//! The 16-color EGA palette MRPGI inherits from the original AGI.
//!
//! Everything in the engine works in palette *indices* (0..=15); we only
//! convert to real RGBA at the very last moment, when we hand pixels to the GPU.

use macroquad::prelude::Color;

/// Standard IBM EGA / CGA 16-color palette, as (R, G, B).
pub const EGA: [(u8, u8, u8); 16] = [
    (0x00, 0x00, 0x00), // 0  black
    (0x00, 0x00, 0xAA), // 1  blue
    (0x00, 0xAA, 0x00), // 2  green
    (0x00, 0xAA, 0xAA), // 3  cyan
    (0xAA, 0x00, 0x00), // 4  red
    (0xAA, 0x00, 0xAA), // 5  magenta
    (0xAA, 0x55, 0x00), // 6  brown
    (0xAA, 0xAA, 0xAA), // 7  light gray
    (0x55, 0x55, 0x55), // 8  dark gray
    (0x55, 0x55, 0xFF), // 9  light blue
    (0x55, 0xFF, 0x55), // 10 light green
    (0x55, 0xFF, 0xFF), // 11 light cyan
    (0xFF, 0x55, 0x55), // 12 light red
    (0xFF, 0x55, 0xFF), // 13 light magenta
    (0xFF, 0xFF, 0x55), // 14 yellow
    (0xFF, 0xFF, 0xFF), // 15 white
];

/// Raw RGBA bytes for a palette index (for writing straight into an Image).
#[inline]
pub fn rgba(idx: u8) -> [u8; 4] {
    let (r, g, b) = EGA[(idx & 0x0F) as usize];
    [r, g, b, 255]
}

/// macroquad `Color` for a palette index (for `draw_*` calls).
#[inline]
pub fn color(idx: u8) -> Color {
    let (r, g, b) = EGA[(idx & 0x0F) as usize];
    Color::new(r as f32 / 255.0, g as f32 / 255.0, b as f32 / 255.0, 1.0)
}