C++ vec3f::multiply方法代码示例

vec3f RayTracer::traceRay( Scene *scene, const ray& r, 
	const vec3f& thresh, int depth, isect& i, vector<const SceneObject*>& stack )
{
	if( depth>=0
		&& thresh[0] > threshold - RAY_EPSILON && thresh[1] > threshold - RAY_EPSILON && thresh[2] > threshold - RAY_EPSILON
		&& scene->intersect( r, i ) ) {
		// YOUR CODE HERE

		// An intersection occured!  We've got work to do.  For now,
		// this code gets the material for the surface that was intersected,
		// and asks that material to provide a color for the ray.  

		// This is a great place to insert code for recursive ray tracing.
		// Instead of just returning the result of shade(), add some
		// more steps: add in the contributions from reflected and refracted
		// rays.
		
		const Material& m = i.getMaterial();
		vec3f color = m.shade(scene, r, i);
		//calculate the reflected ray
		vec3f d = r.getDirection();
		vec3f position = r.at(i.t);
		vec3f direction = d - 2 * i.N * d.dot(i.N);
		ray newray(position, direction);
		if(!m.kr.iszero()) {
			vec3f reflect = m.kr.multiply(traceRay(scene, newray, thresh.multiply(m.kr), depth-1, stack).clamp());
			color += reflect;
		}

		//calculate the refracted ray
		double ref_ratio;
		double sin_ang = d.cross(i.N).length();
		vec3f N = i.N;
		//Decide going in or out
		const SceneObject *mi = NULL, *mt = NULL;
		int stack_idx = -1;
		vector<const SceneObject*>::reverse_iterator itr;
		//1 use the normal to decide whether to go in or out
		//0: travel through, 1: in, 2: out
		char travel = 0;
		if(i.N.dot(d) <= -RAY_EPSILON) {
			//from outer surface in
			//test whether the object has two face
			ray test_ray(r.at(i.t) + d * 2 * RAY_EPSILON, -d);
			isect test_i;
			if(i.obj->intersect(r, test_i) && test_i.N.dot(N) > -RAY_EPSILON) {
				//has interior
				travel = 1;
			}
		}
		else {
			travel = 2;
		}

		if(travel == 1) {
			if(!stack.empty()) {
				mi = stack.back();
			}
			mt = i.obj;
			stack.push_back(mt);
		}
		else if(travel == 2) {
			//if it is in our stack, then we must pop it
			for(itr = stack.rbegin(); itr != stack.rend(); ++itr) {
				if(*itr == i.obj) {
					mi = *itr;
					vector<const SceneObject*>::iterator ii = itr.base() - 1;
					stack_idx = ii - stack.begin();
					stack.erase(ii);
					break;
				}
			}
			if(!stack.empty()) {
				mt = stack.back();
			}
		}

		if(N.dot(d) >= RAY_EPSILON) {
			N = -N;
		}
		
		ref_ratio = (mi?(mi->getMaterial().index):1.0) / (mt?(mt->getMaterial().index):1.0);

		if(!m.kt.iszero() && (ref_ratio < 1.0 + RAY_EPSILON || sin_ang < 1.0 / ref_ratio + RAY_EPSILON)) {
			//No total internal reflection
			//We do refraction now
			double c = N.dot(-d);
			direction = (ref_ratio * c - sqrt(1 - ref_ratio * ref_ratio * (1 - c * c))) * N + ref_ratio * d;
			newray = ray(position, direction);
			vec3f refraction = m.kt.multiply(traceRay(scene, newray, thresh.multiply(m.kt), depth-1, stack).clamp());
			color += refraction;
		}

		if(travel == 1) {
			stack.pop_back();
		}
		else if(travel == 2) {
			if(mi) {
				stack.insert(stack.begin() + stack_idx, mi);
			}
//.........这里部分代码省略.........