main.c

#include <stdio.h>
#include <stdlib.h>
#include <math.h>
#include <float.h>
#include <time.h>
#include <string.h>
#include "sphere.h"
#include "hitable_list.h"
#include "camera.h"
#include "material.h"
#include "metal.h"
#include "dielectric.h"
#include "lambertian.h"

Vector color(const Ray r, Hitable_List *world_list, int depth)
{
    Hit_Record rec;

    if (world_list->hitable.hit((const void *) world_list, r, 0.001, FLT_MAX, &rec)) {
        Ray scattered;
        Vector attenuation;

        if (depth < 50 && rec.mat_ptr.scatter((const void *) rec.mat_ptr.inst, r, rec, &attenuation, &scattered)) {
            return attenuation.mul(attenuation, color(scattered, world_list, depth + 1));
        } else {
            return new_vector(new_point(0, 0, 0));
        }
    } else {
        Vector unit_direction = unit_vector(r.direction(r));
        float t = 0.5 * (unit_direction.point.y + 1.0);

        Vector v1 = new_vector(new_point(1.0, 1.0, 1.0));
        Vector v2 = new_vector(new_point(0.5, 0.7, 1.0));

        return v1.add(v1.mul_scalar(v1, 1.0 - t), v1.mul_scalar(v2, t));
    }
}

int main(int argc, char **argv) {
    if (argc != 3) {
        fprintf(stderr, "%d\n", argc);
        fprintf(stderr, "%s [input file] [output file]\n", argv[0]);
        exit(-1);
    }

    const char *infile = argv[1];
    const char *outfile = argv[2];

    FILE *fin = fopen(infile, "r");
    FILE *fout = fopen(outfile, "wb");

    int nx;      // length
    int ny;      // width
    int ns = 10; // sampling times
    int sphere_count;
    float R = cos(M_PI / 4);

    fscanf(fin, "%d %d", &nx, &ny);
    fscanf(fin, "%d", &sphere_count);

    fprintf(fout, "P3\n%d %d \n255\n", nx, ny);

    Hitable *list[sphere_count];

    Sphere *sphere;
    Lambertian *lam;
    Dielectric *diel;
    Metal *metal;

    for (int i = 0; i < sphere_count; i++) {
        float radius;
        char material_str[11];
        Vector sphere_v = new_vector(new_point(0, 0, 0));
        Vector material_v = new_vector(new_point(0, 0, 0));

        fscanf(fin, "%f %f %f", &sphere_v.point.x, &sphere_v.point.y, &sphere_v.point.z);
        fscanf(fin, "%f", &radius);
        fscanf(fin, "%s", material_str);

        if (!strcmp(material_str, "metal")) {
            fscanf(fin, "%f %f %f", &material_v.point.x, &material_v.point.y, &material_v.point.z);

            sphere = (Sphere *) malloc(sizeof(Sphere));
            metal = (Metal *) malloc(sizeof(Metal));

            *metal = new_metal(material_v, 0.0);
            *sphere = new_sphere(sphere_v, radius, (void *) metal, metal->mat.scatter);
        } else if (!strcmp(material_str, "lambertian")) {
            fscanf(fin, "%f %f %f", &material_v.point.x, &material_v.point.y, &material_v.point.z);

            sphere = (Sphere *) malloc(sizeof(Sphere));
            lam = (Lambertian *) malloc(sizeof(Lambertian));

            *lam = new_lambertian(material_v);
            *sphere = new_sphere(sphere_v, radius, (void *) lam, lam->mat.scatter);
        } else if (!strcmp(material_str, "dielectric")) {
            float ref_idx;
            fscanf(fin, "%f", &ref_idx);

            sphere = (Sphere *) malloc(sizeof(Sphere));
            diel = (Dielectric *) malloc(sizeof(Dielectric));

            *diel = new_dielectric(ref_idx);
            *sphere = new_sphere(sphere_v, radius, (void *) diel, diel->mat.scatter);
        } else {
            fprintf(stderr, "Unkown Material\n");
            exit(-1);
        }

        list[i] = &sphere->hitable;
        list[i]->inst = (void *) sphere;
    }

    Hitable_List world = new_hitable_list(list, sphere_count);

    Vector lookfrom = new_vector(new_point(13, 2, 3));
    Vector lookat = new_vector(new_point(0, 0, 0));
    float dist_to_focus = 10.0;
    float aperture = 0.1;

    clock_t start_time = clock();

    Camera cam = new_camera(lookfrom, lookat, new_vector(new_point(0, 1, 0)), 20, (float) nx / (float) ny, aperture, dist_to_focus);

    for (int j = ny - 1; j >= 0; j--) {
        for (int i = 0; i < nx; i++) {
            Vector col = new_vector(new_point(0, 0, 0));

            /* Sampling ns times per pixel area */
            for (int s = 0; s < ns; s++) {
                /* Centered at the center point of the pixel, the pixel outward distance is (0.0, 1.0] */
                float u = (float) (i + drand48()) / (float) nx;
                float v = (float) (j + drand48()) / (float) ny;

                /* Obtain the color value of the random sampling point in this pixel area */
                Ray r = cam.get_ray(cam, u, v);
                Vector p = r.point_at_parameter(r, 2.0);

                /* Accumulate the color values of all ns random sample points of this point area */
                col = col.add(col, color(r, &world, 0));
            }

            /* Divide the color accumulated value of all ns random sampling points of this pixel area by ns to obtain the average value */
            col = col.div_scalar(col, (float) ns);
            col = new_vector(new_point(sqrt(col.point.x), sqrt(col.point.y), sqrt(col.point.z)));
            int ir = (int) (255.99 * col.point.x);
            int ig = (int) (255.99 * col.point.y);
            int ib = (int) (255.99 * col.point.z);

            fprintf(fout, "%d %d %d\n", ir, ig, ib);
        }
    }

    clock_t end_time = clock();
    printf("Elapsed: %f seconds\n", (double) (end_time - start_time) / CLOCKS_PER_SEC);

    fclose(fin);
    fclose(fout);

    for (int i = 0; i < sphere_count; i++) {
        Sphere *sphere = (Sphere *) list[i]->inst;

        free(sphere->mat_ptr.inst);
        free(sphere);
    }

    return 0;
}