Add MIS
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c48475ca52
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2 changed files with 164 additions and 19 deletions
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@ -1,12 +1,14 @@
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#include "Application1.h"
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#include "helper.hpp"
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#include "lights/light.h"
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#include "math/constants.h"
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#include "math/vec3fa.h"
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#include "random_sampler.hpp"
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#include "ray.hpp"
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#include "sampling.hpp"
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#include <cmath>
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#define EPS 0.1f
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#define EPS 0.01f
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void Application1::initScene() {
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Data_Constructor(&data, 1, 8);
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@ -20,14 +22,14 @@ void Application1::standardScene() {
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FileName file = workingDir + FileName("Framework/scenes/cornell_box.obj");
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/* set default camera */
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camera.from = Vec3fa(278, 273, -800);
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camera.from = Vec3fa(278, 273, -300);
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camera.to = Vec3fa(278, 273, 0);
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Ref<SceneGraph::GroupNode> sceneGraph = loadOBJ(file, false).cast<SceneGraph::GroupNode>();
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auto light = new SceneGraph::QuadLightMesh(Vec3fa(343.0, 548.0, 227.0), Vec3fa(213.0, 548.0, 332.0),
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Vec3fa(343.0, 548.0, 332.0),
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Vec3fa(213.0, 548.0, 227.0), Vec3fa(100, 100, 100));
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Vec3fa(213.0, 548.0, 227.0), Vec3fa(1, 1, 1) * 25);
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sceneGraph->add(light);
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Ref<SceneGraph::GroupNode> flattened_scene = SceneGraph::flatten(sceneGraph, SceneGraph::INSTANCING_NONE);
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@ -54,7 +56,7 @@ void Application1::veachScene() {
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auto light = new SceneGraph::QuadLightMesh(Vec3fa(549.6, 0.0, 559.2), Vec3fa(0.0, 548.8, 559.2),
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Vec3fa(0.0, 0.0, 559.2), Vec3fa(556.0, 548.8, 559.2),
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Vec3fa(10, 10, 10));
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Vec3fa(0.1, 0.1, 0.1) * 25);
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sceneGraph->add(light);
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@ -70,6 +72,7 @@ void Application1::veachScene() {
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scene = nullptr;
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}
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// Function that selects implementation at runtime
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Vec3fa Application1::renderPixel(float x, float y, const ISPCCamera& camera, RayStats& stats, RandomSampler& sampler) {
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if (selected == 0) {
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return renderPixelOrig(x, y, camera, stats, sampler);
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@ -77,11 +80,148 @@ Vec3fa Application1::renderPixel(float x, float y, const ISPCCamera& camera, Ray
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return renderPixelPathTracer(x, y, camera, stats, sampler);
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} else if (selected == 2) {
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return renderPixelNextEventEstimation(x, y, camera, stats, sampler);
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} else if (selected == 3) {
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return renderPixelMIS(x, y, camera, stats, sampler);
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} else {
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return Vec3fa(0.0f);
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}
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}
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Vec3fa Application1::renderPixelMIS(float x, float y, const ISPCCamera& camera, RayStats& stats, RandomSampler& sampler) {
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/* radiance accumulator and weight */
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Vec3fa L = Vec3fa(0.0f);
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Vec3fa Lw = Vec3fa(1.0f);
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/* initialize ray */
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Ray ray(Vec3fa(camera.xfm.p), Vec3fa(normalize(x * camera.xfm.l.vx + y * camera.xfm.l.vy + camera.xfm.l.vz)), 0.0f,
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inf);
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// normal vector of last vertex. Necessary for calculating the mis wheights.
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Vec3fa last_normal = ray.dir;
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for (int i = 0; i < ray_depth; i++) {
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/* intersect ray with scene */
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RTCIntersectArguments iargs;
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rtcInitIntersectArguments(&iargs);
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iargs.feature_mask = RTC_FEATURE_FLAG_TRIANGLE;
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rtcIntersect1(data.g_scene, RTCRayHit_(ray), &iargs);
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RayStats_addRay(stats);
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const Vec3fa wo = neg(ray.dir);
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/* shade pixels */
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if (ray.geomID == RTC_INVALID_GEOMETRY_ID) {
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break;
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}
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Vec3fa Ns = normalize(ray.Ng);
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Sample sample;
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sample.P = ray.org + ray.tfar * ray.dir;
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sample.Ng = ray.Ng;
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sample.Ns = Ns;
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int matId = data.scene->geometries[ray.geomID]->materialID;
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unsigned lightID = data.scene->geometries[ray.geomID]->lightID;
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sample.Ng = face_forward(ray.dir, normalize(sample.Ng));
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sample.Ns = face_forward(ray.dir, normalize(sample.Ns));
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// If a light is hit by ray
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if (lightID != unsigned(-1)) {
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const Light* l = data.scene->lights[lightID];
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Light_EvalRes evalRes = Lights_eval(l, sample, -wo);
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// Calculate MIS wheight
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float dist = ray.tfar / length(ray.dir);
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float nee_pdf;
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if (evalRes.dist == 0.0) {
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// nee_pdf = (evalRes.pdf / data.scene->lights.size()) * (dist * dist) / (std::abs(dot(ray.dir, sample.Ng) * dot(last_normal, ray.dir)));
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nee_pdf = (evalRes.pdf / data.scene->lights.size()) * (dist * dist) / (std::abs(dot(ray.dir, sample.Ng)));
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} else {
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nee_pdf = 0.0;
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}
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float path_pdf = cosineSampleHemispherePDF(dot(last_normal, ray.dir));
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if (i == 0) {
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nee_pdf = 0.0;
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path_pdf = 1.0;
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}
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// apply pwer heuristic
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nee_pdf = std::pow(nee_pdf, beta);
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path_pdf = std::pow(path_pdf, beta);
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float b = (path_pdf / (path_pdf + nee_pdf));
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// test for debugging invalid wheights
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if (b > 1.0 || b != b || b < 0.0) {
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printf("b (Path Tracing): %f, %f, %f, %f, %f\n",b, nee_pdf, path_pdf, dot(ray.dir, sample.Ng), evalRes.dist);
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}
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L += b * Lw * evalRes.value;
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break;
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}
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/* calculate BRDF */
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BRDF brdf;
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std::vector<Material *> material_array = data.scene->materials;
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Material__preprocess(material_array, matId, brdf, wo, sample);
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/* Light ray */
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int id = (int)(RandomSampler_get1D(sampler) * data.scene->lights.size());
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if (id == data.scene->lights.size())
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id = data.scene->lights.size() - 1;
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const Light* l = data.scene->lights[id];
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Light_SampleRes ls = Lights_sample(l, sample, RandomSampler_get2D(sampler));
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Vec3fa light_diffuse = Material__eval(material_array, matId, brdf, wo, sample, ls.dir);
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/* initialize shadow ray */
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Ray shadow(sample.P, ls.dir, EPS, ls.dist - EPS, 0.0f);
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/* trace shadow ray */
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RTCOccludedArguments sargs;
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rtcInitOccludedArguments(&sargs);
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sargs.feature_mask = RTC_FEATURE_FLAG_TRIANGLE;
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rtcOccluded1(data.g_scene, RTCRay_(shadow), &sargs);
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RayStats_addShadowRay(stats);
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/* add light contribution if not occluded (NEE) */
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if (shadow.tfar >= 0.0f) {
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// L += Lw * light_diffuse * ls.weight;
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// calculate MIS wheights
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float nee_pdf = ls.pdf / data.scene->lights.size();
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float path_pdf = cosineSampleHemispherePDF(std::abs(dot(sample.Ng, ls.dir)));
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// apply pwer heuristic
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nee_pdf = std::pow(nee_pdf, beta);
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path_pdf = std::pow(path_pdf, beta);
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float b = (nee_pdf / (nee_pdf + path_pdf));
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if (nee_pdf == INFINITY) {
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b = 1.0;
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}
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if (b > 1.0 || b != b || b < 0.0) {
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printf("b (NEE): %f, %f, %f\n",b, nee_pdf, path_pdf);
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}
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L += b * Lw * light_diffuse * ls.weight * dot(sample.Ng, ls.dir) / data.scene->lights.size();
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}
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// Use cosine sampling
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Vec2f uv = RandomSampler_get2D(sampler);
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Sample3f wi = cosineSampleHemisphere(uv.x, uv.y, sample.Ng);
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Vec3fa diffuse = Material__eval(material_array, matId, brdf, wo, sample, wi.v);
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Lw *= M_PI * diffuse;
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ray = Ray(sample.P,wi.v,EPS,inf);
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last_normal = sample.Ng;
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}
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return L;
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}
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Vec3fa Application1::renderPixelNextEventEstimation(float x, float y, const ISPCCamera& camera, RayStats& stats, RandomSampler& sampler) {
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/* radiance accumulator and weight */
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Vec3fa L = Vec3fa(0.0f);
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@ -118,11 +258,12 @@ Vec3fa Application1::renderPixelNextEventEstimation(float x, float y, const ISPC
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sample.Ng = face_forward(ray.dir, normalize(sample.Ng));
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sample.Ns = face_forward(ray.dir, normalize(sample.Ns));
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// include direct light on first ray
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if (lightID != unsigned(-1)) {
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if (i == 0) {
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const Light* l = data.scene->lights[lightID];
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Light_EvalRes evalRes = Lights_eval(l, sample, -wo);
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L += Lw * evalRes.value * dot(sample.Ng, -ray.dir);
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L += Lw * evalRes.value;
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}
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break;
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}
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@ -152,18 +293,19 @@ Vec3fa Application1::renderPixelNextEventEstimation(float x, float y, const ISPC
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rtcOccluded1(data.g_scene, RTCRay_(shadow), &sargs);
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RayStats_addShadowRay(stats);
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/* add light contribution if not occluded */
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/* add light contribution if not occluded (NEE) */
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if (shadow.tfar >= 0.0f) {
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// L += Lw * light_diffuse * ls.weight;
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L += Lw * light_diffuse * ls.weight * dot(sample.Ng, ls.dir) / data.scene->lights.size();
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// L += Lw * light_diffuse * ls.weight/ data.scene->lights.size();
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}
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/* sample BRDF at hit point */
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// Use cosine sampling
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Vec2f uv = RandomSampler_get2D(sampler);
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Sample3f wi;
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Sample3f wi = cosineSampleHemisphere(uv.x, uv.y, sample.Ng);
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Vec3fa diffuse = Material__sample(material_array, matId, brdf, Lw, wo, sample, wi, uv);
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Vec3fa diffuse = Material__eval(material_array, matId, brdf, wo, sample, wi.v);
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Lw *= M_PI * diffuse;
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@ -211,10 +353,11 @@ Vec3fa Application1::renderPixelPathTracer(float x, float y, const ISPCCamera& c
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sample.Ng = face_forward(ray.dir, normalize(sample.Ng));
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sample.Ns = face_forward(ray.dir, normalize(sample.Ns));
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// evaluate light
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if (lightID != unsigned(-1)) {
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const Light* l = data.scene->lights[lightID];
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Light_EvalRes evalRes = Lights_eval(l, sample, -wo);
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return Lw * evalRes.value * dot(wo, sample.Ng);
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return Lw * evalRes.value;
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break;
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}
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@ -223,12 +366,12 @@ Vec3fa Application1::renderPixelPathTracer(float x, float y, const ISPCCamera& c
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std::vector<Material *> material_array = data.scene->materials;
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Material__preprocess(material_array, matId, brdf, wo, sample);
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/* sample BRDF at hit point */
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// Use cosine sampling
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Vec2f uv = RandomSampler_get2D(sampler);
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Sample3f wi;
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Sample3f wi = cosineSampleHemisphere(uv.x, uv.y, sample.Ng);
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Vec3fa diffuse = Material__sample(material_array, matId, brdf, Lw, wo, sample, wi, uv);
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Vec3fa diffuse = Material__eval(material_array, matId, brdf, wo, sample, wi.v);
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Lw *= M_PI * diffuse;
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@ -239,7 +382,7 @@ Vec3fa Application1::renderPixelPathTracer(float x, float y, const ISPCCamera& c
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return L;
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}
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/* task that renders a single screen tile */
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/* task that renders a single screen tile (original implementation) */
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Vec3fa Application1::renderPixelOrig(float x, float y, const ISPCCamera& camera, RayStats& stats, RandomSampler& sampler) {
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/* radiance accumulator and weight */
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Vec3fa L = Vec3fa(0.0f);
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@ -13,16 +13,18 @@ private:
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Vec3fa renderPixelOrig(float x, float y, const ISPCCamera& camera, RayStats& stats, RandomSampler& sampler);
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Vec3fa renderPixelPathTracer(float x, float y, const ISPCCamera& camera, RayStats& stats, RandomSampler& sampler);
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Vec3fa renderPixelNextEventEstimation(float x, float y, const ISPCCamera& camera, RayStats& stats, RandomSampler& sampler);
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Vec3fa renderPixelMIS(float x, float y, const ISPCCamera& camera, RayStats& stats, RandomSampler& sampler);
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void drawGUI() override {
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ImGui::ColorEdit3("Color", colorLight);
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ImGui::InputInt("Ray depth", &ray_depth);
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if (ray_depth < 1) {
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ray_depth = 1;
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}
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const char* items[] = {"Original", "Path Tracer", "Next Event Estimation"};
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ImGui::Combo("Version", &selected, items, 3);
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ImGui::SliderFloat("beta", &beta, 0.1, 10.0);
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const char* items[] = {"Original", "Path Tracer", "Next Event Estimation", "Multiple Importance Sampling"};
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ImGui::Combo("Version", &selected, items, 4);
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const char* scenes[] = {"Cornell", "Veach"};
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int oldscene = scene;
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@ -44,9 +46,9 @@ private:
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void veachScene();
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float colorLight[3] = {1.0f, 1.0f, 1.0f};
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int ray_depth = 5;
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int selected = 0;
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int scene = 0;
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float beta = 1.0;
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};
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