Coordinate system

Murali uses a right-handed world-space coordinate system with the origin at the center of the screen.

Axes

• X — horizontal, positive to the right
• Y — vertical, positive upward
• Z — depth, positive toward the viewer

Scene frames

Every scene owns its logical composition frame. Landscape is the default:

let landscape = Scene::new();
let portrait = Scene::new().with_frame(Frame::portrait());
let square = Scene::new().with_frame(Frame::square());

The built-in frames have exact, symmetric world-space bounds:

Frame	Logical size	X bounds	Y bounds
Frame::landscape()	16:9	-8 to 8	-4.5 to 4.5
Frame::portrait()	9:16	-4.5 to 4.5	-8 to 8
Frame::square()	1:1	-8 to 8	-8 to 8

Coordinates retain their ordinary world-space meaning in every frame. Selecting portrait does not rearrange or scale scene content automatically; compose deliberately within its 9:16 bounds.

All sizes (font sizes, shape radii, line thickness) are in these world units. The scene frame initializes the camera before composition, so layout helpers such as to_edge use the selected aspect immediately.

For complete portrait, landscape, and square workflows, see Video Formats.

Camera

The camera uses orthographic projection by default. Moving the camera position does not change what's visible — only set_view_width does. For 2D scenes the Z position is irrelevant to the visible area:

scene.camera_mut().position = Vec3::new(0.0, 0.0, 10.0); // Z doesn't affect ortho bounds

For 3D scenes, you can orbit freely in the preview window.

Positioning tattvas

Positions are passed as Vec3 to add_tattva:

// Center of screen
scene.add_tattva(shape, Vec3::new(0.0, 0.0, 0.0));

// Upper left area
scene.add_tattva(shape, Vec3::new(-4.0, 2.5, 0.0));

Colors

Colors are Vec4 in linear RGBA, values from 0.0 to 1.0:

Vec4::new(r, g, b, a)

// White
Vec4::new(1.0, 1.0, 1.0, 1.0)

// Semi-transparent red
Vec4::new(1.0, 0.0, 0.0, 0.5)