use write_file_util::{write_image};

use crate::image::{gen_ray_sphere_normal_ppm_p3};
use crate::types_defined::{Point, Vec3};
mod image;
mod write_file_util;
mod vec3;
mod ray;
mod hittable;
mod sphere;
mod types_defined;
mod color;

fn main() {
    ray_sphere_normal_scene_render();
}


fn ray_sphere_normal_scene_render() {
    let aspect_ratio = 16.0/9.0;
    let image_width = 400;
    // aleast 1px
    let image_height = ((image_width as f32 / aspect_ratio) as i32).max(1);

    let viewport_height = 2.0;
    let viewport_width = viewport_height * (image_width as f32 / image_height as f32);

    println!("set image({},{}), viewport({},{})", image_width, image_height, viewport_width, viewport_height);
    let viewport_u = Vec3::new(viewport_width, 0.0, 0.0);
    // image x--> right
    //       |
    //       y
    // space: y up , x right , z back, -z front
    let viewport_v = Vec3::new(0.0, -viewport_height, 0.0);

    // width per pix
    let viewport_u_delta = viewport_u / (image_width as f32);
    // height per pix
    let viewport_v_delta = viewport_v / (image_height as f32);

    // camerea position
    let camera_center = Point::new(0.0, 0.0, 0.0);
    // -z  1.0  viewport to camera
    let focal_length = Vec3::new(0.0, 0.0, -1.0);
    // camera position --> viewport center ---> top center --> top left
    let viewport_top_left_pixel = camera_center + focal_length - viewport_u / 2.0 - viewport_v / 2.0;
    // padding 0.5* delta u/v
    let viewport_top_left_pixel_center = viewport_top_left_pixel - viewport_u_delta / 2.0 - viewport_v_delta / 2.0;

    let ppm_content = gen_ray_sphere_normal_ppm_p3(image_width, image_height, camera_center, viewport_top_left_pixel_center, viewport_u_delta, viewport_v_delta);

    write_image(ppm_content, "./target/ray_sphere_normal_scene_render.ppm".to_string())
}