pub const ZOOM_MIN: f32 = 200.0;
pub const ZOOM_MAX: f32 = 2000.0;

/// Z-axis range for starfield stars
/// This does not affect scale.
pub const STARFIELD_Z_MIN: f32 = 100.0;
pub const STARFIELD_Z_MAX: f32 = 200.0;

/// Size range for starfield stars, in game units.
/// This is scaled for zoom, but NOT for distance.
pub const STARFIELD_SIZE_MIN: f32 = 0.2;
pub const STARFIELD_SIZE_MAX: f32 = 1.8;

/// Size of a square starfield tile, in game units.
/// A tile of size STARFIELD_Z_MAX * screen-size-in-game-units
/// will completely cover a (square) screen. This depends on zoom!
///
/// Use a value smaller than zoom_max for debug.
pub const STARFIELD_SIZE: u64 = STARFIELD_Z_MAX as u64 * ZOOM_MAX as u64;

/// Average number of stars per game unit
pub const STARFIELD_DENSITY: f64 = 0.01;

/// Number of stars in one starfield tile
/// Must fit inside an i32
pub const STARFIELD_COUNT: u64 = (STARFIELD_SIZE as f64 * STARFIELD_DENSITY) as u64;

/// Name of starfield texture
pub const STARFIELD_TEXTURE_NAME: &'static str = "starfield";

/// Root directory of game content
pub const CONTENT_ROOT: &'static str = "./content";

/// Root directory of game textures
pub const TEXTURE_ROOT: &'static str = "./assets/render";

// We can draw at most this many sprites on the screen.
// TODO: compile-time option or config file
pub const SPRITE_INSTANCE_LIMIT: u64 = 500;

// Must be small enough to fit in an i32
pub const STARFIELD_INSTANCE_LIMIT: u64 = STARFIELD_COUNT * 24;