src/geometry.cpp

   1 #include "geometry.hpp"
   2
   3
   4 namespace blank {
   5
   6 bool Intersection(const Ray &ray, const AABB &aabb, const glm::mat4 &M, float *dist) {
   7         float t_min = 0.0f;
   8         float t_max = 1.0e5f;
   9         const glm::vec3 aabb_pos(M[3].x, M[3].y, M[3].z);
  10         const glm::vec3 delta = aabb_pos - ray.orig;
  11
  12         { // X
  13                 const glm::vec3 xaxis(M[0].x, M[0].y, M[0].z);
  14                 const float e = glm::dot(xaxis, delta);
  15                 const float f = glm::dot(ray.dir, xaxis);
  16
  17                 if (std::abs(f) > 0.001f) {
  18                         float t1 = (e + aabb.min.x) / f;
  19                         float t2 = (e + aabb.max.x) / f;
  20
  21                         if (t1 > t2) {
  22                                 std::swap(t1, t2);
  23                         }
  24                         if (t1 > t_min) {
  25                                 t_min = t1;
  26                         }
  27                         if (t2 < t_max) {
  28                                 t_max = t2;
  29                         }
  30                         if (t_max < t_min) {
  31                                 return false;
  32                         }
  33                 } else {
  34                         if (aabb.min.x - e > 0.0f || aabb.max.x < 0.0f) {
  35                                 return false;
  36                         }
  37                 }
  38         }
  39
  40         { // Y
  41                 const glm::vec3 yaxis(M[1].x, M[1].y, M[1].z);
  42                 const float e = glm::dot(yaxis, delta);
  43                 const float f = glm::dot(ray.dir, yaxis);
  44
  45                 if (std::abs(f) > 0.001f) {
  46                         float t1 = (e + aabb.min.y) / f;
  47                         float t2 = (e + aabb.max.y) / f;
  48
  49                         if (t1 > t2) {
  50                                 std::swap(t1, t2);
  51                         }
  52                         if (t1 > t_min) {
  53                                 t_min = t1;
  54                         }
  55                         if (t2 < t_max) {
  56                                 t_max = t2;
  57                         }
  58                         if (t_max < t_min) {
  59                                 return false;
  60                         }
  61                 } else {
  62                         if (aabb.min.y - e > 0.0f || aabb.max.y < 0.0f) {
  63                                 return false;
  64                         }
  65                 }
  66         }
  67
  68         { // Z
  69                 const glm::vec3 zaxis(M[2].x, M[2].y, M[2].z);
  70                 const float e = glm::dot(zaxis, delta);
  71                 const float f = glm::dot(ray.dir, zaxis);
  72
  73                 if (std::abs(f) > 0.001f) {
  74                         float t1 = (e + aabb.min.z) / f;
  75                         float t2 = (e + aabb.max.z) / f;
  76
  77                         if (t1 > t2) {
  78                                 std::swap(t1, t2);
  79                         }
  80                         if (t1 > t_min) {
  81                                 t_min = t1;
  82                         }
  83                         if (t2 < t_max) {
  84                                 t_max = t2;
  85                         }
  86                         if (t_max < t_min) {
  87                                 return false;
  88                         }
  89                 } else {
  90                         if (aabb.min.z - e > 0.0f || aabb.max.z < 0.0f) {
  91                                 return false;
  92                         }
  93                 }
  94         }
  95
  96         if (dist) {
  97                 *dist = t_min;
  98         }
  99         return true;
 100 }
 101
 102 }