Renders scenes with a single hardcoded light and green objects

8 files changed, 210 insertions, 14 deletions

diff --git a/src/object.cpp b/src/object.cpp
index e88ae13..179785a 100644
--- a/src/object.cpp
+++ b/src/object.cpp
@@ -1,6 +1,7 @@
 #include "object.hpp"
 
 #include <math.h>
+#include <iostream>
 #include "common.hpp"
 
 Sphere::Sphere(Vec3d center, double radius) {
@@ -15,10 +16,6 @@ Plane::Plane(Vec3d start, Vec3d norm) {
     m_norm.normalize();
 }
 
-void Object::setMaterial(std::shared_ptr<Material> m) {
-    m_mat = m;
-}
-
 Vec3d Sphere::norm_at(const Vec3d &point, const Vec3d&) const {
     auto res = point - m_center;
     res.normalize();
diff --git a/src/object.hpp b/src/object.hpp
index 3194dac..ac5122f 100644
--- a/src/object.hpp
+++ b/src/object.hpp
@@ -8,17 +8,15 @@
 class Material {
 };
 
-class Object {
+class Shape {
     public:
         void setMaterial(std::shared_ptr<Material> m);
 
-        std::shared_ptr<Material> m_mat;
-
         virtual Vec3d norm_at(const Vec3d &point, const Vec3d &indir) const = 0;
         virtual double intersect(const Ray &ray, bool skip_dist) const = 0;
 };
 
-class Sphere : Object {
+class Sphere : public Shape {
     public:
         Sphere(Vec3d center, double radius);
         Vec3d norm_at(const Vec3d &point, const Vec3d &indir) const;
@@ -29,7 +27,7 @@ class Sphere : Object {
         double m_radius;
 };
 
-class Plane : Object {
+class Plane : public Shape {
     public:
         Plane(Vec3d start, Vec3d norm);
         Vec3d norm_at(const Vec3d &point, const Vec3d &indir) const;
diff --git a/src/render.cpp b/src/render.cpp
new file mode 100644
index 0000000..5601863
--- /dev/null
+++ b/src/render.cpp
@@ -0,0 +1,124 @@
+#include "render.hpp"
+#include "vector.hpp"
+#include "common.hpp"
+
+#include <math.h>
+#include <iostream>
+
+#define FOV 1.74533
+
+const Vec3d up = Vec3d(0, 1, 0);
+
+void Color::clamp() {
+    if (m_x > 1) { m_x = 1; }
+    if (m_y > 1) { m_y = 1; }
+    if (m_z > 1) { m_z = 1; }
+}
+
+Renderer::Renderer(const Scene &scn, Vec3d eye, Vec3d target, unsigned width, unsigned height) : 
+    m_scn(scn)
+{
+    m_eye = eye;
+    m_target = target;
+    m_width = width;
+    m_height = height;
+
+    recalculate();
+}
+
+void Renderer::recalculate() {
+    auto tmp = m_target - m_eye;
+
+    // Orthogonal vector to E
+    auto b = up.cross(tmp);
+
+    b.normalize();
+    tmp.normalize();
+
+    auto v = tmp.cross(b);
+
+    // Calculate size of viewplane
+    double gx = tan( FOV / 2);
+    double gy = gx * ((double) m_height / m_width);
+
+    // Calculate scaling vectors
+    m_qx = b * ((2 * gx) / (m_width - 1));
+    m_qy = v * ((2 * gy) / (m_height - 1));
+
+    // Calculate starting point
+    m_blc = tmp - (b * gx) - (v * gy);
+}
+
+Ray Renderer::findray(double x, double y) const {
+    auto dir = m_blc + (m_qx * x) + (m_qy * y);
+    return Ray(m_eye, dir, true);
+}
+
+Color Renderer::render(unsigned x, unsigned y) {
+    auto r = findray(x, y);
+    return pathtrace_sample(r, 0);
+}
+
+Color Renderer::pathtrace_sample(const Ray &r, unsigned hop) {
+    double dist;
+    auto res = cast_ray(r, 0, &dist);
+
+    if (!res) {
+        return Color(0, 0, 0);
+    }
+
+    // Calculate endpoint
+    auto end = r.m_start + r.m_direction * dist;
+
+    auto norm = res->norm_at(end, r.m_direction);
+
+    // Simulate single light
+    auto l = Vec3d(0, 7, 0);
+
+    auto tolight = l - end;
+    auto distance = tolight.length();
+    tolight.normalize();
+    auto lightray = Ray(end, tolight, false);
+
+    if (cast_ray(lightray, distance, nullptr)) {
+        return Color(0, 0, 0);
+    }
+
+    auto green = Color(0, 1, 0);
+    return Color(green * norm.dot(tolight));
+}
+
+const Shape* Renderer::cast_ray(const Ray &r, double chk_dist, double *dist_ret) {
+    const Shape *smallest = nullptr;
+    double dist = 0;
+
+    for (auto obj : m_scn.objs) {
+        if (!obj) {
+            continue;
+        }
+        auto d = obj->intersect(r, false);
+        if (d > ZERO_APPROX) {
+            if (chk_dist > 0 && d < chk_dist) {
+                dist = d; smallest = obj;
+                goto exit;
+            }
+            if (d < dist || smallest == nullptr) {
+                dist = d; smallest = obj;
+            }
+        }
+    }
+
+    if (chk_dist > 0) {
+        // If we reach this it means none of the
+        // object where within distance.
+        return nullptr;
+    }
+
+exit:
+
+    if (dist_ret) {
+        *dist_ret = dist;
+    }
+
+    return smallest;
+}
diff --git a/src/render.hpp b/src/render.hpp
new file mode 100644
index 0000000..3fd84b1
--- /dev/null
+++ b/src/render.hpp
@@ -0,0 +1,50 @@
+#ifndef RENDER_H
+#define RENDER_H
+
+#include "vector.hpp"
+#include "ray.hpp"
+#include "scene.hpp"
+
+class Color : public Vec3d {
+    public:
+        Color() {}
+        Color(const Vec3d &v) : Vec3d(v) {}
+        Color(double r, double g, double b) : Vec3d(r, g, b) {}
+
+        uint8_t r() { return m_x * 255; }
+        uint8_t g() { return m_y * 255; }
+        uint8_t b() { return m_z * 255; }
+
+        void clamp();
+
+};
+
+class Renderer {
+    public:
+    Renderer(const Scene &scn, Vec3d eye, Vec3d target, unsigned width, unsigned height);
+
+    Color render(unsigned x, unsigned y);
+
+    unsigned m_width, m_height;
+
+    private:
+    void recalculate();
+    Ray findray(double x, double y) const ;
+
+    Color pathtrace_sample(const Ray &r, unsigned hop);
+    // Will return first result less than chk_dist. 
+    // This is ignored if chk_dist is 0.
+    // If dist is non-null the resulting distance is written here.
+    const Shape* cast_ray(const Ray &r, double chk_dist, double *dist);
+
+    const Scene &m_scn;
+
+    // User options
+    Vec3d m_eye, m_target;
+
+    // Calculated values
+    Vec3d m_qx, m_qy, m_blc;
+
+};
+
+#endif
diff --git a/src/scene.cpp b/src/scene.cpp
index d866fe4..a8c0695 100644
--- a/src/scene.cpp
+++ b/src/scene.cpp
@@ -1,5 +1,5 @@
 #include "scene.hpp"
 
-void Scene::addObject(Object &obj) {
-    objs.push_back(&obj);
+void Scene::addShape(const Shape *obj) {
+    objs.push_back(obj);
 }
diff --git a/src/scene.hpp b/src/scene.hpp
index a06ccb4..f270409 100644
--- a/src/scene.hpp
+++ b/src/scene.hpp
@@ -6,9 +6,9 @@
 
 class Scene {
     public:
-        void addObject(Object &obj);
+        void addShape(const Shape *obj);
 
-        std::vector<Object*> objs;
+        std::vector<const Shape*> objs;
 
 };
 
diff --git a/src/vector.cpp b/src/vector.cpp
index 070f956..1e4f5a1 100644
--- a/src/vector.cpp
+++ b/src/vector.cpp
@@ -1,6 +1,7 @@
 #include "vector.hpp"
 
 #include <math.h>
+#include <stdexcept>
 
 Vec3d::Vec3d() {
     set(0, 0, 0);
@@ -19,7 +20,7 @@ void Vec3d::set(double x, double y, double z) {
 void Vec3d::normalize() {
     auto len = length();
     if (len == 0) {
-        throw "Normalizing zero vector";
+        throw std::runtime_error("Normalizing zero vector");
     }
 
     m_x /= len;
@@ -35,6 +36,22 @@ double Vec3d::dot(const Vec3d &vec) const {
     return m_x * vec.m_x + m_y * vec.m_y + m_z * vec.m_z;
 }
 
+Vec3d Vec3d::cross(const Vec3d &vec) const {
+    return Vec3d(
+        m_y * vec.m_z - m_z * vec.m_y,
+        m_z * vec.m_x - m_x * vec.m_z,
+        m_x * vec.m_y - m_y * vec.m_x
+        );
+}
+
+Vec3d Vec3d::operator+(const Vec3d &vec) const {
+    return Vec3d(
+            m_x + vec.m_x, 
+            m_y + vec.m_y,
+            m_z + vec.m_z
+            );
+}
+
 Vec3d Vec3d::operator-(const Vec3d &vec) const {
     return Vec3d(
             m_x - vec.m_x, 
@@ -51,3 +68,11 @@ Vec3d Vec3d::operator-() const {
             );
 }
 
+
+Vec3d Vec3d::operator*(double op) const {
+    return Vec3d(
+            m_x * op,
+            m_y * op,
+            m_z * op
+            );
+}
diff --git a/src/vector.hpp b/src/vector.hpp
index 76eb883..05de25c 100644
--- a/src/vector.hpp
+++ b/src/vector.hpp
@@ -15,8 +15,10 @@ class Vec3d {
         Vec3d cross(const Vec3d &vec) const;
 
         // Operators
+        Vec3d operator+(const Vec3d &vec) const;
         Vec3d operator-(const Vec3d &vec) const;
         Vec3d operator-() const;
+        Vec3d operator*(double) const;
 
         double m_x, m_y, m_z;
 };