79 lines
2.3 KiB
C++
79 lines
2.3 KiB
C++
#include <stdio.h>
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#include <stdint.h>
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#include "rtweekend.hpp"
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#include "color.hpp"
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#include "hittable_list.hpp"
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#include "sphere.hpp"
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color ray_color(const ray& r, const hittable& world);
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double hit_sphere(const point3& center, double radius, const ray& r);
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color ray_color(const ray& r, const hittable& world)
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{
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hit_record rec;
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if (world.hit(r, 0, INFINITY, rec))
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{
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return 0.5 * (rec.normal + color(1,1,1));
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}
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vec3 unit_direction = normalize(r.direction);
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double t = 0.5 * (unit_direction.y + 1.0);
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return (1-t) * color(1,1,1) + t*color(0.5,0.7,1.0);
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}
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double hit_sphere(const point3& center, double radius, const ray& r)
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{
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vec3 oc = r.origin - center;
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double a = r.direction.length_squared();
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double half_b = dot(oc, r.direction);
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double c = oc.length_squared() - radius*radius;
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double discriminant = half_b*half_b - a*c;
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if (discriminant < 0)
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return -1;
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else
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return (-half_b - sqrt(discriminant)) / a;
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}
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int main()
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{
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// Image
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double aspect_ratio = 16.0 / 9;
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const int32_t image_width = 400;
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const int32_t image_height = (int32_t) (image_width / aspect_ratio);
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// World
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hittable_list world;
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world.add(std::make_shared<sphere>(point3(0,0,-1), 0.5));
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world.add(std::make_shared<sphere>(point3(0,-100.5,-1), 100));
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// Camera
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double viewport_height = 2.0;
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double viewport_width = aspect_ratio * viewport_height;
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double focal_length = 1.0;
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point3 origin = point3(0,0,0);
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vec3 horizontal = vec3(viewport_width, 0, 0);
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vec3 vertical = vec3(0, viewport_height, 0);
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vec3 lower_left_corner = origin - horizontal/2 - vertical/2 - vec3(0, 0, focal_length);
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// Render
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printf("P3\n%d %d\n255\n", image_width, image_height);
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for (int32_t j = image_height - 1; j >= 0; --j)
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{
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fprintf(stderr, "\rScanlines remaining: %d ", j);
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fflush(stderr);
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for (int32_t i = 0; i < image_width; ++i)
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{
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double u = (double)i / (image_width-1);
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double v = (double)j / (image_height-1);
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ray r = ray(origin, lower_left_corner + u*horizontal + v*vertical - origin);
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color pixel_color = ray_color(r, world);
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write_color(stdout, pixel_color);
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}
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}
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fprintf(stderr, "\nDone\n");
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}
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