use super::*;

pub struct Fbo<S, F> {
	pub fb: Framebuffer,
	pub tex: Tex2d<S, F>,
}
impl<S: TexSize, F: TexFmt> Fbo<S, F> {
	pub fn new(args: impl FboArgs) -> Self {
		let (w, h) = args.get();
		let tex = Tex2d::<S, F>::new_empty((w, h), 1);
		let fb = Framebuffer::new().attach((&tex, gl::COLOR_ATTACHMENT0));
		Self { fb, tex }
	}
}
impl<S: TexSize, F: TexFmt> Frame for Fbo<S, F> {
	fn ClearColor(&self, args: impl ClearArgs) {
		self.fb.Clear(gl::COLOR, args);
	}
	fn size(&self) -> uVec2 {
		let TexParam { w, h, .. } = self.tex.param;
		uVec2((w, h))
	}
	fn bind(&self) -> Binding<Framebuff> {
		self.fb.Bind(&self.tex)
	}
}

pub struct Slab<S, F> {
	pub src: Fbo<S, F>,
	pub tgt: Fbo<S, F>,
}
impl<S: TexSize, F: TexFmt> Slab<S, F> {
	pub fn new(args: impl FboArgs) -> Self {
		Self { src: Fbo::new(args), tgt: Fbo::new(args) }
	}
	pub fn swap(&mut self) {
		mem::swap(&mut self.src, &mut self.tgt);
	}
}

pub trait FboArgs: Copy {
	fn get(self) -> iVec2;
}
impl<W: Copy, H: Copy> FboArgs for (W, H)
where
	i32: Cast<W> + Cast<H>,
{
	fn get(self) -> iVec2 {
		iVec2(self)
	}
}