Camera

Murali's camera is pure state — no input handling, no magic. It owns a position, a target, and a projection mode. The scene owns the camera.

scene.camera_mut().position = Vec3::new(0.0, 0.0, 10.0);

Projection modes

Orthographic (default)

The default for 2D math scenes. Objects don't shrink with distance — only view_width controls how much of the world is visible.

use murali::engine::camera::{Camera, Projection};

scene.camera_mut().projection = Projection::Orthographic {
    width: 16.0,   // visible world units horizontally
    height: 9.0,   // visible world units vertically
    near: -100.0,
    far: 100.0,
};

The default is width: 16.0, height: 9.0 — giving a canonical [-8, 8] × [-4.5, 4.5] world space. Moving the camera position in orthographic mode does not change what's visible. Use set_view_width instead.

Perspective

For 3D scenes where depth perception matters.

scene.camera_mut().projection = Projection::Perspective {
    fov_y_rad: std::f32::consts::FRAC_PI_4, // 45°
    aspect: 16.0 / 9.0,
    near: 0.1,
    far: 1000.0,
};

Controlling the viewport (orthographic)

set_view_width — the ground truth

Controls how much of the world is visible horizontally. Height is derived automatically to maintain 16:9.

scene.camera_mut().set_view_width(8.0);  // zoom in — less world visible, objects appear larger
scene.camera_mut().set_view_width(24.0); // zoom out — more world visible, objects appear smaller

view_width — the getter

let w = scene.camera().view_width(); // 16.0 by default

Useful for relative adjustments:

// Zoom in to half the current view
scene.camera_mut().set_view_width(scene.camera().view_width() * 0.5);

zoom_in / zoom_out

Convenience wrappers around set_view_width. The factor describes how much larger or smaller objects appear.

scene.camera_mut().zoom_in(2.0);  // objects appear 2× bigger  (width /= 2)
scene.camera_mut().zoom_out(2.0); // objects appear 2× smaller (width *= 2)

Positioning the camera

scene.camera_mut().position = Vec3::new(0.0, 0.0, 10.0); // standard 2D setup
scene.camera_mut().target   = Vec3::ZERO;                 // look at origin
scene.camera_mut().up       = Vec3::Y;                    // Y is up

For 2D scenes, keep position.z positive and target at the origin. The Z value doesn't affect orthographic rendering but is needed for the view matrix.

For 3D scenes, orbit freely — the preview window's orbit controller handles mouse drag automatically.

Animating the camera

Camera animations go through the timeline like any other animation:

timeline
    .animate_camera()
    .at(0.0)
    .for_duration(2.0)
    .ease(Ease::InOutQuad)
    .move_to(Vec3::new(2.0, 1.0, 10.0))
    .spawn();

Available camera animation kinds:

Method	Effect
.move_to(Vec3)	Animate camera position
.look_at(Vec3)	Animate camera target
.frame_to(position, target)	Animate both position and target together
.zoom_to(width)	Animate orthographic view width
.fov_to(radians)	Animate perspective field of view

Example — zoom in over 2 seconds:

timeline
    .animate_camera()
    .at(1.0)
    .for_duration(2.0)
    .ease(Ease::InOutCubic)
    .zoom_to(8.0)  // from default 16.0 → 8.0
    .spawn();

Preview controls

When running in preview mode, the camera is controlled by mouse input:

Action	Effect
Left drag	Orbit (3D)
Scroll	Zoom
Right drag	Pan