Sample both position and direction

pshriwise · Aug 19, 2023 · 8085914 · 8085914
1 parent 4682b2f
commit 8085914
Showing 1 changed file with 15 additions and 11 deletions.
diff --git a/test/test_find_vol.cpp b/test/test_find_vol.cpp
@@ -8,6 +8,15 @@
 
 using namespace double_down;
 
+void sample_dir(double p[3]) {
+  double mu = -1.0 + 2.0 * (double)std::rand() / (double)RAND_MAX;
+  double phi = 2.0 * M_PI * (double)std::rand() / (double)RAND_MAX;
+  double rh = sqrt(1.0 - mu*mu);
+  p[0] = rh*cos(phi);
+  p[1] = rh*sin(phi);
+  p[2] = mu;
+}
+
 int main() {
 
   // create new MOAB instance
@@ -30,13 +39,10 @@ int main() {
   moab::EntityHandle sphere_vol = vols[0];
 
   // fire a test ray
-  double org[3] = {0.0, 0.0, 0.0};
-  double dir[3] = {1.0, 0.0, 0.0};
+  double org[3] {0.0, 0.0, 0.0};
+  double dir[3] {1.0, 0.0, 0.0};
 
-  double dist = 0.0;
-  moab::EntityHandle surf;
   for (int i = 0; i < 1000; i++) {
-    std::cout << org[0] << " " << org[1] << " " << org[2] << std::endl;
     moab::EntityHandle volume = 0;
     RTI->find_volume(org, volume, dir);
     if (volume != sphere_vol) { return 1; }
@@ -46,13 +52,11 @@ int main() {
     RTI->find_volume(org, volume);
     if (volume != sphere_vol) { return 1; }
 
-    // sample a random point in the sphere volume
-    double mu = -1.0 + 2.0 * (double)std::rand() / (double)RAND_MAX;
-    double phi = 2.0 * M_PI * (double)std::rand() / (double)RAND_MAX;
+    // sample a new position and direction for subsequent checks
     double r = 9.9 * (double)std::rand() / (double)RAND_MAX;
-    org[0] = sqrt(1-mu*mu)*cos(phi)*r;
-    org[1] = sqrt(1-mu*mu)*sin(phi)*r;
-    org[2] = r*mu;
+    sample_dir(org);
+    for (auto& val : org) { val *= r; }
+    sample_dir(dir);
   }
 
   return 0;