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use super::texture2d::Texture2D;
use crate::object::{Value, parser::FromValue};
use anyhow::Result;
use glam::{UVec2, Vec3Swizzles, uvec2, vec2, vec3};
use image::{DynamicImage, ImageBuffer, Rgba};
use log::info;
use rayon::iter::ParallelIterator;
use serde::Serialize;
use std::f32::consts::PI;
#[derive(Debug, Serialize)]
pub struct Cubemap {
pub texture: Texture2D,
}
impl FromValue for Cubemap {
fn from_value(v: Value) -> Result<Self> {
let fields = v.as_class("Cubemap")?;
Ok(Cubemap {
texture: Texture2D::from_fields(fields)?,
})
}
}
impl Cubemap {
pub fn to_image(&self) -> Result<DynamicImage> {
self.texture.to_image()
}
}
/// Face ordering is Left, Right, Back, Front, Down, Up
pub fn cubemap_to_equirectangular(
faces: &[ImageBuffer<Rgba<f32>, Vec<f32>>; 6],
output_width: u32,
output_height: u32,
) -> ImageBuffer<Rgba<f32>, Vec<f32>> {
info!(
"reprojecting {}x{} cubemap faces to {output_width}x{output_height} equirectangular",
faces[0].width(),
faces[0].height()
);
let mut output_image = ImageBuffer::<Rgba<f32>, Vec<f32>>::new(output_width, output_height);
output_image
.par_enumerate_pixels_mut()
.for_each(|(er_x, er_y, out)| {
let phi = er_x as f32 / output_width as f32 * PI * 2.;
let theta = (1. - er_y as f32 / output_height as f32) * PI;
let normal = vec3(
phi.sin() * theta.sin(),
phi.cos() * theta.sin(),
theta.cos(),
);
assert!(normal.is_normalized());
let normal_abs = normal.abs();
let (axis, max_comp, other_comps) = if normal_abs.x > normal_abs.y.max(normal_abs.z) {
(0, normal.x, normal.yz())
} else if normal_abs.y > normal_abs.z {
(1, normal.y, normal.xz())
} else {
(2, normal.z, normal.xy())
};
let face = axis as usize * 2 + if max_comp < 0. { 1 } else { 0 };
let face_texture = &faces[face];
let face_size = uvec2(face_texture.width(), face_texture.height());
let face_uv = other_comps / max_comp * vec2(1., -max_comp.signum());
let face_uv = face_uv / 2. + 0.5;
let face_xy = (face_uv * face_size.as_vec2())
.floor()
.as_uvec2()
.clamp(UVec2::MIN, face_size - UVec2::ONE);
out.0 = face_texture.get_pixel(face_xy.x, face_xy.y).0;
});
output_image
}
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