From d2a6aec56cf741c42441aeb059a8dd9f37489c8b Mon Sep 17 00:00:00 2001 From: Jean-Michel Gorius Date: Thu, 10 Nov 2022 23:26:18 +0100 Subject: [PATCH] Add a simple camera and antialiasing --- camera.c | 23 +++++++++++++++++++++++ camera.h | 19 +++++++++++++++++++ color.c | 20 +++++++++++++++++--- color.h | 4 +++- main.c | 56 ++++++++++++++++++++++++++------------------------------ utils.c | 17 +++++++++++++++-- utils.h | 5 +++++ 7 files changed, 108 insertions(+), 36 deletions(-) create mode 100644 camera.c create mode 100644 camera.h diff --git a/camera.c b/camera.c new file mode 100644 index 0000000..daa1c2b --- /dev/null +++ b/camera.c @@ -0,0 +1,23 @@ +#include "camera.h" + +void camera_init(Camera *camera, double aspect_ratio) { + double viewport_height = 2; + double viewport_width = aspect_ratio * viewport_height; + double focal_length = 1.0; + + camera->origin = (Point3){0, 0, 0}; + camera->horizontal = (Vec3){viewport_width, 0, 0}; + camera->vertical = (Vec3){0, viewport_height, 0}; + Vec3 offset = + vec3_add(vec3_div(camera->horizontal, 2), vec3_div(camera->vertical, 2)); + offset = vec3_add(offset, (Vec3){0, 0, focal_length}); + camera->lower_left_corner = point3_add(camera->origin, vec3_neg(offset)); +} + +Ray camera_get_ray(const Camera *camera, double u, double v) { + Point3 screen_point = point3_add( + camera->lower_left_corner, + vec3_add(vec3_mul(u, camera->horizontal), vec3_mul(v, camera->vertical))); + Vec3 direction = point3_sub(screen_point, camera->origin); + return (Ray){camera->origin, direction}; +} diff --git a/camera.h b/camera.h new file mode 100644 index 0000000..b9d1fb1 --- /dev/null +++ b/camera.h @@ -0,0 +1,19 @@ +#ifndef INCLUDED_CAMERA_H +#define INCLUDED_CAMERA_H + +#include "point3.h" +#include "ray.h" +#include "vec3.h" + +typedef struct Camera { + Point3 origin; + Point3 lower_left_corner; + Vec3 horizontal; + Vec3 vertical; +} Camera; + +void camera_init(Camera *camera, double aspect_ratio); + +Ray camera_get_ray(const Camera *camera, double u, double v); + +#endif /* INCLUDED_CAMERA_H */ diff --git a/color.c b/color.c index 484fcb4..ae222a7 100644 --- a/color.c +++ b/color.c @@ -1,6 +1,12 @@ #include "color.h" +#include "utils.h" + #include +Color color_add(Color c1, Color c2) { + return (Color){c1.r + c2.r, c1.g + c2.g, c1.b + c2.b}; +} + Color color_lerp(Color c1, Color c2, double t) { return (Color){ (1.0 - t) * c1.r + t * c2.r, @@ -9,7 +15,15 @@ Color color_lerp(Color c1, Color c2, double t) { }; } -void color_write(FILE *out, Color c) { - fprintf(out, "%d %d %d\n", (int)(255.999 * c.r), (int)(255.999 * c.g), - (int)(255.999 * c.b)); +void color_write(FILE *out, Color c, int samples_per_pixel) { + double scale = 1.0 / samples_per_pixel; + double r = c.r * scale; + double g = c.g * scale; + double b = c.b * scale; + + int ir = (int)(256 * clamp(r, 0.0, 0.999)); + int ig = (int)(256 * clamp(g, 0.0, 0.999)); + int ib = (int)(256 * clamp(b, 0.0, 0.999)); + + fprintf(out, "%d %d %d\n", ir, ig, ib); } diff --git a/color.h b/color.h index dbffda3..4126c91 100644 --- a/color.h +++ b/color.h @@ -7,8 +7,10 @@ typedef struct Color { double r, g, b; } Color; +Color color_add(Color c1, Color c2); + Color color_lerp(Color c1, Color c2, double t); -void color_write(FILE *out, Color c); +void color_write(FILE *out, Color c, int samples_per_pixel); #endif /* INCLUDED_COLOR_H */ diff --git a/main.c b/main.c index 9f87af7..4b3e7ae 100644 --- a/main.c +++ b/main.c @@ -3,10 +3,12 @@ #include #include +#include "camera.h" #include "color.h" #include "hittable.h" #include "point3.h" #include "ray.h" +#include "utils.h" #include "vec3.h" Color ray_color(Ray r, Hittable world) { @@ -27,54 +29,48 @@ int main(void) { const double aspect_ratio = 16.0 / 9.0; const int image_width = 256; const int image_height = (int)(image_width / aspect_ratio); + const int samples_per_pixel = 100; /* World */ - HittableList world = {0}; - hittable_list_add(&world, make_hittable_sphere(&(Sphere){ - .center = (Point3){0, 0, -1}, - .radius = 0.5, - })); - hittable_list_add(&world, make_hittable_sphere(&(Sphere){ - .center = (Point3){0, -100.5, -1}, - .radius = 100, - })); + HittableList object_list = {0}; + hittable_list_add(&object_list, make_hittable_sphere(&(Sphere){ + .center = (Point3){0, 0, -1}, + .radius = 0.5, + })); + hittable_list_add(&object_list, make_hittable_sphere(&(Sphere){ + .center = (Point3){0, -100.5, -1}, + .radius = 100, + })); + Hittable world = make_hittable_list(&object_list); - /* Camera parameters */ - double viewport_height = 2; - double viewport_width = aspect_ratio * viewport_height; - double focal_length = 1.0; - - Point3 origin = {0}; - Vec3 horizontal = {viewport_width, 0, 0}; - Vec3 vertical = {0, viewport_height, 0}; - Vec3 offset = vec3_add(vec3_div(horizontal, 2), vec3_div(vertical, 2)); - offset = vec3_add(offset, (Vec3){0, 0, focal_length}); - Point3 lower_left_corner = point3_add(origin, vec3_neg(offset)); + /* Camera */ + Camera camera; + camera_init(&camera, aspect_ratio); printf("P3\n%u %u\n255\n", image_width, image_height); for (int j = image_height - 1; j >= 0; --j) { fprintf(stderr, "\rScanlines remaining: %d ", j); for (int i = 0; i < image_width; ++i) { - double u = (double)i / (image_width - 1); - double v = (double)j / (image_height - 1); - Point3 screen_point = - point3_add(lower_left_corner, - vec3_add(vec3_mul(u, horizontal), vec3_mul(v, vertical))); - Vec3 direction = point3_sub(screen_point, origin); - Ray r = {origin, direction}; - Color pixel_color = ray_color(r, make_hittable_list(&world)); - color_write(stdout, pixel_color); + Color pixel_color = {0, 0, 0}; + for (int s = 0; s < samples_per_pixel; ++s) { + double u = (i + random_double()) / (image_width - 1); + double v = (j + random_double()) / (image_height - 1); + Ray r = camera_get_ray(&camera, u, v); + pixel_color = color_add(pixel_color, ray_color(r, world)); + } + color_write(stdout, pixel_color, samples_per_pixel); } } fprintf(stderr, "\nDone.\n"); - hittable_list_free(&world); + hittable_list_free(&object_list); return 0; } +#include "camera.c" #include "color.c" #include "hittable.c" #include "point3.c" diff --git a/utils.c b/utils.c index a964d72..87adba8 100644 --- a/utils.c +++ b/utils.c @@ -1,7 +1,20 @@ #include "utils.h" #include +#include -double degrees_to_radians(double degrees) { - return degrees * M_PI / 180.0; +double degrees_to_radians(double degrees) { return degrees * M_PI / 180.0; } + +double random_double(void) { return rand() / (RAND_MAX + 1.0); } + +double random_double_in_range(double min, double max) { + return min + (max - min) * random_double(); +} + +double clamp(double x, double min, double max) { + if (x < min) + return min; + if (x > max) + return max; + return x; } diff --git a/utils.h b/utils.h index 82e3478..93a1be0 100644 --- a/utils.h +++ b/utils.h @@ -3,4 +3,9 @@ double degrees_to_radians(double degrees); +double random_double(void); +double random_double_in_range(double min, double max); + +double clamp(double x, double min, double max); + #endif /* INCLUDED_UTILS_H */