6 files changed, 94 insertions, 1 deletions
diff --git a/src/camera/camera.rs b/src/camera/camera.rs
new file mode 100644
index 0000000..102e57b
--- /dev/null
+++ b/src/camera/camera.rs
@@ -0,0 +1,40 @@
+//! Implements ray generation
+//!
+//! Rays are generated by transforming between different spaces summed below.
+//!
+//! - *World space*: Where objects are located in the scene, this will be 3d coordinates
+//! - *Camera space*: Originated at the origin of the camera, with z mapped to the viewing
+//! direction
+//!
+//! Camera space will be represented in different ways:
+//! - *Screen space*: Everything in the screen space is projected onto the film, when z=0 this will
+//! correspond 
+//! - *Normalized Device Coordinates(NDC) space*: Is defined as (0, 0, 0) as the upper-left corner of
+//! the film, and (1, 1, 0) to be the bottom right corner.
+//! - *Raster space*: Same as NDC space but, (1, 1, 0) is mapped to (width, height, 0)
+//!
+//! More in depth description is in pbr-book chapter 6
+use crate::Float;
+use crate::core::{Transform, Ray, Vector2i, Bound2f};
+
+/// General implementation for all projective based cameras
+struct ProjectiveCamera {
+    cam2wor: Transform,
+    cam2scr: Transform,
+}
+
+impl ProjectiveCamera {
+    fn new(cam2wor: Transform, cam2scr: Transform, resolution: &Vector2i, screenwindow: &Bound2f) -> Self {
+        let screensize = screenwindow.diagonal();
+        // Calculate the conversion from screen space to raster space
+        let scr2ras = Transform::new_scale(resolution.x as Float, resolution.y as Float, 1.0) *
+            Transform::new_scale(1.0 / (screensize.x), 1.0 / (screensize.y), 1.0) *
+            Transform::new_translate(-screenwindow.min.x, -screenwindow.min.y, 0.0);
+        let ras2scr = 
+
+        Self {
+            cam2wor,
+            cam2scr,
+        }
+    }
+}
diff --git a/src/camera/mod.rs b/src/camera/mod.rs
index 4865a36..41f9598 100644
--- a/src/camera/mod.rs
+++ b/src/camera/mod.rs
@@ -7,4 +7,4 @@
 
 pub mod film;
 //pub mod filter;
-//pub mod camera;
+pub mod camera;
diff --git a/src/core/matrix4x4.rs b/src/core/matrix4x4.rs
index 521d7ab..f8c685d 100644
--- a/src/core/matrix4x4.rs
+++ b/src/core/matrix4x4.rs
@@ -1,4 +1,5 @@
 use crate::{Number, Float};
+use std::ops;
 
 pub struct Matrix4x4<T: Number> {
     pub m: [[T; 4]; 4],
@@ -20,6 +21,36 @@ impl<T: Number> Matrix4x4<T> {
             ],
         }
     }
+
+    pub fn initial(initial: T) -> Self {
+        Self {
+            m : [ [initial; 4]; 4]
+        }
+    }
+
+    pub fn inverse(&self) -> Self {
+
+    }
+}
+
+impl<T: Number> ops::Mul for &Matrix4x4<T> {
+    type Output = Matrix4x4<T>;
+
+    fn mul(self, op: Self) -> Self::Output {
+        let mut res = Self::Output::initial(Default::default());
+
+        // Not very fast
+        for i in 0..4 {
+            for j in 0..4 {
+                res.m[i][j] = self.m[i][0] * op.m[0][j] +
+                    self.m[i][1] * op.m[1][j] +
+                    self.m[i][2] * op.m[2][j] +
+                    self.m[i][3] * op.m[3][j];
+            }
+        }
+
+        res
+    }
 }
 
 impl Matrix4x4f {
diff --git a/src/core/transform.rs b/src/core/transform.rs
index f64710c..337d9b1 100644
--- a/src/core/transform.rs
+++ b/src/core/transform.rs
@@ -17,6 +17,7 @@
 use super::matrix4x4::Matrix4x4f;
 use crate::Float;
 use crate::core::Vector3f;
+use std::ops;
 
 pub struct Transform {
     m: Matrix4x4f,
@@ -56,6 +57,22 @@ impl Transform {
 
         Vector3f::new_xyz(x, y, z)
     }
+
+    pub fn inverse(&self) -> Self {
+        Transform {
+            m: self.m.inverse(),
+        }
+    }
+}
+
+impl ops::Mul for Transform {
+    type Output = Transform;
+
+    fn mul(self, op: Self) -> Self::Output {
+        Transform {
+            m: &self.m * &op.m
+        }
+    }
 }
 
 // Creation of different transformations
diff --git a/src/lib.rs b/src/lib.rs
index df9bc1d..e9ca2f8 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -10,6 +10,7 @@ use std::cmp;
 /// This is used in Bound and Vectors
 pub trait Number:
     Copy +
+    Default +
     cmp::PartialOrd +
     Sub<Output = Self> +
     Add<Output = Self> +
diff --git a/src/render/mod.rs b/src/render/mod.rs
new file mode 100644
index 0000000..ee4e8bc
--- /dev/null
+++ b/src/render/mod.rs
@@ -0,0 +1,4 @@
+
+struct SimpleRender {
+
+}