diff options
| -rw-r--r-- | main.c | 56 | ||||
| -rw-r--r-- | pgm.c | 27 | ||||
| -rw-r--r-- | pgm.h | 16 | ||||
| -rw-r--r-- | ray.c | 141 | ||||
| -rw-r--r-- | ray.h | 24 | ||||
| -rw-r--r-- | scene.c | 56 | ||||
| -rw-r--r-- | scene.h | 52 | ||||
| -rw-r--r-- | vector.h | 2 | ||||
| -rw-r--r-- | viewpoint.c | 4 |
9 files changed, 328 insertions, 50 deletions
@@ -3,39 +3,47 @@ #include <stdlib.h> #include "vector.h" -#include "viewpoint.h" #include "ray.h" +#include "scene.h" +#include "pgm.h" -typedef struct { - viewpoint_t view; -} space_t; +#define TESTW 1000 +#define TESTH 1000 + +color_t back = {0, 0, 0}; int main() { - printf("Starting\n"); - + //printf("Starting\n"); space_t s; + s.objects = NULL; + s.lights = NULL; - vector_set(&s.view.position, 10, 20, 10); + vector_set(&s.view.position, 0, 15, 10); vector_set(&s.view.target, 0, 0, 0); - s.view.width = 100; - s.view.height = 100; + s.view.width = TESTW; + s.view.height = TESTH; viewpoint_init(&s.view); - - ray_t r; - r.start = &s.view.position; - viewpoint_ray(&s.view, &r.direction, 66, 33); - - vector_print(&r.direction); - - plane_t pl; - pl.start = vector_set(NULL, 0, 0, 12); - vector_set(&pl.norm, 6, 2, 0); - vector_scale_inv(&pl.norm, &pl.norm, vector_len(&pl.norm)); - vector_print(&pl.norm); - - printf("Intersect distance %f\n", ray_intersect_plane(&pl, &r)); - + + // Setup plane + add_sphere(&s, vector_set(NULL, 0, 0, 5), 5); + add_sphere(&s, vector_set(NULL, 10, 0, 5), 5); + add_plane(&s, vector_set(NULL, 0, 0, 2), vector_set(NULL, 0, 0, 1)); + add_light(&s, vector_set(NULL, 10, 0, 20), color_set(NULL, 255, 255, 255)); + + pgm_write_header(stdout, TESTW, TESTH); + for (int y = TESTH; y; y--) { + for (int x = TESTW; x; x--) { + color_t *c = ray_trace(&s, x, y); + + if (c) { + pgm_write_pixel(stdout, c); + } else { + pgm_write_pixel(stdout, &back); + } + free(c); + } + } } @@ -0,0 +1,27 @@ +#include "pgm.h" + +#include <stdio.h> +#include <stdlib.h> + +int pgm_write_header(FILE *fp, unsigned int w, unsigned int h) +{ + return fprintf(fp, "P3\n%d %d\n255\n", w, h); +} + +int pgm_write_pixel(FILE *fp, color_t *c) +{ + return fprintf(fp, "%d %d %d\n", c->r, c->g, c->b); +} + +color_t *color_set(color_t *c, uint8_t r, uint8_t g, uint8_t b) +{ + if (!c) { + c = (color_t *) malloc(sizeof(c)); + } + + c->r = r; + c->g = g; + c->b = b; + + return c; +} @@ -0,0 +1,16 @@ +#ifndef PGM_H +#define PGM_H + +#include <stdio.h> +#include <stdint.h> + +typedef struct { + uint8_t r, g, b; +} color_t; + +color_t *color_set(color_t *c, uint8_t r, uint8_t g, uint8_t b); + +int pgm_write_header(FILE *fp, unsigned int w, unsigned int h); +int pgm_write_pixel(FILE *fp, color_t *c); + +#endif @@ -1,3 +1,4 @@ +#include <stdio.h> #include <math.h> #include "vector.h" @@ -5,7 +6,8 @@ // https://en.wikipedia.org/wiki/Line%E2%80%93sphere_intersection // http://viclw17.github.io/2018/07/16/raytracing-ray-sphere-intersection/ -COORD_T ray_intersect_sphere(sphere_t *s, ray_t *ray) +// https://www.scratchapixel.com/lessons/3d-basic-rendering/minimal-ray-tracer-rendering-simple-shapes/ray-sphere-intersection +COORD_T ray_intersect_sphere(sphere_t *s, ray_t *ray, bool skip_dist) { // Vector between vector start and center of circle vector_t oc; @@ -13,8 +15,8 @@ COORD_T ray_intersect_sphere(sphere_t *s, ray_t *ray) // Solve quadratic function // TODO Not sure if this step i neccesary because dir is unit - COORD_T a = vector_dot(&ray->direction, &ray->direction); - COORD_T b = 2 * vector_dot(&oc, &ray->direction); + COORD_T a = vector_dot(ray->direction, ray->direction); + COORD_T b = 2 * vector_dot(&oc, ray->direction); COORD_T c = vector_dot(&oc, &oc) - s->radius * s->radius; COORD_T d = b * b - 4 * a * c; @@ -23,29 +25,150 @@ COORD_T ray_intersect_sphere(sphere_t *s, ray_t *ray) if (d < 0) { return -1; } + if (skip_dist) { + return 1; + } + + // Else take the closest intersection, reuse d + COORD_T q = (b > 0) ? + -0.5 * (b + sqrt(d)) : + -0.5 * (b - sqrt(d)); + + COORD_T x0 = q / a; + COORD_T x1 = c / q; + + // Take the correct result. If one is zero take the other. + if (x0 <= 0) { + if (x1 <= 0) { + return -1; + } + + x0 = x1; + } + + // If point is on sphere it will be zero close to zero + if (x0 < 1e-3) { + return -1; + } - // Else take the closest intersection - return (-b - sqrt(d) ) / (2.0 * a); + return x0; } // Requires that vectors are normalized // https://www.scratchapixel.com/lessons/3d-basic-rendering/minimal-ray-tracer-rendering-simple-shapes/ray-plane-and-ray-disk-intersection -COORD_T ray_intersect_plane(plane_t *p, ray_t *ray) +COORD_T ray_intersect_plane(plane_t *p, ray_t *ray, bool skip_dist) { // If zero ray is parralel to plane - COORD_T nr = vector_dot(&p->norm, &ray->direction); - vector_print(&ray->direction); + COORD_T nr = vector_dot(p->norm, ray->direction); // // Take care of rounding errors if (nr < ZERO_APROX && nr > -ZERO_APROX) { return -1; } + if (skip_dist) { + return 1; + } // Calculate distance vector_t tmp; vector_copy(&tmp, p->start); vector_sub(&tmp, &tmp, ray->start); - COORD_T t = vector_dot(&tmp, &p->norm) / nr; + COORD_T t = vector_dot(&tmp, p->norm) / nr; return t; } + +COORD_T ray_intersect(object_t *o, ray_t *ray, bool skip_dist) +{ + switch (o->type) { + case TYPE_PLANE: + return ray_intersect_plane(&o->pl, ray, skip_dist); + case TYPE_SPHERE: + return ray_intersect_sphere(&o->sph, ray, skip_dist); + default: + printf("Unknown object type %d\n", o->type); + return -1; + } +} + +// If chk is true, will return at first hit less than chk_dist +object_t *ray_cast(space_t *s, ray_t *r, COORD_T *dist_ret, bool chk, COORD_T chk_dist) +{ + object_t *o = s->objects; + + object_t *smallest = NULL; + COORD_T dist = 0; + + while (o) { + COORD_T d = ray_intersect(o, r, false); + + if (d > 0) { + if (chk && chk_dist > d) { + if (dist_ret) { + *dist_ret = d; + } + return o; + } + if (d < dist || smallest == NULL) { + dist = d; + smallest = o; + } + } + + o = o->next; + } + + if (chk) { + return NULL; + } + + if (dist_ret) { + *dist_ret = dist; + } + return smallest; +} + +color_t *ray_trace(space_t *s, unsigned int x, unsigned int y) +{ + // Setup primary ray + ray_t r; + r.start = &s->view.position; + r.direction = vector_copy(NULL, NULL); + viewpoint_ray(&s->view, r.direction, x, y); + + // Cast it + COORD_T dist; + object_t *o = ray_cast(s, &r, &dist, false, 0); + if (!o) { + return NULL; + } + //printf("dist: %f\n", dist); + + // Calculate new ray point + r.start = vector_scale(NULL, r.direction, dist); + vector_add(r.start, r.start, &s->view.position); + + // Cast light rays + light_t *l = s->lights; + while (l) { + vector_t tmp; + // Calculate distance to light + vector_sub(&tmp, l->pos, r.start); + COORD_T d = vector_len(&tmp); + + // Calculate unit + vector_scale_inv(&tmp, &tmp, vector_len(&tmp)); + + // Find obstacles + r.direction = &tmp; + object_t *obs = ray_cast(s, &r, NULL, true, d); + + if (!obs) { + return color_set(NULL, 100, 100, o->type == TYPE_SPHERE ? 200 :0); + } + + l = l->next; + } + + return NULL; +} @@ -1,28 +1,22 @@ #ifndef RAY_H #define RAY_H +#include <stdbool.h> +#include <stdint.h> #include "vector.h" +#include "scene.h" typedef struct { // Start is not unique so it's a pointer to save copying time vector_t *start; - - vector_t direction; + vector_t *direction; } ray_t; -typedef struct { - vector_t *center; - COORD_T radius; -} sphere_t; - -// TODO make this less inconsistent -typedef struct { - vector_t *start; - vector_t norm; -} plane_t; - +COORD_T ray_intersect(object_t *o, ray_t *ray, bool skip_dist); +COORD_T ray_intersect_sphere(sphere_t *s, ray_t *ray, bool skip_dist); +COORD_T ray_intersect_plane(plane_t *p, ray_t *ray, bool skip_dist); -COORD_T ray_intersect_sphere(sphere_t *s, ray_t *ray); -COORD_T ray_intersect_plane(plane_t *p, ray_t *ray); +object_t *ray_cast(space_t *s, ray_t *r, COORD_T *dist_ret, bool chk, COORD_T chk_dist); +color_t *ray_trace(space_t *s, unsigned int x, unsigned int y); #endif @@ -0,0 +1,56 @@ +#include "scene.h" + +#include <stdlib.h> + +static inline void link_object(space_t *s, object_t *o) +{ + if (s) { + o->next = s->objects; + s->objects = o; + } else { + o->next = 0; + } +} + +object_t *add_sphere(space_t *s, vector_t *c, COORD_T r) +{ + object_t *o = (object_t *) malloc(sizeof(object_t)); + + o->type = TYPE_SPHERE; + o->sph.center = c; + o->sph.radius = r; + + link_object(s, o); + + return o; +} + +object_t *add_plane(space_t *s, vector_t *start, vector_t *dir) +{ + object_t *o = (object_t *) malloc(sizeof(object_t)); + + o->type = TYPE_PLANE; + o->pl.start = start; + o->pl.norm = dir; + + link_object(s, o); + + return o; +} + +light_t *add_light(space_t *s, vector_t *pos, color_t *c) +{ + light_t *o = (light_t *) malloc(sizeof(light_t)); + + o->pos = pos; + o->col = c; + + if (s) { + o->next = s->lights; + s->lights = o; + } else { + o->next = NULL; + } + + return o; +} @@ -0,0 +1,52 @@ + +#ifndef SCENE_H +#define SCENE_H + +#include <stdbool.h> +#include <stdint.h> +#include "vector.h" +#include "viewpoint.h" +#include "pgm.h" + +#define TYPE_SPHERE 1 +#define TYPE_PLANE 2 + +typedef struct { + vector_t *center; + COORD_T radius; +} sphere_t; + +typedef struct { + vector_t *start; + vector_t *norm; +} plane_t; + +typedef struct light_s{ + vector_t *pos; + color_t *col; + + struct light_s *next; +} light_t; + +// General object structure +typedef struct object_s{ + uint8_t type; + struct object_s *next; + + union { + sphere_t sph; + plane_t pl; + }; +} object_t; + +typedef struct { + viewpoint_t view; + object_t *objects; + light_t *lights; +} space_t; + +object_t *add_sphere(space_t *s, vector_t *c, COORD_T r); +object_t *add_plane(space_t *s, vector_t *start, vector_t *dir); +light_t *add_light(space_t *s, vector_t *pos, color_t *c); + +#endif @@ -2,7 +2,7 @@ #define VECTOR_H #define COORD_T float -#define ZERO_APROX 1e-6 +#define ZERO_APROX 1e-5 typedef struct { COORD_T x; diff --git a/viewpoint.c b/viewpoint.c index d51e646..7786c12 100644 --- a/viewpoint.c +++ b/viewpoint.c @@ -4,7 +4,7 @@ #include <math.h> #include <stdlib.h> -static const vector_t up = {0, 1, 0}; +static const vector_t up = {0, 0, 1}; void viewpoint_init(viewpoint_t *view) { @@ -37,10 +37,12 @@ void viewpoint_init(viewpoint_t *view) vector_sub(&view->blc, &view->blc, vector_scale(&v, &v, gy)); // Debug print + /* printf("Calculated the following viewpoint stuff\n"); printf("qx"); vector_print(&view->qx); printf("qy"); vector_print(&view->qy); printf("blc"); vector_print(&view->blc); + */ } // Calculate ray for viewport w, h |