add hexagon sdf

1 files changed, 19 insertions, 1 deletions

diff --git a/ray_marching_maps.slang b/ray_marching_maps.slang
index 002ef90..1b8fe84 100644
--- a/ray_marching_maps.slang
+++ b/ray_marching_maps.slang
@@ -1,7 +1,6 @@
 #ifndef __RAY_MARCHING_MAPS_INC
 #define __RAY_MARCHING_MAPS_INC
 
-
 #include "math.cginc"
 #include "pema99.cginc"
 
@@ -42,5 +41,24 @@ public void map_ball_normal(float r, inout float3 xyz, inout float3 normal,
   R3R1_RAY_MARCH_NORMALS(xyz, normal, tangent, map_ball, r);
 }
 
+[Differentiable]
+public float map_hexagon(float3 p, no_diff float2 h)
+{
+  float3 q = abs(p);
+
+  const float3 k = float3(-0.8660254, 0.5, 0.57735);
+  p = abs(p);
+  p.xy -= 2.0*min(dot(k.xy, p.xy), 0.0)*k.xy;
+  float2 d = float2(
+      length(p.xy - float2(clamp(p.x, -k.z*h.x, k.z*h.x), h.x))*sign(p.y - h.x),
+      p.z-h.y );
+  return min(max(d.x,d.y),0.0) + length(max(d,0.0));
+}
+
+public void map_hexagon_normal(float2 h, inout float3 xyz, inout float3 normal,
+    inout float3 tangent) {
+  R3R1_RAY_MARCH_NORMALS(xyz, normal, tangent, map_hexagon, h);
+}
+
 #endif  // __RAY_MARCHING_MAPS_INC