1 files changed, 84 insertions, 0 deletions
diff --git a/rorschach.cginc b/rorschach.cginc
new file mode 100644
index 0000000..bfa550d
--- /dev/null
+++ b/rorschach.cginc
@@ -0,0 +1,84 @@
+#ifndef __RORSCHACH_INC
+#define __RORSCHACH_INC
+
+#if defined(_RORSCHACH)
+
+#include "globals.cginc"
+#include "interpolators.cginc"
+#include "iq_sdf.cginc"
+#include "pema99.cginc"
+
+struct RorschachPBR {
+  float4 albedo;
+};
+
+float map_sdf(float3 p, float2 e, float3 period)
+{
+  float r = 1 * min(period.x, min(period.y, period.z));
+  float st = sin(_Time[1] * e.y * e.y + e.x * 3.14159265 * 2);
+  r *= st;
+  return distance_from_sphere(p, r);
+}
+
+float map_dr(
+    float3 p,
+    float3 period,
+    float3 count,
+    out float3 which
+    )
+{
+  which = round(p / period);
+  // Direction to nearest neighboring cell.
+  float3 min_d = p - period * which;
+  float3 o = sign(min_d);
+
+  float d = 1E9;
+  float3 which_tmp = which;
+  for (int xi = -2; xi < 3; xi++)
+  for (int yi = -2; yi < 3; yi++)
+  {
+    float3 rid = which + float3(xi, yi, 0) * o;
+    float3 r = p - period * rid;
+    float2 e = float2(
+        rand3(rid),
+        rand3(rid + 1));
+    float cur_d = map_sdf(r, e, period);
+    which_tmp = cur_d < d ? rid : which;
+    d = min(d, cur_d);
+  }
+
+  which = which_tmp;
+  return d;
+}
+
+RorschachPBR get_rorschach(v2f i)
+{
+  RorschachPBR result;
+  result.albedo = float4(0, 0, 0, 1);
+
+  float3 ro = float3(i.uv0.x - 0.5, i.uv0.y - 0.5, 0);
+  float3 rd = float3(0, 0, 1);
+
+  float3 which;
+  float3 period = float3(1 / (_Rorschach_Count_X+1), 1 / (_Rorschach_Count_Y+1), 1);
+  float3 count = float3(_Rorschach_Count_X, _Rorschach_Count_Y, 1);
+  float d = map_dr(ro, period, count, which);
+  d -= map_dr(1 - ro, period, count, which) * 4;
+
+  d = 1 - d;
+  d *= d;
+  d *= d;
+  d *= d;
+  d = 1 - d;
+
+  d *= 3;
+  d = saturate(d);
+
+  result.albedo.rgb = d;
+
+  return result;
+}
+
+#endif  // _RORSCHACH
+#endif  // __RORSCHACH_INC
+