update projection matrices

src/projection.rs

@@ -29,8 +29,8 @@ pub fn make_projection_rh_from_frustum(
     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, c, -1.0),
-        Vec4::new(0.0, 0.0, d, 0.0),
+        Vec4::new(a, b, d, 0.0),
     )
 }
 
@@ -48,18 +48,22 @@ pub fn make_projection_rh_from_frustum_reversed(
     info!("near {:?}", z_near);
 
     //
-    // reversed z 0..1 projection based on https://thxforthefish.com/posts/reverse_z/
+    // reversed z 0..1 projection based on https://thxforthefish.com/posts/reverse_z/ and
+    // https://vincent-p.github.io/posts/vulkan_perspective_matrix/
     //
-    let a = (right + left) / (right - left);
-    let b = (top + bottom) / (top - bottom);
 
-    let c = z_near / (z_far - z_near);
-    let d = z_far * z_near / (z_far - z_near);
 
-    let sx = 2.0 * z_near / (right - left);
+    let a = (right + left) / (right - left); // position in frame horizontal
-    let sy = 2.0 * z_near / (top - bottom);
+    let b = (top + bottom) / (top - bottom); // position in frame vertical
 
-    // for reverse z 0..1
+    let c = z_near / (z_far - z_near); // lower bound
+    let d = z_far * z_near / (z_far - z_near); // upper bound
+
+    let sx = 2.0 * z_near / (right - left); // scale x
+    let sy = 2.0 * z_near / (top - bottom); // scale y
+
+    // reverse z 0..1
+    // --------------
     // sx   0   a   0
     // 0    sy  b   0
     // 0    0   c   d
@@ -68,8 +72,8 @@ pub fn make_projection_rh_from_frustum_reversed(
     Mat4::from_cols(
         Vec4::new(sx,   0.0,    0.0,    0.0),
         Vec4::new(0.0,  sy,     0.0,    0.0),
-        Vec4::new(0.0, 0.0, c, -1.0),
+        Vec4::new(a,    b,      c,     -1.0),
-        Vec4::new(a, b, d, 0.0),
+        Vec4::new(0.0,  0.0,    d,      0.0),
     )
 }
 
@@ -166,7 +170,8 @@ pub fn create_offaxis_matrices(
     let view_matrix_eye = Mat4::from_cols(Vec4::X, Vec4::Y, Vec4::Z, (-pos_eye).extend(1.0));
 
     // create resulting view matrix (this should be much simpler using glam API)
-    let view_matrix = view_matrix_rotation * view_matrix_eye;
+    let view_matrix = view_matrix_eye * view_matrix_rotation;
+        //view_matrix_rotation * view_matrix_eye;
 
     // info!("{:?}",view_matrix_eye);
 

src/scene.rs

@@ -7,7 +7,7 @@ pub fn build_scene(
 ) {
     // plane
     commands.spawn(PbrBundle {
-        mesh: meshes.add(Mesh::from(shape::Plane { size: 4.0 })),
+        mesh: meshes.add(Mesh::from(shape::Plane { size: 2.5 })),
         material: materials.add(Color::rgb(0.3, 0.5, 0.3).into()),
         transform: Transform::from_xyz(0.0, -0.5, 0.0),
         ..default()
@@ -16,7 +16,7 @@ pub fn build_scene(
     commands.spawn(PbrBundle {
         mesh: meshes.add(Mesh::from(shape::Cube { size: 1.5 })),
         material: materials.add(Color::rgb(0.8, 0.7, 0.6).into()),
-        transform: Transform::from_xyz(0.0, 0.5, -3.0),
+        transform: Transform::from_xyz(0.0, 0.5, -1.5),
         ..default()
     });
     // light
@@ -26,7 +26,7 @@ pub fn build_scene(
             shadows_enabled: true,
             ..default()
         },
-        transform: Transform::from_xyz(4.0, 1.0, -4.0),
+        transform: Transform::from_xyz(4.0, 4.0, -1.5),
         ..default()
     });
 }

src/viewer.rs

@@ -87,7 +87,7 @@ pub fn simulate_viewer_with_keyboard(
     for mut viewer in query.iter_mut() {
         if input.pressed(KeyCode::W) {
             viewer.position += Vec3::Z * time.delta_seconds();
-        } else if (input.pressed(KeyCode::S)) {
+        } else if input.pressed(KeyCode::S) {
             viewer.position -= Vec3::Z * time.delta_seconds();
         } else if input.pressed(KeyCode::A) {
             viewer.position -= Vec3::X * time.delta_seconds();