2011-12-27 21:18:07 +00:00
commit 9f98ea7e22
192 changed files with 77747 additions and 0 deletions
@@ -0,0 +1,123 @@
+// File: crn_intersect.h
+// See Copyright Notice and license at the end of inc/crnlib.h
+#pragma once
+#include "crn_ray.h"
+
+namespace crnlib
+{
+   namespace intersection
+   {
+      enum result 
+      {
+         cBackfacing = -1,
+         cFailure = 0,
+         cSuccess,
+         cParallel,
+         cInside,
+      };
+      
+      // Returns cInside, cSuccess, or cFailure.
+      // Algorithm: Graphics Gems 1
+      template<typename vector_type, typename scalar_type, typename ray_type, typename aabb_type>
+      result ray_aabb(vector_type& coord, scalar_type& t, const ray_type& ray, const aabb_type& box)
+      {
+         enum 
+         { 
+            cNumDim = vector_type::num_elements, 
+            cRight = 0, 
+            cLeft = 1, 
+            cMiddle = 2 
+         };
+
+         bool inside = true;
+         int quadrant[cNumDim];
+         scalar_type candidate_plane[cNumDim];
+
+         for (int i = 0; i < cNumDim; i++)
+         {
+            if (ray.get_origin()[i] < box[0][i])
+            {
+               quadrant[i] = cLeft;
+               candidate_plane[i] = box[0][i];
+               inside = false;
+            }
+            else if (ray.get_origin()[i] > box[1][i])
+            {
+               quadrant[i] = cRight;
+               candidate_plane[i] = box[1][i];
+               inside = false;
+            }
+            else
+            {
+               quadrant[i] = cMiddle;
+            }
+         }
+
+         if (inside)
+         {
+            coord = ray.get_origin();
+            t = 0.0f;
+            return cInside;
+         }
+
+         scalar_type max_t[cNumDim];
+         for (int i = 0; i < cNumDim; i++)
+         {
+            if ((quadrant[i] != cMiddle) && (ray.get_direction()[i] != 0.0f))
+               max_t[i] = (candidate_plane[i] - ray.get_origin()[i]) / ray.get_direction()[i];
+            else
+               max_t[i] = -1.0f;
+         }         
+
+         int which_plane = 0;
+         for (int i = 1; i < cNumDim; i++)
+            if (max_t[which_plane] < max_t[i])
+               which_plane = i;
+
+         if (max_t[which_plane] < 0.0f)
+            return cFailure;               
+
+         for (int i = 0; i < cNumDim; i++)
+         {
+            if (i != which_plane)
+            {
+               coord[i] = ray.get_origin()[i] + max_t[which_plane] * ray.get_direction()[i];
+
+               if ( (coord[i] < box[0][i]) || (coord[i] > box[1][i]) )
+                  return cFailure;
+            }
+            else
+            {
+               coord[i] = candidate_plane[i];
+            }
+
+            CRNLIB_ASSERT(coord[i] >= box[0][i] && coord[i] <= box[1][i]); 
+         }               
+
+         t = max_t[which_plane];
+         return cSuccess;
+      }
+      
+      template<typename vector_type, typename scalar_type, typename ray_type, typename aabb_type>
+      result ray_aabb(bool& started_within, vector_type& coord, scalar_type& t, const ray_type& ray, const aabb_type& box)
+      {
+         if (!box.contains(ray.get_origin()))
+         {
+            started_within = false;
+            return ray_aabb(coord, t, ray, box);
+         }
+         
+         started_within = true;
+         
+         float diag_dist = box.diagonal_length() * 1.5f;
+         ray_type outside_ray(ray.eval(diag_dist), -ray.get_direction());
+         
+         result res(ray_aabb(coord, t, outside_ray, box));
+         if (res != cSuccess)
+            return res;
+         
+         t = math::maximum(0.0f, diag_dist - t);
+         return cSuccess;
+      }
+   }
+}