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package main
import (
"fmt"
"os"
"time"
)
func main() {
start := time.Now();
image_width := 400;
aspect := 16.0 / 9.0;
var world Hittables;
world.Add(Sphere{Vec3{0, 0 , -1}, 0.5});
world.Add(Sphere{Vec3{0, -100.5, -1}, 100 });
image_height := int(float64(image_width) / aspect);
if image_height < 1 {
image_height = 1;
}
focal_length := 1.0;
viewport_height := 2.0;
viewport_width := viewport_height *
(float64(image_width) / float64(image_height));
camera_centre := Splat(0);
viewport_u := Vec3{viewport_width, 0, 0};
viewport_v := Vec3{0, -viewport_height, 0};
pd_u := viewport_u.Div(Splat(float64(image_width)));
pd_v := viewport_v.Div(Splat(float64(image_height)));
viewport_upperleft := camera_centre.
Sub(Vec3{0, 0, focal_length}).
Sub(viewport_u.Div(Splat(2))).
Sub(viewport_v.Div(Splat(2)));
pixel00_loc := viewport_upperleft.
Add(pd_u.Add(pd_v).Div(Splat(2)));
fmt.Printf("P3\n%d %d\n255\n", image_width, image_height);
for row := 0; row < image_height; row++ {
fmt.Fprintf(os.Stderr,
"[GScanlines remaining: %3d...",
(image_height - row));
for col := 0; col < image_width; col++ {
pixel_centre := pixel00_loc.
Add(pd_u.Mul(Splat(float64(col)))).
Add(pd_v.Mul(Splat(float64(row))));
ray_direction := pixel_centre.Sub(camera_centre);
ray := Ray{camera_centre, ray_direction}
pixel_colour := ray.Colour(world);
fmt.Printf("%s ", pixel_colour.ToPPM());
}
fmt.Printf("\n");
}
dur := time.Since(start);
fmt.Fprintf(os.Stderr,
"[GDone, in %5.2f seconds! \n",
dur.Seconds());
}
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