refactor projections into their own module

src/main.rs

@@ -9,6 +9,7 @@ use crate::scene::*;
 use crate::utils::*;
 use crate::viewer::*;
 
+
 use bevy::{prelude::*, window::PresentMode, render::camera::CameraProjectionPlugin};
 use offaxis::{offaxis_camera_setup, OffAxisProjection};
 
@@ -17,6 +18,7 @@ mod scene;
 mod screeninfo;
 mod utils;
 mod viewer;
+mod projection;
 
 fn main() {
     App::new()

src/offaxis.rs

@@ -7,6 +7,7 @@ use bevy::math::Mat4;
 
 use crate::screeninfo::ScreenInfo;
 use crate::viewer::*;
+use crate::projection::*;
 
 #[derive(Component, Debug, Clone, Reflect)]
 #[reflect(Component, Default)]
@@ -16,66 +17,10 @@ pub struct OffAxisProjection {
     aspect: f32,
 }
 
-
-pub fn make_projection_rh_from_frustum(left: f32, right: f32, bottom: f32, top: f32, near:f32, far:f32) -> Mat4
-{
-    // based on OpenSceneGraph / glFrustum implementation
-    let a = (right + left) / (right - left);
-    let b: f32 = (top + bottom) / (top - bottom);
-    let c= if far.abs() > f32::MAX  { -1.0 } else { -(far + near) / (far - near)};
-    let d = if far.abs() > f32::MAX { -2.0 * near } else { -2.0 * far * near / (far - near) };
-
-    Mat4::from_cols( 
-        Vec4::new(2.0 * near/(right-left),0.0,0.0,0.0), 
-        Vec4::new(0.0,2.0*near/(top-bottom), 0.0,0.0),
-        Vec4::new(a, b, c, -1.0),
-        Vec4::new(0.0, 0.0, d, 0.0))
-}
-
-
-pub fn make_projection_rh_from_frustum_reversed(left: f32, right: f32, bottom: f32, top: f32, near:f32, far:f32) -> Mat4
-{
-
-    assert!(near > 0.0);
-
-    //
-    // reversed z 0..1 projection based on https://thxforthefish.com/posts/reverse_z/
-    //
-    let a = (right + left) / (right - left);
-    let b: f32 = (top + bottom) / (top - bottom);
-    // let c= if far.abs() > f32::MAX  { -1.0 } else { -(far + near) / (far - near)};
-    // let d = if far.abs() > f32::MAX { -2.0 * near } else { -2.0 * far * near / (far - near) };
-
-    let c =  near / (far - near);
-    let d =  far * near / (far - near);
-
-
-    Mat4::from_cols( 
-        Vec4::new(2.0 * near/(right-left),0.0,0.0,0.0), 
-        Vec4::new(0.0,2.0*near/(top-bottom), 0.0,0.0),
-        Vec4::new(a, b, c, -1.0),
-        Vec4::new(0.0, 0.0, d, 0.0))
-}
-
-
-pub fn make_projection_rh_custom(fov_y: f32, aspect_ratio: f32, z_near: f32, z_far: f32) -> Mat4
-{
-    let tan_fovy = (fov_y * 0.5).tan(); // use half angle beta
-    let right = tan_fovy * aspect_ratio * z_near;
-    let left = -right;
-    let top = tan_fovy * z_near;
-    let bottom = -top;
-
-    //make_projection_rh_from_frustum(left, right, bottom, top, z_near, z_far)
-
-    make_projection_rh_from_frustum_reversed(left, right, bottom, top, z_near, z_far)
-}
-
-
-
 impl CameraProjection for OffAxisProjection {
     fn get_projection_matrix(&self) -> Mat4 {
 
+
         make_projection_rh_custom(45.0_f32.to_radians(), self.aspect, self.near, self.far)
 
         // Mat4::perspective_rh(45.0_f32.to_radians(), 
@@ -101,7 +46,7 @@ impl Default for OffAxisProjection {
         Self {
             near: 0.1,
             far: 1000.0,
-            aspect: 1.0,
+            aspect: 1.5,
         }
     }
 }
@@ -141,42 +86,3 @@ pub fn offaxis_camera_setup(mut commands: Commands) {
 }
 
 
-
-#[cfg(test)]
-mod tests {
-    use bevy::prelude::Mat4;
-
-    use super::make_projection_rh_from_frustum;
-
-
-    #[test]
-    fn compare_projections() {
-
-        // build an on-axis frustum
-        let fovy = 33.0_f32;
-        let aspect_ratio = 1.6666_f32;
-        let z_near = 1.0_f32;
-        let z_far = 500.0_f32;
-
-        let tan_fovy = (fovy * 0.5).to_radians().tan(); // use half angle beta
-        let right = tan_fovy * aspect_ratio * z_near;
-        let left = -right;
-        let top = tan_fovy * z_near;
-        let bottom = -top;
-
-        let mat_frust = make_projection_rh_from_frustum(left, right, bottom, top, z_near, z_far);
-
-        println!("mat 1 {:?}",mat_frust);
-
-        let mat_pers = Mat4::perspective_rh_gl(fovy.to_radians(),aspect_ratio,z_near,z_far);
-
-        println!("mat 2 {:?}",mat_pers);
-
-        assert!(mat_frust.abs_diff_eq(mat_pers, f32::EPSILON));
-
-    }
-
-
-
-
-}

src/projection.rs

@@ -0,0 +1,94 @@
+use bevy::prelude::*;
+use bevy::math::Mat4;
+
+/// creates a conventional projection matrix from frustum planes
+/// 
+/// returns a potentially off-axis projection matrix
+pub fn make_projection_rh_from_frustum(left: f32, right: f32, bottom: f32, top: f32, near:f32, far:f32) -> Mat4
+{
+    // based on OpenSceneGraph / glFrustum implementation
+    let a = (right + left) / (right - left);
+    let b: f32 = (top + bottom) / (top - bottom);
+    let c= if far.abs() > f32::MAX  { -1.0 } else { -(far + near) / (far - near)};
+    let d = if far.abs() > f32::MAX { -2.0 * near } else { -2.0 * far * near / (far - near) };
+
+    Mat4::from_cols( 
+        Vec4::new(2.0 * near / (right-left),0.0,0.0,0.0), 
+        Vec4::new(0.0, 2.0 *near / (top-bottom), 0.0,0.0),
+        Vec4::new(a, b, c, -1.0),
+        Vec4::new(0.0, 0.0, d, 0.0))
+}
+
+
+/// creates a projection from a frustum planes with a reversed depth mapped to [0..1]
+pub fn make_projection_rh_from_frustum_reversed(left: f32, right: f32, bottom: f32, top: f32, z_near:f32, z_far:f32) -> Mat4
+{
+    assert!(z_near > 0.0 && z_far > 0.0);
+
+    //
+    // reversed z 0..1 projection based on https://thxforthefish.com/posts/reverse_z/
+    //
+    let a = (right + left) / (right - left);
+    let b: f32 = (top + bottom) / (top - bottom);
+    
+    let c =  z_near / (z_far - z_near);
+    let d =  z_far * z_near / (z_far - z_near);
+
+
+    Mat4::from_cols( 
+        Vec4::new(2.0 * z_near / (right-left),0.0,0.0,0.0), 
+        Vec4::new(0.0, 2.0 * z_near / (top-bottom), 0.0,0.0),
+        Vec4::new(a, b, c, -1.0),
+        Vec4::new(0.0, 0.0, d, 0.0))
+}
+
+
+pub fn make_projection_rh_custom(fov_y: f32, aspect_ratio: f32, z_near: f32, z_far: f32) -> Mat4
+{
+    let tan_fovy = (fov_y * 0.5).tan(); // use half angle beta
+    let right = tan_fovy * aspect_ratio * z_near;
+    let left = -right;
+    let top = tan_fovy * z_near;
+    let bottom = -top;
+
+    //make_projection_rh_from_frustum(left, right, bottom, top, z_near, z_far)
+
+    make_projection_rh_from_frustum_reversed(left, right, bottom, top, z_near, z_far)
+}
+
+
+#[cfg(test)]
+mod tests {
+    use bevy::prelude::Mat4;
+
+    use super::make_projection_rh_from_frustum;
+
+
+    #[test]
+    fn compare_projections() {
+
+        // build an on-axis frustum
+        let fovy = 33.0_f32;
+        let aspect_ratio = 1.6666_f32;
+        let z_near = 1.0_f32;
+        let z_far = 1000.0_f32;
+
+        let tan_fovy = (fovy * 0.5).to_radians().tan(); // use half angle beta
+        let right = tan_fovy * aspect_ratio * z_near;
+        let left = -right;
+        let top = tan_fovy * z_near;
+        let bottom = -top;
+
+        let mat_frust = make_projection_rh_from_frustum(left, right, bottom, top, z_near, z_far);
+
+        println!("mat 1 {:?}",mat_frust);
+
+        let mat_pers = Mat4::perspective_rh_gl(fovy.to_radians(),aspect_ratio,z_near,z_far);
+
+        println!("mat 2 {:?}",mat_pers);
+
+        assert!(mat_frust.abs_diff_eq(mat_pers, f32::EPSILON));
+
+    }
+
+}    

src/scene.rs

@@ -33,7 +33,6 @@ fn generalized_projection_stereo(eyePos : Vec3)
 
 }
 
-
 fn generalized_projection (
     projectionScreen: ProjectionScreen,
     eyePos: Vec3,
@@ -100,77 +99,4 @@ pub fn build_scene(
         ..default()
     });
 
-
-    // camera
-
-    // let mut cam = Camera3dBundle {
-    //     transform: Transform::from_xyz(-2.0, 2.5, 5.0).looking_at(Vec3::ZERO, Vec3::Y),
-
-    //     ..default()
-    // };
-
-
-
-    // commands.spawn(cam);
-
-    // commands.spawn((Person, Position { x: 10.0, y: 10.0 }));
-    // commands.spawn()
-    // .insert(Person)
-    // .insert(Position { x: 10.0, y: 10.0 } );
-
-    // camera
-    // commands.spawn_bundle(OffAxisProjection {
-    //     transform: Transform::from_xyz(-2.0, 2.5, 5.0).looking_at(Vec3::ZERO, Vec3::Y),
-    //     ..default()
-    // });
 }
-
-
-
-// pub fn modify_frustum(mut query: Query<&Frustum>)
-// {
-//     let mut rng = rand::thread_rng();
-
-//     for mut q in query.iter() {
-
-//         for mut p in q.planes {
-
-//             println!("{:?}",p);
-
-//             let mut n = p.normal_d();
-
-//             n.w += rng.gen::<f32>();
-
-//             p = Plane::new(n);
-
-//             println!("{:?}",p);
-
-
-
-//             // p.normal_d() += rng.gen();
-//         }
-
-//         // println!("{:?}",q.frustum.planes.len()); 
-//     }
-// }
-
-
-// pub fn modify_projection(mut query: Query<&Projection>)
-// {
-//     let mut rng = rand::thread_rng();
-
-//     for mut q in query.iter() {
-        
-//         print!("{:?}",q);
-//     }
-// }
-
-// pub fn print_positions(query: Query<&Position>) {
-//     for _position in query.iter() {
-//         _ = 33;
-//         // println!("position {:?} {:?}", position.x, position.y)
-//     }
-// }
-
-// Problem with off-axis
-// projection 2401, 240

src/screeninfo.rs

@@ -1,5 +1,5 @@
 
-use bevy::{prelude::*, math::bool, render::primitives::Frustum};
+use bevy::{prelude::*, math::bool, prelude::shape::Quad };
 use rand::prelude::*;
 use bevy::render::primitives::Plane;
 
@@ -44,6 +44,19 @@ impl ScreenInfo {
         }
     }
 
+    pub fn build_debug_geometry(&self,
+        mut commands: Commands,
+        mut meshes: ResMut<Assets<Mesh>>,
+        mut materials: ResMut<Assets<StandardMaterial>>,
+        )
+    {
+            // plane
+        commands.spawn(PbrBundle {
+        mesh: meshes.add(Mesh::from( Quad { size: Vec2 { x: self.width, y: self.height }, flip:false })),
+        material: materials.add(Color::rgb(0.3, 0.5, 0.3).into()),
+        ..default()
+        });
+    }
 
     pub fn update(&mut self) -> &mut Self {
         

src/viewer.rs

@@ -1,4 +1,6 @@
 use bevy::{prelude::*, window::PresentMode, render::camera::CameraProjectionPlugin};
+
+use crate::screeninfo::ScreenInfo;
 // use offaxis::{offaxis_camera_setup, OffAxisProjection};
 
 
@@ -36,10 +38,17 @@ pub fn simulate_viewer(mut query: Query<&mut Viewer>)
         //v.position += Vec3::Y * 0.005;
         v.alpha += 0.01;
         let radius = 1.5;
-        v.position = Vec3::new(v.alpha.sin()*radius,v.alpha.cos()*radius + 1.0_f32,15.0);
+
+        let z_distance = 8.0_f32;
+
+        v.position = Vec3::new(v.alpha.sin()*radius,v.alpha.cos()*radius + 1.0_f32,z_distance);
 
         let vm = Mat4::look_at_rh(v.position, Vec3::ZERO, Vec3::Y);
 
+
+
+
+
         println!("{:?}",vm);
 
         // view matrices should be orientation only