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

Aspect ratio

Murali uses a canonical 16:9 coordinate system. The default visible world space is:

• X: -8 to 8
• Y: -4.5 to 4.5

This is exact and symmetric — not derived or approximate. x = 4 is exactly one quarter of the screen width. x = 8 is the right edge.

All sizes (font sizes, shape radii, line thickness) are in these world units. The camera is the single source of truth for these bounds — layout helpers like to_edge derive from it automatically.

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)