From b64c7e972c52b7d015d661866f0cf902370343e5 Mon Sep 17 00:00:00 2001
From: Julian T <julian@jtle.dk>
Date: Sat, 6 Feb 2021 23:43:06 +0100
Subject: Implement pathtracing

---
 src/core/ray.rs      |  8 ++++++++
 src/core/spectrum.rs | 26 +++++++++++++++++++++++---
 src/core/vector3.rs  | 13 +++++++++++++
 3 files changed, 44 insertions(+), 3 deletions(-)

(limited to 'src/core')

diff --git a/src/core/ray.rs b/src/core/ray.rs
index f5517ce..c944184 100644
--- a/src/core/ray.rs
+++ b/src/core/ray.rs
@@ -8,6 +8,14 @@ pub struct Ray {
 }
 
 impl Ray {
+    pub fn new_to(origin: Vector3f, target: Vector3f) -> Ray {
+        let dir = (target - origin).norm();
+        Ray {
+            origin,
+            direction: dir
+        }
+    }
+
     pub fn at(&self, t: Float) -> Vector3f {
         self.origin + self.direction * t
     }
diff --git a/src/core/spectrum.rs b/src/core/spectrum.rs
index 41b3342..727a1b6 100644
--- a/src/core/spectrum.rs
+++ b/src/core/spectrum.rs
@@ -6,7 +6,7 @@ use std::ops;
 
 // TODO implement SampledSpectrum instead for nicer images
 
-#[derive(Clone, Default)]
+#[derive(Clone, Copy, Default)]
 pub struct Spectrum {
     c: [Float; 3],
 }
@@ -19,9 +19,17 @@ impl Spectrum {
     pub fn to_rgb(&self, scale: Float) -> (Float, Float, Float) {
         (self.c[0] * scale, self.c[1] * scale, self.c[2] * scale)
     }
+
+    pub fn gamma_correct(&self) -> Self {
+        Self::new_rgb(
+            self.c[0].sqrt(),
+            self.c[1].sqrt(),
+            self.c[2].sqrt(),
+            )
+    }
 }
 
-impl std::ops::Mul<Float> for &Spectrum {
+impl std::ops::Mul<Float> for Spectrum {
     type Output = Spectrum;
 
     fn mul(self, op: Float) -> Self::Output {
@@ -33,7 +41,7 @@ impl std::ops::Mul<Float> for &Spectrum {
     }
 }
 
-impl std::ops::Div<Float> for &Spectrum {
+impl std::ops::Div<Float> for Spectrum {
     type Output = Spectrum;
 
     fn div(self, op: Float) -> Self::Output {
@@ -45,6 +53,18 @@ impl std::ops::Div<Float> for &Spectrum {
     }
 }
 
+impl std::ops::Add for Spectrum {
+    type Output = Spectrum;
+
+    fn add(self, op: Self) -> Self::Output {
+        Self::Output::new_rgb(
+            self.c[0] + op.c[0],
+            self.c[1] + op.c[1],
+            self.c[2] + op.c[2],
+            )
+    }
+}
+
 impl std::ops::AddAssign<&Self> for Spectrum {
     fn add_assign(&mut self, op: &Self) {
         self.c[0] += op.c[0];
diff --git a/src/core/vector3.rs b/src/core/vector3.rs
index 10de647..ef067aa 100644
--- a/src/core/vector3.rs
+++ b/src/core/vector3.rs
@@ -50,6 +50,18 @@ impl<T: Number> Add for Vector3<T> {
     }
 }
 
+impl<T: Number> Add<T> for Vector3<T> {
+    type Output = Self;
+
+    fn add(self, op: T) -> Self::Output {
+        Self::new_xyz(
+            self.x + op,
+            self.y + op,
+            self.z + op,
+        )
+    }
+}
+
 impl<T: Number> Mul<T> for Vector3<T> {
     type Output = Self;
     fn mul(self, op: T) -> Self::Output {
@@ -114,6 +126,7 @@ impl Vector3f {
     /// assert!(v.x == 1.0);
     /// ```
     pub fn norm_in(&mut self) {
+        // TODO Experiment with checking for normality with len_squared
         let len = self.len();
         if len == 0.0 {
             *self = Self::new(0.0);
-- 
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