Extract first public LiterateLB version

1 files changed, 75 insertions, 0 deletions

diff --git a/tangle/LLBM/sdf.h b/tangle/LLBM/sdf.h
new file mode 100644
index 0000000..656c109
--- /dev/null
+++ b/tangle/LLBM/sdf.h
@@ -0,0 +1,75 @@
+#pragma once
+#include <vector_types.h>
+#include <cuda-samples/Common/helper_math.h>
+
+template <typename SDF, typename V>
+__device__ __host__
+float approximateDistance(SDF sdf, V origin, V dir, float d0, float d1, float eps=1e-2, unsigned N=128) {
+  float distance = d0;
+  float delta = (d1-d0) / N;
+  for (unsigned i=0; i < N; ++i) {
+    float d = sdf(origin + distance*dir);
+    if (d < eps) {
+      return distance;
+    }
+    distance += d;
+    if (distance > d1) {
+      return d1;
+    }
+  }
+  return d1;
+}
+
+namespace sdf {
+
+template <typename V>
+__device__ __host__ float sphere(V p, float r) {
+  return length(p) - r;
+}
+
+__device__ __host__ float box(float3 p, float3 b) {
+  float3 q = fabs(p) - b;
+  return length(fmaxf(q,make_float3(0))) + fmin(fmax(q.x,fmax(q.y,q.z)),0);
+}
+
+__device__ __host__ float cylinder(float3 p, float r, float h) {
+	return fmax(length(make_float2(p.x,p.y)) - r, fabs(p.z) - 0.5*h);
+}
+
+__device__ __host__ float add(float a, float b) {
+  return fmin(a, b);
+}
+
+__device__ __host__ float intersect(float a, float b) {
+  return fmax(a, b);
+}
+
+__device__ __host__ float sub(float a, float b) {
+  return intersect(-a, b);
+}
+
+__device__ __host__ float sadd(float a, float b, float k) {
+  float h = clamp(0.5f + 0.5f*(b-a)/k, 0.0f, 1.0f);
+  return lerp(b, a, h) - k*h*(1.f-h);
+}
+
+__device__ __host__ float ssub(float a, float b, float k) {
+  float h = clamp(0.5f - 0.5f*(b+a)/k, 0.f, 1.f);
+  return lerp(b, -a, h) + k*h*(1.f-h);
+}
+
+__device__ __host__ float sintersect(float a, float b, float k) {
+  float h = clamp(0.5f - 0.5f*(b-a)/k, 0.f, 1.f);
+  return lerp(b, a, h) + k*h*(1.f-h);
+}
+
+}
+
+template <typename SDF>
+__device__ float3 sdf_normal(SDF sdf, float3 v, float eps=1e-4) {
+  return normalize(make_float3(
+    sdf(make_float3(v.x + eps, v.y, v.z)) - sdf(make_float3(v.x - eps, v.y, v.z)),
+    sdf(make_float3(v.x, v.y + eps, v.z)) - sdf(make_float3(v.x, v.y - eps, v.z)),
+    sdf(make_float3(v.x, v.y, v.z + eps)) - sdf(make_float3(v.x, v.y, v.z - eps))
+  ));
+}