Add raster module to graphene_core

node-graph/gcore/src/raster.rs

@@ -0,0 +1,18 @@
+use core::marker::PhantomData;
+
+use crate::Node;
+
+use self::color::Color;
+
+pub mod color;
+
+pub struct GrayscaleNode<'n, N: Node<'n, Output = Color>>(pub N, PhantomData<&'n ()>);
+
+impl<'n, N: Node<'n, Output = Color>> Node<'n> for GrayscaleNode<'n, N> {
+	type Output = Color;
+	fn eval(&'n self) -> Color {
+		let color = self.0.eval();
+		let avg = (color.r() + color.g() + color.b()) / 3.0;
+		Color::from_rgbaf32(avg, avg, avg, color.a()).expect("Grayscale node created an invalid color")
+	}
+}