Struct Camera

Source

pub struct Camera {
    pub position: Vec2,
    pub rotation: f32,
    pub zoom: f32,
    pub min_zoom: f32,
    pub max_zoom: f32,
    /* private fields */
}

Expand description

A 2D camera that controls the view transform.

By default, the camera is at the center of the screen looking “down” the Y axis (screen-space: +Y = down).

Fields§

§position: Vec2

World-space position (the “eye” point — center of the screen).

§rotation: f32

Rotation in radians.

§zoom: f32

Zoom level (1.0 = default, >1 = zoom in, <1 = zoom out).

§min_zoom: f32

Minimum zoom level.

§max_zoom: f32

Maximum zoom level.

Implementations§

Source §

impl Camera

Source

pub fn new(x: f32, y: f32) -> Self

Create a new camera at the given position.

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pub fn centered() -> Self

Create a camera centered at the origin.

Source

pub fn set_zoom(&mut self, zoom: f32)

Set the zoom level (clamped to min/max).

Examples found in repository ?

examples/basics.rs (line 99)

44    fn update(&mut self, ctx: &mut Context) {
45        let dt = ctx.time.delta() as f32;
46
47        // --- Ball physics ---
48        self.ball.velocity.y += 600.0 * dt; // Gravity
49        self.ball.position += self.ball.velocity * dt;
50
51        // Bounce off walls
52        let w = ctx.screen_width();
53        let h = ctx.screen_height();
54
55        if self.ball.position.x - self.ball.radius < 0.0 {
56            self.ball.position.x = self.ball.radius;
57            self.ball.velocity.x = self.ball.velocity.x.abs();
58        }
59        if self.ball.position.x + self.ball.radius > w {
60            self.ball.position.x = w - self.ball.radius;
61            self.ball.velocity.x = -self.ball.velocity.x.abs();
62        }
63        if self.ball.position.y - self.ball.radius < 0.0 {
64            self.ball.position.y = self.ball.radius;
65            self.ball.velocity.y = self.ball.velocity.y.abs();
66        }
67        if self.ball.position.y + self.ball.radius > h {
68            self.ball.position.y = h - self.ball.radius;
69            self.ball.velocity.y = -self.ball.velocity.y.abs() * 0.95; // Damping
70        }
71
72        // Update trail
73        self.ball.trail.push((self.ball.position, 1.0));
74        if self.ball.trail.len() > 60 {
75            self.ball.trail.remove(0);
76        }
77        for (_, alpha) in &mut self.ball.trail {
78            *alpha -= dt * 2.0;
79        }
80        self.ball.trail.retain(|(_, a)| *a > 0.0);
81
82        // --- Input ---
83        if ctx.input.is_action_pressed("shake") {
84            ctx.graphics.camera.shake(10.0, 0.3);
85        }
86
87        if ctx.input.mouse.is_pressed(MouseButton::Left) {
88            self.click_count += 1;
89            // Change ball color
90            self.hue = (self.hue + 30.0) % 360.0;
91            self.ball.color = Color::from_hsla(self.hue, 0.8, 0.6, 1.0);
92            // Boost ball toward click
93            let dir = ctx.input.mouse.position - self.ball.position;
94            self.ball.velocity += dir.normalize_or_zero() * 200.0;
95        }
96
97        // Zoom with scroll
98        let zoom = ctx.graphics.camera.zoom + ctx.input.mouse.scroll.y * 0.1;
99        ctx.graphics.camera.set_zoom(zoom);
100
101        // Escape to quit
102        if ctx.input.keyboard.is_pressed(KeyCode::Escape) {
103            ctx.quit();
104        }
105
106        // Update camera follow target
107        ctx.graphics.camera.follow(self.ball.position, 0.05);
108    }

Source

pub fn set_zoom_limits(&mut self, min: f32, max: f32)

Set zoom limits.

Source

pub fn follow(&mut self, target: Vec2, lerp_speed: f32)

Make the camera follow a target position with smooth lerp.

Examples found in repository ?

examples/basics.rs (line 41)

34    fn on_enter(&mut self, ctx: &mut Context) {
35        // Register input actions
36        let mut jump = InputAction::new("shake");
37        jump.bind_key(KeyCode::Space);
38        ctx.input.register_action(jump);
39
40        // Set up camera with follow
41        ctx.graphics.camera.follow(self.ball.position, 0.05);
42    }
43
44    fn update(&mut self, ctx: &mut Context) {
45        let dt = ctx.time.delta() as f32;
46
47        // --- Ball physics ---
48        self.ball.velocity.y += 600.0 * dt; // Gravity
49        self.ball.position += self.ball.velocity * dt;
50
51        // Bounce off walls
52        let w = ctx.screen_width();
53        let h = ctx.screen_height();
54
55        if self.ball.position.x - self.ball.radius < 0.0 {
56            self.ball.position.x = self.ball.radius;
57            self.ball.velocity.x = self.ball.velocity.x.abs();
58        }
59        if self.ball.position.x + self.ball.radius > w {
60            self.ball.position.x = w - self.ball.radius;
61            self.ball.velocity.x = -self.ball.velocity.x.abs();
62        }
63        if self.ball.position.y - self.ball.radius < 0.0 {
64            self.ball.position.y = self.ball.radius;
65            self.ball.velocity.y = self.ball.velocity.y.abs();
66        }
67        if self.ball.position.y + self.ball.radius > h {
68            self.ball.position.y = h - self.ball.radius;
69            self.ball.velocity.y = -self.ball.velocity.y.abs() * 0.95; // Damping
70        }
71
72        // Update trail
73        self.ball.trail.push((self.ball.position, 1.0));
74        if self.ball.trail.len() > 60 {
75            self.ball.trail.remove(0);
76        }
77        for (_, alpha) in &mut self.ball.trail {
78            *alpha -= dt * 2.0;
79        }
80        self.ball.trail.retain(|(_, a)| *a > 0.0);
81
82        // --- Input ---
83        if ctx.input.is_action_pressed("shake") {
84            ctx.graphics.camera.shake(10.0, 0.3);
85        }
86
87        if ctx.input.mouse.is_pressed(MouseButton::Left) {
88            self.click_count += 1;
89            // Change ball color
90            self.hue = (self.hue + 30.0) % 360.0;
91            self.ball.color = Color::from_hsla(self.hue, 0.8, 0.6, 1.0);
92            // Boost ball toward click
93            let dir = ctx.input.mouse.position - self.ball.position;
94            self.ball.velocity += dir.normalize_or_zero() * 200.0;
95        }
96
97        // Zoom with scroll
98        let zoom = ctx.graphics.camera.zoom + ctx.input.mouse.scroll.y * 0.1;
99        ctx.graphics.camera.set_zoom(zoom);
100
101        // Escape to quit
102        if ctx.input.keyboard.is_pressed(KeyCode::Escape) {
103            ctx.quit();
104        }
105
106        // Update camera follow target
107        ctx.graphics.camera.follow(self.ball.position, 0.05);
108    }

Source

pub fn set_follow_deadzone(&mut self, deadzone: f32)

Set the deadzone for follow (camera won’t move while target is within this distance).

Source

pub fn stop_following(&mut self)

Stop following.

Source

pub fn shake(&mut self, intensity: f32, duration: f32)

Trigger screen shake.

intensity — maximum pixel offset in each direction
duration — how long the shake lasts (seconds)

Examples found in repository ?

examples/basics.rs (line 84)

44    fn update(&mut self, ctx: &mut Context) {
45        let dt = ctx.time.delta() as f32;
46
47        // --- Ball physics ---
48        self.ball.velocity.y += 600.0 * dt; // Gravity
49        self.ball.position += self.ball.velocity * dt;
50
51        // Bounce off walls
52        let w = ctx.screen_width();
53        let h = ctx.screen_height();
54
55        if self.ball.position.x - self.ball.radius < 0.0 {
56            self.ball.position.x = self.ball.radius;
57            self.ball.velocity.x = self.ball.velocity.x.abs();
58        }
59        if self.ball.position.x + self.ball.radius > w {
60            self.ball.position.x = w - self.ball.radius;
61            self.ball.velocity.x = -self.ball.velocity.x.abs();
62        }
63        if self.ball.position.y - self.ball.radius < 0.0 {
64            self.ball.position.y = self.ball.radius;
65            self.ball.velocity.y = self.ball.velocity.y.abs();
66        }
67        if self.ball.position.y + self.ball.radius > h {
68            self.ball.position.y = h - self.ball.radius;
69            self.ball.velocity.y = -self.ball.velocity.y.abs() * 0.95; // Damping
70        }
71
72        // Update trail
73        self.ball.trail.push((self.ball.position, 1.0));
74        if self.ball.trail.len() > 60 {
75            self.ball.trail.remove(0);
76        }
77        for (_, alpha) in &mut self.ball.trail {
78            *alpha -= dt * 2.0;
79        }
80        self.ball.trail.retain(|(_, a)| *a > 0.0);
81
82        // --- Input ---
83        if ctx.input.is_action_pressed("shake") {
84            ctx.graphics.camera.shake(10.0, 0.3);
85        }
86
87        if ctx.input.mouse.is_pressed(MouseButton::Left) {
88            self.click_count += 1;
89            // Change ball color
90            self.hue = (self.hue + 30.0) % 360.0;
91            self.ball.color = Color::from_hsla(self.hue, 0.8, 0.6, 1.0);
92            // Boost ball toward click
93            let dir = ctx.input.mouse.position - self.ball.position;
94            self.ball.velocity += dir.normalize_or_zero() * 200.0;
95        }
96
97        // Zoom with scroll
98        let zoom = ctx.graphics.camera.zoom + ctx.input.mouse.scroll.y * 0.1;
99        ctx.graphics.camera.set_zoom(zoom);
100
101        // Escape to quit
102        if ctx.input.keyboard.is_pressed(KeyCode::Escape) {
103            ctx.quit();
104        }
105
106        // Update camera follow target
107        ctx.graphics.camera.follow(self.ball.position, 0.05);
108    }