Merge pull request #10 from vonhyou/ray

Add ray class and impl ray casting

src/Geometry.cc

@@ -1,9 +1,43 @@
 #include "Geometry.h"
 
+#include <Eigen/Dense>
+
 void Geometry::setTransform(const Matrix4f &transform) {
   this->transform = transform;
 }
 
-bool Sphere::intersect() const { return false; }
+bool Sphere::intersect(const Ray &r) const {
+  Vector3f originCenter = r.getOrigin() - center;
+  float a = r.getDirection().dot(r.getDirection());
+  float b = 2.0f * originCenter.dot(r.getDirection());
+  float c = originCenter.dot(originCenter) - radius * radius;
 
-bool Rectangle::intersect() const { return false; }
+  return b * b - 4 * a * c >= 0;
+}
+
+bool isInRectangle(const Vector3f &p, const Vector3f &a, const Vector3f &b,
+                   const Vector3f &c, const Vector3f &d, const Vector3f &n) {
+  float s1 = (b - a).cross(p - a).dot(n);
+  float s2 = (c - b).cross(p - b).dot(n);
+  float s3 = (d - c).cross(p - c).dot(n);
+  float s4 = (a - d).cross(p - d).dot(n);
+
+  return (s1 >= 0 && s2 >= 0 && s3 >= 0 && s4 >= 0) ||
+         (s1 <= 0 && s2 <= 0 && s3 <= 0 && s4 <= 0);
+}
+
+bool Rectangle::intersect(const Ray &r) const {
+  Vector3f normal = (p2 - p1).cross(p3 - p1).normalized();
+
+  float denom = normal.dot(r.getDirection());
+  if (abs(denom) < 1e-6f)
+    return false;
+
+  float t = -normal.dot(r.getOrigin() - p1) / denom;
+  if (t <= 0)
+    return false;
+
+  Vector3f p = r.getOrigin() + t * r.getDirection();
+
+  return isInRectangle(p, p1, p2, p3, p4, normal);
+}

src/Geometry.h

@@ -1,6 +1,8 @@
 #ifndef GEOMETRY_H_
 #define GEOMETRY_H_
 
+#include "Ray.h"
+
 #include <Eigen/Core>
 
 using Eigen::Matrix;
@@ -13,7 +15,7 @@ public:
   enum class Type { SPHERE, RECTANGLE };
 
   virtual ~Geometry() = default;
-  virtual bool intersect() const = 0;
+  virtual bool intersect(const Ray &) const = 0;
 
 protected:
   Geometry(Type type, float ka, float kd, float ks, const Vector3f &ca,
@@ -37,7 +39,7 @@ public:
       : Geometry(Type::SPHERE, ka, kd, ks, ca, cd, cs, pc), radius(radius),
         center(center) {}
 
-  bool intersect() const override;
+  bool intersect(const Ray &) const override;
 
 private:
   float radius;
@@ -47,14 +49,15 @@ private:
 class Rectangle : public Geometry {
 public:
   Rectangle(float ka, float kd, float ks, const Vector3f &ca, const Vector3f cd,
-            const Vector3f &cs, float pc, const Matrix<float, 3, 4> &corners)
-      : Geometry(Type::RECTANGLE, ka, kd, ks, ca, cd, cs, pc),
-        corners(corners) {}
+            const Vector3f &cs, float pc, const Vector3f &p1,
+            const Vector3f &p2, const Vector3f &p3, const Vector3f &p4)
+      : Geometry(Type::RECTANGLE, ka, kd, ks, ca, cd, cs, pc), p1(p1), p2(p2),
+        p3(p3), p4(p4) {}
 
-  bool intersect() const override;
+  bool intersect(const Ray &) const override;
 
 private:
-  Matrix<float, 3, 4> corners;
+  Vector3f p1, p2, p3, p4;
 };
 
 #endif // !GEOMETRY_H_

src/Light.h

@@ -46,14 +46,14 @@ private:
 
 class AreaLight : public Light {
 public:
-  AreaLight(const Vector3f &id, const Vector3f &is,
-            const Matrix<float, 3, 4> &corners)
-      : Light(Type::Area, id, is), corners(corners) {}
+  AreaLight(const Vector3f &id, const Vector3f &is, const Vector3f &p1,
+            const Vector3f &p2, const Vector3f &p3, const Vector3f &p4)
+      : Light(Type::Area, id, is), p1(p1), p2(p2), p3(p3), p4(p4) {}
 
   virtual void illumination() const override;
 
 private:
-  Matrix<float, 3, 4> corners; // stores `p1`, `p2`, `p3` and `p4`
+  Vector3f p1, p2, p3, p4;
 };
 
 #endif // !LIGHT_H_

src/Parser.cc

@@ -72,15 +72,6 @@ Geometry *Parser::getGeometry(const nlohmann::json &j) {
   return g;
 }
 
-// helper function to get four corners of a rectangle
-const Matrix<float, 3, 4> getCorners(const nlohmann::json &j) {
-  Matrix<float, 3, 4> corners;
-  for (int i = 0; i < 4; ++i) {
-    corners.col(i) = getVector3f(j["p" + std::to_string(i + 1)]);
-  }
-  return corners;
-}
-
 Sphere *Parser::getSphere(const nlohmann::json &j, float ka, float kd, float ks,
                           const Vector3f &ca, const Vector3f &cd,
                           const Vector3f &cs, float pc) {
@@ -94,9 +85,12 @@ Rectangle *Parser::getRectangle(const nlohmann::json &j, float ka, float kd,
                                 float ks, const Vector3f &ca,
                                 const Vector3f &cd, const Vector3f &cs,
                                 float pc) {
-  Matrix<float, 3, 4> corners = getCorners(j);
+  Vector3f p1 = getVector3f(j["p1"]);
+  Vector3f p2 = getVector3f(j["p2"]);
+  Vector3f p3 = getVector3f(j["p3"]);
+  Vector3f p4 = getVector3f(j["p4"]);
 
-  return new Rectangle(ka, kd, ks, ca, cd, cs, pc, corners);
+  return new Rectangle(ka, kd, ks, ca, cd, cs, pc, p1, p2, p3, p4);
 }
 
 Light *Parser::getLight(const nlohmann::json &j) {
@@ -121,9 +115,12 @@ Light *Parser::getLight(const nlohmann::json &j) {
 
 AreaLight *Parser::getAreaLight(const nlohmann::json &j, const Vector3f &id,
                                 const Vector3f &is) {
-  Matrix<float, 3, 4> corners = getCorners(j);
 
-  return new AreaLight(id, is, corners);
+  Vector3f p1 = getVector3f(j["p1"]);
+  Vector3f p2 = getVector3f(j["p2"]);
+  Vector3f p3 = getVector3f(j["p3"]);
+  Vector3f p4 = getVector3f(j["p4"]);
+  return new AreaLight(id, is, p1, p2, p3, p4);
 }
 
 PointLight *Parser::getPointLight(const nlohmann::json &j, const Vector3f &id,

src/Ray.cc

@@ -0,0 +1,5 @@
+#include "Ray.h"
+
+Vector3f Ray::getOrigin() const { return origin; }
+
+Vector3f Ray::getDirection() const { return direction; }

src/Ray.h

@@ -0,0 +1,21 @@
+#ifndef RAY_H_
+#define RAY_H_
+
+#include <Eigen/Core>
+
+using Eigen::Vector3f;
+
+class Ray {
+public:
+  Ray(const Vector3f &o, const Vector3f &d) : origin(o), direction(d) {}
+
+private:
+  Vector3f origin;
+  Vector3f direction;
+
+public:
+  Vector3f getOrigin() const;
+  Vector3f getDirection() const;
+};
+
+#endif // !RAY_H_

src/RayTracer.cc

@@ -1,10 +1,10 @@
 #include "RayTracer.h"
 #include "../external/simpleppm.h"
 #include "Parser.h"
+#include "Ray.h"
 
-#include <vector>
-
-using std::vector;
+#include <Eigen/Core>
+#include <cmath>
 
 void RayTracer::parse() {
   for (auto i = json["output"].begin(); i != json["output"].end(); ++i)
@@ -17,19 +17,60 @@ void RayTracer::parse() {
     lights.push_back(Parser::getLight(*i));
 }
 
-void RayTracer::render() {}
+Ray getRay(int x, int y, const Vector3f &camPos, const Vector3f &pxUpperLeft,
+           const Vector3f &du, const Vector3f &dv) {
+  return Ray(camPos, pxUpperLeft + x * du + y * dv - camPos);
+}
 
-void RayTracer::output() {
-  for (auto scene : scenes) {
+void RayTracer::render(Scene *scene) {
   int width = scene->getWidth();
   int height = scene->getHeight();
-    vector<double> buffer(3 * width * height);
-    save_ppm(scene->getName(), buffer, width, height);
+  float fov = scene->getFov();
+  Vector3f cameraPos = scene->getCenter();
+  Vector3f lookAt = scene->getLookAt();
+  Vector3f up = scene->getUpVector();
+  float vpHeight = 2 * tan(fov / 180 * M_PI / 2) * lookAt.norm();
+  float vpWidth = vpHeight * width / height;
+  Vector3f vpU = Vector3f(vpWidth, 0, 0);
+  Vector3f vpV = Vector3f(0, -vpHeight, 0);
+  Vector3f du = vpU / width;
+  Vector3f dv = vpV / height;
+
+  Vector3f vpUpperLeft = cameraPos + lookAt - vpU / 2.0 - vpV / 2.0;
+  Vector3f pxUpperLeft = vpUpperLeft + (du + dv) / 2.0;
+
+  Buffer buffer(width * height * 3);
+  for (int y = 0; y < height; ++y)
+    for (int x = 0; x < width; ++x) {
+      Ray ray = getRay(x, y, cameraPos, pxUpperLeft, du, dv);
+
+      for (auto geometry : geometries)
+        if (geometry->intersect(ray)) {
+          buffer[3 * y * width + 3 * x + 0] = 1;
+          buffer[3 * y * width + 3 * x + 1] = 1;
+          buffer[3 * y * width + 3 * x + 2] = 1;
+          break;
         }
+    }
+
+  Task *task = new Task(scene, buffer);
+  tasks.push_back(task);
+}
+
+void RayTracer::output(Task *task) {
+  string path = task->first->getName();
+  int width = task->first->getWidth();
+  int height = task->first->getHeight();
+
+  save_ppm(path, task->second, width, height);
 }
 
 void RayTracer::run() {
   parse();
-  render();
-  output();
+
+  for (auto scene : scenes)
+    render(scene);
+
+  for (auto task : tasks)
+    output(task);
 }

src/RayTracer.h

@@ -6,8 +6,12 @@
 #include "Light.h"
 #include "Scene.h"
 
+#include <utility>
 #include <vector>
 
+using Buffer = std::vector<double>;
+using Task = std::pair<Scene *, Buffer>;
+
 class RayTracer {
 public:
   RayTracer(const nlohmann::json &j) : json(j) {}
@@ -19,9 +23,11 @@ private:
   std::vector<Light *> lights;
   std::vector<Geometry *> geometries;
 
+  std::vector<Task *> tasks;
+
   void parse();
-  void render();
-  void output();
+  void render(Scene *);
+  void output(Task *);
 };
 
 #endif // !RAY_TRACER_H_

src/Scene.cc

@@ -1,11 +1,19 @@
 #include "Scene.h"
 
-string Scene::getName() { return name; }
+string Scene::getName() const { return name; }
 
 int Scene::getWidth() { return width; }
 
 int Scene::getHeight() { return height; }
 
+float Scene::getFov() { return fov; }
+
+Vector3f Scene::getCenter() const { return center; }
+
+Vector3f Scene::getUpVector() const { return up; }
+
+Vector3f Scene::getLookAt() const { return lookAt; }
+
 void Scene::setRaysPerPixel(const Eigen::VectorXi &raysPerPixel) {
   this->raysPerPixel = raysPerPixel;
 }

src/Scene.h

@@ -32,9 +32,13 @@ private:
   bool globalIllum = false;
 
 public:
-  string getName();
+  string getName() const;
   int getWidth();
   int getHeight();
+  float getFov();
+  Vector3f getCenter() const;
+  Vector3f getUpVector() const;
+  Vector3f getLookAt() const;
   void setRaysPerPixel(const Eigen::VectorXi &);
   void setAntialiasing(bool);
   void setTwoSideRender(bool);