add geometry shader

8 files changed, 99 insertions, 31 deletions

diff --git a/3ner.cginc b/3ner.cginc
index 0536fb5..bac74ad 100644
--- a/3ner.cginc
+++ b/3ner.cginc
@@ -9,6 +9,7 @@
 #include "AutoLight.cginc"
 
 #include "brdf.cginc"
+#include "geometry.cginc"
 #include "pbr.cginc"
 #include "lighting.cginc"
 #include "globals.cginc"
@@ -50,6 +51,7 @@ v2f vert(appdata v) {
     return o;
 }
 
+//ifex _Tessellation_Enabled==0
 struct tess_factors {
   float edge[3] : SV_TessFactor;
   float inside : SV_InsideTessFactor;
@@ -170,6 +172,50 @@ v2f domain(
   UNITY_INITIALIZE_VERTEX_OUTPUT_STEREO(o);
   return o;
 }
+//endex
+
+//ifex _Geometry_Shader_Enabled==0
+// maxvertexcount == the number of vertices we create
+[maxvertexcount(3)]
+void geom(triangle v2f tri_in[3],
+  uint pid: SV_PrimitiveID,
+  inout TriangleStream<v2f> tri_out)
+{
+  v2f v0 = tri_in[0];
+  v2f v1 = tri_in[1];
+  v2f v2 = tri_in[2];
+
+#if defined(_CENTER_OFFSET)
+  float3 n0 = v0.normal;
+  float3 n1 = v1.normal;
+  float3 n2 = v2.normal;
+#if defined(_CUSTOM31_FRAGMENT_NORMALS) || defined(_CUSTOM31_TESSELLATION)
+  float3 tmp;
+  deform_normal(v0.objPos_orig, n0, tmp);
+  deform_normal(v1.objPos_orig, n1, tmp);
+  deform_normal(v2.objPos_orig, n2, tmp);
+  // the average direction doesn't have to be precise, so don't bother with
+  // normalize().
+  float3 n = (n0 + n1 + n2) * 0.333f;
+#else
+  float3 n = (v0.normal + v1.normal + v2.normal) * 0.333f;
+#endif
+  float height = center_offset(v0.uv0);
+  v0.objPos += n * height;
+  v1.objPos += n * height;
+  v2.objPos += n * height;
+  propagateObjPos(v0);
+  propagateObjPos(v1);
+  propagateObjPos(v2);
+#endif
+
+  // Output transformed geometry.
+  tri_out.Append(v0);
+  tri_out.Append(v1);
+  tri_out.Append(v2);
+  tri_out.RestartStrip();
+}
+//endex
 
 float4 frag(v2f i, uint facing : SV_IsFrontFace
 #if defined(_CUSTOM31_TUBES)
diff --git a/3ner.shader b/3ner.shader
index 7e6564c..aad3949 100644
--- a/3ner.shader
+++ b/3ner.shader
@@ -40,6 +40,21 @@ Shader "yum_food/3ner"
       [HideInInspector] m_end_Main("Main", Float) = 0
 
       [HideInInspector] m_start_Gimmicks("Gimmicks", Float) = 0
+        //ifex _Geometry_Shader_Enabled==0
+        [HideInInspector] m_start_Geometry_Shader("Geometry Shader", Float) = 0
+          [ThryToggle(_GEOMETRY_SHADER)] _Geometry_Shader_Enabled("Enable", Float) = 0
+
+          //ifex _Center_Offset_Enabled==0
+          [HideInInspector] m_start_Center_Offset("Center offset", Float) = 0
+            [ThryToggle(_CENTER_OFFSET)] _Center_Offset_Enabled("Enable", Float) = 0
+            _Center_Offset_Heightmap("Heightmap", 2D) = "black" {}
+            _Center_Offset_Factor("Factor", Range(-1, 1)) = 1
+          [HideInInspector] m_end_Center_Offset("Center offset", Float) = 0
+          //endex
+
+        [HideInInspector] m_end_Geometry_Shader("Geometry Shader", Float) = 0
+        //endex
+
         //ifex _Custom31_Enabled==0
         [HideInInspector] m_start_Custom31("Custom31", Float) = 0
           [ThryToggle(_CUSTOM31)] _Custom31_Enabled("Enable", Float) = 0
@@ -53,6 +68,7 @@ Shader "yum_food/3ner"
             //ifex _Custom31_XZ_Tube_Enabled==0
             [HideInInspector] m_start_Custom31_XZ_Tube("XZ Tube", Float) = 0
               [ThryToggle(_CUSTOM31_XZ_TUBE)] _Custom31_XZ_Tube_Enabled("Enable", Float) = 0
+              // 0.999... limit prevents NaNs which show up at 1.0
               _Custom31_XZ_Tube_t("t", Range(-1,1)) = 0
             [HideInInspector] m_end_Custom31_XZ_Tube("XZ Tube", Float) = 0
             //endex
@@ -188,6 +204,9 @@ Shader "yum_food/3ner"
       #pragma multi_compile_instancing
       #pragma multi_compile_fog
       #pragma vertex vert
+      //ifex _Geometry_Enabled==0
+      #pragma geometry geom
+      //endex
       //ifex _Tessellation_Enabled==0
       #pragma hull hull
       #pragma domain domain
@@ -215,6 +234,9 @@ Shader "yum_food/3ner"
       #pragma multi_compile_instancing
       #pragma multi_compile_fog
       #pragma vertex vert
+      //ifex _Geometry_Enabled==0
+      #pragma geometry geom
+      //endex
       //ifex _Tessellation_Enabled==0
       #pragma hull hull
       #pragma domain domain
diff --git a/custom31.slang b/custom31.slang
index 61afe4a..441daeb 100644
--- a/custom31.slang
+++ b/custom31.slang
@@ -62,34 +62,6 @@ float3x3 inverse(float3x3 m, float det) {
   return inv;
 }
 
-[Differentiable]
-public float3 c31_deform(float3 xyz, no_diff float A, no_diff float k, no_diff float t) {
-  float x = xyz.x;
-  float y = xyz.y;
-  float z = xyz.z;
-
-  float x0 = x + sin(y * k) * 0.1;
-  float y0 = y + sin(x * k * 2) * 0.5 + cos(z);
-  float z0 = (z + sin(x * y * k * PI + t) * A) * (1.0 + sin(y * k) * sin(x * k));
-
-  x0 += z0 * 0.1 * sin(z0 * PI + 1.5);
-  y0 += z0 * 0.1 * sin(z0 * PI + 1.5);
-
-  x0 -= 0.0;
-  y0 -= 1.2;
-
-  return float3(
-      x0, y0, z0
-  );
-}
-
-
-// Deform a normal vector using the inverse transpose of the jacobian.
-public void c31_deform_normal(float3 xyz, inout float3 normal,
-    inout float3 tangent, float A, float k, float t) {
-  R3R3_NORMALS(normal, tangent, c31_deform, A, k, t);
-}
-
 // Takes map a 2x2 quad on the xy plane to a tube. The circular cross section
 // is on the xz plane.
 [Differentiable]
diff --git a/features.cginc b/features.cginc
index c6786d4..ce8d07d 100644
--- a/features.cginc
+++ b/features.cginc
@@ -43,4 +43,8 @@
 #pragma shader_feature_local _UV_SCROLL
 //endex
 
+//ifex _Center_Offset_Enabled==0
+#pragma shader_feature_local _CENTER_OFFSET
+//endex
+
 #endif  // __FEATURES_INC
diff --git a/geometry.cginc b/geometry.cginc
new file mode 100644
index 0000000..9ddb011
--- /dev/null
+++ b/geometry.cginc
@@ -0,0 +1,16 @@
+#ifndef __GEOMETRY_INC
+#define __GEOMETRY_INC
+
+#include "interpolators.cginc"
+#include "globals.cginc"
+
+#if defined(_CENTER_OFFSET)
+float center_offset(float2 uv) {
+  float height = _Center_Offset_Heightmap.SampleLevel(point_repeat_s,
+        uv * _Center_Offset_Heightmap_ST.xy + _Center_Offset_Heightmap_ST.zw, 0).r;
+  return height * _Center_Offset_Factor;
+}
+#endif  // _CENTER_OFFSET
+
+
+#endif // __GEOMETRY_INC
diff --git a/globals.cginc b/globals.cginc
index 1bd9498..3ba2e60 100644
--- a/globals.cginc
+++ b/globals.cginc
@@ -72,4 +72,10 @@ float _Custom31_YZ_Tube_t;
 float2 _UV_Scroll_Speed;
 #endif  // _UV_SCROLL
 
+#if defined(_CENTER_OFFSET)
+texture2D _Center_Offset_Heightmap;
+float4 _Center_Offset_Heightmap_ST;
+float _Center_Offset_Factor;
+#endif  // _CENTER_OFFSET
+
 #endif  // __GLOBALS_INC
diff --git a/math.cginc b/math.cginc
index af71fc6..4cfed67 100644
--- a/math.cginc
+++ b/math.cginc
@@ -4,6 +4,7 @@
 #define PI 3.14159265358979f
 #define RCP_PI (1.0f / PI)
 #define TAU (2.0f * PI)
+#define SQRT_3 1.73205081f
 
 float sin_noise_3d(float3 uvw) {
   return sin(uvw[0]) * sin(uvw[1]) * sin(uvw[2]);
diff --git a/vertex.cginc b/vertex.cginc
index 2f5b5f5..58c5209 100644
--- a/vertex.cginc
+++ b/vertex.cginc
@@ -4,22 +4,23 @@
 #include "custom31.hlsl"
 
 void deform(inout float3 objPos) {
+  float t_eps = 1e-9;
 #if defined(_CUSTOM31_XZ_TUBE)
   {
-    float t = _Custom31_XZ_Tube_t;
+    float t = clamp(_Custom31_XZ_Tube_t, -1+t_eps, 1-t_eps);;
     objPos = plane_to_tube(objPos.xyz, t);
   }
 #endif  // _CUSTOM31_XZ_TUBE
 #if defined(_CUSTOM31_YZ_TUBE)
   {
-    float t = _Custom31_YZ_Tube_t;
+    float t = clamp(_Custom31_YZ_Tube_t, -1+t_eps, 1-t_eps);
     objPos = plane_to_tube(objPos.yxz, t);
     objPos = objPos.yxz;
   }
 #endif  // _CUSTOM31_YZ_TUBE
 #if defined(_CUSTOM31_XY_TUBE)
   {
-    float t = _Custom31_XY_Tube_t;
+    float t = clamp(_Custom31_XY_Tube_t, -1+t_eps, 1-t_eps);
     objPos = plane_to_tube(objPos.xzy, t);
     objPos = objPos.xzy;
   }