1e6;
   } else {
     p = glsl_mod(p + half_period, period) - half_period;
   }
 
-  p.z += half_period.x;
   return length(p) - half_period.x;
 }
 
-public void map_normal(inout float3 xyz, inout float3 normal,
+public void map_ball_grid_normal(float3 count, inout float3 xyz, inout float3 normal,
     inout float3 tangent) {
-  R3R1_RAY_MARCH_NORMALS(xyz, normal, tangent, map);
+  R3R1_RAY_MARCH_NORMALS(xyz, normal, tangent, map_ball_grid, count);
 }
 
 #endif  // __RAY_MARCHING_MAPS_INC
diff --git a/vertex.cginc b/vertex.cginc
index cd3382c..1cbeb6d 100644
--- a/vertex.cginc
+++ b/vertex.cginc
@@ -59,6 +59,19 @@
 #define VERTEX_DEFORM_XY_TUBE_NORM
 #endif  // VERTEX_DEFORMATION_XY_TUBE
 
+#if defined(_VERTEX_DEFORMATION_L2_LINF)
+#define VERTEX_DEFORM_L2_LINF_PREAMBLE                    \
+  float t = _Vertex_Deformation_L2_Linf_t
+#define VERTEX_DEFORM_L2_LINF_POS                         \
+  objPos = l2_to_linf(objPos.xyz, t)
+#define VERTEX_DEFORM_L2_LINF_NORM                        \
+  l2_to_linf_normal(objPos, objNorm, objTan, t)
+#else
+#define VERTEX_DEFORM_L2_LINF_PREAMBLE
+#define VERTEX_DEFORM_L2_LINF_POS
+#define VERTEX_DEFORM_L2_LINF_NORM
+#endif  // _VERTEX_DEFORMATION_L2_LINF
+
 #if defined(_VERTEX_DEFORMATION_SEAL)
 #define VERTEX_DEFORM_SEAL_PREAMBLE \
   float A = _Vertex_Deformation_Seal_A;                   \
@@ -125,6 +138,10 @@ void deform(inout float3 objPos) {
     VERTEX_DEFORM_XY_TUBE_POS;
   }
   {
+    VERTEX_DEFORM_L2_LINF_PREAMBLE;
+    VERTEX_DEFORM_L2_LINF_POS;
+  }
+  {
     VERTEX_DEFORM_SEAL_PREAMBLE;
     VERTEX_DEFORM_SEAL_POS;
   }
@@ -153,6 +170,10 @@ void deform_normal(inout float3 objPos, inout float3 objNorm, inout float3 objTa
     VERTEX_DEFORM_XY_TUBE_NORM;
   }
   {
+    VERTEX_DEFORM_L2_LINF_PREAMBLE;
+    VERTEX_DEFORM_L2_LINF_NORM;
+  }
+  {
     VERTEX_DEFORM_SEAL_PREAMBLE;
     VERTEX_DEFORM_SEAL_NORM;
   }
@@ -180,7 +201,7 @@ void deform_normal(inout float3 objPos, inout float3 objNorm, inout float3 objTa
 //     that we evaluate the normal deformation at the correct point in space.
 void undeform_normal(inout float3 objPos, inout float3 objNorm, inout float3 objTan) {
   const float t = getTime();
-  const int kMaxDeformations = 8;
+  const int kMaxDeformations = 32;
   // Cache each intermediate position so we can undo stages in reverse order.
   float3 posHistory[kMaxDeformations + 1];
   int posCount = 0;
@@ -207,6 +228,13 @@ void undeform_normal(inout float3 objPos, inout float3 objNorm, inout float3 obj
     posHistory[posCount++] = objPos;
   }
 #endif
+#if defined(_VERTEX_DEFORMATION_L2_LINF)
+  {
+    VERTEX_DEFORM_L2_LINF_PREAMBLE;
+    VERTEX_DEFORM_L2_LINF_POS;
+    posHistory[posCount++] = objPos;
+  }
+#endif
 #if defined(_VERTEX_DEFORMATION_SEAL)
   {
     VERTEX_DEFORM_SEAL_PREAMBLE;
diff --git a/vertex_deformation.slang b/vertex_deformation.slang
index c1faf44..5337e8a 100644
--- a/vertex_deformation.slang
+++ b/vertex_deformation.slang
@@ -43,8 +43,8 @@
   );                                                      \
   float jac_det = determinant(jacobian);                  \
   float3x3 itjac = inverse(transpose(jacobian), jac_det); \
-  normal = normalize(mul(itjac, normal) * jac_det);            \
-  tangent = normalize(mul(jacobian, tangent))
+  normal = mul(itjac, normal) * jac_det;            \
+  tangent = mul(jacobian, tangent) * jac_det
 
 #define R3R3_UNDEFORM_NORMAL_AND_TANGENT(normal, tangent) \
   float3x3 jacobian = float3x3(                           \
@@ -55,8 +55,8 @@
   float jac_det = determinant(jacobian);                  \
   float3x3 inv_jac = inverse(jacobian, jac_det);          \
   float3x3 trans_jac = transpose(jacobian);               \
-  normal = normalize(mul(trans_jac, normal) / jac_det); \
-  tangent = normalize(mul(inv_jac, tangent) / jac_det)
+  normal = mul(trans_jac, normal) * jac_det; \
+  tangent = mul(inv_jac, tangent) * jac_det
 
 // Syntactic sugar - wraps the previous three macros.
 #define R3R3_NORMALS(xyz, normal, tangent, fun, ...)  \
@@ -171,6 +171,28 @@ public void sine_wave_undeform_normal(float3 xyz, inout float3 normal,
   R3R3_UNDEFORM_NORMAL_AND_TANGENT(normal, tangent);
 }
 
+// Map from l2 (euclidean) norm to l-infinity (supremum, max) norm.
+[Differentiable]
+public float3 l2_to_linf(float3 xyz, no_diff float t) {
+  float l2 = length(xyz);
+  float3 abs_xyz = abs(xyz);
+  float linf = max(abs_xyz.x, max(abs_xyz.y, abs_xyz.z));
+
+  float scale = lerp(1.0f, linf / l2, t);
+
+  return xyz * scale;
+}
+
+public void l2_to_linf_normal(float3 xyz, inout float3 normal, inout float3 tangent, float t) {
+  R3R3_NORMALS(xyz, normal, tangent, l2_to_linf, t);
+}
+
+public void l2_to_linf_undeform_normal(float3 xyz, inout float3 normal, inout float3 tangent, float t) {
+  R3R3_DECLARE_BASIS_VECTORS(xyz);
+  R3R3_AUTODIFF_BASIS_VECTORS(l2_to_linf, t);
+  R3R3_UNDEFORM_NORMAL_AND_TANGENT(normal, tangent);
+}
+
 [Differentiable]
 float3 rand3_hash3(float3 p)
 {