ROTATION WORKS!!!!

src/ray.rs

@@ -1,5 +1,5 @@
 use std::ops::Mul;
-use cgmath::{Angle, InnerSpace, Matrix4, SquareMatrix, Vector3, Vector4};
+use cgmath::{Angle, InnerSpace, Matrix3, Matrix4, Point3, SquareMatrix, Vector3, Vector4};
 use easy_gltf::{Camera, Projection};
 
 pub struct Ray {
@@ -15,24 +15,25 @@ pub fn construct_primary_rays(camera: &Camera,
     //TODO: ignoring aspect ratio here
     let (fovy, aspect_ratio) = match camera.projection {
         Projection::Perspective { yfov, aspect_ratio } => {
-            (yfov, aspect_ratio) }
+            (yfov, aspect_ratio)
+        }
         Projection::Orthographic { .. } => { panic!("Orthographic rendering not supported.") }
     };
 
     //ray origin in world space
     let origin_world_space = camera.position();
-    //dbg!(camera.transform);
+
+    //use a custom transform matrix because the one from easy_gltf is fucked
+    let transform_matrix = Matrix4::from_cols(
+        camera.right().extend(0.0),
+        -camera.up().extend(0.0),
+        -camera.forward().extend(0.0),
+        origin_world_space.extend(1.0),
+    );
 
     // the distance from the camera origin to the view plane
     let z: f32 = height as f32 / (2.0 * fovy.mul(0.5).tan());
 
-    //obtain the inverse transformation Matrix
-    let inverse_transform = camera.transform.invert().unwrap_or_else(||
-        panic!("Non invertible transform Matrix. giving up.")
-    );
-
-    dbg!(camera.transform);
-
     //TODO: take ray multiplier per pixel into account here
     let mut rays: Vec<Ray> = Vec::with_capacity(height * width);
 
@@ -41,7 +42,7 @@ pub fn construct_primary_rays(camera: &Camera,
     rays.push(generate_single_primary_ray(
         width,
         height,
-        &inverse_transform,
+        &transform_matrix,
         z,
         pixel_x_coord,
         pixel_y_coord,
@@ -52,7 +53,7 @@ pub fn construct_primary_rays(camera: &Camera,
 
 fn generate_single_primary_ray(image_width: usize,
                                image_height: usize,
-                               inverse_transform: &Matrix4<f32>,
+                               cam_to_world_transform: &Matrix4<f32>,
                                focal_length: f32,
                                u: usize,
                                v: usize,
@@ -63,9 +64,8 @@ fn generate_single_primary_ray(image_width: usize,
                      v as f32 - (image_height as f32 / 2.0),
                      focal_length,
                      0.0);
-    //TODO: Rotation is fucked
-    //x rotation has sign wrong, y and z are flipped
-    let direction_world_space = inverse_transform * direction_view_space.normalize();
+
+    let direction_world_space = cam_to_world_transform * direction_view_space.normalize();
 
     Ray { source: ray_origin, direction: direction_world_space.truncate().normalize() }
 }