#include <u.h>#include <libc.h>#include <draw.h>#include <memdraw.h>#include <geometry.h> #include "scene.h" Hittraceshadow(int depth, Obj *obj, Hit pos, Hit light){	Obj *o;	Hit hit, minhit; 	minhit.d = 0;	minhit.o = nil;	for(o = obj; o != nil; o = o->next){		if(o == pos.o)			continue;		switch(o->type){		case SPHERE:			hit = spherehit(o, pos.p, unit3(light.id));			break;		case PLANE:			hit = planehit(o, pos.p, unit3(light.id));			break;		case LIGHT:			hit = lighthit(o, pos.p, unit3(light.id));			break;		default:			hit.d = 0;			break;		}		if(minhit.d == 0 || (hit.d > 0 && hit.d < minhit.d))			minhit = hit;	} 	return minhit;} Colourblinnphong(Hit pos, Hit light){	Point3 h;	double specdot, bp; 	h = unit3(add3(neg3(unit3(pos.id)), unit3(light.id))); 	specdot = dot3(unit3(pos.n), h);	if(specdot < 0)		specdot = 0; 	bp = pow(specdot, 99); 	return cscale(light.c, bp);} Colourtracelight(int depth, Obj *obj, Hit pos){	Obj *o;	Hit hit, shadow;	Colour bp, bpt, c;	double ct; 	bp = (Colour){0, 0, 0};	c = (Colour){0, 0, 0};	for(o = obj; o != nil; o = o->next){		if(o->type != LIGHT)			continue;		hit = lighthit(o, pos.p, sub3(o->p, pos.p));		shadow = traceshadow(depth+1, obj, pos, hit);		if(shadow.d == 0 || shadow.o != hit.o)			continue; 		ct = dot3(unit3(hit.id), unit3(pos.n));		bpt = blinnphong(pos, hit);		if(ct < 0)			ct = 0;		c = csum(c, cscale(hit.c, ct));		bp = csum(bp, bpt);	} 	return csum(cmul(pos.c, c), bp);} Colourtracerefl(int depth, Obj *obj, Hit pos){	Point3 peps, refldir; 	peps = add3(pos.p, mul3(pos.n, 0.01));	refldir = sub3(pos.id, mul3(pos.n, 2*dot3(pos.id, pos.n))); 	return trace(depth, obj, peps, refldir);} Colourtrace(int depth, Obj *obj, Point3 e, Point3 d){	Obj *o;	Hit hit, minhit;	Colour c1, c2; 	if(depth > maxdepth)		return (Colour){0, 0, 0}; 	if(obj == nil)		return (Colour){0, 0, 0}; 	minhit.d = -1;	for(o = obj; o != nil; o = o->next){		if(o->type == PLANE)			hit = planehit(o, e, d);		else if(o->type == SPHERE)			hit = spherehit(o, e, d);		else			hit.d = -1; 		if(hit.d > 0)			if(hit.d < minhit.d || minhit.d <= 0){				minhit = hit;			}	} 	if(minhit.d <= 0)		return (Colour){0, 0, 0}; 	c1 = tracelight(depth+1, obj, minhit); 	c2 = tracerefl(depth+1, obj, minhit); 	return csum(cscale(c2, 0.5), c1);}