From a6655eebe2a69ee427264bd43df5747851ed96df Mon Sep 17 00:00:00 2001
From: hachem <im@hachem.wtf>
Date: Fri, 15 Aug 2025 03:18:29 +0200
Subject: feat: complete first geodesic 3D raytracing

---
 src/engine/scene.h | 55 +++++++++++++++++++++++++++++++++++++++++++++++++++---
 1 file changed, 52 insertions(+), 3 deletions(-)

(limited to 'src/engine/scene.h')

diff --git a/src/engine/scene.h b/src/engine/scene.h
index abe582e..2ac9cd8 100644
--- a/src/engine/scene.h
+++ b/src/engine/scene.h
@@ -2,7 +2,6 @@
 
 #include <vector>
 #include <limits>
-#include <glm/glm.hpp>
 
 #include "object.h"
 
@@ -14,7 +13,57 @@ namespace Donut
         std::vector<Object> objs;
         glm::vec3 m_light_pos;
 
-        Scene();
-        glm::vec3 trace(Ray &ray);
+        Scene() 
+            : m_light_pos(5.0f, 5.0f, 5.0f) { }
+    
+        glm::vec3 trace(Ray &ray)
+        {
+            float closest = std::numeric_limits<float>::infinity();
+            const Object* hit_obj = nullptr;
+    
+            for(auto& obj : objs)
+            {
+                float t;
+
+                if(obj.intersect(ray, t))
+                    if(t < closest) 
+                    {
+                        closest = t;
+                        hit_obj = &obj;
+                    }
+            }
+            
+            if(hit_obj)
+            {
+                glm::vec3 hit_point = ray.m_origin + ray.m_direction * closest;
+                glm::vec3 normal = hit_obj->get_normal(hit_point);
+                glm::vec3 light_dir = glm::normalize(m_light_pos - hit_point);
+    
+                float diff = std::max(glm::dot(normal, light_dir), 0.0f);
+    
+                Ray shadow_ray(hit_point + normal * 0.001f, light_dir);
+                bool in_shadow = false;
+                
+                for(auto& obj : objs) 
+                {
+                    float t;
+
+                    if(obj.intersect(shadow_ray, t)) 
+                    {
+                        in_shadow = true;
+                        break;
+                    }
+                }
+    
+                glm::vec3 color = hit_obj->m_material.m_color;
+                float ambient = 0.1f;
+    
+                if (in_shadow) 
+                    return color * ambient;
+                return color * (ambient + diff * 0.9f);
+            }
+    
+            return glm::vec3(0.0f, 0.0f, 0.1f); 
+        }
     };
 };
-- 
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