[Ray/h12-hard] Added solution

1 files changed, 173 insertions, 0 deletions

diff --git a/Year 3/Raytracing/1006-hw12-hard-Implemented-proper-solid-angle-for-rectang.patch b/Year 3/Raytracing/1006-hw12-hard-Implemented-proper-solid-angle-for-rectang.patch
new file mode 100644
index 0000000..24cb7ed
--- /dev/null
+++ b/Year 3/Raytracing/1006-hw12-hard-Implemented-proper-solid-angle-for-rectang.patch
@@ -0,0 +1,173 @@
+From ca0480a8c55b38d9a5651c34b7b9b0defac22b3a Mon Sep 17 00:00:00 2001
+From: Syndamia <kamen@syndamia.com>
+Date: Tue, 4 Jun 2024 12:22:39 +0300
+Subject: [PATCH] [hw12-hard] Implemented proper solid angle for rectangular
+ lights
+
+---
+ flake.lock     | 27 +++++++++++++++++++++++++++
+ flake.nix      | 26 ++++++++++++++++++++++++++
+ src/lights.cpp | 32 +++++++++++++++++++-------------
+ src/lights.h   |  2 ++
+ src/main.cpp   |  2 +-
+ src/vector.h   |  4 ++++
+ 6 files changed, 79 insertions(+), 14 deletions(-)
+ create mode 100644 flake.lock
+ create mode 100644 flake.nix
+
+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 f6edef4..d5b0ed6 100644
+--- a/src/lights.cpp
++++ b/src/lights.cpp
+@@ -74,9 +74,8 @@ int RectLight::intersect(const Ray& ray, double& intersectionDist)
+ 
+ void RectLight::beginFrame()
+ {
+-	Vector pts[3];
+-	for (int i = 0; i < 3; i++) {
+-		pts[i].x = (i % 2) ? -0.5 : 0.5;
++	for (int i = 0; i < 4; i++) {
++		pts[i].x = (i % 3) ? -0.5 : 0.5;
+ 		pts[i].y = 0;
+ 		pts[i].z = (i < 2) ? -0.5 : 0.5;
+ 		pts[i] = T.transformPoint(pts[i]);
+@@ -87,16 +86,23 @@ void RectLight::beginFrame()
+ 	scaleFactor = 1 / m_area;
+ }
+ 
++static Vector projectOnUnitSphere(const Vector& toProj, const Vector& sphereCenter) {
++	return sphereCenter + normalize(toProj - sphereCenter);
++}
++
+ double RectLight::getSolidAngle(const Vector& p)
+ {
+-	Vector lightDirCanonic(0, -1, 0);
+-	//
+-	Vector lightDirWorld = T.transformDir(lightDirCanonic);
+-	Vector lightPosWorld = T.transformPoint(Vector(0, 0, 0));
+-	Vector lightToP = p - lightPosWorld;
+-	double cosTerm = dot(lightToP, lightDirWorld);
+-	if (cosTerm < 0) return 0;
+-	double d = lightToP.length();
+-	cosTerm /= d;
+-	return m_area * cosTerm / sqr(1 + d);
++	Vector ppts[4];
++	for (int i = 0; i < 4; i++) {
++		ppts[i] = projectOnUnitSphere(this->pts[i], p);
++	}
++
++	double dihedrals = 0.0;
++	for (int i = 0; i < 4; i++) {
++		Vector n1 = (ppts[(i - 1 + 4) % 4] - p) ^ (ppts[i] - p);
++		Vector n2 = (ppts[(i + 1) % 4] - p) ^ (ppts[i] - p);
++		dihedrals += radBetween(n1, n2);
++	}
++
++	return dihedrals - 2.0 * M_PI;
+ }
+diff --git a/src/lights.h b/src/lights.h
+index c144577..e469c9d 100644
+--- a/src/lights.h
++++ b/src/lights.h
+@@ -100,6 +100,8 @@ class RectLight: public Light {
+ 	int xSubd = 3, ySubd = 3;
+ 	float scaleFactor;
+ 	double m_area;
++
++	Vector pts[4];
+ public:
+ 	void fillProperties(ParsedBlock& pb) override
+ 	{
+diff --git a/src/main.cpp b/src/main.cpp
+index 5af773d..f0a71e5 100644
+--- a/src/main.cpp
++++ b/src/main.cpp
+@@ -379,7 +379,7 @@ bool renderStatic()
+ 	return render(true);
+ }
+ 
+-const char* DEFAULT_SCENE = "data/smallpt.hexray";
++const char* DEFAULT_SCENE = "data/hw12/sphtri.hexray";
+ 
+ int main(int argc, char** argv)
+ {
+diff --git a/src/vector.h b/src/vector.h
+index ed4c8cf..149d173 100644
+--- a/src/vector.h
++++ b/src/vector.h
+@@ -205,3 +205,7 @@ inline std::pair<Vector, Vector> othonormedBasis(const Vector& v)
+ 	result.second = result.first ^ v;
+ 	return result;
+ }
++
++inline double radBetween(const Vector& a, const Vector& b) {
++	return acos(dot(normalize(a), normalize(b)));
++}
+-- 
+2.42.0
+