gpu invert node demo

node-graph/gcore-shader/src/color.rs

@@ -0,0 +1,782 @@
+use bytemuck::{Pod, Zeroable};
+use core::hash::Hash;
+use glam::Vec4;
+#[cfg(target_arch = "spirv")]
+use spirv_std::num_traits::Euclid;
+#[cfg(target_arch = "spirv")]
+use spirv_std::num_traits::float::Float;
+
+// -----------------------------------------------------
+// custom color start
+// -----------------------------------------------------
+
+impl From<Vec4> for Color {
+	fn from(value: Vec4) -> Self {
+		Color {
+			red: value.x,
+			green: value.y,
+			blue: value.z,
+			alpha: value.w,
+		}
+	}
+}
+
+impl From<Color> for Vec4 {
+	fn from(value: Color) -> Self {
+		Vec4::new(value.red, value.green, value.blue, value.alpha)
+	}
+}
+
+// -----------------------------------------------------
+// custom color end
+// -----------------------------------------------------
+
+#[repr(C)]
+#[derive(Debug, Default, Clone, Copy, PartialEq, Pod, Zeroable)]
+pub struct SRGBA8 {
+	red: u8,
+	green: u8,
+	blue: u8,
+	alpha: u8,
+}
+
+#[repr(C)]
+#[derive(Debug, Default, Clone, Copy, PartialEq, Pod, Zeroable)]
+pub struct Luma(pub f32);
+
+/// Structure that represents a color.
+/// Internally alpha is stored as `f32` that ranges from `0.0` (transparent) to `1.0` (opaque).
+/// The other components (RGB) are stored as `f32` that range from `0.0` up to `f32::MAX`,
+/// the values encode the brightness of each channel proportional to the light intensity in cd/m² (nits) in HDR, and `0.0` (black) to `1.0` (white) in SDR color.
+#[repr(C)]
+#[derive(Debug, Default, Clone, Copy, PartialEq, Pod, Zeroable)]
+pub struct Color {
+	red: f32,
+	green: f32,
+	blue: f32,
+	alpha: f32,
+}
+
+#[allow(clippy::derived_hash_with_manual_eq)]
+impl Hash for Color {
+	fn hash<H: core::hash::Hasher>(&self, state: &mut H) {
+		self.red.to_bits().hash(state);
+		self.green.to_bits().hash(state);
+		self.blue.to_bits().hash(state);
+		self.alpha.to_bits().hash(state);
+	}
+}
+
+impl Color {
+	pub const BLACK: Color = Color::from_rgbf32_unchecked(0., 0., 0.);
+	pub const WHITE: Color = Color::from_rgbf32_unchecked(1., 1., 1.);
+	pub const RED: Color = Color::from_rgbf32_unchecked(1., 0., 0.);
+	pub const GREEN: Color = Color::from_rgbf32_unchecked(0., 1., 0.);
+	pub const BLUE: Color = Color::from_rgbf32_unchecked(0., 0., 1.);
+	pub const YELLOW: Color = Color::from_rgbf32_unchecked(1., 1., 0.);
+	pub const CYAN: Color = Color::from_rgbf32_unchecked(0., 1., 1.);
+	pub const MAGENTA: Color = Color::from_rgbf32_unchecked(1., 0., 1.);
+	pub const TRANSPARENT: Color = Self {
+		red: 0.,
+		green: 0.,
+		blue: 0.,
+		alpha: 0.,
+	};
+
+	/// Returns `Some(Color)` if `red`, `green`, `blue` and `alpha` have a valid value. Negative numbers (including `-0.0`), NaN, and infinity are not valid values and return `None`.
+	/// Alpha values greater than `1.0` are not valid.
+	///
+	/// # Examples
+	/// ```
+	/// use graphene_core::raster::color::Color;
+	/// let color = Color::from_rgbaf32(0.3, 0.14, 0.15, 0.92).unwrap();
+	/// assert!(color.components() == (0.3, 0.14, 0.15, 0.92));
+	///
+	/// let color = Color::from_rgbaf32(1., 1., 1., f32::NAN);
+	/// assert!(color == None);
+	/// ```
+	#[inline(always)]
+	pub fn from_rgbaf32(red: f32, green: f32, blue: f32, alpha: f32) -> Option<Color> {
+		if alpha > 1. || [red, green, blue, alpha].iter().any(|c| c.is_sign_negative() || !c.is_finite()) {
+			return None;
+		}
+		let color = Color { red, green, blue, alpha };
+		Some(color)
+	}
+
+	/// Return an opaque `Color` from given `f32` RGB channels.
+	#[inline(always)]
+	pub const fn from_rgbf32_unchecked(red: f32, green: f32, blue: f32) -> Color {
+		Color { red, green, blue, alpha: 1. }
+	}
+
+	/// Return an opaque `Color` from given `f32` RGB channels.
+	#[inline(always)]
+	pub const fn from_rgbaf32_unchecked(red: f32, green: f32, blue: f32, alpha: f32) -> Color {
+		Color { red, green, blue, alpha }
+	}
+
+	/// Return an opaque `Color` from given `f32` RGB channels.
+	#[inline(always)]
+	pub fn from_unassociated_alpha(red: f32, green: f32, blue: f32, alpha: f32) -> Color {
+		Color::from_rgbaf32_unchecked(red * alpha, green * alpha, blue * alpha, alpha)
+	}
+
+	/// Return an opaque SDR `Color` given RGB channels from `0` to `255`, premultiplied by alpha.
+	///
+	/// # Examples
+	/// ```
+	/// use graphene_core::raster::color::Color;
+	/// let color = Color::from_rgb8_srgb(0x72, 0x67, 0x62);
+	/// let color2 = Color::from_rgba8_srgb(0x72, 0x67, 0x62, 0xFF);
+	/// assert_eq!(color, color2)
+	/// ```
+	#[inline(always)]
+	pub fn from_rgb8_srgb(red: u8, green: u8, blue: u8) -> Color {
+		Color::from_rgba8_srgb(red, green, blue, 255)
+	}
+
+	// TODO: Should this be premult?
+	/// Return an SDR `Color` given RGBA channels from `0` to `255`, premultiplied by alpha.
+	///
+	/// # Examples
+	/// ```
+	/// use graphene_core::raster::color::Color;
+	/// let color = Color::from_rgba8_srgb(0x72, 0x67, 0x62, 0x61);
+	/// ```
+	#[inline(always)]
+	pub fn from_rgba8_srgb(red: u8, green: u8, blue: u8, alpha: u8) -> Color {
+		let map_range = |int_color| int_color as f32 / 255.;
+
+		let red = map_range(red);
+		let green = map_range(green);
+		let blue = map_range(blue);
+		let alpha = map_range(alpha);
+		Color { red, green, blue, alpha }.to_linear_srgb().map_rgb(|channel| channel * alpha)
+	}
+
+	/// Create a [Color] from a hue, saturation, lightness and alpha (all between 0 and 1)
+	///
+	/// # Examples
+	/// ```
+	/// use graphene_core::raster::color::Color;
+	/// let color = Color::from_hsla(0.5, 0.2, 0.3, 1.);
+	/// ```
+	pub fn from_hsla(hue: f32, saturation: f32, lightness: f32, alpha: f32) -> Color {
+		let temp1 = if lightness < 0.5 {
+			lightness * (saturation + 1.)
+		} else {
+			lightness + saturation - lightness * saturation
+		};
+		let temp2 = 2. * lightness - temp1;
+		#[cfg(not(target_arch = "spirv"))]
+		let rem = |x: f32| x.rem_euclid(1.);
+		#[cfg(target_arch = "spirv")]
+		let rem = |x: f32| x.rem_euclid(&1.);
+
+		let mut red = rem(hue + 1. / 3.);
+		let mut green = rem(hue);
+		let mut blue = rem(hue - 1. / 3.);
+
+		fn map_channel(channel: &mut f32, temp2: f32, temp1: f32) {
+			*channel = if *channel * 6. < 1. {
+				temp2 + (temp1 - temp2) * 6. * *channel
+			} else if *channel * 2. < 1. {
+				temp1
+			} else if *channel * 3. < 2. {
+				temp2 + (temp1 - temp2) * (2. / 3. - *channel) * 6.
+			} else {
+				temp2
+			}
+			.clamp(0., 1.);
+		}
+		map_channel(&mut red, temp2, temp1);
+		map_channel(&mut green, temp2, temp1);
+		map_channel(&mut blue, temp2, temp1);
+
+		Color { red, green, blue, alpha }
+	}
+
+	/// Return the `red` component.
+	///
+	/// # Examples
+	/// ```
+	/// use graphene_core::raster::color::Color;
+	/// let color = Color::from_rgbaf32(0.114, 0.103, 0.98, 0.97).unwrap();
+	/// assert!(color.r() == 0.114);
+	/// ```
+	#[inline(always)]
+	pub fn r(&self) -> f32 {
+		self.red
+	}
+
+	/// Return the `green` component.
+	///
+	/// # Examples
+	/// ```
+	/// use graphene_core::raster::color::Color;
+	/// let color = Color::from_rgbaf32(0.114, 0.103, 0.98, 0.97).unwrap();
+	/// assert!(color.g() == 0.103);
+	/// ```
+	#[inline(always)]
+	pub fn g(&self) -> f32 {
+		self.green
+	}
+
+	/// Return the `blue` component.
+	///
+	/// # Examples
+	/// ```
+	/// use graphene_core::raster::color::Color;
+	/// let color = Color::from_rgbaf32(0.114, 0.103, 0.98, 0.97).unwrap();
+	/// assert!(color.b() == 0.98);
+	/// ```
+	#[inline(always)]
+	pub fn b(&self) -> f32 {
+		self.blue
+	}
+
+	/// Return the `alpha` component without checking its expected `0.0` to `1.0` range.
+	///
+	/// # Examples
+	/// ```
+	/// use graphene_core::raster::color::Color;
+	/// let color = Color::from_rgbaf32(0.114, 0.103, 0.98, 0.97).unwrap();
+	/// assert!(color.a() == 0.97);
+	/// ```
+	#[inline(always)]
+	pub fn a(&self) -> f32 {
+		self.alpha
+	}
+
+	#[inline(always)]
+	pub fn average_rgb_channels(&self) -> f32 {
+		(self.red + self.green + self.blue) / 3.
+	}
+
+	#[inline(always)]
+	pub fn minimum_rgb_channels(&self) -> f32 {
+		self.red.min(self.green).min(self.blue)
+	}
+
+	#[inline(always)]
+	pub fn maximum_rgb_channels(&self) -> f32 {
+		self.red.max(self.green).max(self.blue)
+	}
+
+	// From https://stackoverflow.com/a/56678483/775283
+	#[inline(always)]
+	pub fn luminance_srgb(&self) -> f32 {
+		0.2126 * self.red + 0.7152 * self.green + 0.0722 * self.blue
+	}
+
+	// From https://en.wikipedia.org/wiki/Luma_(video)#Rec._601_luma_versus_Rec._709_luma_coefficients
+	#[inline(always)]
+	pub fn luminance_rec_601(&self) -> f32 {
+		0.299 * self.red + 0.587 * self.green + 0.114 * self.blue
+	}
+
+	// From https://en.wikipedia.org/wiki/Luma_(video)#Rec._601_luma_versus_Rec._709_luma_coefficients
+	#[inline(always)]
+	pub fn luminance_rec_601_rounded(&self) -> f32 {
+		0.3 * self.red + 0.59 * self.green + 0.11 * self.blue
+	}
+
+	// From https://stackoverflow.com/a/56678483/775283
+	#[inline(always)]
+	pub fn luminance_perceptual(&self) -> f32 {
+		let luminance = self.luminance_srgb();
+
+		if luminance <= 0.008856 {
+			(luminance * 903.3) / 100.
+		} else {
+			(luminance.cbrt() * 116. - 16.) / 100.
+		}
+	}
+
+	#[inline(always)]
+	pub fn from_luminance(luminance: f32) -> Color {
+		Color {
+			red: luminance,
+			green: luminance,
+			blue: luminance,
+			alpha: 1.,
+		}
+	}
+
+	#[inline(always)]
+	pub fn with_luminance(&self, luminance: f32) -> Color {
+		let delta = luminance - self.luminance_rec_601_rounded();
+		self.map_rgb(|c| (c + delta).clamp(0., 1.))
+	}
+
+	#[inline(always)]
+	pub fn saturation(&self) -> f32 {
+		let max = (self.red).max(self.green).max(self.blue);
+		let min = (self.red).min(self.green).min(self.blue);
+
+		max - min
+	}
+
+	#[inline(always)]
+	pub fn with_saturation(&self, saturation: f32) -> Color {
+		let [hue, _, lightness, alpha] = self.to_hsla();
+		Color::from_hsla(hue, saturation, lightness, alpha)
+	}
+
+	pub fn with_alpha(&self, alpha: f32) -> Color {
+		Color {
+			red: self.red,
+			green: self.green,
+			blue: self.blue,
+			alpha,
+		}
+	}
+
+	pub fn with_red(&self, red: f32) -> Color {
+		Color {
+			red,
+			green: self.green,
+			blue: self.blue,
+			alpha: self.alpha,
+		}
+	}
+
+	pub fn with_green(&self, green: f32) -> Color {
+		Color {
+			red: self.red,
+			green,
+			blue: self.blue,
+			alpha: self.alpha,
+		}
+	}
+
+	pub fn with_blue(&self, blue: f32) -> Color {
+		Color {
+			red: self.red,
+			green: self.green,
+			blue,
+			alpha: self.alpha,
+		}
+	}
+
+	#[inline(always)]
+	pub fn blend_normal(_c_b: f32, c_s: f32) -> f32 {
+		c_s
+	}
+
+	#[inline(always)]
+	pub fn blend_multiply(c_b: f32, c_s: f32) -> f32 {
+		c_s * c_b
+	}
+
+	#[inline(always)]
+	pub fn blend_darken(c_b: f32, c_s: f32) -> f32 {
+		c_s.min(c_b)
+	}
+
+	#[inline(always)]
+	pub fn blend_color_burn(c_b: f32, c_s: f32) -> f32 {
+		if c_b == 1. {
+			1.
+		} else if c_s == 0. {
+			0.
+		} else {
+			1. - ((1. - c_b) / c_s).min(1.)
+		}
+	}
+
+	#[inline(always)]
+	pub fn blend_linear_burn(c_b: f32, c_s: f32) -> f32 {
+		c_b + c_s - 1.
+	}
+
+	#[inline(always)]
+	pub fn blend_darker_color(&self, other: Color) -> Color {
+		if self.average_rgb_channels() <= other.average_rgb_channels() { *self } else { other }
+	}
+
+	#[inline(always)]
+	pub fn blend_screen(c_b: f32, c_s: f32) -> f32 {
+		1. - (1. - c_s) * (1. - c_b)
+	}
+
+	#[inline(always)]
+	pub fn blend_lighten(c_b: f32, c_s: f32) -> f32 {
+		c_s.max(c_b)
+	}
+
+	#[inline(always)]
+	pub fn blend_color_dodge(c_b: f32, c_s: f32) -> f32 {
+		if c_s == 1. { 1. } else { (c_b / (1. - c_s)).min(1.) }
+	}
+
+	#[inline(always)]
+	pub fn blend_linear_dodge(c_b: f32, c_s: f32) -> f32 {
+		c_b + c_s
+	}
+
+	#[inline(always)]
+	pub fn blend_lighter_color(&self, other: Color) -> Color {
+		if self.average_rgb_channels() >= other.average_rgb_channels() { *self } else { other }
+	}
+
+	pub fn blend_softlight(c_b: f32, c_s: f32) -> f32 {
+		if c_s <= 0.5 {
+			c_b - (1. - 2. * c_s) * c_b * (1. - c_b)
+		} else {
+			let d: fn(f32) -> f32 = |x| if x <= 0.25 { ((16. * x - 12.) * x + 4.) * x } else { x.sqrt() };
+			c_b + (2. * c_s - 1.) * (d(c_b) - c_b)
+		}
+	}
+
+	pub fn blend_hardlight(c_b: f32, c_s: f32) -> f32 {
+		if c_s <= 0.5 {
+			Color::blend_multiply(2. * c_s, c_b)
+		} else {
+			Color::blend_screen(2. * c_s - 1., c_b)
+		}
+	}
+
+	pub fn blend_vivid_light(c_b: f32, c_s: f32) -> f32 {
+		if c_s <= 0.5 {
+			Color::blend_color_burn(2. * c_s, c_b)
+		} else {
+			Color::blend_color_dodge(2. * c_s - 1., c_b)
+		}
+	}
+
+	pub fn blend_linear_light(c_b: f32, c_s: f32) -> f32 {
+		if c_s <= 0.5 {
+			Color::blend_linear_burn(2. * c_s, c_b)
+		} else {
+			Color::blend_linear_dodge(2. * c_s - 1., c_b)
+		}
+	}
+
+	pub fn blend_pin_light(c_b: f32, c_s: f32) -> f32 {
+		if c_s <= 0.5 {
+			Color::blend_darken(2. * c_s, c_b)
+		} else {
+			Color::blend_lighten(2. * c_s - 1., c_b)
+		}
+	}
+
+	pub fn blend_hard_mix(c_b: f32, c_s: f32) -> f32 {
+		if Color::blend_linear_light(c_b, c_s) < 0.5 { 0. } else { 1. }
+	}
+
+	pub fn blend_difference(c_b: f32, c_s: f32) -> f32 {
+		(c_b - c_s).abs()
+	}
+
+	pub fn blend_exclusion(c_b: f32, c_s: f32) -> f32 {
+		c_b + c_s - 2. * c_b * c_s
+	}
+
+	pub fn blend_subtract(c_b: f32, c_s: f32) -> f32 {
+		c_b - c_s
+	}
+
+	pub fn blend_divide(c_b: f32, c_s: f32) -> f32 {
+		if c_b == 0. { 1. } else { c_b / c_s }
+	}
+
+	pub fn blend_hue(&self, c_s: Color) -> Color {
+		let sat_b = self.saturation();
+		let lum_b = self.luminance_rec_601();
+		c_s.with_saturation(sat_b).with_luminance(lum_b)
+	}
+
+	pub fn blend_saturation(&self, c_s: Color) -> Color {
+		let sat_s = c_s.saturation();
+		let lum_b = self.luminance_rec_601();
+
+		self.with_saturation(sat_s).with_luminance(lum_b)
+	}
+
+	pub fn blend_color(&self, c_s: Color) -> Color {
+		let lum_b = self.luminance_rec_601();
+
+		c_s.with_luminance(lum_b)
+	}
+
+	pub fn blend_luminosity(&self, c_s: Color) -> Color {
+		let lum_s = c_s.luminance_rec_601();
+
+		self.with_luminance(lum_s)
+	}
+
+	/// Return the all components as a tuple, first component is red, followed by green, followed by blue, followed by alpha.
+	///
+	/// # Examples
+	/// ```
+	/// use graphene_core::raster::color::Color;
+	/// let color = Color::from_rgbaf32(0.114, 0.103, 0.98, 0.97).unwrap();
+	/// assert_eq!(color.components(),  (0.114, 0.103, 0.98, 0.97));
+	/// ```
+	#[inline(always)]
+	pub fn components(&self) -> (f32, f32, f32, f32) {
+		(self.red, self.green, self.blue, self.alpha)
+	}
+
+	/// Return the all components as a u8 slice, first component is red, followed by green, followed by blue, followed by alpha. Use this if the [`Color`] is in linear space.
+	///
+	/// # Examples
+	/// ```
+	/// use graphene_core::raster::color::Color;
+	/// let color = Color::from_rgbaf32(0.114, 0.103, 0.98, 0.97).unwrap();
+	/// // TODO: Add test
+	/// ```
+	#[inline(always)]
+	pub fn to_rgba8_srgb(&self) -> [u8; 4] {
+		let gamma = self.to_gamma_srgb();
+		[(gamma.red * 255.) as u8, (gamma.green * 255.) as u8, (gamma.blue * 255.) as u8, (gamma.alpha * 255.) as u8]
+	}
+
+	// https://www.niwa.nu/2013/05/math-behind-colorspace-conversions-rgb-hsl/
+	/// Convert a [Color] to a hue, saturation, lightness and alpha (all between 0 and 1)
+	///
+	/// # Examples
+	/// ```
+	/// use graphene_core::raster::color::Color;
+	/// let color = Color::from_hsla(0.5, 0.2, 0.3, 1.).to_hsla();
+	/// ```
+	pub fn to_hsla(&self) -> [f32; 4] {
+		let min_channel = self.red.min(self.green).min(self.blue);
+		let max_channel = self.red.max(self.green).max(self.blue);
+
+		let lightness = (min_channel + max_channel) / 2.;
+		let saturation = if min_channel == max_channel {
+			0.
+		} else if lightness <= 0.5 {
+			(max_channel - min_channel) / (max_channel + min_channel)
+		} else {
+			(max_channel - min_channel) / (2. - max_channel - min_channel)
+		};
+		let hue = if self.red >= self.green && self.red >= self.blue {
+			(self.green - self.blue) / (max_channel - min_channel)
+		} else if self.green >= self.red && self.green >= self.blue {
+			2. + (self.blue - self.red) / (max_channel - min_channel)
+		} else {
+			4. + (self.red - self.green) / (max_channel - min_channel)
+		} / 6.;
+		#[cfg(not(target_arch = "spirv"))]
+		let hue = hue.rem_euclid(1.);
+		#[cfg(target_arch = "spirv")]
+		let hue = hue.rem_euclid(&1.);
+
+		[hue, saturation, lightness, self.alpha]
+	}
+
+	// TODO: Readd formatting
+
+	/// Creates a color from a 8-character RGBA hex string (without a # prefix).
+	///
+	/// # Examples
+	/// ```
+	/// use graphene_core::raster::color::Color;
+	/// let color = Color::from_rgba_str("7C67FA61").unwrap();
+	/// ```
+	pub fn from_rgba_str(color_str: &str) -> Option<Color> {
+		if color_str.len() != 8 {
+			return None;
+		}
+		let r = u8::from_str_radix(&color_str[0..2], 16).ok()?;
+		let g = u8::from_str_radix(&color_str[2..4], 16).ok()?;
+		let b = u8::from_str_radix(&color_str[4..6], 16).ok()?;
+		let a = u8::from_str_radix(&color_str[6..8], 16).ok()?;
+
+		Some(Color::from_rgba8_srgb(r, g, b, a))
+	}
+
+	/// Creates a color from a 6-character RGB hex string (without a # prefix).
+	///
+	/// ```
+	/// use graphene_core::raster::color::Color;
+	/// let color = Color::from_rgb_str("7C67FA").unwrap();
+	/// ```
+	pub fn from_rgb_str(color_str: &str) -> Option<Color> {
+		if color_str.len() != 6 {
+			return None;
+		}
+		let r = u8::from_str_radix(&color_str[0..2], 16).ok()?;
+		let g = u8::from_str_radix(&color_str[2..4], 16).ok()?;
+		let b = u8::from_str_radix(&color_str[4..6], 16).ok()?;
+
+		Some(Color::from_rgb8_srgb(r, g, b))
+	}
+
+	/// Linearly interpolates between two colors based on t.
+	///
+	/// T must be between 0 and 1.
+	#[inline(always)]
+	pub fn lerp(&self, other: &Color, t: f32) -> Self {
+		assert!((0. ..=1.).contains(&t));
+		Color::from_rgbaf32_unchecked(
+			self.red + ((other.red - self.red) * t),
+			self.green + ((other.green - self.green) * t),
+			self.blue + ((other.blue - self.blue) * t),
+			self.alpha + ((other.alpha - self.alpha) * t),
+		)
+	}
+
+	#[inline(always)]
+	pub fn gamma(&self, gamma: f32) -> Color {
+		let gamma = gamma.max(0.0001);
+
+		// From https://www.dfstudios.co.uk/articles/programming/image-programming-algorithms/image-processing-algorithms-part-6-gamma-correction/
+		let inverse_gamma = 1. / gamma;
+		self.map_rgb(|c: f32| c.powf(inverse_gamma))
+	}
+
+	#[inline(always)]
+	pub fn to_linear_srgb(&self) -> Self {
+		Self {
+			red: Self::srgb_to_linear(self.red),
+			green: Self::srgb_to_linear(self.green),
+			blue: Self::srgb_to_linear(self.blue),
+			alpha: self.alpha,
+		}
+	}
+
+	#[inline(always)]
+	pub fn to_gamma_srgb(&self) -> Self {
+		Self {
+			red: Self::linear_to_srgb(self.red),
+			green: Self::linear_to_srgb(self.green),
+			blue: Self::linear_to_srgb(self.blue),
+			alpha: self.alpha,
+		}
+	}
+
+	#[inline(always)]
+	pub fn srgb_to_linear(channel: f32) -> f32 {
+		if channel <= 0.04045 { channel / 12.92 } else { ((channel + 0.055) / 1.055).powf(2.4) }
+	}
+
+	#[inline(always)]
+	pub fn linear_to_srgb(channel: f32) -> f32 {
+		if channel <= 0.0031308 { channel * 12.92 } else { 1.055 * channel.powf(1. / 2.4) - 0.055 }
+	}
+
+	#[inline(always)]
+	pub fn map_rgba<F: Fn(f32) -> f32>(&self, f: F) -> Self {
+		Self::from_rgbaf32_unchecked(f(self.r()), f(self.g()), f(self.b()), f(self.a()))
+	}
+
+	#[inline(always)]
+	pub fn map_rgb<F: Fn(f32) -> f32>(&self, f: F) -> Self {
+		Self::from_rgbaf32_unchecked(f(self.r()), f(self.g()), f(self.b()), self.a())
+	}
+
+	#[inline(always)]
+	pub fn apply_opacity(&self, opacity: f32) -> Self {
+		Self::from_rgbaf32_unchecked(self.r() * opacity, self.g() * opacity, self.b() * opacity, self.a() * opacity)
+	}
+
+	#[inline(always)]
+	pub fn to_associated_alpha(&self, alpha: f32) -> Self {
+		Self {
+			red: self.red * alpha,
+			green: self.green * alpha,
+			blue: self.blue * alpha,
+			alpha: self.alpha * alpha,
+		}
+	}
+
+	#[inline(always)]
+	pub fn to_unassociated_alpha(&self) -> Self {
+		if self.alpha == 0. {
+			return *self;
+		}
+		let unmultiply = 1. / self.alpha;
+		Self {
+			red: self.red * unmultiply,
+			green: self.green * unmultiply,
+			blue: self.blue * unmultiply,
+			alpha: self.alpha,
+		}
+	}
+
+	#[inline(always)]
+	pub fn blend_rgb<F: Fn(f32, f32) -> f32>(&self, other: Color, f: F) -> Self {
+		let background = self.to_unassociated_alpha();
+		Color {
+			red: f(background.red, other.red).clamp(0., 1.),
+			green: f(background.green, other.green).clamp(0., 1.),
+			blue: f(background.blue, other.blue).clamp(0., 1.),
+			alpha: other.alpha,
+		}
+	}
+
+	#[inline(always)]
+	pub fn alpha_blend(&self, other: Color) -> Self {
+		let inv_alpha = 1. - other.alpha;
+		Self {
+			red: self.red * inv_alpha + other.red,
+			green: self.green * inv_alpha + other.green,
+			blue: self.blue * inv_alpha + other.blue,
+			alpha: self.alpha * inv_alpha + other.alpha,
+		}
+	}
+
+	#[inline(always)]
+	pub fn alpha_add(&self, other: Color) -> Self {
+		Self {
+			alpha: (self.alpha + other.alpha).clamp(0., 1.),
+			..*self
+		}
+	}
+
+	#[inline(always)]
+	pub fn alpha_subtract(&self, other: Color) -> Self {
+		Self {
+			alpha: (self.alpha - other.alpha).clamp(0., 1.),
+			..*self
+		}
+	}
+
+	#[inline(always)]
+	pub fn alpha_multiply(&self, other: Color) -> Self {
+		Self {
+			alpha: (self.alpha * other.alpha).clamp(0., 1.),
+			..*self
+		}
+	}
+}
+
+#[test]
+fn hsl_roundtrip() {
+	for (red, green, blue) in [
+		(24, 98, 118),
+		(69, 11, 89),
+		(54, 82, 38),
+		(47, 76, 50),
+		(25, 15, 73),
+		(62, 57, 33),
+		(55, 2, 18),
+		(12, 3, 82),
+		(91, 16, 98),
+		(91, 39, 82),
+		(97, 53, 32),
+		(76, 8, 91),
+		(54, 87, 19),
+		(56, 24, 88),
+		(14, 82, 34),
+		(61, 86, 31),
+		(73, 60, 75),
+		(95, 79, 88),
+		(13, 34, 4),
+		(82, 84, 84),
+		(255, 255, 178),
+	] {
+		let col = Color::from_rgb8_srgb(red, green, blue);
+		let [hue, saturation, lightness, alpha] = col.to_hsla();
+		let result = Color::from_hsla(hue, saturation, lightness, alpha);
+		assert!((col.r() - result.r()) < f32::EPSILON * 100.);
+		assert!((col.g() - result.g()) < f32::EPSILON * 100.);
+		assert!((col.b() - result.b()) < f32::EPSILON * 100.);
+		assert!((col.a() - result.a()) < f32::EPSILON * 100.);
+	}
+}

node-graph/gcore-shader/src/fullscreen_vertex.rs

@@ -0,0 +1,14 @@
+use glam::{Vec2, Vec4};
+use spirv_std::spirv;
+
+/// webgpu NDC is like OpenGL: (-1.0 .. 1.0, -1.0 .. 1.0, 0.0 .. 1.0)
+/// https://www.w3.org/TR/webgpu/#coordinate-systems
+const FULLSCREEN_VERTICES: [Vec2; 3] = [Vec2::new(-1., -1.), Vec2::new(-1., 3.), Vec2::new(3., -1.)];
+
+#[spirv(vertex)]
+pub fn fullscreen_vertex(#[spirv(vertex_index)] vertex_index: u32, #[spirv(position)] gl_position: &mut Vec4) {
+	// broken on edition 2024 branch
+	// let vertex = unsafe { *FULLSCREEN_VERTICES.index_unchecked(vertex_index as usize) };
+	let vertex = FULLSCREEN_VERTICES[vertex_index as usize];
+	*gl_position = Vec4::from((vertex, 0., 1.));
+}

node-graph/gcore-shader/src/gpu_invert.rs

@@ -0,0 +1,39 @@
+use crate::color::Color;
+
+// exact copy of the invert node
+// #[node_macro::node(category("Raster: Adjustment"))]
+fn invert_copy(
+	// _: impl Ctx,
+	// #[implementations(
+	// 	Color,
+	// 	ImageFrameTable<Color>,
+	// 	GradientStops,
+	// )]
+	// mut input: T,
+	color: Color,
+) -> Color {
+	// input.adjust(|color| {
+	let color = color.to_gamma_srgb();
+
+	let color = color.map_rgb(|c| color.a() - c);
+
+	color.to_linear_srgb()
+	// });
+	// input
+}
+
+pub mod gpu_invert_shader {
+	use crate::color::Color;
+	use crate::gpu_invert::invert_copy;
+	use glam::{Vec4, Vec4Swizzles};
+	use spirv_std::image::sample_with::lod;
+	use spirv_std::image::{Image2d, ImageWithMethods};
+	use spirv_std::spirv;
+
+	#[spirv(fragment)]
+	pub fn gpu_invert_fragment(#[spirv(frag_coord)] frag_coord: Vec4, #[spirv(descriptor_set = 0, binding = 0)] texture: &Image2d, color_out: &mut Vec4) {
+		let color = Color::from(texture.fetch_with(frag_coord.xy().as_uvec2(), lod(0)));
+		let color = invert_copy(color);
+		*color_out = Vec4::from(color);
+	}
+}

node-graph/gcore-shader/src/lib.rs

@@ -0,0 +1,5 @@
+#![no_std]
+
+pub mod color;
+pub mod fullscreen_vertex;
+pub mod gpu_invert;