From 27bdd95fa6df5c52cdb3fa43e9444773dd771da0 Mon Sep 17 00:00:00 2001
From: vonhyou <moi@rfung.dev>
Date: Thu, 29 Feb 2024 01:16:49 -0500
Subject: [PATCH] calculate ambient, diffuse and specular

---
 src/Geometry.cc  |  1 +
 src/Geometry.h   |  1 +
 src/HitRecord.cc |  4 ++++
 src/HitRecord.h  |  1 +
 src/Light.cc     | 15 ++++++++++++++-
 5 files changed, 21 insertions(+), 1 deletion(-)

diff --git a/src/Geometry.cc b/src/Geometry.cc
index 1969397..0a29ab8 100644
--- a/src/Geometry.cc
+++ b/src/Geometry.cc
@@ -9,6 +9,7 @@ Vector3f Geometry::ambient() const { return ca; }
 float Geometry::coefDiffuse() const { return kd; }
 float Geometry::coefSpecular() const { return ks; }
 float Geometry::coefAmbient() const { return ka; }
+float Geometry::getPhong() const { return phong; }
 
 void Geometry::setTransform(const Matrix4f &transform) {
   this->transform = transform;
diff --git a/src/Geometry.h b/src/Geometry.h
index dc3be95..b3d1eee 100644
--- a/src/Geometry.h
+++ b/src/Geometry.h
@@ -39,6 +39,7 @@ public:
   float coefDiffuse() const;
   float coefSpecular() const;
   float coefAmbient() const;
+  float getPhong() const;
   void setTransform(const Matrix4f &);
 };
 
diff --git a/src/HitRecord.cc b/src/HitRecord.cc
index 9f50540..6a07ee7 100644
--- a/src/HitRecord.cc
+++ b/src/HitRecord.cc
@@ -10,6 +10,10 @@ Vector3f HitRecord::getPoint() const {
   return r.getOrigin() + t * r.getDirection();
 }
 
+Vector3f HitRecord::viewDirection() const {
+  return -r.getDirection().normalized();
+}
+
 Vector3f HitRecord::normal() const { return n; }
 
 void HitRecord::calcNormal() { n = g->getNormal(getPoint()); }
diff --git a/src/HitRecord.h b/src/HitRecord.h
index 87290fc..c7fad17 100644
--- a/src/HitRecord.h
+++ b/src/HitRecord.h
@@ -21,6 +21,7 @@ private:
 public:
   Geometry *geometry() const;
   Vector3f getPoint() const;
+  Vector3f viewDirection() const;
   Vector3f normal() const;
   void calcNormal();
 };
diff --git a/src/Light.cc b/src/Light.cc
index 68fb168..724dade 100644
--- a/src/Light.cc
+++ b/src/Light.cc
@@ -1,4 +1,6 @@
 #include "Light.h"
+#include <algorithm>
+#include <cmath>
 
 void Light::setTransform(const Matrix4f &transform) {
   this->transform = transform;
@@ -19,7 +21,18 @@ Vector3f PointLight::illumination(const HitRecord &hit,
     if (g != geometry && g->intersect(shadowRay).hasValue())
       return Vector3f::Zero();
 
-  return Vector3f::Zero();
+  float distance = (center - shadingPoint).norm();
+  float att = 1.0f / distance / distance;
+
+  Vector3f ambient_ = geometry->coefAmbient() * geometry->ambient();
+  Vector3f diffuse_ = att * geometry->coefDiffuse() * diffuse *
+                      std::max(0.0f, hit.normal().dot(rayDirection));
+
+  Vector3f halfWay = (hit.viewDirection() + rayDirection).normalized();
+  Vector3f specular_ =
+      att * geometry->coefSpecular() * specular *
+      pow(std::max(0.0f, hit.normal().dot(halfWay)), geometry->getPhong());
+  return ambient_ + diffuse_ + specular_;
 }
 
 Vector3f AreaLight::illumination(const HitRecord &hit,