From 6b1f0264273f44158abd5787fe35a1b7af0de19b Mon Sep 17 00:00:00 2001
From: vonhyou <moi@rfung.dev>
Date: Sun, 3 Mar 2024 21:52:38 -0500
Subject: [PATCH] make area light

---
 CMakeLists.txt |  4 ++--
 src/Light.cc   | 32 +++++++++++++++++++++++++-------
 src/Light.h    | 30 +++++++++++++++++-------------
 3 files changed, 44 insertions(+), 22 deletions(-)

diff --git a/CMakeLists.txt b/CMakeLists.txt
index 801846f..dfefc30 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -21,8 +21,8 @@ add_compile_options(-DSTUDENT_SOLUTION)
 
 # When testing large scenes the debug mode will be very slow
 # so switch to release
-set(CMAKE_BUILD_TYPE Debug)
-#set(CMAKE_BUILD_TYPE Release)
+#set(CMAKE_BUILD_TYPE Debug)
+set(CMAKE_BUILD_TYPE Release)
 
 set(CMAKE_CXX_STANDARD 14)
 
diff --git a/src/Light.cc b/src/Light.cc
index 724dade..83c5cc8 100644
--- a/src/Light.cc
+++ b/src/Light.cc
@@ -1,6 +1,7 @@
 #include "Light.h"
 #include <algorithm>
 #include <cmath>
+#include <iostream>
 
 void Light::setTransform(const Matrix4f &transform) {
   this->transform = transform;
@@ -10,6 +11,10 @@ void Light::setGridSize(unsigned int gridSize) { this->gridSize = gridSize; }
 
 void Light::setUseCenter(bool useCenter) { this->useCenter = useCenter; }
 
+Vector3f Light::getDiffuse() const { return diffuse; }
+
+Vector3f Light::getSpecular() const { return specular; }
+
 Vector3f PointLight::illumination(const HitRecord &hit,
                                   const vector<Geometry *> &geometries) const {
   Vector3f shadingPoint = hit.getPoint();
@@ -21,21 +26,34 @@ Vector3f PointLight::illumination(const HitRecord &hit,
     if (g != geometry && g->intersect(shadowRay).hasValue())
       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 *
+  Vector3f diffuse_ = geometry->coefDiffuse() * diffuse.array() *
+                      geometry->diffuse().array() *
                       std::max(0.0f, hit.normal().dot(rayDirection));
 
   Vector3f halfWay = (hit.viewDirection() + rayDirection).normalized();
   Vector3f specular_ =
-      att * geometry->coefSpecular() * specular *
+      geometry->coefSpecular() * specular.array() *
+      geometry->specular().array() *
       pow(std::max(0.0f, hit.normal().dot(halfWay)), geometry->getPhong());
-  return ambient_ + diffuse_ + specular_;
+  return diffuse_ + specular_ + ambient_;
 }
 
 Vector3f AreaLight::illumination(const HitRecord &hit,
                                  const vector<Geometry *> &geometries) const {
-  return Vector3f::Zero();
+  Vector3f u = p4 - p1;
+  Vector3f v = p2 - p1;
+
+  Vector3f color = Vector3f::Zero();
+
+  if (useCenter) {
+    color += PointLight(*this, (u + v) / 2).illumination(hit, geometries);
+  } else {
+    for (int y = 0; y < gridSize; ++y)
+      for (int x = 0; x < gridSize; ++x)
+        color += PointLight(*this, (u * x + v * y) / gridSize)
+                     .illumination(hit, geometries);
+  }
+
+  return color / gridSize / gridSize;
 }
diff --git a/src/Light.h b/src/Light.h
index 84163ed..be87209 100644
--- a/src/Light.h
+++ b/src/Light.h
@@ -31,22 +31,11 @@ protected:
   bool useCenter = false;                    // optional member `usecenter`
 
 public:
-  // setters for optional members
   void setTransform(const Matrix4f &);
   void setGridSize(unsigned int);
   void setUseCenter(bool);
-};
-
-class PointLight : public Light {
-public:
-  PointLight(const Vector3f &id, const Vector3f &is, Vector3f &center)
-      : Light(Type::Point, id, is), center(center) {}
-
-  virtual Vector3f illumination(const HitRecord &,
-                                const vector<Geometry *> &) const override;
-
-private:
-  Vector3f center;
+  Vector3f getDiffuse() const;
+  Vector3f getSpecular() const;
 };
 
 class AreaLight : public Light {
@@ -62,4 +51,19 @@ private:
   Vector3f p1, p2, p3, p4;
 };
 
+class PointLight : public Light {
+public:
+  PointLight(const Vector3f &id, const Vector3f &is, const Vector3f &center)
+      : Light(Type::Point, id, is), center(center) {}
+
+  PointLight(const AreaLight &al, const Vector3f &center)
+      : PointLight(al.getDiffuse(), al.getSpecular(), center) {}
+
+  virtual Vector3f illumination(const HitRecord &,
+                                const vector<Geometry *> &) const override;
+
+private:
+  Vector3f center;
+};
+
 #endif // !LIGHT_H_