101ray.cc

#include <iostream>
#include "ray.h"

vec3 colour (const ray& r) {
	vec3 unit_direction = unit_vector(r.direction());
	double t = 0.5  * (unit_direction.y() + 1.0);
	return (1.0 - t) * vec3(1.0, 1.0, 1.0) + t * vec3(0.5, 0.7, 1.0);
}

int main () {

	freopen("101ray.ppm", "w", stdout);

	int nx = 2000;
	int ny = 1000;

	std::cout << "P3\n" << nx << " " << ny << "\n255\n";

	vec3 lower_left_corner (-2.0, -1.0, -1.0);
	vec3 horizontal (4.0, 0.0, 0.0);
	vec3 vertical (0.0, 2.0, 0.0);
	vec3 origin (0.0, 0.0, 0.0);

	for (int j = ny - 1; j >= 0; j--) {
		for (int i = 0; i < nx; i++) {
			double u = double(i) / double(nx);
			double v = double(j) / double(ny);
			ray r (origin, lower_left_corner + u * horizontal + v * vertical);
			vec3 col = colour(r);
			int ir = int(255.99 * col[0]);
			int ig = int(255.99 * col[1]);
			int ib = int(255.99 * col[2]);

			std::cout << ir << " " << ig << " " << ib << "\n";
		}
	}

	fclose(stdout);
	return 0;
}