From 7a5ea75e1fb2bd699fe47381c880410709b9a945 Mon Sep 17 00:00:00 2001
From: gered <gered@blarg.ca>
Date: Sat, 1 Apr 2023 18:45:58 -0400
Subject: [PATCH] add color-component-to/from-packed functions for normalized
 components

---
 ggdt/src/graphics/color.rs | 64 ++++++++++++++++++++++++++++++++++++++
 1 file changed, 64 insertions(+)

diff --git a/ggdt/src/graphics/color.rs b/ggdt/src/graphics/color.rs
index 8c9aabf..dd81380 100644
--- a/ggdt/src/graphics/color.rs
+++ b/ggdt/src/graphics/color.rs
@@ -65,6 +65,24 @@ pub fn to_argb32(a: u8, r: u8, g: u8, b: u8) -> u32 {
 	(b as u32) + ((g as u32) << 8) + ((r as u32) << 16) + ((a as u32) << 24)
 }
 
+/// Converts a set of individual ARGB normalized components to a combined 32-bit color value,
+/// packed into the format 0xAARRGGBB.
+///
+/// # Arguments
+///
+/// * `a`: the normalized alpha component (0.0 to 1.0)
+/// * `r`: the normalized red component (0.0 to 1.0)
+/// * `g`: the normalized green component (0.0 to 1.0)
+/// * `b`: the normalized blue component (0.0 to 1.0)
+///
+/// returns: the u32 packed color
+pub fn to_argb32_normalized(a: f32, r: f32, g: f32, b: f32) -> u32 {
+	(((b * 255.0) as u32) & 0xff)
+		+ ((((g * 255.0) as u32) & 0xff) << 8)
+		+ ((((r * 255.0) as u32) & 0xff) << 16)
+		+ ((((a * 255.0) as u32) & 0xff) << 24)
+}
+
 /// Extracts the individual ARGB components out of a combined 32-bit color value which is in the
 /// format 0xAARRGGBB
 ///
@@ -82,6 +100,22 @@ pub fn from_argb32(argb: u32) -> (u8, u8, u8, u8) {
 	(a, r, g, b)
 }
 
+/// Extracts the individual ARGB normalized components out of a combined 32-bit color value which
+/// is in the format 0xAARRGGBB
+///
+/// # Arguments
+///
+/// * `argb`: the 32-bit packed color
+///
+/// returns: the individual ARGB normalized color components (0.0 to 1.0 each) in order: alpha, red, green, blue
+pub fn from_argb32_normalized(argb: u32) -> (f32, f32, f32, f32) {
+	let a = ((argb & 0xff000000) >> 24) as f32 / 255.0;
+	let r = ((argb & 0x00ff0000) >> 16) as f32 / 255.0;
+	let g = ((argb & 0x0000ff00) >> 8) as f32 / 255.0;
+	let b = (argb & 0x000000ff) as f32 / 255.0;
+	(a, r, g, b)
+}
+
 /// Converts a set of individual RGB components to a combined 32-bit color value, packed into
 /// the format 0xAARRGGBB. Substitutes a value of 255 for the missing alpha component.
 ///
@@ -97,6 +131,20 @@ pub fn to_rgb32(r: u8, g: u8, b: u8) -> u32 {
 	to_argb32(255, r, g, b)
 }
 
+/// Converts a set of individual RGB normalized components to a combined 32-bit color value, packed
+/// into the format 0xAARRGGBB. Substitutes a value of 1.0 for the missing alpha component.
+///
+/// # Arguments
+///
+/// * `r`: the normalized red component (0.0 to 1.0)
+/// * `g`: the normalized green component (0.0 to 1.0)
+/// * `b`: the normalized blue component (0.0 to 1.0)
+///
+/// returns: the u32 packed color
+pub fn to_rgb32_normalized(r: f32, g: f32, b: f32) -> u32 {
+	to_argb32_normalized(1.0, r, g, b)
+}
+
 /// Extracts the individual RGB components out of a combined 32-bit color value which is in the
 /// format 0xAARRGGBB. Ignores the alpha component.
 ///
@@ -114,6 +162,22 @@ pub fn from_rgb32(rgb: u32) -> (u8, u8, u8) {
 	(r, g, b)
 }
 
+/// Extracts the individual RGB normalized components out of a combined 32-bit color value which
+/// is in the format 0xAARRGGBB. Ignores the alpha component.
+///
+/// # Arguments
+///
+/// * `argb`: the 32-bit packed color
+///
+/// returns: the individual ARGB normalized color components (0.0 to 1.0 each) in order: red, green, blue
+pub fn from_rgb32_normalized(rgb: u32) -> (f32, f32, f32) {
+	// ignore alpha component at 0xff000000 ...
+	let r = ((rgb & 0x00ff0000) >> 16) as f32 / 255.0;
+	let g = ((rgb & 0x0000ff00) >> 8) as f32 / 255.0;
+	let b = (rgb & 0x000000ff) as f32 / 255.0;
+	(r, g, b)
+}
+
 /// Blends two color components together using a "strength" factor to control how much of the source
 /// color versus destination color is represented in the result. This is using the formula:
 /// `(source * strength) + (dest * (1 - strength))`