C++ BSDF::SampleF方法代码示例

//.........这里部分代码省略.........
			SWCSpectrum Le(pathThroughput);
			if (isect.Le(sample, ray, &ibsdf, NULL, NULL, &Le)) {
				L[isect.arealight->group] += Le;
				V[isect.arealight->group] += Le.Filter(sw) * VContrib;
			}
		}


		const Point &p = bsdf->dgShading.p;
		const Normal &n = bsdf->dgShading.nn;

		// Estimate direct lighting
		if (renderer->sppmi->directLightSampling && (nLights > 0)) {
			for (u_int i = 0; i < lightGroupCount; ++i) {
				Ld[i] = 0.f;
				Vd[i] = 0.f;
			}

			renderer->sppmi->hints.SampleLights(scene, sample, p, n,
				wo, bsdf, pathLength, pathThroughput, Ld, &Vd);

			for (u_int i = 0; i < lightGroupCount; ++i) {
				L[i] += Ld[i];
				V[i] += Vd[i] * VContrib;
			}
		}

		// Choose between storing or bouncing the hitpoint on the surface
		bool const has_store_component = bsdf->NumComponents(store_component) > 0;
		bool const has_bounce_component = bsdf->NumComponents(bounce_component) > 0;

		float pdf_event;
		bool store;

		if (has_store_component && has_bounce_component)
		{
			// There is both bounce and store component, we choose with a
			// random number
			// TODO: do this by importance
			store = data[4] < .5f;
			pdf_event = 0.5;
		}
		else
		{
			// If there is only bounce/store component, we bounce/store
			// accordingly
			store = has_store_component;
			pdf_event = 1.f;
		}

		if(store)
		{
			hp->SetSurface();
			hpep->pathThroughput = pathThroughput * rayWeight / pdf_event * invPixelPdf;
			hpep->wo = wo;

			hpep->bsdf = bsdf;
			hpep->single = sw.single;
			sample.arena.Commit();
			break;
		}

		// Sample BSDF to get new path direction
		Vector wi;
		float pdf;
		BxDFType flags;
		SWCSpectrum f;
		if (pathLength == maxDepth || !bsdf->SampleF(sw, wo, &wi,
			data[1], data[2], data[3], &f, &pdf, bounce_component, &flags,
			NULL, true)) {
			hp->SetConstant();
			break;
		}

		if (flags != (BSDF_TRANSMISSION | BSDF_SPECULAR) ||
			!(bsdf->Pdf(sw, wi, wo, BxDFType(BSDF_TRANSMISSION | BSDF_SPECULAR)) > 0.f))
		{
			++vertexIndex;
			specularBounce = (flags & BSDF_SPECULAR) != 0;
		}

		pathThroughput *= f / pdf_event;
		if (pathThroughput.Black()) {
			hp->SetConstant();
			break;
		}

		ray = Ray(p, wi);
		ray.time = sample.realTime;
		volume = bsdf->GetVolume(wi);
	}
	for(unsigned int i = 0; i < lightGroupCount; ++i)
	{
		if (!L[i].Black())
			V[i] /= L[i].Filter(sw);
		sample.AddContribution(hp->imageX, hp->imageY,
			XYZColor(sw, L[i]) * rayWeight, hp->eyePass.alpha, hp->eyePass.distance,
			0, renderer->sppmi->bufferEyeId, i);
	}
}

//.........这里部分代码省略.........
			}
		}

		// trace Diffuse reflection & transmission rays
		if (rayDepth < diffuseReflectDepth) {
			ComputeEvent(scene, sample, bsdf, wo, diffuseReflectSamples,
				indirectDiffuseReflectSampleOffset, indirectDiffuseReflectComponentOffset,
				diffuseReflectSampleOffset, diffuseReflectComponentOffset,
				BxDFType(BSDF_REFLECTION | BSDF_DIFFUSE),
				diffuseReflectReject, diffuseReflectRejectThreshold,
				L, alpha, zdepth, rayDepth, nrContribs);
		}
		if (rayDepth < diffuseRefractDepth) {
			ComputeEvent(scene, sample, bsdf, wo, diffuseRefractSamples,
				indirectDiffuseRefractSampleOffset, indirectDiffuseRefractComponentOffset,
				diffuseRefractSampleOffset, diffuseRefractComponentOffset,
				BxDFType(BSDF_TRANSMISSION | BSDF_DIFFUSE),
				diffuseRefractReject, diffuseRefractRejectThreshold,
				L, alpha, zdepth, rayDepth, nrContribs);
		}

		// trace Glossy reflection & transmission rays
		if (rayDepth < glossyReflectDepth) {
			ComputeEvent(scene, sample, bsdf, wo, glossyReflectSamples,
				indirectGlossyReflectSampleOffset, indirectGlossyReflectComponentOffset,
				glossyReflectSampleOffset, glossyReflectComponentOffset,
				BxDFType(BSDF_REFLECTION | BSDF_GLOSSY),
				glossyReflectReject, glossyReflectRejectThreshold,
				L, alpha, zdepth, rayDepth, nrContribs);
		}
		if (rayDepth < glossyRefractDepth) {
			ComputeEvent(scene, sample, bsdf, wo, glossyRefractSamples,
				indirectGlossyRefractSampleOffset, indirectGlossyRefractComponentOffset,
				glossyRefractSampleOffset, glossyRefractComponentOffset,
				BxDFType(BSDF_TRANSMISSION | BSDF_GLOSSY),
				glossyRefractReject, glossyRefractRejectThreshold,
				L, alpha, zdepth, rayDepth, nrContribs);
		}
		
		// trace specular reflection & transmission rays
		if (rayDepth < specularReflectDepth) {
			float pdf;
			Vector wi;
			SWCSpectrum f;
			if (bsdf->SampleF(sw, wo, &wi, .5f, .5f, .5f, &f, &pdf,
				BxDFType(BSDF_REFLECTION | BSDF_SPECULAR),
				NULL, NULL, true)) {
				Ray rd(p, wi);
				rd.time = time;
				vector<SWCSpectrum> Ll(L.size(),
					SWCSpectrum(0.f));
				LiInternal(scene, sample, bsdf->GetVolume(wi),
					bsdf->dgShading.scattered, rd, Ll,
					alpha, zdepth, rayDepth + 1, true,
					nrContribs);
				for (u_int j = 0; j < L.size(); ++j)
					L[j] += f * Ll[j];
			}
		}
		if (rayDepth < specularRefractDepth) {
			float pdf;
			Vector wi;
			SWCSpectrum f;
			if (bsdf->SampleF(sw, wo, &wi, .5f, .5f, .5f, &f, &pdf,
				BxDFType(BSDF_TRANSMISSION | BSDF_SPECULAR),
				NULL, NULL, true)) {
				Ray rd(p, wi);
				rd.time = time;
				vector<SWCSpectrum> Ll(L.size(),
					SWCSpectrum(0.f));
				LiInternal(scene, sample, bsdf->GetVolume(wi),
					bsdf->dgShading.scattered, rd, Ll,
					alpha, zdepth, rayDepth + 1, true,
					nrContribs);
				for (u_int j = 0; j < L.size(); ++j)
					L[j] += f * Ll[j];
			}
		}
	} else {
		// Handle ray with no intersection
		BSDF *ibsdf;
		for (u_int i = 0; i < scene.lights.size(); ++i) {
			SWCSpectrum Le(1.f);
			if (scene.lights[i]->Le(scene, sample, ray, &ibsdf,
				NULL, NULL, &Le)) {
				L[scene.lights[i]->group] += Le;
				++nrContribs;
			}
		}
		if (rayDepth == 0)
			*alpha = 0.f;
	}
	Lt /= spdf;

	for (u_int i = 0; i < L.size(); ++i)
		L[i] *= Lt;
	SWCSpectrum Lv(0.f);
	u_int g = scene.volumeIntegrator->Li(scene, ray, sample, &Lv, alpha);
	L[g] += Lv;
}