Rotate view in example

engine/src/scene/general/camera.rs

@@ -1,11 +1,12 @@
 use crate::prelude::*;
 use utilities::prelude::cgmath::{
-    vec3, EuclideanSpace, InnerSpace, Matrix4, One, Point3, Rad, Vector3, Zero,
+    EuclideanSpace, InnerSpace, Matrix4, One, Point3, Rad, Vector3, Zero, vec3,
 };
 
 #[derive(Clone)]
 pub struct Camera {
     eye_offset: Vector3<f32>,
+    eye_dir: Vector3<f32>,
     center: Vector3<f32>,
     center_offset: Vector3<f32>,
     up_vector: Vector3<f32>,
@@ -15,6 +16,7 @@ pub struct Camera {
     eye_rotation: f32,
 
     view: Matrix4<f32>,
+    look_at: bool,
 
     update: bool,
 }
@@ -23,6 +25,7 @@ impl Camera {
     pub fn new(fov: f32) -> Camera {
         let mut me = Camera {
             eye_offset: Vector3::zero(),
+            eye_dir: Vector3::unit_y(),
             center: Vector3::zero(),
             center_offset: Vector3::zero(),
             up_vector: vec3(0.0, 0.0, 1.0),
@@ -32,6 +35,7 @@ impl Camera {
             eye_rotation: 0.0,
 
             view: Matrix4::one(),
+            look_at: true,
 
             update: true,
         };
@@ -41,6 +45,11 @@ impl Camera {
         me
     }
 
+    pub fn look_at(&mut self, look_at: bool) {
+        self.look_at = look_at;
+        self.update = true;
+    }
+
     pub fn set_fov(&mut self, fov: f32) {
         let fovy = fov.to_radians() / 2.0;
 
@@ -94,10 +103,15 @@ impl Camera {
     }
 
     // view matrix handling
-    pub fn eye_position(&self) -> Vector3<f32> {
+    fn eye_position(&self) -> Vector3<f32> {
         rotate_z(self.eye_offset, self.eye_rotation) + self.center + self.center_offset
     }
 
+    pub fn set_eye_dir(&mut self, eye_dir: Vector3<f32>) {
+        self.eye_dir = eye_dir;
+        self.update = true;
+    }
+
     pub fn view_matrix(&mut self) -> Matrix4<f32> {
         if self.update {
             self.calculate_view_matrix();
@@ -112,11 +126,19 @@ impl Camera {
 
     pub fn calculate_view_matrix(&mut self) {
         self.update = false;
-        self.view = Matrix4::look_at_rh(
+        self.view = if self.look_at {
+            Matrix4::look_at_rh(
                 Point3::from_vec(self.eye_position()),
                 Point3::from_vec(self.center + self.center_offset),
                 self.up_vector,
-        );
+            )
+        } else {
+            Matrix4::look_to_rh(
+                Point3::from_vec(self.center + self.center_offset),
+                self.eye_dir,
+                self.up_vector,
+            )
+        };
     }
 
     pub fn tan(&self) -> f32 {
@@ -140,6 +162,11 @@ impl Camera {
         self.up_vector
     }
 
+    pub fn set_up(&mut self, up: Vector3<f32>) {
+        self.up_vector = up;
+        self.update = true;
+    }
+
     // calculation helper
     pub fn add_rotation(&mut self, rotation: f32) {
         self.eye_rotation += rotation;

examples/simple_window/src/main.rs

@@ -1,9 +1,12 @@
-use std::path::Path;
+use std::{path::Path, time::Duration};
 
 use anyhow::Result;
 
 use ecs::*;
-use engine::prelude::{cgmath::vec3, *};
+use engine::prelude::{
+    cgmath::{Deg, Matrix3, Vector3, vec3},
+    *,
+};
 use skybox::SkyBox;
 
 fn main() -> Result<()> {
@@ -12,7 +15,7 @@ fn main() -> Result<()> {
     Engine::new::<GameState>(EngineCreateInfo::default(), &mut world_builder)?;
 
     world_builder.add_system(GameState::update);
-    world_builder.resources.insert(GameState::Startup);
+    world_builder.resources.insert(GameState::default());
 
     // let dir = Path::new("C:/Users/M.Huebner/Downloads/Space Skybox Generator/Export");
     let dir = Path::new("/home/michaelh/Sync/skybox");
@@ -32,13 +35,17 @@ fn main() -> Result<()> {
     let view = world_builder.resources.get_mut::<Scene>().view_mut();
     let camera = view.camera_mut();
 
-    camera.set_eye_offset(vec3(0.0, 1.0, 0.0));
+    camera.look_at(false);
+    camera.set_center(vec3(0.0, 0.0, 0.0));
+    camera.set_eye_dir(Vector3::unit_y());
     view.update_buffer()?;
 
     world_builder.build().run()
 }
 
+#[derive(Default)]
 enum GameState {
+    #[default]
     Startup,
     Loading,
     Menu,
@@ -47,8 +54,10 @@ enum GameState {
 
 impl GameState {
     fn update(world: &mut World) -> Result<bool> {
-        match world.resources.get_mut_unchecked::<Self>() {
-            GameState::Startup => (),
+        let me = world.resources.get_mut_unchecked::<Self>();
+
+        match me {
+            GameState::Startup => *me = GameState::Game(Game { start: world.now() }),
             GameState::Loading => (),
             GameState::Menu => (),
             GameState::Game(game) => game.update(world)?,
@@ -71,10 +80,24 @@ impl EventConsumer for GameState {
     }
 }
 
-struct Game {}
+struct Game {
+    start: Duration,
+}
 
 impl Game {
     fn update(&mut self, world: &mut World) -> Result<()> {
+        let now = world.now();
+        let view = world.resources.get_mut::<Scene>().view_mut();
+        let camera = view.camera_mut();
+
+        camera.set_eye_dir(
+            Matrix3::from_angle_z(Deg((now.as_secs_f32() - self.start.as_secs_f32())
+                * 36.0
+                * 2.0))
+                * Vector3::unit_y(),
+        );
+        view.update_buffer()?;
+
         Ok(())
     }