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Project Information
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(Last update: 20 May, 2012)
AO bench is a small ambient occlusion renderer for benchmarking realworld floating point performance in various languages. AO bench is originally coded in "Proce55ing":http://processing.org/. AO bench consists just about 400 lines of code and requires only standard math functions, therefore it is easy to understand and port AO bench for your favorite language. Follow me at twitter for updates: http://twitter.com/aobench Media and publications
Revision 2012 (PC-64k intro) - SCOTTIE by qatnonoil & kioku/System K & Machia ( aobench was used as a loading screen for demoscene )
AO bench debut at SC11! aobench was cited in
Languages and performancesHere's list of languages AO bench was ported to. Your effort to porting AO bench to another language or reporting performance of AO bench is appreciate(let me know your work by following "aobench@twitter":http://twitter.com/aobench or by mail).
C version code#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <assert.h>
#include <math.h>
#define WIDTH 256
#define HEIGHT 256
#define NSUBSAMPLES 2
#define NAO_SAMPLES 8
typedef struct _vec
{
double x;
double y;
double z;
} vec;
typedef struct _Isect
{
double t;
vec p;
vec n;
int hit;
} Isect;
typedef struct _Sphere
{
vec center;
double radius;
} Sphere;
typedef struct _Plane
{
vec p;
vec n;
} Plane;
typedef struct _Ray
{
vec org;
vec dir;
} Ray;
Sphere spheres[3];
Plane plane;
static double vdot(vec v0, vec v1)
{
return v0.x * v1.x + v0.y * v1.y + v0.z * v1.z;
}
static void vcross(vec *c, vec v0, vec v1)
{
c->x = v0.y * v1.z - v0.z * v1.y;
c->y = v0.z * v1.x - v0.x * v1.z;
c->z = v0.x * v1.y - v0.y * v1.x;
}
static void vnormalize(vec *c)
{
double length = sqrt(vdot((*c), (*c)));
if (fabs(length) > 1.0e-17) {
c->x /= length;
c->y /= length;
c->z /= length;
}
}
void
ray_sphere_intersect(Isect *isect, const Ray *ray, const Sphere *sphere)
{
vec rs;
rs.x = ray->org.x - sphere->center.x;
rs.y = ray->org.y - sphere->center.y;
rs.z = ray->org.z - sphere->center.z;
double B = vdot(rs, ray->dir);
double C = vdot(rs, rs) - sphere->radius * sphere->radius;
double D = B * B - C;
if (D > 0.0) {
double t = -B - sqrt(D);
if ((t > 0.0) && (t < isect->t)) {
isect->t = t;
isect->hit = 1;
isect->p.x = ray->org.x + ray->dir.x * t;
isect->p.y = ray->org.y + ray->dir.y * t;
isect->p.z = ray->org.z + ray->dir.z * t;
isect->n.x = isect->p.x - sphere->center.x;
isect->n.y = isect->p.y - sphere->center.y;
isect->n.z = isect->p.z - sphere->center.z;
vnormalize(&(isect->n));
}
}
}
void
ray_plane_intersect(Isect *isect, const Ray *ray, const Plane *plane)
{
double d = -vdot(plane->p, plane->n);
double v = vdot(ray->dir, plane->n);
if (fabs(v) < 1.0e-17) return;
double t = -(vdot(ray->org, plane->n) + d) / v;
if ((t > 0.0) && (t < isect->t)) {
isect->t = t;
isect->hit = 1;
isect->p.x = ray->org.x + ray->dir.x * t;
isect->p.y = ray->org.y + ray->dir.y * t;
isect->p.z = ray->org.z + ray->dir.z * t;
isect->n = plane->n;
}
}
void
orthoBasis(vec *basis, vec n)
{
basis[2] = n;
basis[1].x = 0.0; basis[1].y = 0.0; basis[1].z = 0.0;
if ((n.x < 0.6) && (n.x > -0.6)) {
basis[1].x = 1.0;
} else if ((n.y < 0.6) && (n.y > -0.6)) {
basis[1].y = 1.0;
} else if ((n.z < 0.6) && (n.z > -0.6)) {
basis[1].z = 1.0;
} else {
basis[1].x = 1.0;
}
vcross(&basis[0], basis[1], basis[2]);
vnormalize(&basis[0]);
vcross(&basis[1], basis[2], basis[0]);
vnormalize(&basis[1]);
}
void ambient_occlusion(vec *col, const Isect *isect)
{
int i, j;
int ntheta = NAO_SAMPLES;
int nphi = NAO_SAMPLES;
double eps = 0.0001;
vec p;
p.x = isect->p.x + eps * isect->n.x;
p.y = isect->p.y + eps * isect->n.y;
p.z = isect->p.z + eps * isect->n.z;
vec basis[3];
orthoBasis(basis, isect->n);
double occlusion = 0.0;
for (j = 0; j < ntheta; j++) {
for (i = 0; i < nphi; i++) {
double theta = sqrt(drand48());
double phi = 2.0 * M_PI * drand48();
double x = cos(phi) * theta;
double y = sin(phi) * theta;
double z = sqrt(1.0 - theta * theta);
// local -> global
double rx = x * basis[0].x + y * basis[1].x + z * basis[2].x;
double ry = x * basis[0].y + y * basis[1].y + z * basis[2].y;
double rz = x * basis[0].z + y * basis[1].z + z * basis[2].z;
Ray ray;
ray.org = p;
ray.dir.x = rx;
ray.dir.y = ry;
ray.dir.z = rz;
Isect occIsect;
occIsect.t = 1.0e+17;
occIsect.hit = 0;
ray_sphere_intersect(&occIsect, &ray, &spheres[0]);
ray_sphere_intersect(&occIsect, &ray, &spheres[1]);
ray_sphere_intersect(&occIsect, &ray, &spheres[2]);
ray_plane_intersect (&occIsect, &ray, &plane);
if (occIsect.hit) occlusion += 1.0;
}
}
occlusion = (ntheta * nphi - occlusion) / (double)(ntheta * nphi);
col->x = occlusion;
col->y = occlusion;
col->z = occlusion;
}
unsigned char
clamp(double f)
{
int i = (int)(f * 255.5);
if (i < 0) i = 0;
if (i > 255) i = 255;
return (unsigned char)i;
}
void
render(unsigned char *img, int w, int h, int nsubsamples)
{
int x, y;
int u, v;
double *fimg = (double *)malloc(sizeof(double) * w * h * 3);
memset((void *)fimg, 0, sizeof(double) * w * h * 3);
for (y = 0; y < h; y++) {
for (x = 0; x < w; x++) {
for (v = 0; v < nsubsamples; v++) {
for (u = 0; u < nsubsamples; u++) {
double px = (x + (u / (double)nsubsamples) - (w / 2.0)) / (w / 2.0);
double py = -(y + (v / (double)nsubsamples) - (h / 2.0)) / (h / 2.0);
Ray ray;
ray.org.x = 0.0;
ray.org.y = 0.0;
ray.org.z = 0.0;
ray.dir.x = px;
ray.dir.y = py;
ray.dir.z = -1.0;
vnormalize(&(ray.dir));
Isect isect;
isect.t = 1.0e+17;
isect.hit = 0;
ray_sphere_intersect(&isect, &ray, &spheres[0]);
ray_sphere_intersect(&isect, &ray, &spheres[1]);
ray_sphere_intersect(&isect, &ray, &spheres[2]);
ray_plane_intersect (&isect, &ray, &plane);
if (isect.hit) {
vec col;
ambient_occlusion(&col, &isect);
fimg[3 * (y * w + x) + 0] += col.x;
fimg[3 * (y * w + x) + 1] += col.y;
fimg[3 * (y * w + x) + 2] += col.z;
}
}
}
fimg[3 * (y * w + x) + 0] /= (double)(nsubsamples * nsubsamples);
fimg[3 * (y * w + x) + 1] /= (double)(nsubsamples * nsubsamples);
fimg[3 * (y * w + x) + 2] /= (double)(nsubsamples * nsubsamples);
img[3 * (y * w + x) + 0] = clamp(fimg[3 *(y * w + x) + 0]);
img[3 * (y * w + x) + 1] = clamp(fimg[3 *(y * w + x) + 1]);
img[3 * (y * w + x) + 2] = clamp(fimg[3 *(y * w + x) + 2]);
}
}
}
void
init_scene()
{
spheres[0].center.x = -2.0;
spheres[0].center.y = 0.0;
spheres[0].center.z = -3.5;
spheres[0].radius = 0.5;
spheres[1].center.x = -0.5;
spheres[1].center.y = 0.0;
spheres[1].center.z = -3.0;
spheres[1].radius = 0.5;
spheres[2].center.x = 1.0;
spheres[2].center.y = 0.0;
spheres[2].center.z = -2.2;
spheres[2].radius = 0.5;
plane.p.x = 0.0;
plane.p.y = -0.5;
plane.p.z = 0.0;
plane.n.x = 0.0;
plane.n.y = 1.0;
plane.n.z = 0.0;
}
void
saveppm(const char *fname, int w, int h, unsigned char *img)
{
FILE *fp;
fp = fopen(fname, "wb");
assert(fp);
fprintf(fp, "P6\n");
fprintf(fp, "%d %d\n", w, h);
fprintf(fp, "255\n");
fwrite(img, w * h * 3, 1, fp);
fclose(fp);
}
int
main(int argc, char **argv)
{
unsigned char *img = (unsigned char *)malloc(WIDTH * HEIGHT * 3);
init_scene();
render(img, WIDTH, HEIGHT, NSUBSAMPLES);
saveppm("ao.ppm", WIDTH, HEIGHT, img);
return 0;
}Images
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