1 files changed, 76 insertions, 0 deletions
diff --git a/src/engine/object.h b/src/engine/object.h
new file mode 100644
index 0000000..8101540
--- /dev/null
+++ b/src/engine/object.h
@@ -0,0 +1,76 @@
+#pragma once
+
+#include <glm/glm.hpp>
+
+namespace Donut
+{
+    class Ray
+    {
+    public:
+        Ray(glm::vec3 o, glm::vec3 d)
+            : m_origin(o),
+              m_direction(glm::normalize(d)) { }
+
+    public:
+        glm::vec3 m_direction;
+        glm::vec3 m_origin;
+    };
+
+    class Material
+    {
+    public:
+        Material() : m_color(1.0f, 1.0f, 1.0f), m_specular(0.5f), m_emission(0.0f) { }
+        Material(glm::vec3 c, float s, float e)
+            : m_color(c),
+              m_specular(s),
+              m_emission(e) { }
+
+    public:
+        glm::vec3 m_color;
+        float     m_specular;
+        float     m_emission;
+    };
+
+    class Object
+    {
+    public:
+        Object() : m_centre(0.0f, 0.0f, 0.0f), m_radius(1.0f), m_material() { }
+        Object(glm::vec3 c, float r, Material m)
+            : m_centre(c),
+              m_radius(r),
+              m_material(m) { }
+
+        auto intersect(Ray& ray, float& t) -> bool
+        {
+            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;
+            float discriminant = static_cast<float>(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;
+        }
+
+        auto get_normal(glm::vec3& point) const -> glm::vec3
+        {
+            return glm::normalize(point - m_centre);
+        }
+
+    public:
+        glm::vec3 m_centre;
+        float     m_radius;
+        Material  m_material;
+    };
+};