Add NEE for heterogenous media.

Assignments/Assignment2/Application2.cpp

@@ -141,11 +141,175 @@ Vec3fa Application2::renderPixel(float x, float y, const ISPCCamera& camera, Ray
         return renderPixelHomogeneous(x, y, camera, stats, sampler);
     } else if (selected == 2) {
         return renderPixelHeterogeneous(x, y, camera, stats, sampler);
+    } else if (selected == 3) {
+        return renderPixelHeterogeneousNEE(x, y, camera, stats, sampler);
     } else {
         return Vec3fa(0.0f);
     }
 }
 
+Vec3fa Application2::renderPixelHeterogeneousNEE(float x, float y, const ISPCCamera& camera, RayStats& stats, RandomSampler& sampler) {
+
+    Vec3fa L = Vec3fa(0.0f);
+    Vec3fa Lw = Vec3fa(1.0f);
+
+    bool in_volume = false;
+    float max_density = 1.32 * density; // tested
+
+    /* initialize ray */
+    Ray ray(Vec3fa(camera.xfm.p), Vec3fa(normalize(x * camera.xfm.l.vx + y * camera.xfm.l.vy + camera.xfm.l.vz)), 0.0f,
+            inf);
+
+    for (int i = 0; i < ray_depth; i++) {
+
+
+        /* intersect ray with scene */
+        RTCIntersectArguments iargs;
+        rtcInitIntersectArguments(&iargs);
+        iargs.feature_mask = RTC_FEATURE_FLAG_TRIANGLE;
+        rtcIntersect1(data.g_scene, RTCRayHit_(ray), &iargs);
+        RayStats_addRay(stats);
+
+        const Vec3fa wo = neg(ray.dir);
+
+        float t;
+        if (!in_volume | (density == 0)) {
+            t = inf;
+        } else {
+            // printf("%f\n", density);
+            t = - std::log(1.0 - RandomSampler_get1D(sampler)) / max_density;
+        }
+
+        if (t > 0.0 && t < ray.tfar) {
+
+            if (ray.geomID == RTC_INVALID_GEOMETRY_ID) {
+                // printf("here(%f,%f,%f)\n", ray.org.x, ray.org.y, ray.org.z);
+                break;
+            }
+
+            float r = RandomSampler_get1D(sampler);
+            Vec3fa p = ray.org + t * ray.dir;
+            // printf("%f\t%f\t(%f,%f,%f)\n", t, ray.tfar, p.x, p.y, p.z);
+            float s = data.densityGrid->sampleW(p);
+            // if (s != -1.0) {
+            //     printf("(%f,%f,%f)\tt: %f\ttfar: %f\tr: %f\t%f\ts: %f\t%f\tp:%f\n",p.x, p.y, p.z, t, ray.tfar, r, r * max_density, s, s * density, (s * density) / max_density);
+            // }
+            // if (s > 0.5) {
+            //     printf("(%f,%f,%f)\tr: %f\t%f\ts: %f\t%f\tp:%f\n",p.x, p.y, p.z , r, r * max_density, s, s * density, (s * density) / max_density);
+            // }
+
+            if (RandomSampler_get1D(sampler) * max_density < s * density) {
+
+                // NEE
+                int id = (int)(RandomSampler_get1D(sampler) * data.scene->lights.size());
+                if (id == data.scene->lights.size())
+                    id = data.scene->lights.size() - 1;
+                const Light* l = data.scene->lights.at(id);
+                Sample sample;
+                sample.P = ray.org + t * ray.dir;
+                sample.Ng = ray.dir;
+                sample.Ns = ray.dir;
+
+                Light_SampleRes ls = Lights_sample(l, sample, RandomSampler_get2D(sampler));
+
+                /* initialize shadow ray */
+                Ray shadow(sample.P, ls.dir, EPS, ls.dist - EPS, 0.0f);
+                
+                /* trace shadow ray */
+                RTCOccludedArguments sargs;
+                rtcInitOccludedArguments(&sargs);
+                sargs.feature_mask = RTC_FEATURE_FLAG_TRIANGLE;
+                rtcOccluded1(data.g_scene, RTCRay_(shadow), &sargs);
+                RayStats_addShadowRay(stats);
+
+                if (shadow.tfar >= 0.0) {
+
+                    float nee_T = 1.0;
+                    float nee_t = 0.0;
+                    while (1) {
+                        float r = RandomSampler_get1D(sampler);
+
+                        nee_t -= std::log(1 - r) / max_density;
+                        
+                        if (shadow.tfar >= nee_t) {
+                            break;
+                        }
+
+                        nee_T *= 1 - data.densityGrid->sampleW(shadow.org + nee_t * shadow.dir) / max_density;
+                
+                    }
+
+                    float scatter = phase(scattering_parameter, -dot(-ray.dir,shadow.dir));
+                    /* add light contribution if not occluded (NEE) */
+                    L += Lw * nee_T * scatter * (1.0 - absorbtion) * ls.weight / data.scene->lights.size();
+                    
+                }
+                
+                
+                float pdf;
+                Vec3fa o = sample_phase_function(-ray.dir, scattering_parameter, RandomSampler_get2D(sampler), pdf);
+
+                float temp = data.tempGrid->sampleW(p); // Sample density from the grid
+                // float temp = 20;
+                float redWavelength = 700;
+                float greenWavelength = 530;
+                float blueWavelength = 470;
+                Vec3fa emissive = Vec3fa(0.0, 0.0, 0.0);
+                if (temp != -1.0f && temp > 0.001) {
+                    temp *= tempearture_multiplier;
+                    emissive = Vec3f(blackbody_radiance_normalized(redWavelength, temp),
+                                     blackbody_radiance_normalized(greenWavelength, temp),
+                                     blackbody_radiance_normalized(blueWavelength, temp));
+                }
+                
+                L += Lw * absorbtion * emissive;
+                Lw *= 1.0 - absorbtion;
+
+                ray = Ray(ray.org + t * ray.dir,o,EPS,inf);
+                
+            } else {
+                // printf("volume(%f,%f,%f), t: %f, tfar: %f\n", ray.org.x, ray.org.y, ray.org.z, t, ray.tfar);
+                ray = Ray(ray.org + t * ray.dir, ray.dir, EPS, inf);
+                i--;
+            }
+
+        } else if (ray.geomID != RTC_INVALID_GEOMETRY_ID) {
+
+            Sample sample = createSample(ray);
+            int matId = data.scene->geometries.at(ray.geomID)->materialID;
+            unsigned lightID = data.scene->geometries.at(ray.geomID)->lightID;
+            
+            if (lightID != unsigned(-1)) {
+                if (i == 0) {
+                    const Light* l = data.scene->lights[lightID];
+                    Light_EvalRes evalRes = Lights_eval(l, sample, -wo);
+                    L += Lw * evalRes.value;
+                }
+                break;
+            }
+            
+            /* calculate BRDF */
+            BRDF brdf;
+            std::vector<Material *> material_array = data.scene->materials;
+            Material__preprocess(material_array, matId, brdf, wo, sample);
+            if (brdf.name == "default") {
+                // printf("surface\n");
+
+                in_volume = !in_volume;
+                // in_volume = dot(normalize(ray.Ng), ray.dir) < 0;
+                
+                ray = Ray(ray.org + ray.tfar * ray.dir, ray.dir, EPS, inf);
+
+                i--;
+
+            }
+        }
+
+    }
+    
+    return L;
+}
+
 Vec3fa Application2::renderPixelHeterogeneous(float x, float y, const ISPCCamera& camera, RayStats& stats, RandomSampler& sampler) {
 
     Vec3fa L = Vec3fa(0.0f);
@@ -181,6 +345,7 @@ Vec3fa Application2::renderPixelHeterogeneous(float x, float y, const ISPCCamera
         if (t > 0.0 && t < ray.tfar) {
 
             if (ray.geomID == RTC_INVALID_GEOMETRY_ID) {
+                // printf("here(%f,%f,%f)\n", ray.org.x, ray.org.y, ray.org.z);
                 break;
             }
 

Assignments/Assignment2/Application2.h

@@ -14,6 +14,7 @@ private:
     Vec3fa renderPixelOrig(float x, float y, const ISPCCamera& camera, RayStats& stats, RandomSampler& sampler);
     Vec3fa renderPixelHomogeneous(float x, float y, const ISPCCamera& camera, RayStats& stats, RandomSampler& sampler);
     Vec3fa renderPixelHeterogeneous(float x, float y, const ISPCCamera& camera, RayStats& stats, RandomSampler& sampler);
+    Vec3fa renderPixelHeterogeneousNEE(float x, float y, const ISPCCamera& camera, RayStats& stats, RandomSampler& sampler);
 
     void drawGUI() override {
         ImGui::Checkbox("Bounding Box", &boundingBox);
@@ -24,8 +25,8 @@ private:
             ray_depth = 1;
         }
 
-        const char* items[] = {"Original", "Homogeneous", "Heterogeneous"};
+        const char* items[] = {"Original", "Homogeneous", "Heterogeneous", "HeterogeneousNEE"};
-        if (ImGui::Combo("Version", &selected, items, 3))
+        if (ImGui::Combo("Version", &selected, items, 4))
             clear();
 
         if (ImGui::SliderFloat("density", &density, 0.0, 1.0))