ocean wave work

- add sea foam feature, which takes horizontal displacement derivatives
  and calculates folding areas (with a bias) using the Tessendorf
  Jacobian method.
- add "isInViewFrustum" method to tessellation

1 files changed, 99 insertions, 59 deletions

diff --git a/tessellation.cginc b/tessellation.cginc
index fce9979..24d53ab 100644
--- a/tessellation.cginc
+++ b/tessellation.cginc
@@ -13,6 +13,79 @@ struct tess_factors {
   float inside : SV_InsideTessFactor;
 };
 
+bool isInViewFrustum(float4 clipPos, float radius) {
+  return -clipPos.w - radius < clipPos.x && clipPos.x < clipPos.w + radius &&
+         -clipPos.w - radius < clipPos.y && clipPos.y < clipPos.w + radius &&
+         -clipPos.w - radius < clipPos.z && clipPos.z < clipPos.w + radius;
+}
+
+#if defined(_TESSELLATION_HEIGHTMAP_0) || defined(_TESSELLATION_HEIGHTMAP_1) || defined(_TESSELLATION_HEIGHTMAP_2) || defined(_TESSELLATION_HEIGHTMAP_3) || defined(_TESSELLATION_HEIGHTMAP_4) || defined(_TESSELLATION_HEIGHTMAP_5) || defined(_TESSELLATION_HEIGHTMAP_6) || defined(_TESSELLATION_HEIGHTMAP_7)
+#define _TESSELLATION_HEIGHTMAP
+#endif
+
+float4 applyHeightmap(float4 objPos, float2 uv, float3 normal, float3 tangent, float3 binormal) {
+#if defined(_TESSELLATION) && defined(_TESSELLATION_HEIGHTMAP)
+  float3 height = 0;
+#if defined(_TESSELLATION_HEIGHTMAP_0)
+  float3 heightmap_0_sample = _Tessellation_Heightmap_0.SampleLevel(bilinear_repeat_s,
+      uv * _Tessellation_Heightmap_0_ST.xy, 0);
+  height += heightmap_0_sample * _Tessellation_Heightmap_0_Scale + _Tessellation_Heightmap_0_Offset;
+#endif
+#if defined(_TESSELLATION_HEIGHTMAP_1)
+  float3 heightmap_1_sample = _Tessellation_Heightmap_1.SampleLevel(bilinear_repeat_s,
+      uv * _Tessellation_Heightmap_1_ST.xy, 0);
+  height += heightmap_1_sample * _Tessellation_Heightmap_1_Scale + _Tessellation_Heightmap_1_Offset;
+#endif
+#if defined(_TESSELLATION_HEIGHTMAP_2)
+  float3 heightmap_2_sample = _Tessellation_Heightmap_2.SampleLevel(bilinear_repeat_s,
+      uv * _Tessellation_Heightmap_2_ST.xy, 0);
+  height += heightmap_2_sample * _Tessellation_Heightmap_2_Scale + _Tessellation_Heightmap_2_Offset;
+#endif
+#if defined(_TESSELLATION_HEIGHTMAP_3)
+  float3 heightmap_3_sample = _Tessellation_Heightmap_3.SampleLevel(bilinear_repeat_s,
+      uv * _Tessellation_Heightmap_3_ST.xy, 0);
+  height += heightmap_3_sample * _Tessellation_Heightmap_3_Scale + _Tessellation_Heightmap_3_Offset;
+#endif
+#if defined(_TESSELLATION_HEIGHTMAP_4)
+  float3 heightmap_4_sample = _Tessellation_Heightmap_4.SampleLevel(bilinear_repeat_s,
+      uv * _Tessellation_Heightmap_4_ST.xy, 0);
+  height += heightmap_4_sample * _Tessellation_Heightmap_4_Scale + _Tessellation_Heightmap_4_Offset;
+#endif
+#if defined(_TESSELLATION_HEIGHTMAP_5)
+  float3 heightmap_5_sample = _Tessellation_Heightmap_5.SampleLevel(bilinear_repeat_s,
+      uv * _Tessellation_Heightmap_5_ST.xy, 0);
+  height += heightmap_5_sample * _Tessellation_Heightmap_5_Scale + _Tessellation_Heightmap_5_Offset;
+#endif
+#if defined(_TESSELLATION_HEIGHTMAP_6)
+  float3 heightmap_6_sample = _Tessellation_Heightmap_6.SampleLevel(bilinear_repeat_s,
+      uv * _Tessellation_Heightmap_6_ST.xy, 0);
+  height += heightmap_6_sample * _Tessellation_Heightmap_6_Scale + _Tessellation_Heightmap_6_Offset;
+#endif
+#if defined(_TESSELLATION_HEIGHTMAP_7)
+  float3 heightmap_7_sample = _Tessellation_Heightmap_7.SampleLevel(bilinear_repeat_s,
+      uv * _Tessellation_Heightmap_7_ST.xy, 0);
+  height += heightmap_7_sample * _Tessellation_Heightmap_7_Scale + _Tessellation_Heightmap_7_Offset;
+#endif
+
+#if defined(_TESSELLATION_HEIGHTMAP_WORLD_SPACE)
+  objPos.xyz += mul(unity_WorldToObject, height).xyz;
+#else
+#if defined(OUTLINE_PASS) && defined(_TESSELLATION_HEIGHTMAP_DIRECTION_CONTROL)
+  float3 heightmap_direction = mul(transpose(-float3x3(normal, tangent, binormal)), _Tessellation_Heightmap_Direction_Control_Vector);
+#elif defined(OUTLINE_PASS) && !defined(_TESSELLATION_HEIGHTMAP_DIRECTION_CONTROL)
+  float3 heightmap_direction = -normal;
+#elif !defined(OUTLINE_PASS) && defined(_TESSELLATION_HEIGHTMAP_DIRECTION_CONTROL)
+  float3 heightmap_direction = mul(transpose(float3x3(normal, tangent, binormal)), _Tessellation_Heightmap_Direction_Control_Vector);
+#else
+  float3 heightmap_direction = normal;
+#endif
+  objPos.xyz += heightmap_direction * height;
+#endif
+
+#endif  // _TESSELLATION_HEIGHTMAP
+  return objPos;
+}
+
 tess_factors patch_constant(InputPatch<v2f, 3> patch) {
   tess_factors f;
 #if defined(_TESSELLATION)
@@ -32,6 +105,31 @@ tess_factors patch_constant(InputPatch<v2f, 3> patch) {
 #else
   float factor = 1;
 #endif
+
+#if defined(_TESSELLATION_HEIGHTMAP)
+  [branch] 
+  if (factor > 3) {
+    // Scuffed occlusion culling. Need to know what the position will be after displacement
+    // in order to do it right. "Scuffed" because we repeat work :/ this same transform gets
+    // applied in the domain shader. This isn't so bad if we assume that we're tessellating
+    // at a relatively high factor.
+    float3 p0newObjPos = applyHeightmap(patch[0].objPos, patch[0].uv01.xy, patch[0].normal, patch[0].tangent, patch[0].binormal);
+    float3 p1newObjPos = applyHeightmap(patch[1].objPos, patch[1].uv01.xy, patch[1].normal, patch[1].tangent, patch[1].binormal);
+    float3 p2newObjPos = applyHeightmap(patch[2].objPos, patch[2].uv01.xy, patch[2].normal, patch[2].tangent, patch[2].binormal);
+    float4 p0newClipPos = UnityObjectToClipPos(p0newObjPos);
+    float4 p1newClipPos = UnityObjectToClipPos(p1newObjPos);
+    float4 p2newClipPos = UnityObjectToClipPos(p2newObjPos);
+    // Dirty hack to prevent objects that are currently outside the view frustum,
+    // but which are after displacement, from being culled.
+    float radius = 0.3;
+    bool inViewFrustum0 = isInViewFrustum(p0newClipPos, radius);
+    bool inViewFrustum1 = isInViewFrustum(p1newClipPos, radius);
+    bool inViewFrustum2 = isInViewFrustum(p2newClipPos, radius);
+    bool inViewFrustum = inViewFrustum0 || inViewFrustum1 || inViewFrustum2;
+    factor = inViewFrustum ? factor : 1;
+  }
+#endif
+
   f.edge[0] = factor;
   f.edge[1] = factor;
   f.edge[2] = factor;
@@ -82,65 +180,7 @@ v2f domain(
 #endif
 #endif
 
-#if defined(_TESSELLATION) && (defined(_TESSELLATION_HEIGHTMAP_0) || defined(_TESSELLATION_HEIGHTMAP_1) || defined(_TESSELLATION_HEIGHTMAP_2) || defined(_TESSELLATION_HEIGHTMAP_3) || defined(_TESSELLATION_HEIGHTMAP_4) || defined(_TESSELLATION_HEIGHTMAP_5) || defined(_TESSELLATION_HEIGHTMAP_6) || defined(_TESSELLATION_HEIGHTMAP_7))
-  float3 height = 0;
-#if defined(_TESSELLATION_HEIGHTMAP_0)
-  float3 heightmap_0_sample = _Tessellation_Heightmap_0.SampleLevel(bilinear_repeat_s,
-      o.uv01.xy * _Tessellation_Heightmap_0_ST.xy, 0);
-  height += heightmap_0_sample * _Tessellation_Heightmap_0_Scale + _Tessellation_Heightmap_0_Offset;
-#endif
-#if defined(_TESSELLATION_HEIGHTMAP_1)
-  float3 heightmap_1_sample = _Tessellation_Heightmap_1.SampleLevel(bilinear_repeat_s,
-      o.uv01.xy * _Tessellation_Heightmap_1_ST.xy, 0);
-  height += heightmap_1_sample * _Tessellation_Heightmap_1_Scale + _Tessellation_Heightmap_1_Offset;
-#endif
-#if defined(_TESSELLATION_HEIGHTMAP_2)
-  float3 heightmap_2_sample = _Tessellation_Heightmap_2.SampleLevel(bilinear_repeat_s,
-      o.uv01.xy * _Tessellation_Heightmap_2_ST.xy, 0);
-  height += heightmap_2_sample * _Tessellation_Heightmap_2_Scale + _Tessellation_Heightmap_2_Offset;
-#endif
-#if defined(_TESSELLATION_HEIGHTMAP_3)
-  float3 heightmap_3_sample = _Tessellation_Heightmap_3.SampleLevel(bilinear_repeat_s,
-      o.uv01.xy * _Tessellation_Heightmap_3_ST.xy, 0);
-  height += heightmap_3_sample * _Tessellation_Heightmap_3_Scale + _Tessellation_Heightmap_3_Offset;
-#endif
-#if defined(_TESSELLATION_HEIGHTMAP_4)
-  float3 heightmap_4_sample = _Tessellation_Heightmap_4.SampleLevel(bilinear_repeat_s,
-      o.uv01.xy * _Tessellation_Heightmap_4_ST.xy, 0);
-  height += heightmap_4_sample * _Tessellation_Heightmap_4_Scale + _Tessellation_Heightmap_4_Offset;
-#endif
-#if defined(_TESSELLATION_HEIGHTMAP_5)
-  float3 heightmap_5_sample = _Tessellation_Heightmap_5.SampleLevel(bilinear_repeat_s,
-      o.uv01.xy * _Tessellation_Heightmap_5_ST.xy, 0);
-  height += heightmap_5_sample * _Tessellation_Heightmap_5_Scale + _Tessellation_Heightmap_5_Offset;
-#endif
-#if defined(_TESSELLATION_HEIGHTMAP_6)
-  float3 heightmap_6_sample = _Tessellation_Heightmap_6.SampleLevel(bilinear_repeat_s,
-      o.uv01.xy * _Tessellation_Heightmap_6_ST.xy, 0);
-  height += heightmap_6_sample * _Tessellation_Heightmap_6_Scale + _Tessellation_Heightmap_6_Offset;
-#endif
-#if defined(_TESSELLATION_HEIGHTMAP_7)
-  float3 heightmap_7_sample = _Tessellation_Heightmap_7.SampleLevel(bilinear_repeat_s,
-      o.uv01.xy * _Tessellation_Heightmap_7_ST.xy, 0);
-  height += heightmap_7_sample * _Tessellation_Heightmap_7_Scale + _Tessellation_Heightmap_7_Offset;
-#endif
-
-#if defined(_TESSELLATION_HEIGHTMAP_WORLD_SPACE)
-  o.objPos.xyz += mul(unity_WorldToObject, height).xyz;
-#else
-#if defined(OUTLINE_PASS) && defined(_TESSELLATION_HEIGHTMAP_DIRECTION_CONTROL)
-  float3 heightmap_direction = mul(transpose(-float3x3(o.normal, o.tangent, o.binormal)), _Tessellation_Heightmap_Direction_Control_Vector);
-#elif defined(OUTLINE_PASS) && !defined(_TESSELLATION_HEIGHTMAP_DIRECTION_CONTROL)
-  float3 heightmap_direction = -o.normal;
-#elif !defined(OUTLINE_PASS) && defined(_TESSELLATION_HEIGHTMAP_DIRECTION_CONTROL)
-  float3 heightmap_direction = mul(transpose(float3x3(o.normal, o.tangent, o.binormal)), _Tessellation_Heightmap_Direction_Control_Vector);
-#else
-  float3 heightmap_direction = o.normal;
-#endif
-  o.objPos.xyz += heightmap_direction * height;
-#endif
-
-#endif  // _TESSELLATION_HEIGHTMAP
+  o.objPos = applyHeightmap(o.objPos, o.uv01.xy, o.normal, o.tangent, o.binormal);
 
   o.pos      = UnityObjectToClipPos(o.objPos);
   o.worldPos = mul(unity_ObjectToWorld, o.objPos).xyz;