[raytracing] Added solutions to raytracing exercises

3 files changed, 1033 insertions, 0 deletions

diff --git a/Year 3/Raytracing/0004-h9-Added-Wireframe-shader.patch b/Year 3/Raytracing/0004-h9-Added-Wireframe-shader.patch
new file mode 100644
index 0000000..8c0d3f7
--- /dev/null
+++ b/Year 3/Raytracing/0004-h9-Added-Wireframe-shader.patch
@@ -0,0 +1,649 @@
+From f9cb883ef657806c5de5d5268856f740c151ff69 Mon Sep 17 00:00:00 2001
+From: Syndamia <kamen@syndamia.com>
+Date: Sun, 26 May 2024 14:42:39 +0300
+Subject: [PATCH] [h9] Added Wireframe shader
+
+---
+ data/hw9/dragon.hexray    |  86 ++++++++++++++++++++++
+ data/hw9/nonconvex.hexray | 119 ++++++++++++++++++++++++++++++
+ data/hw9/testmesh.hexray  | 150 ++++++++++++++++++++++++++++++++++++++
+ data/hw9/wireframe.hexray |  72 ++++++++++++++++++
+ flake.lock                |  27 +++++++
+ flake.nix                 |  26 +++++++
+ src/geometry.h            |   4 +-
+ src/main.cpp              |   2 +-
+ src/mesh.cpp              |   2 +
+ src/scene.cpp             |   1 +
+ src/shading.cpp           |   8 ++
+ src/shading.h             |  20 +++++
+ 12 files changed, 515 insertions(+), 2 deletions(-)
+ create mode 100644 data/hw9/dragon.hexray
+ create mode 100644 data/hw9/nonconvex.hexray
+ create mode 100644 data/hw9/testmesh.hexray
+ create mode 100644 data/hw9/wireframe.hexray
+ create mode 100644 flake.lock
+ create mode 100644 flake.nix
+
+diff --git a/data/hw9/dragon.hexray b/data/hw9/dragon.hexray
+new file mode 100644
+index 0000000..ba924da
+--- /dev/null
++++ b/data/hw9/dragon.hexray
+@@ -0,0 +1,86 @@
++//
++// A scene with a "heavy" mesh (the stanford dragon)
++//
++//
++
++// 1. First, some global settings
++GlobalSettings {
++	frameWidth          768
++	frameHeight         512
++	ambientLight        (0.28, 0.30, 0.35)
++	lightPos           (160, 80, 40)
++	lightIntensity      5000
++}
++
++// 2. A camera
++Camera camera {
++	pos          (140, 23, 70)
++	yaw           66
++	pitch        -10
++	roll          0.0
++	fov           90
++	aspectRatio   1.5
++}
++
++Plane floor {
++	y      0
++	limit   128
++}
++
++CheckerTexture checker {
++	color1    (0.5, 0.5, 0.25)
++	color2    (0.25, 0.25, 0.25)
++	scaling 8
++}
++
++Lambert floorDiffuse {
++	color (1, 1, 1)
++	texture  checker
++}
++
++Reflection floorMirror {
++	reflColor (0.05, 0.03, 0.03)
++}
++
++Reflection floorGlossy {
++	glossiness 0.50
++	numSamples 25
++	reflColor (0.06, 0.06, 0.10)
++}
++
++Layered floorShader {
++	layer floorMirror (1, 1, 1)
++	layer floorGlossy (0.05, 0.05, 0.075)
++}
++
++// 3. A floor node, using a plane as a geometry, and a flat shader with a checker texture
++Node floorNode {
++	geometry  floor
++	shader    floorGlossy
++	translate (100, 0, 96)
++}
++
++Mesh dragon {
++	useKDTree true
++	file      "dragon.obj"
++	useSAH    off
++}
++
++Phong white {
++	color (0.7, 0.7, 0.7)
++	exponent 133
++}
++
++Node dragonNode {
++	geometry   dragon
++	shader     white
++	translate  (104, 13.44, 93)
++	rotate     (90, 90, 0)
++	scale      (30, 30, 30)
++}
++
++
++// 5. The cubemap environment:
++CubemapEnvironment environment {
++	folder "../env/forest"
++}
+diff --git a/data/hw9/nonconvex.hexray b/data/hw9/nonconvex.hexray
+new file mode 100644
+index 0000000..bb609ac
+--- /dev/null
++++ b/data/hw9/nonconvex.hexray
+@@ -0,0 +1,119 @@
++//
++// Sample scene with non-convex geometries
++//
++
++GlobalSettings {
++	frameWidth          640
++	frameHeight         480
++	ambientLight (0, 0, 0)
++	lightPos     (-30, 100, -250)
++	lightIntensity      50000
++	
++}
++
++Camera camera {
++	pos     (0, 50, -50)
++	//pos       (0, 100, -100)
++	aspectRatio   1.33333
++	yaw      0
++	pitch   -30
++	roll     0
++	fov     90
++}
++
++Plane floor {
++	y      2
++}
++
++CheckerTexture checker {
++	color1 (0,   0, 0)
++	color2 (0, 0.5, 1)
++	size    5
++}
++
++Lambert floor_shader {
++	texture checker
++}
++
++Node floor {
++	geometry floor
++	shader   floor_shader
++}
++
++
++Mesh 1 {
++	file "fig1.obj"
++	faceted true
++}
++
++Lambert L1 {
++	color (0.6, 0.5, 0.5)
++}
++
++Node 1 {
++	geometry 1
++	shader  L1
++	scale (10, 10, 10)
++}
++
++/*
++Mesh 2 {
++	file "fig2.obj"
++	faceted true
++}
++
++Lambert L2 {
++	color (0.5, 0.7, 0.5)
++}
++
++Node 2 {
++	geometry 2
++	shader  L2
++	scale (10, 10, 10)
++}
++
++Mesh 3 {
++	file "fig3.obj"
++	faceted true
++}
++
++Lambert L3 {
++	color (0.5, 0.5, 0.7)
++}
++
++Node 3 {
++	geometry 3
++	shader  L3
++	scale (10, 10, 10)
++}
++
++Mesh 4 {
++	file "fig4.obj"
++	faceted true
++}
++
++Lambert L4 {
++	color (0.7, 0.5, 0.5)
++}
++
++Node 4 {
++	geometry 4
++	shader  L4
++	scale (10, 10, 10)
++}
++
++Mesh 5 {
++	file "fig5.obj"
++	faceted true
++}
++
++Lambert L5 {
++	color (0.5, 0.7, 0.7)
++}
++
++Node 5 {
++	geometry 5
++	shader  L5
++	scale (10, 10, 10)
++}
++*/
+diff --git a/data/hw9/testmesh.hexray b/data/hw9/testmesh.hexray
+new file mode 100644
+index 0000000..3ef4847
+--- /dev/null
++++ b/data/hw9/testmesh.hexray
+@@ -0,0 +1,150 @@
++//
++// An example scene, which represents the same scenery as what the initializeScene()
++// function used to create around the tag 'homework6'
++// Namely:
++//  1) A shiny floor, made of a woody Lambert shader and a mirror layer on top
++//  2) A soccer ball
++//  3) A shiny ball using a glossy shader
++//  4) Three small phong-lit balls, using red, yellow and green colors
++
++// 1. First, some global settings
++GlobalSettings {
++	frameWidth          640
++	frameHeight         480
++	ambientLight (0.08, 0.08, 0.08)
++	lightPos (-750, 1200, -750)
++	lightIntensity 1200000
++}
++
++// 2. A camera
++Camera camera {
++	pos     (90, 160, -320)
++	aspectRatio   1.33333
++	yaw      15
++	pitch   -5
++	roll     0
++	fov     75
++//	focalPlaneDist 300
++//	fNumber 2.0
++//	dof     false
++//	numSamples 100
++}
++
++// 3. The floor node:
++Plane floor {
++	y      -0.01
++	limit    200
++}
++
++BitmapTexture wood_tex {
++	file "../texture/wood.bmp"
++	scaling 400
++}
++
++Lambert floor_diffuse {
++	texture wood_tex
++}
++
++Reflection mirror {
++}
++
++Fresnel mirror_fresnel {
++	ior 1.33
++}
++
++Layered floor_shader {
++	layer floor_diffuse (1, 1, 1)
++	layer mirror        (1, 1, 1) mirror_fresnel
++}
++
++Node floor {
++	geometry floor
++	shader   floor_shader
++}
++
++Reflection refl {
++}
++
++Refraction refr {
++	ior 1.6
++}
++
++Fresnel fresnel {
++	ior 1.6
++}
++
++Layered glass {
++	layer refr (1, 1, 1)
++	layer refl (1, 1, 1) fresnel
++}
++
++// 4. The mesh:
++Mesh mesh {
++//	file        "geom/3pyramid.obj"
++//	file        "geom/teapot_lowres.obj"
++//	file        "geom/heart.obj"
++	file		"../geom/newwine.obj"
++//	file	 	"geom/truncated_cube.obj"
++//	backfaceCulling false
++	faceted     false
++}
++
++CheckerTexture checker {
++	color1 (0.70, 0.70, 0.70)
++	color2 (0.15, 0.15, 0.15)
++	scaling 100
++}
++
++Lambert checker_shader {
++	texture checker
++}
++
++BitmapTexture heart_lava {
++	file "../texture/zar-texture.bmp"
++}
++
++Lambert heart_shader {
++	texture heart_lava
++}
++
++Reflection reflection {
++}
++
++Refraction refraction {
++	ior 1.5
++}
++
++Fresnel fresnel {
++	ior 1.5
++}
++
++Layered glass {
++	layer refraction (1, 1, 1)
++	layer reflection (1, 1, 1) fresnel
++}
++
++CheckerTexture checker1 {
++	color1 (0.2, 0.2, 0.2)
++	color2 (0.8, 0.8, 0.8)
++	scaling 10
++}
++
++Lambert lambert {
++	color (0.7, 0.7, 0.7)
++	texture checker
++}
++
++Node soccer_ball {
++	geometry     mesh
++	shader       glass
++	scale        (230, 230, 230)
++	rotate       (135, 0, 0)
++	translate    (0, 0, 0)
++//	bump bumptex
++}
++
++
++// 7. And, finally, an environment
++CubemapEnvironment {
++	folder "../env/forest"
++}
+diff --git a/data/hw9/wireframe.hexray b/data/hw9/wireframe.hexray
+new file mode 100644
+index 0000000..0f0a54b
+--- /dev/null
++++ b/data/hw9/wireframe.hexray
+@@ -0,0 +1,72 @@
++//
++// A sample scene for the homeworks for Lecture 9
++//
++
++// 1. First, some global settings
++GlobalSettings {
++	frameWidth          640
++	frameHeight         480
++	ambientLight        (0.28, 0.30, 0.35)
++	lightPos            (160, 80, 33)
++	lightIntensity      10000
++}
++
++// 2. A camera
++Camera camera {
++	pos          (120, 33, 40)
++	yaw           10
++	pitch         -15
++	roll          0.0
++	fov           90
++	aspectRatio   1.333
++}
++
++Plane floor {
++	y        0
++	limit 128
++}
++
++CheckerTexture checker {
++	color1    (0.5, 0.5, 0.25)
++	color2    (0.25, 0.25, 0.25)
++	scaling    8
++}
++
++Lambert floorShader {
++	color (1, 1, 1)
++	texture  checker
++}
++
++// 3. A floor node, using a plane as a geometry, and a flat shader with a checker texture
++Node floorNode {
++	geometry  floor
++	shader    floorShader
++	translate (100, 0, 96)
++}
++
++Mesh heart {
++	file              "../geom/heart.obj"
++}
++
++Lambert white_flat {
++	color (0.7, 0.7, 0.7)
++}
++
++Wireframe wireframe {
++	wireSize  0.08
++	wireColor (0, 1, 0)
++	outColor  (0, 0, 0)
++}
++
++Node heartNode {
++	geometry    heart
++	shader      wireframe
++	translate   (100, 12.1, 80)
++	rotate      (120, 0, 0)
++	scale       (6, 6, 6)
++}
++
++// 5. The cubemap environment:
++CubemapEnvironment environment {
++	folder "../env/forest"
++}
+diff --git a/flake.lock b/flake.lock
+new file mode 100644
+index 0000000..25db693
+--- /dev/null
++++ b/flake.lock
+@@ -0,0 +1,27 @@
++{
++  "nodes": {
++    "nixpkgs": {
++      "locked": {
++        "lastModified": 1716061101,
++        "narHash": "sha256-H0eCta7ahEgloGIwE/ihkyGstOGu+kQwAiHvwVoXaA0=",
++        "owner": "nixos",
++        "repo": "nixpkgs",
++        "rev": "e7cc61784ddf51c81487637b3031a6dd2d6673a2",
++        "type": "github"
++      },
++      "original": {
++        "owner": "nixos",
++        "ref": "nixos-23.11",
++        "repo": "nixpkgs",
++        "type": "github"
++      }
++    },
++    "root": {
++      "inputs": {
++        "nixpkgs": "nixpkgs"
++      }
++    }
++  },
++  "root": "root",
++  "version": 7
++}
+diff --git a/flake.nix b/flake.nix
+new file mode 100644
+index 0000000..d0a99fd
+--- /dev/null
++++ b/flake.nix
+@@ -0,0 +1,26 @@
++# Този файл, заедно с flake.lock са си за моета система, да имам копие ако случайно изтрия нещо
++{
++  description = "hexray raytracer in FMI elective";
++
++  inputs = {
++    nixpkgs.url = "github:nixos/nixpkgs/nixos-23.11";
++  };
++
++  outputs = inputs:
++  let
++    pkgs = inputs.nixpkgs.legacyPackages."x86_64-linux";
++  in {
++    devShells."x86_64-linux".default = pkgs.mkShell {
++      nativeBuildInputs = with pkgs; [
++        cmake
++        pkg-config
++      ];
++
++      buildInputs = with pkgs; [
++        SDL2
++        openexr_3
++        zlib
++      ];
++    };
++  };
++}
+diff --git a/src/geometry.h b/src/geometry.h
+index 4af6360..e7b4a8c 100644
+--- a/src/geometry.h
++++ b/src/geometry.h
+@@ -37,6 +37,8 @@ struct IntersectionInfo {
+     Vector dNdx, dNdy;
+     double u, v;
+     Geometry *geom;
++	double lambda2;
++	double lambda3;
+ };
+ 
+ /**
+@@ -133,4 +135,4 @@ public:
+ class CSGDiff: public CSGBase { // A - B
+ public:
+     virtual bool inside(bool inA, bool inB) override { return inA && !inB; }
+-};
+\ No newline at end of file
++};
+diff --git a/src/main.cpp b/src/main.cpp
+index 780804c..93a18ea 100644
+--- a/src/main.cpp
++++ b/src/main.cpp
+@@ -183,7 +183,7 @@ bool renderStatic()
+ 	return render(true);
+ }
+ 
+-const char* DEFAULT_SCENE = "data/heightfield.hexray";
++const char* DEFAULT_SCENE = "data/hw9/wireframe.hexray";
+ 
+ int main(int argc, char** argv)
+ {
+diff --git a/src/mesh.cpp b/src/mesh.cpp
+index 2f6da05..86a6b0b 100644
+--- a/src/mesh.cpp
++++ b/src/mesh.cpp
+@@ -160,8 +160,10 @@ bool Mesh::intersectTriangle(const Ray& ray, const Triangle& t, IntersectionInfo
+ 	double rDcr = 1/Dcr;
+ 	double lambda2 = det(H, AC, -ray.dir) * rDcr;
+ 	if (lambda2 < 0 || lambda2 > 1) return false;
++	info.lambda2 = lambda2;
+ 	double lambda3 = det(AB, H, -ray.dir) * rDcr;
+ 	if (lambda3 < 0 || lambda3 > 1) return false;
++	info.lambda3 = lambda3;
+ 	double lambda1 = 1 - (lambda2 + lambda3);
+ 	if (lambda1 < 0 || lambda1 > 1) return false;
+ 	double gamma = det(AB, AC, H) * rDcr;
+diff --git a/src/scene.cpp b/src/scene.cpp
+index 149320e..5ac4633 100644
+--- a/src/scene.cpp
++++ b/src/scene.cpp
+@@ -804,6 +804,7 @@ SceneElement* DefaultSceneParser::newSceneElement(const char* className)
+ 	if (!strcmp(className, "Heightfield")) return new Heightfield;
+ 	if (!strcmp(className, "BumpTexture")) return new BumpTexture;
+ 	if (!strcmp(className, "Bumps")) return new Bumps;
++	if (!strcmp(className, "Wireframe")) return new Wireframe;
+ 	if (!strcmp(className, "Const")) return new Const;
+ 
+ 	return NULL;
+diff --git a/src/shading.cpp b/src/shading.cpp
+index 25f3c80..f4d3f0a 100644
+--- a/src/shading.cpp
++++ b/src/shading.cpp
+@@ -270,3 +270,11 @@ void Bumps::modifyNormal(IntersectionInfo& data)
+ 		data.norm.normalize();
+ 	}
+ }
++
++Color Wireframe::computeColor(Ray ray, const IntersectionInfo& info) {
++	double lambda1 = 1.0 - info.lambda2 - info.lambda3;
++	if (lambda1 < wireSize || info.lambda2 < wireSize || info.lambda3 < wireSize) {
++		return wireColor;
++	}
++	return outColor;
++}
+diff --git a/src/shading.h b/src/shading.h
+index 95e26c5..5a77b71 100644
+--- a/src/shading.h
++++ b/src/shading.h
+@@ -199,3 +199,23 @@ public:
+ 	}
+ 
+ };
++
++class Wireframe : public Shader {
++public:
++	double wireSize = 0.08;
++	Color wireColor = Color(0, 1, 0);
++	Color outColor  = Color(0, 0, 0);
++	Wireframe(double wireSize = 0.08,
++	          Color wireColor = Color(0, 1, 0),
++	          Color outColor  = Color(0, 0, 0)) :
++		wireSize(wireSize), wireColor(wireColor), outColor(outColor)
++	{}
++	Color computeColor(Ray ray, const IntersectionInfo& info) override;
++
++	void fillProperties(ParsedBlock& pb) override
++	{
++		pb.getDoubleProp("wireSize", &wireSize);
++		pb.getColorProp("wireColor", &wireColor);
++		pb.getColorProp("outColor", &outColor);
++	}
++};
+-- 
+2.42.0
+
diff --git a/Year 3/Raytracing/0005-h10-Implemented-SpotLight.patch b/Year 3/Raytracing/0005-h10-Implemented-SpotLight.patch
new file mode 100644
index 0000000..f1fbfd6
--- /dev/null
+++ b/Year 3/Raytracing/0005-h10-Implemented-SpotLight.patch
@@ -0,0 +1,223 @@
+From 7b19946dab9bc0399214a36dc9067f56c4e0d3a8 Mon Sep 17 00:00:00 2001
+From: Syndamia <kamen@syndamia.com>
+Date: Mon, 27 May 2024 09:22:23 +0300
+Subject: [PATCH] [h10] Implemented SpotLight
+
+---
+ data/boxed.hexray | 37 ++++++++++++++++++-------------------
+ flake.lock        | 27 +++++++++++++++++++++++++++
+ flake.nix         | 26 ++++++++++++++++++++++++++
+ src/lights.cpp    | 17 +++++++++++++++++
+ src/lights.h      | 19 +++++++++++++++++++
+ src/main.cpp      |  2 +-
+ src/scene.cpp     |  1 +
+ src/vector.h      |  4 ++++
+ 8 files changed, 113 insertions(+), 20 deletions(-)
+ create mode 100644 flake.lock
+ create mode 100644 flake.nix
+
+diff --git a/data/boxed.hexray b/data/boxed.hexray
+index e128db3..9ed1793 100644
+--- a/data/boxed.hexray
++++ b/data/boxed.hexray
+@@ -18,25 +18,24 @@ Camera camera {
+ //////////////////////// LIGHTS ////////////////////////////////////////////
+ 
+ 
+-RectLight l2 {
+-	xSubd 4
+-	ySubd 4
+-	translate	(50, 50, -20)
+-	scale   (8, 8, 8)
+-	color	(1, 1, 1)
+-	power   4000
+-	rotate  (0, 45, 0)
+-}
+-
+-RectLight l_small {
+-	translate  (0, 28, 50)
+-	rotate     (0, -62, 0)
+-	scale      (10, 10, 10)
+-	color	   (1, 1, 1)
+-	power      4000
+-	xSubd  4
+-	ySubd  4
+-}
++SpotLight mylight {
++	color   (1, 1, 1)
++	power   7000
++	pos     (50, 50, -20)
++	dir     (-0.727, -0.582, 0.364)
++	innerAngle 13.8
++	outerAngle 15.5
++}
++
++// RectLight l_small {
++// 	translate  (0, 28, 50)
++// 	rotate     (0, -62, 0)
++// 	scale      (10, 10, 10)
++// 	color	   (1, 1, 1)
++// 	power      4000
++// 	xSubd  4
++// 	ySubd  4
++// }
+ 
+ 
+ //////////////////////// GEOMETRIES ////////////////////////////////////////
+diff --git a/flake.lock b/flake.lock
+new file mode 100644
+index 0000000..25db693
+--- /dev/null
++++ b/flake.lock
+@@ -0,0 +1,27 @@
++{
++  "nodes": {
++    "nixpkgs": {
++      "locked": {
++        "lastModified": 1716061101,
++        "narHash": "sha256-H0eCta7ahEgloGIwE/ihkyGstOGu+kQwAiHvwVoXaA0=",
++        "owner": "nixos",
++        "repo": "nixpkgs",
++        "rev": "e7cc61784ddf51c81487637b3031a6dd2d6673a2",
++        "type": "github"
++      },
++      "original": {
++        "owner": "nixos",
++        "ref": "nixos-23.11",
++        "repo": "nixpkgs",
++        "type": "github"
++      }
++    },
++    "root": {
++      "inputs": {
++        "nixpkgs": "nixpkgs"
++      }
++    }
++  },
++  "root": "root",
++  "version": 7
++}
+diff --git a/flake.nix b/flake.nix
+new file mode 100644
+index 0000000..d0a99fd
+--- /dev/null
++++ b/flake.nix
+@@ -0,0 +1,26 @@
++# Този файл, заедно с flake.lock са си за моета система, да имам копие ако случайно изтрия нещо
++{
++  description = "hexray raytracer in FMI elective";
++
++  inputs = {
++    nixpkgs.url = "github:nixos/nixpkgs/nixos-23.11";
++  };
++
++  outputs = inputs:
++  let
++    pkgs = inputs.nixpkgs.legacyPackages."x86_64-linux";
++  in {
++    devShells."x86_64-linux".default = pkgs.mkShell {
++      nativeBuildInputs = with pkgs; [
++        cmake
++        pkg-config
++      ];
++
++      buildInputs = with pkgs; [
++        SDL2
++        openexr_3
++        zlib
++      ];
++    };
++  };
++}
+diff --git a/src/lights.cpp b/src/lights.cpp
+index d1b5a42..f1e6406 100644
+--- a/src/lights.cpp
++++ b/src/lights.cpp
+@@ -44,3 +44,20 @@ void RectLight::getNthSample(int sampleIdx, const Vector& shadePos, Vector& samp
+         color.makeZero();
+     }
+ }
++
++void SpotLight::getNthSample(int sampleIdx, const Vector& shadePos, Vector& samplePos, Color& color) {
++	samplePos = pos;
++
++	Vector shadeDir = shadePos - pos;
++	double degr = degreesBetween(shadeDir, dir);
++	if (degr < innerAngle) {
++		color = this->color;
++	}
++	else if (degr > outerAngle) {
++		color = Color(0, 0, 0);
++	}
++	else {
++		double alpha = (degr - innerAngle) / (outerAngle - innerAngle);
++		color = (1 - alpha) * this->color + alpha * Color(0, 0, 0);
++	}
++}
+diff --git a/src/lights.h b/src/lights.h
+index 548b53f..c76b9be 100644
+--- a/src/lights.h
++++ b/src/lights.h
+@@ -79,3 +79,22 @@ public:
+ 	void getNthSample(int sampleIdx, const Vector& shadePos, Vector& samplePos, Color& color) override;
+ };
+ 
++
++class SpotLight : public Light {
++	Vector pos;
++	Vector dir;
++	double innerAngle;
++	double outerAngle;
++public:
++	void fillProperties(ParsedBlock& pb) override
++	{
++		Light::fillProperties(pb);
++		pb.getVectorProp("pos", &pos);
++		pb.getVectorProp("dir", &dir);
++		pb.getDoubleProp("innerAngle", &innerAngle);
++		pb.getDoubleProp("outerAngle", &outerAngle);
++	}
++
++	int getNumSamples() const override { return 1; }
++	void getNthSample(int sampleIdx, const Vector& shadePos, Vector& samplePos, Color& color) override;
++};
+diff --git a/src/main.cpp b/src/main.cpp
+index d523f60..7a181cb 100644
+--- a/src/main.cpp
++++ b/src/main.cpp
+@@ -222,7 +222,7 @@ bool renderStatic()
+ 	return render(true);
+ }
+ 
+-const char* DEFAULT_SCENE = "data/meshes.hexray";
++const char* DEFAULT_SCENE = "data/boxed.hexray";
+ 
+ int main(int argc, char** argv)
+ {
+diff --git a/src/scene.cpp b/src/scene.cpp
+index f5fbdb0..82c8d98 100644
+--- a/src/scene.cpp
++++ b/src/scene.cpp
+@@ -799,6 +799,7 @@ SceneElement* DefaultSceneParser::newSceneElement(const char* className)
+ 	if (!strcmp(className, "Const")) return new Const;
+ 	if (!strcmp(className, "PointLight")) return new PointLight;
+ 	if (!strcmp(className, "RectLight")) return new RectLight;
++	if (!strcmp(className, "SpotLight")) return new SpotLight;
+ 
+ 	return NULL;
+ }
+diff --git a/src/vector.h b/src/vector.h
+index a21b432..cd140fb 100644
+--- a/src/vector.h
++++ b/src/vector.h
+@@ -199,3 +199,7 @@ inline std::pair<Vector, Vector> othonormedBasis(const Vector& v)
+ 	result.second = result.first ^ v;
+ 	return result;
+ }
++
++inline double degreesBetween(const Vector& a, const Vector& b) {
++	return acos(dot(normalize(a), normalize(b))) * 180 / M_PI;
++}
+-- 
+2.42.0
+
diff --git a/Year 3/Raytracing/0006-h12-Implemented-Russian-roulette-raytracing.patch b/Year 3/Raytracing/0006-h12-Implemented-Russian-roulette-raytracing.patch
new file mode 100644
index 0000000..32372da
--- /dev/null
+++ b/Year 3/Raytracing/0006-h12-Implemented-Russian-roulette-raytracing.patch
@@ -0,0 +1,161 @@
+From 6cf50cd269931e95f058e17c15dc210fc49fa216 Mon Sep 17 00:00:00 2001
+From: Syndamia <kamen@syndamia.com>
+Date: Mon, 27 May 2024 17:46:57 +0300
+Subject: [PATCH] [h12] Implemented Russian-roulette raytracing
+
+---
+ data/smallpt.hexray |  1 +
+ flake.lock          | 27 +++++++++++++++++++++++++++
+ flake.nix           | 26 ++++++++++++++++++++++++++
+ src/main.cpp        | 14 ++++++++++++--
+ src/scene.cpp       |  1 +
+ src/scene.h         |  3 +++
+ 6 files changed, 70 insertions(+), 2 deletions(-)
+ create mode 100644 flake.lock
+ create mode 100644 flake.nix
+
+diff --git a/data/smallpt.hexray b/data/smallpt.hexray
+index dfdc6e5..cdb0cf9 100644
+--- a/data/smallpt.hexray
++++ b/data/smallpt.hexray
+@@ -11,6 +11,7 @@ GlobalSettings {
+ 	gi 			on
+ 	numPaths 	40
+ 	prepassSamples 300
++	roulette on
+ }
+ 
+ Camera camera {
+diff --git a/flake.lock b/flake.lock
+new file mode 100644
+index 0000000..25db693
+--- /dev/null
++++ b/flake.lock
+@@ -0,0 +1,27 @@
++{
++  "nodes": {
++    "nixpkgs": {
++      "locked": {
++        "lastModified": 1716061101,
++        "narHash": "sha256-H0eCta7ahEgloGIwE/ihkyGstOGu+kQwAiHvwVoXaA0=",
++        "owner": "nixos",
++        "repo": "nixpkgs",
++        "rev": "e7cc61784ddf51c81487637b3031a6dd2d6673a2",
++        "type": "github"
++      },
++      "original": {
++        "owner": "nixos",
++        "ref": "nixos-23.11",
++        "repo": "nixpkgs",
++        "type": "github"
++      }
++    },
++    "root": {
++      "inputs": {
++        "nixpkgs": "nixpkgs"
++      }
++    }
++  },
++  "root": "root",
++  "version": 7
++}
+diff --git a/flake.nix b/flake.nix
+new file mode 100644
+index 0000000..d0a99fd
+--- /dev/null
++++ b/flake.nix
+@@ -0,0 +1,26 @@
++# Този файл, заедно с flake.lock са си за моета система, да имам копие ако случайно изтрия нещо
++{
++  description = "hexray raytracer in FMI elective";
++
++  inputs = {
++    nixpkgs.url = "github:nixos/nixpkgs/nixos-23.11";
++  };
++
++  outputs = inputs:
++  let
++    pkgs = inputs.nixpkgs.legacyPackages."x86_64-linux";
++  in {
++    devShells."x86_64-linux".default = pkgs.mkShell {
++      nativeBuildInputs = with pkgs; [
++        cmake
++        pkg-config
++      ];
++
++      buildInputs = with pkgs; [
++        SDL2
++        openexr_3
++        zlib
++      ];
++    };
++  };
++}
+diff --git a/src/main.cpp b/src/main.cpp
+index 5af773d..47c0028 100644
+--- a/src/main.cpp
++++ b/src/main.cpp
+@@ -115,6 +115,16 @@ Color pathtrace(Ray ray, Color pathMultiplier = Color(1, 1, 1))
+ 	TraceContext tc;
+ 	auto earlyResult = tc.raycast(ray);
+ 	if (earlyResult) return (*earlyResult) * pathMultiplier;
++
++	double rating = pathMultiplier.intensity();
++	double rouletteContribution = 1.0;
++	if (scene.settings.roulette && ray.depth < 4 && rating < 1) {
++		double kill = randDouble();
++		if (kill <= 1 - rating) {
++			return Color(0, 0, 0);
++		}
++		rouletteContribution = 1 / rating;
++	}
+ 	// Continue building the path:
+ 	// Option A: continue randomly
+ 	Ray newRay = ray;
+@@ -123,7 +133,7 @@ Color pathtrace(Ray ray, Color pathMultiplier = Color(1, 1, 1))
+ 	newRay.depth++;
+ 	tc.closestNode->shader->spawnRay(tc.closestIntersection, ray.dir, newRay, brdfColor, brdfPDF);
+ 	if (brdfPDF <= 0) return Color(0, 0, 0);
+-	Color fromGI = pathtrace(newRay, pathMultiplier * brdfColor / brdfPDF);
++	Color fromGI = pathtrace(newRay, pathMultiplier * brdfColor / brdfPDF) * rouletteContribution;
+ 	//
+ 	// Option B: explicit light sampling
+ 	// scheme:
+@@ -160,7 +170,7 @@ Color pathtrace(Ray ray, Color pathMultiplier = Color(1, 1, 1))
+ 	float pChooseLight = 1.0f / scene.lights.size();
+ 	float pHitLight = 1.0f / solidAngle;
+ 	float pThisPath = pChooseLight * pHitLight;
+-	return fromGI + fromLight * pathMultiplier / pThisPath;
++	return fromGI + fromLight * pathMultiplier / pThisPath * rouletteContribution;
+ }
+ 
+ bool visible(Vector A, Vector B)
+diff --git a/src/scene.cpp b/src/scene.cpp
+index c909d0c..69f9206 100644
+--- a/src/scene.cpp
++++ b/src/scene.cpp
+@@ -772,6 +772,7 @@ void GlobalSettings::fillProperties(ParsedBlock& pb)
+ 	pb.getIntProp("prepassSamples", &prepassSamples, 0);
+ 	pb.getBoolProp("gi", &gi);
+ 	pb.getIntProp("numPaths", &numPaths, 1);
++	pb.getBoolProp("roulette", &roulette);
+ }
+ 
+ SceneElement* DefaultSceneParser::newSceneElement(const char* className)
+diff --git a/src/scene.h b/src/scene.h
+index 250d561..327c828 100644
+--- a/src/scene.h
++++ b/src/scene.h
+@@ -259,6 +259,9 @@ struct GlobalSettings: public SceneElement {
+ 	bool gi = false;
+ 	int numPaths = 32;
+ 
++	// Russian roulette-related
++	bool roulette;
++
+ 	void fillProperties(ParsedBlock& pb);
+ 	ElementType getElementType() const { return ELEM_SETTINGS; }
+ };
+-- 
+2.42.0
+