orca/ext/wasm3/test/wasi/c-ray/c-ray-f.c

584 lines
16 KiB
C

/* c-ray-f - a simple raytracing filter.
* Copyright (C) 2006 John Tsiombikas <nuclear@siggraph.org>
*
* You are free to use, modify and redistribute this program under the
* terms of the GNU General Public License v2 or (at your option) later.
* see "http://www.gnu.org/licenses/gpl.txt" for details.
* ---------------------------------------------------------------------
* Usage:
* compile: cc -o c-ray-f c-ray-f.c -lm
* run: cat scene | ./c-ray-f >foo.ppm
* enjoy: display foo.ppm (with imagemagick)
* or: imgview foo.ppm (on IRIX)
* ---------------------------------------------------------------------
* Scene file format:
* # sphere (many)
* s x y z rad r g b shininess reflectivity
* # light (many)
* l x y z
* # camera (one)
* c x y z fov tx ty tz
* ---------------------------------------------------------------------
*/
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <math.h>
#include <ctype.h>
#include <errno.h>
/* find the appropriate way to define explicitly sized types */
#if (__STDC_VERSION__ >= 199900) || defined(__GLIBC__) /* C99 or GNU libc */
#include <stdint.h>
#elif defined(__unix__) || defined(unix)
#include <sys/types.h>
#elif defined(_MSC_VER) /* the nameless one */
typedef unsigned __int8 uint8_t;
typedef unsigned __int32 uint32_t;
#endif
struct vec3 {
double x, y, z;
};
struct ray {
struct vec3 orig, dir;
};
struct material {
struct vec3 col; /* color */
double spow; /* specular power */
double refl; /* reflection intensity */
};
struct sphere {
struct vec3 pos;
double rad;
struct material mat;
struct sphere *next;
};
struct spoint {
struct vec3 pos, normal, vref; /* position, normal and view reflection */
double dist; /* parametric distance of intersection along the ray */
};
struct camera {
struct vec3 pos, targ;
double fov;
};
void render(int xsz, int ysz, uint32_t *fb, int samples);
struct vec3 trace(struct ray ray, int depth);
struct vec3 shade(struct sphere *obj, struct spoint *sp, int depth);
struct vec3 reflect(struct vec3 v, struct vec3 n);
struct vec3 cross_product(struct vec3 v1, struct vec3 v2);
struct ray get_primary_ray(int x, int y, int sample);
struct vec3 get_sample_pos(int x, int y, int sample);
struct vec3 jitter(int x, int y, int s);
int ray_sphere(const struct sphere *sph, struct ray ray, struct spoint *sp);
void load_scene(FILE *fp);
unsigned long get_msec(void);
#define MAX_LIGHTS 16 /* maximum number of lights */
#define RAY_MAG 1000.0 /* trace rays of this magnitude */
#define MAX_RAY_DEPTH 5 /* raytrace recursion limit */
#define FOV 0.78539816 /* field of view in rads (pi/4) */
#define HALF_FOV (FOV * 0.5)
#define ERR_MARGIN 1e-6 /* an arbitrary error margin to avoid surface acne */
/* bit-shift amount for packing each color into a 32bit uint */
#ifdef LITTLE_ENDIAN
#define RSHIFT 16
#define BSHIFT 0
#else /* big endian */
#define RSHIFT 0
#define BSHIFT 16
#endif /* endianness */
#define GSHIFT 8 /* this is the same in both byte orders */
/* some helpful macros... */
#define SQ(x) ((x) * (x))
#define MAX(a, b) ((a) > (b) ? (a) : (b))
#define MIN(a, b) ((a) < (b) ? (a) : (b))
#define DOT(a, b) ((a).x * (b).x + (a).y * (b).y + (a).z * (b).z)
#define NORMALIZE(a) do {\
double len = sqrt(DOT(a, a));\
(a).x /= len; (a).y /= len; (a).z /= len;\
} while(0);
/* global state */
int xres = 800;
int yres = 600;
double aspect = 1.333333;
struct sphere *obj_list;
struct vec3 lights[MAX_LIGHTS];
int lnum = 0;
struct camera cam;
#define NRAN 1024
#define MASK (NRAN - 1)
struct vec3 urand[NRAN];
int irand[NRAN];
const char *usage = {
"Usage: c-ray-f [options]\n"
" Reads a scene file from stdin, writes the image to stdout, and stats to stderr.\n\n"
"Options:\n"
" -s WxH where W is the width and H the height of the image\n"
" -r <rays> shoot <rays> rays per pixel (antialiasing)\n"
" -i <file> read from <file> instead of stdin\n"
" -o <file> write to <file> instead of stdout\n"
" -h this help screen\n\n"
};
int main(int argc, char **argv) {
int i;
unsigned long rend_time, start_time;
uint32_t *pixels;
int rays_per_pixel = 1;
FILE *infile = stdin, *outfile = stdout;
for(i=1; i<argc; i++) {
if(argv[i][0] == '-' && argv[i][2] == 0) {
char *sep;
switch(argv[i][1]) {
case 's':
if(!isdigit(argv[++i][0]) || !(sep = strchr(argv[i], 'x')) || !isdigit(*(sep + 1))) {
fputs("-s must be followed by something like \"640x480\"\n", stderr);
return EXIT_FAILURE;
}
xres = atoi(argv[i]);
yres = atoi(sep + 1);
aspect = (double)xres / (double)yres;
break;
case 'i':
if(!(infile = fopen(argv[++i], "r"))) {
fprintf(stderr, "failed to open input file %s: %s\n", argv[i], strerror(errno));
return EXIT_FAILURE;
}
break;
case 'o':
if(!(outfile = fopen(argv[++i], "w"))) {
fprintf(stderr, "failed to open output file %s: %s\n", argv[i], strerror(errno));
return EXIT_FAILURE;
}
break;
case 'r':
if(!isdigit(argv[++i][0])) {
fputs("-r must be followed by a number (rays per pixel)\n", stderr);
return EXIT_FAILURE;
}
rays_per_pixel = atoi(argv[i]);
break;
case 'h':
fputs(usage, stdout);
return 0;
default:
fprintf(stderr, "unrecognized argument: %s\n", argv[i]);
fputs(usage, stderr);
return EXIT_FAILURE;
}
} else {
fprintf(stderr, "unrecognized argument: %s\n", argv[i]);
fputs(usage, stderr);
return EXIT_FAILURE;
}
}
if(!(pixels = malloc(xres * yres * sizeof *pixels))) {
perror("pixel buffer allocation failed");
return EXIT_FAILURE;
}
load_scene(infile);
/* initialize the random number tables for the jitter */
for(i=0; i<NRAN; i++) urand[i].x = (double)rand() / RAND_MAX - 0.5;
for(i=0; i<NRAN; i++) urand[i].y = (double)rand() / RAND_MAX - 0.5;
for(i=0; i<NRAN; i++) irand[i] = (int)(NRAN * ((double)rand() / RAND_MAX));
start_time = get_msec();
render(xres, yres, pixels, rays_per_pixel);
rend_time = get_msec() - start_time;
/* output statistics to stderr */
fprintf(stderr, "Rendering took: %lu seconds (%lu milliseconds)\n", rend_time / 1000, rend_time);
/* output the image */
fprintf(outfile, "P6\n%d %d\n255\n", xres, yres);
for(i=0; i<xres * yres; i++) {
fputc((pixels[i] >> RSHIFT) & 0xff, outfile);
fputc((pixels[i] >> GSHIFT) & 0xff, outfile);
fputc((pixels[i] >> BSHIFT) & 0xff, outfile);
}
fflush(outfile);
if(infile != stdin) fclose(infile);
if(outfile != stdout) fclose(outfile);
return 0;
}
/* render a frame of xsz/ysz dimensions into the provided framebuffer */
void render(int xsz, int ysz, uint32_t *fb, int samples) {
int i, j, s;
double rcp_samples = 1.0 / (double)samples;
/* for each subpixel, trace a ray through the scene, accumulate the
* colors of the subpixels of each pixel, then pack the color and
* put it into the framebuffer.
* XXX: assumes contiguous scanlines with NO padding, and 32bit pixels.
*/
for(j=0; j<ysz; j++) {
for(i=0; i<xsz; i++) {
double r, g, b;
r = g = b = 0.0;
for(s=0; s<samples; s++) {
struct vec3 col = trace(get_primary_ray(i, j, s), 0);
r += col.x;
g += col.y;
b += col.z;
}
r = r * rcp_samples;
g = g * rcp_samples;
b = b * rcp_samples;
*fb++ = ((uint32_t)(MIN(r, 1.0) * 255.0) & 0xff) << RSHIFT |
((uint32_t)(MIN(g, 1.0) * 255.0) & 0xff) << GSHIFT |
((uint32_t)(MIN(b, 1.0) * 255.0) & 0xff) << BSHIFT;
}
}
}
/* trace a ray through the scene recursively (the recursion happens through
* shade() to calculate reflection rays if necessary).
*/
struct vec3 trace(struct ray ray, int depth) {
struct vec3 col;
struct spoint sp, nearest_sp;
struct sphere *nearest_obj = 0;
struct sphere *iter = obj_list->next;
/* if we reached the recursion limit, bail out */
if(depth >= MAX_RAY_DEPTH) {
col.x = col.y = col.z = 0.0;
return col;
}
/* find the nearest intersection ... */
while(iter) {
if(ray_sphere(iter, ray, &sp)) {
if(!nearest_obj || sp.dist < nearest_sp.dist) {
nearest_obj = iter;
nearest_sp = sp;
}
}
iter = iter->next;
}
/* and perform shading calculations as needed by calling shade() */
if(nearest_obj) {
col = shade(nearest_obj, &nearest_sp, depth);
} else {
col.x = col.y = col.z = 0.0;
}
return col;
}
/* Calculates direct illumination with the phong reflectance model.
* Also handles reflections by calling trace again, if necessary.
*/
struct vec3 shade(struct sphere *obj, struct spoint *sp, int depth) {
int i;
struct vec3 col = {0, 0, 0};
/* for all lights ... */
for(i=0; i<lnum; i++) {
double ispec, idiff;
struct vec3 ldir;
struct ray shadow_ray;
struct sphere *iter = obj_list->next;
int in_shadow = 0;
ldir.x = lights[i].x - sp->pos.x;
ldir.y = lights[i].y - sp->pos.y;
ldir.z = lights[i].z - sp->pos.z;
shadow_ray.orig = sp->pos;
shadow_ray.dir = ldir;
/* shoot shadow rays to determine if we have a line of sight with the light */
while(iter) {
if(ray_sphere(iter, shadow_ray, 0)) {
in_shadow = 1;
break;
}
iter = iter->next;
}
/* and if we're not in shadow, calculate direct illumination with the phong model. */
if(!in_shadow) {
NORMALIZE(ldir);
idiff = MAX(DOT(sp->normal, ldir), 0.0);
ispec = obj->mat.spow > 0.0 ? pow(MAX(DOT(sp->vref, ldir), 0.0), obj->mat.spow) : 0.0;
col.x += idiff * obj->mat.col.x + ispec;
col.y += idiff * obj->mat.col.y + ispec;
col.z += idiff * obj->mat.col.z + ispec;
}
}
/* Also, if the object is reflective, spawn a reflection ray, and call trace()
* to calculate the light arriving from the mirror direction.
*/
if(obj->mat.refl > 0.0) {
struct ray ray;
struct vec3 rcol;
ray.orig = sp->pos;
ray.dir = sp->vref;
ray.dir.x *= RAY_MAG;
ray.dir.y *= RAY_MAG;
ray.dir.z *= RAY_MAG;
rcol = trace(ray, depth + 1);
col.x += rcol.x * obj->mat.refl;
col.y += rcol.y * obj->mat.refl;
col.z += rcol.z * obj->mat.refl;
}
return col;
}
/* calculate reflection vector */
struct vec3 reflect(struct vec3 v, struct vec3 n) {
struct vec3 res;
double dot = v.x * n.x + v.y * n.y + v.z * n.z;
res.x = -(2.0 * dot * n.x - v.x);
res.y = -(2.0 * dot * n.y - v.y);
res.z = -(2.0 * dot * n.z - v.z);
return res;
}
struct vec3 cross_product(struct vec3 v1, struct vec3 v2) {
struct vec3 res;
res.x = v1.y * v2.z - v1.z * v2.y;
res.y = v1.z * v2.x - v1.x * v2.z;
res.z = v1.x * v2.y - v1.y * v2.x;
return res;
}
/* determine the primary ray corresponding to the specified pixel (x, y) */
struct ray get_primary_ray(int x, int y, int sample) {
struct ray ray;
float m[3][3];
struct vec3 i, j = {0, 1, 0}, k, dir, orig, foo;
k.x = cam.targ.x - cam.pos.x;
k.y = cam.targ.y - cam.pos.y;
k.z = cam.targ.z - cam.pos.z;
NORMALIZE(k);
i = cross_product(j, k);
j = cross_product(k, i);
m[0][0] = i.x; m[0][1] = j.x; m[0][2] = k.x;
m[1][0] = i.y; m[1][1] = j.y; m[1][2] = k.y;
m[2][0] = i.z; m[2][1] = j.z; m[2][2] = k.z;
ray.orig.x = ray.orig.y = ray.orig.z = 0.0;
ray.dir = get_sample_pos(x, y, sample);
ray.dir.z = 1.0 / HALF_FOV;
ray.dir.x *= RAY_MAG;
ray.dir.y *= RAY_MAG;
ray.dir.z *= RAY_MAG;
dir.x = ray.dir.x + ray.orig.x;
dir.y = ray.dir.y + ray.orig.y;
dir.z = ray.dir.z + ray.orig.z;
foo.x = dir.x * m[0][0] + dir.y * m[0][1] + dir.z * m[0][2];
foo.y = dir.x * m[1][0] + dir.y * m[1][1] + dir.z * m[1][2];
foo.z = dir.x * m[2][0] + dir.y * m[2][1] + dir.z * m[2][2];
orig.x = ray.orig.x * m[0][0] + ray.orig.y * m[0][1] + ray.orig.z * m[0][2] + cam.pos.x;
orig.y = ray.orig.x * m[1][0] + ray.orig.y * m[1][1] + ray.orig.z * m[1][2] + cam.pos.y;
orig.z = ray.orig.x * m[2][0] + ray.orig.y * m[2][1] + ray.orig.z * m[2][2] + cam.pos.z;
ray.orig = orig;
ray.dir.x = foo.x + orig.x;
ray.dir.y = foo.y + orig.y;
ray.dir.z = foo.z + orig.z;
return ray;
}
struct vec3 get_sample_pos(int x, int y, int sample) {
struct vec3 pt;
double xsz = 2.0, ysz = xres / aspect;
static double sf = 0.0;
if(sf == 0.0) {
sf = 2.0 / (double)xres;
}
pt.x = ((double)x / (double)xres) - 0.5;
pt.y = -(((double)y / (double)yres) - 0.65) / aspect;
if(sample) {
struct vec3 jt = jitter(x, y, sample);
pt.x += jt.x * sf;
pt.y += jt.y * sf / aspect;
}
return pt;
}
/* jitter function taken from Graphics Gems I. */
struct vec3 jitter(int x, int y, int s) {
struct vec3 pt;
pt.x = urand[(x + (y << 2) + irand[(x + s) & MASK]) & MASK].x;
pt.y = urand[(y + (x << 2) + irand[(y + s) & MASK]) & MASK].y;
return pt;
}
/* Calculate ray-sphere intersection, and return {1, 0} to signify hit or no hit.
* Also the surface point parameters like position, normal, etc are returned through
* the sp pointer if it is not NULL.
*/
int ray_sphere(const struct sphere *sph, struct ray ray, struct spoint *sp) {
double a, b, c, d, sqrt_d, t1, t2;
a = SQ(ray.dir.x) + SQ(ray.dir.y) + SQ(ray.dir.z);
b = 2.0 * ray.dir.x * (ray.orig.x - sph->pos.x) +
2.0 * ray.dir.y * (ray.orig.y - sph->pos.y) +
2.0 * ray.dir.z * (ray.orig.z - sph->pos.z);
c = SQ(sph->pos.x) + SQ(sph->pos.y) + SQ(sph->pos.z) +
SQ(ray.orig.x) + SQ(ray.orig.y) + SQ(ray.orig.z) +
2.0 * (-sph->pos.x * ray.orig.x - sph->pos.y * ray.orig.y - sph->pos.z * ray.orig.z) - SQ(sph->rad);
if((d = SQ(b) - 4.0 * a * c) < 0.0) return 0;
sqrt_d = sqrt(d);
t1 = (-b + sqrt_d) / (2.0 * a);
t2 = (-b - sqrt_d) / (2.0 * a);
if((t1 < ERR_MARGIN && t2 < ERR_MARGIN) || (t1 > 1.0 && t2 > 1.0)) return 0;
if(sp) {
if(t1 < ERR_MARGIN) t1 = t2;
if(t2 < ERR_MARGIN) t2 = t1;
sp->dist = t1 < t2 ? t1 : t2;
sp->pos.x = ray.orig.x + ray.dir.x * sp->dist;
sp->pos.y = ray.orig.y + ray.dir.y * sp->dist;
sp->pos.z = ray.orig.z + ray.dir.z * sp->dist;
sp->normal.x = (sp->pos.x - sph->pos.x) / sph->rad;
sp->normal.y = (sp->pos.y - sph->pos.y) / sph->rad;
sp->normal.z = (sp->pos.z - sph->pos.z) / sph->rad;
sp->vref = reflect(ray.dir, sp->normal);
NORMALIZE(sp->vref);
}
return 1;
}
/* Load the scene from an extremely simple scene description file */
#define DELIM " \t\n"
void load_scene(FILE *fp) {
char line[256], *ptr, type;
obj_list = malloc(sizeof(struct sphere));
obj_list->next = 0;
while((ptr = fgets(line, 256, fp))) {
int i;
struct vec3 pos, col;
double rad, spow, refl;
while(*ptr == ' ' || *ptr == '\t') ptr++;
if(*ptr == '#' || *ptr == '\n') continue;
if(!(ptr = strtok(line, DELIM))) continue;
type = *ptr;
for(i=0; i<3; i++) {
if(!(ptr = strtok(0, DELIM))) break;
*((double*)&pos.x + i) = atof(ptr);
}
if(type == 'l') {
lights[lnum++] = pos;
continue;
}
if(!(ptr = strtok(0, DELIM))) continue;
rad = atof(ptr);
for(i=0; i<3; i++) {
if(!(ptr = strtok(0, DELIM))) break;
*((double*)&col.x + i) = atof(ptr);
}
if(type == 'c') {
cam.pos = pos;
cam.targ = col;
cam.fov = rad;
continue;
}
if(!(ptr = strtok(0, DELIM))) continue;
spow = atof(ptr);
if(!(ptr = strtok(0, DELIM))) continue;
refl = atof(ptr);
if(type == 's') {
struct sphere *sph = malloc(sizeof *sph);
sph->next = obj_list->next;
obj_list->next = sph;
sph->pos = pos;
sph->rad = rad;
sph->mat.col = col;
sph->mat.spow = spow;
sph->mat.refl = refl;
} else {
fprintf(stderr, "unknown type: %c\n", type);
}
}
}
/* provide a millisecond-resolution timer for each system */
#if defined(__unix__) || defined(unix)
#include <time.h>
#include <sys/time.h>
unsigned long get_msec(void) {
static struct timeval timeval, first_timeval;
gettimeofday(&timeval, 0);
if(first_timeval.tv_sec == 0) {
first_timeval = timeval;
return 0;
}
return (timeval.tv_sec - first_timeval.tv_sec) * 1000 + (timeval.tv_usec - first_timeval.tv_usec) / 1000;
}
#elif defined(__WIN32__) || defined(WIN32)
#include <windows.h>
unsigned long get_msec(void) {
return GetTickCount();
}
#else
#error "I don't know how to measure time on your platform"
#endif