Begin sketching out tessellation feature

1 files changed, 70 insertions, 0 deletions

diff --git a/tessellation.cginc b/tessellation.cginc
new file mode 100644
index 0000000..c77cd83
--- /dev/null
+++ b/tessellation.cginc
@@ -0,0 +1,70 @@
+#ifndef __TESSELLATION_INC
+#define __TESSELLATION_INC
+
+#include "globals.cginc"
+#include "interpolators.cginc"
+
+//ifex _Tessellation_Enabled==0
+
+struct tess_factors {
+  float edge[3] : SV_TessFactor;
+  float inside : SV_InsideTessFactor;
+};
+
+tess_factors patch_constant(InputPatch<v2f, 3> patch) {
+  tess_factors f;
+#if defined(_TESSELLATION)
+  f.edge[0] = _Tessellation_Edge_Factors[0];
+  f.edge[1] = _Tessellation_Edge_Factors[1];
+  f.edge[2] = _Tessellation_Edge_Factors[2];
+  f.inside = _Tessellation_Inside_Factor;
+#else
+  f.edge[0] = 1;
+  f.edge[1] = 1;
+  f.edge[2] = 1;
+  f.inside = 1;
+#endif
+  return f;
+}
+
+[UNITY_domain("tri")]
+[UNITY_outputcontrolpoints(3)]
+[UNITY_outputtopology("triangle_cw")]
+[UNITY_partitioning("fractional_odd")]
+[UNITY_patchconstantfunc("patch_constant")]
+v2f hull(
+    InputPatch<v2f, 3> patch,
+    uint id : SV_OutputControlPointID)
+{
+  return patch[id];
+}
+
+[UNITY_domain("tri")]
+v2f domain(
+    tess_factors factors,
+    OutputPatch<v2f, 3> patch,
+    float3 baryc : SV_DomainLocation)
+{
+  v2f o;
+#define DOMAIN_INTERP(fieldName) \
+  patch[0].fieldName * baryc.x + \
+  patch[1].fieldName * baryc.y + \
+  patch[2].fieldName * baryc.z
+  o.pos      = DOMAIN_INTERP(pos);
+  o.uv01     = DOMAIN_INTERP(uv01);
+  o.objPos   = DOMAIN_INTERP(pos);
+  o.worldPos = DOMAIN_INTERP(worldPos);
+  o.normal   = DOMAIN_INTERP(normal);
+  o.tangent  = DOMAIN_INTERP(tangent);
+  o.binormal = DOMAIN_INTERP(binormal);
+  o.eyeVec   = DOMAIN_INTERP(eyeVec);
+
+  // TODO what about UNITY_LIGHTING_COORDS(7,8) and instance id and shit?
+  return o;
+}
+
+
+//endex
+
+#endif  // __TESSELLATION_INC
+