earth

Show a rotating 3D textured earth. Renders the sphere with lookup-table-based trigonometry (fasin/fatan2) and supports mouse and touch interaction. Falls back to a built-in 1024×512 JPEG earth texture when no texture is given.

Usage

earth [texture] [-f=framebuffer] [-i=input]

Options

Option	Description
texture	Optional earth texture file (equirectangular projection); uses the built-in texture when omitted
-f=<fb>	Target framebuffer device
-i=<input>	Input device

Notes

• The texture is loaded from XFS; a file that resolves but fails to load now reports an error and exits instead of silently falling back to the built-in image
• Auto-rotates horizontally by default, roughly one revolution per 120 seconds
• Supports mouse drag to rotate and wheel to zoom
• Supports single-touch drag to rotate and two-finger pinch to zoom
• Zoom is clamped to 0.2 ~ 5.0×
• Latitude rotation is clamped to ±90°
• Refreshes at roughly 60 FPS, press Ctrl-C to exit

Examples

# Use the built-in texture
earth

# Specify framebuffer and input device
earth -f=fb.0 -i=input.0

# Use a custom texture
earth earth_texture.jpg