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// std
use std::sync::Arc;
// pbrt
use crate::core::geometry::{Point2f, Vector2f};
use crate::core::interaction::SurfaceInteraction;
use crate::core::texture::{Texture, TextureMapping2D};

// checkerboard.h

pub struct Checkerboard2DTexture<T> {
    pub tex1: Arc<dyn Texture<T> + Send + Sync>,
    pub tex2: Arc<dyn Texture<T> + Send + Sync>,
    pub mapping: Box<TextureMapping2D>,
    // TODO: const AAMethod aaMethod;
}

impl<T: Copy> Checkerboard2DTexture<T> {
    pub fn new(
        mapping: Box<TextureMapping2D>,
        tex1: Arc<dyn Texture<T> + Send + Sync>,
        tex2: Arc<dyn Texture<T> + Send + Sync>, // , TODO: aaMethod
    ) -> Self {
        Checkerboard2DTexture {
            tex1,
            tex2,
            mapping,
        }
    }
}

impl<T: Copy> Texture<T> for Checkerboard2DTexture<T> {
    fn evaluate(&self, si: &SurfaceInteraction) -> T {
        let mut dstdx: Vector2f = Vector2f::default();
        let mut dstdy: Vector2f = Vector2f::default();
        let st: Point2f = self.mapping.map(si, &mut dstdx, &mut dstdy);
        // TODO: if (aaMethod == AAMethod::None) {
        if (st.x.floor() as u32 + st.y.floor() as u32) % 2 == 0 {
            self.tex1.evaluate(si)
        } else {
            self.tex2.evaluate(si)
        }
    }
}