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raytracer.c
304 lines (280 loc) · 7.45 KB
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raytracer.c
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#include "raytracer.h"
double double_max(double a, double b)
{
return a>b ? a : b;
}
hit_test intersect(ray r, sphere s)
{
hit_test result = {0}; /* {0} to quiet the compiler */
vec sc = s.center;
double sr = s.radius;
vec A = vec_sub(r.origin, sc);
double B = vec_dot(A, r.direction);
double C = vec_dot(A, A) - (sr * sr);
double D = (B * B) - C;
double t = (-B - sqrt(D));
result.miss = 1;
if (D > 0 && t > 0) {
result.miss = 0;
result.dist = t;
result.surf = s.surf;
result.shine = s.shine;
result.surf_norm = vec_norm(vec_sub(ray_position(r,t),sc));
}
return result;
}
int shadow(vec pt, light l, sphere_list *ss)
{
vec nudge = vec_scale(0.0001, l.direction);
vec lifted = vec_add(pt, nudge);
ray test_ray = {lifted, l.direction};
while (ss!=NULL) {
hit_test h = intersect(test_ray, ss->s);
if (!h.miss)
return 1;
ss = ss->next;
}
return 0;
}
int rgb_nonzero(rgb c)
{
return (c.r>0 || c.g>0 || c.b>0);
}
rgb lighting(scene s, ray r, hit_test h)
{
rgb result;
if (h.miss)
return s.bg;
vec hit_position = ray_position(r, h.dist);
if (shadow(hit_position, s.light, s.spheres)) {
result = rgb_modulate(h.surf, s.amb);
}
else {
double dot = vec_dot(h.surf_norm, s.light.direction);
double d = double_max(0, dot);
rgb diffuse_light = rgb_scale(d, s.light.color);
rgb lsum = rgb_add(s.amb, diffuse_light);
result = rgb_modulate(h.surf, lsum);
}
/**** === implement specular reflection here === ****/
if (rgb_nonzero(h.shine)) {
rgb ss;
vec N = h.surf_norm;
vec L = s.light.direction;
rgb S = h.shine;
vec R = vec_sub( vec_scale(2* vec_dot(N,L),N),L);
vec V = vec_neg(r.direction);
if (vec_dot(N,L)>0){
ss = rgb_scale( pow( double_max( vec_dot(R,V),0), 6), S);
//rgb_print(k);
}
else
ss = rgb_expr(0,0,0);
return rgb_add(result,ss);
}
return result;
}
vec logical_loc(camera c, vec p)
{
double pixw, pixh;
double lx, ly;
if (c.h>c.w)
pixh = pixw = 2.0 / c.h;
else
pixh = pixw = 2.0 / c.w;
if (p.x>c.w || p.y>c.h) {
fprintf(stderr, "logical_loc: bad position (%lg, %lg)\n", p.x, p.y);
exit(1);
}
lx = -1.0 + (pixw * p.x) + (pixw / 2.0);
ly = 1.0 - ((pixh * p.y) + (pixh / 2.0));
if (c.w>c.h)
ly -= (c.w-c.h) / 2.0 * pixh;
else
lx += (c.h-c.w) / 2.0 * pixw;
vec result = {lx, ly, 0};
return result;
}
rgb trace_ray(scene s, ray r)
{
hit_test closest_hit = {0}, /* {0} to quiet the compiler */
temp_hit = {0};
sphere_list *ss = s.spheres;
closest_hit.miss=1;
while (ss!=NULL) {
temp_hit = intersect(r, ss->s);
if (closest_hit.miss)
closest_hit = temp_hit;
else if (!(temp_hit.miss) && !(closest_hit.miss) &&
temp_hit.dist < closest_hit.dist)
closest_hit = temp_hit;
ss = ss->next;
}
return lighting(s, r, closest_hit);
}
void render(stage g)
{
int i, j;
camera c = g.c;
scene sc = g.s;
printf("P3\n");
printf("%d %d\n", c.w, c.h);
printf("255\n");
for(i=0; i < c.h; i++) {
for(j=0; j < c.w; j++) {
vec p = {j,i,0};
vec loc = logical_loc(c, p);
vec dir = vec_sub(loc, c.loc);
vec normdir = vec_norm(dir);
ray r = {c.loc, normdir};
rgb col = trace_ray(sc, r);
rgb_print_bytes(col);
}
}
}
/* ===== Project 2 Code ===== */
/* fintersect is like intersect, but uses the timestamp */
/* to compute the surface color and specular reflection */
/* color of the intersecting fsphere (if there is one) */
hit_test fintersect(ray r, fsphere s, timestamp ts)
{
hit_test result = {0}; /* {0} to quiet the compiler */
vec sc = s.center;
double sr = s.radius;
vec A = vec_sub(r.origin, sc);
double B = vec_dot(A, r.direction);
double C = vec_dot(A, A) - (sr * sr);
double D = (B * B) - C;
double t = (-B - sqrt(D));
result.miss = 1;
if (D > 0 && t > 0) {
result.miss = 0;
result.dist = t;
result.surf = s.compute_surf(s.center, ray_position(r,t), ts);
result.shine = s.compute_shine(ts);
result.surf_norm = vec_norm(vec_sub(ray_position(r,t),sc));
}
return result;
}
/* fshadow is like shadow, but needs to pass a timestamp */
/* to fintersect */
int fshadow(vec p, light l, fsphere_list *ss, timestamp ts)
{
vec nudge = vec_scale(0.0001, l.direction);
vec lifted = vec_add(p, nudge);
ray test_ray = {lifted, l.direction};
while (ss!=NULL) {
hit_test h = fintersect(test_ray, ss->s, ts);
if (!h.miss)
return 1;
ss = ss->next;
}
return 0;
}
/* flighting is like lighting, but consumes a frame */
/* rather than a scene */
rgb flighting(frame f, ray r, hit_test h)
{
rgb result;
if (h.miss)
return f.bg;
vec hit_position = ray_position(r, h.dist);
if (fshadow(hit_position, f.light, f.spheres, f.ts)) {
result = rgb_modulate(h.surf, f.amb);
}
else {
double dot = vec_dot(h.surf_norm, f.light.direction);
double d = double_max(0, dot);
rgb diffuse_light = rgb_scale(d, f.light.color);
rgb lsum = rgb_add(f.amb, diffuse_light);
result = rgb_modulate(h.surf, lsum);
}
/**** === implement specular reflection here === ****/
if (rgb_nonzero(h.shine)) {
rgb ss;
vec N = h.surf_norm;
vec L = f.light.direction;
rgb S = h.shine;
vec R = vec_sub( vec_scale(2* vec_dot(N,L),N),L);
vec V = vec_neg(r.direction);
if (vec_dot(N,L)>0){
ss = rgb_scale( pow( double_max( vec_dot(R,V),0), 6), S);
//rgb_print(k);
}
else
ss = rgb_expr(0,0,0);
return rgb_add(result,ss);
}
return result;
}
/* ftrace is like trace, but for frames rather than scenes */
rgb ftrace(ray r, frame f)
//rgb trace_ray(scene s, ray r)
{
hit_test closest_hit = {0}, /* {0} to quiet the compiler */
temp_hit = {0};
fsphere_list *ss = f.spheres;
closest_hit.miss=1;
while (ss!=NULL) {
temp_hit = fintersect(r, ss->s, f.ts);
if (closest_hit.miss)
closest_hit = temp_hit;
else if (!(temp_hit.miss) && !(closest_hit.miss) &&
temp_hit.dist < closest_hit.dist)
closest_hit = temp_hit;
ss = ss->next;
}
return flighting(f, r, closest_hit);
}
/* frender consumes a camera and a frame and renders the frame, */
/* writing a ppm file to the given filename */
/* - use fopen to open the file, and fclose when you're done */
void frender(camera c, frame f, char *filename)
//void render(stage g)
{
char name[32];
int i, j;
for (i=0; i<32; i++)
name[i]='\0';
sprintf(name, "%s.ppm", filename);
FILE *fp = fopen (name, "a");
fprintf(fp, "P3\n");
fprintf(fp, "%d %d\n", c.w, c.h);
fprintf(fp, "255\n");
for(i=0; i < c.h; i++) {
for(j=0; j < c.w; j++) {
vec p = {j,i,0};
vec loc = logical_loc(c, p);
vec dir = vec_sub(loc, c.loc);
vec normdir = vec_norm(dir);
ray r = {c.loc, normdir};
rgb col = ftrace(r, f);
//rgb_print_bytes(col);
fprintf(fp, "%d %d %d\n",bytify(col.r),bytify(col.g),bytify(col.b));
}
}
fclose(fp);
}
void frender_frames(fstage g, char *name_stem)
{
unsigned int frames = g.n_frames;
int i;
char tmp[16];
for (i=0; i<16; i++)
tmp[i]='\0';
for (i=0; i<frames; i++){
sprintf(tmp, "%s%06d", name_stem, i);
frender(g.c, g.compute_frame(i), tmp);
}
}
int main(int argc, char *argv[])
{
fstage g = get_fstage(NULL);
char name[16];
int i;
for (i=0; i<16; i++)
name[i]='\0';
sprintf(name, "Hithere");
frender_frames(g, name);
return 0;
}