src/engine/scene.cpp


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#include "scene.h"

namespace Donut
{
    Scene::Scene() 
        : m_light_pos(5.0f, 5.0f, 5.0f) { }

    glm::vec3 Scene::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); 
    }
}