feat: complete first geodesic 3D raytracing

1 files changed, 38 insertions, 5 deletions

diff --git a/src/engine/object.h b/src/engine/object.h
index 5f5d86f..c45815b 100644
--- a/src/engine/object.h
+++ b/src/engine/object.h
@@ -10,7 +10,9 @@ namespace Donut
         glm::vec3 m_direction;
         glm::vec3 m_origin;
 
-        Ray(glm::vec3 o, glm::vec3 d);
+        Ray(glm::vec3 o, glm::vec3 d) 
+            : m_origin(o), 
+              m_direction(glm::normalize(d)) { }
     };
 
     class Material
@@ -20,7 +22,10 @@ namespace Donut
         float     m_specular;
         float     m_emission;
 
-        Material(glm::vec3 c, float s, float e);
+        Material(glm::vec3 c, float s, float e)
+            : m_color(c), 
+              m_specular(s), 
+              m_emission(e) { }
     };
 
     class Object
@@ -30,9 +35,37 @@ namespace Donut
         float     m_radius;
         Material  m_material;
     
-        Object(glm::vec3 c, float r, Material m);
+        Object(glm::vec3 c, float r, Material m) 
+            : m_centre(c), 
+              m_radius(r), 
+              m_material(m) { }
     
-        bool intersect(Ray &ray, float &t);
-        glm::vec3 get_normal(glm::vec3 &point) const;
+        bool intersect(Ray &ray, float &t)
+        {
+            glm::vec3 oc = ray.m_origin - m_centre;
+            float a = glm::dot(ray.m_direction, ray.m_direction); 
+            float b = 2.0f * glm::dot(oc, ray.m_direction);
+            float c = glm::dot(oc, oc) - m_radius * m_radius;
+            double discriminant = b*b - 4*a*c;
+
+            if(discriminant < 0)
+                return false;
+    
+            float intercept = (-b - sqrt(discriminant)) / (2.0f*a);
+            if(intercept < 0)
+            {
+                intercept = (-b + sqrt(discriminant)) / (2.0f*a);
+                if(intercept<0)
+                    return false;
+            }
+
+            t = intercept;
+            return true;
+        }
+    
+        glm::vec3 get_normal(glm::vec3 &point) const
+        {
+            return glm::normalize(point - m_centre);
+        }
     };
 };