Update render loop, added priority test in render-mx-medium-vdf-glass

Author: ThyOwen

Testing/Temporary/CTestCostData.txt

@@ -0,0 +1 @@
+---

src/cmake/testing.cmake

@@ -373,6 +373,7 @@ macro (osl_add_all_tests)
                 render-mx-layer
                 render-mx-sheen
                 render-mx-medium-vdf
+                render-mx-medium-vdf-glass
 		render-microfacet render-oren-nayar
                 render-spi-thinlayer
                 render-uv render-veachmis render-ward

src/testrender/shading.cpp

@@ -1573,25 +1573,21 @@ struct HomogeneousVolume final : public Medium {
         return volume;
     }
 
-    OSL_HOSTDEVICE Medium::Sample sample(const Ray &ray, Sampler &sampler, Intersection& hit) const
+    OSL_HOSTDEVICE Medium::Sample sample(Ray& r, Sampler &sampler, Intersection& hit) const
     {
         Vec3 rand_vol = sampler.get();
-        float max_sigma_t = fmaxf(fmaxf(params.sigma_t.x, params.sigma_t.y), params.sigma_t.z);
 
-        float t_volume = -logf(1.0f - rand_vol.x) / max_sigma_t;
+        float t_volume = -logf(1.0f - rand_vol.x) / params.avg_sigma_t();
         bool volume_scatter = (t_volume < hit.t);
 
         Color3 weight;
         Color3 tr;
 
         if (volume_scatter) {
+            r.origin = r.point(t_volume);
             tr = transmittance(t_volume);
 
-            Color3 albedo = Color3(
-                params.sigma_s.x / params.sigma_t.x,
-                params.sigma_s.y / params.sigma_t.y,
-                params.sigma_s.z / params.sigma_t.z
-            );
+            Color3 albedo = params.sigma_s / params.sigma_t;
 
             weight = albedo / tr;
         } else {
@@ -1631,7 +1627,7 @@ struct EmptyVolume final : public Medium {
         return volume;
     }
 
-    OSL_HOSTDEVICE Medium::Sample sample(const Ray &ray, Sampler &sampler, Intersection& hit) const
+    OSL_HOSTDEVICE Medium::Sample sample(Ray& ray, Sampler &sampler, Intersection& hit) const
     {
         return { false, 0.0f, Color3(1.0f), Color3(1.0f) };
     }
@@ -1783,7 +1779,7 @@ process_medium_closure(const ShaderGlobalsType& sg, float path_roughness,
             result.medium_data.medium_g              = params.anisotropy;
             result.medium_data.priority              = 0;
 
-            if (!sg.backfacing) { // if entering
+            if (!sg.backfacing) { // if entering 
                 if (result.medium_data.is_vaccum()) {
                     medium_stack.add_medium<EmptyVolume>(result.medium_data);
                 } else {
@@ -1812,7 +1808,7 @@ process_medium_closure(const ShaderGlobalsType& sg, float path_roughness,
             result.medium_data.refraction_ior = sg.backfacing ? 1.0f / params.ior : params.ior;
             result.medium_data.priority = params.priority;
 
-            if (!sg.backfacing) { // if entering
+            if (!sg.backfacing) { // if entering 
                 if (result.medium_data.is_vaccum()) {
                     medium_stack.add_medium<EmptyVolume>(result.medium_data);
                 } else {
@@ -1840,25 +1836,25 @@ process_medium_closure(const ShaderGlobalsType& sg, float path_roughness,
             break;
         }
         case MX_GENERALIZED_SCHLICK_ID: {
-        const ClosureComponent* comp = closure->as_comp();
-        const auto& params = *comp->as<MxGeneralizedSchlickParams>();
-        if (!is_black(weight * comp->w * params.transmission_tint)) {
-            float avg_F0  = clamp((params.f0.x + params.f0.y + params.f0.z) / 3.0f,
-                                  0.0f, 0.99f);
-            float sqrt_F0 = sqrtf(avg_F0);
-            float ior     = (1 + sqrt_F0) / (1 - sqrt_F0);
-            float new_ior = sg.backfacing ? 1.0f / ior : ior;
-            
-            result.medium_data.refraction_ior = new_ior; 
+            const ClosureComponent* comp = closure->as_comp();
+            const auto& params = *comp->as<MxGeneralizedSchlickParams>();
+            if (!is_black(weight * comp->w * params.transmission_tint)) {
+                float avg_F0  = clamp((params.f0.x + params.f0.y + params.f0.z) / 3.0f,
+                                    0.0f, 0.99f);
+                float sqrt_F0 = sqrtf(avg_F0);
+                float ior     = (1 + sqrt_F0) / (1 - sqrt_F0);
+                float new_ior = sg.backfacing ? 1.0f / ior : ior;
+                
+                result.medium_data.refraction_ior = new_ior; 
 
-            const MediumParams* current_params = medium_stack.current_params();
-            if (current_params && result.medium_data.priority <= current_params->priority) {
-                result.medium_data.refraction_ior = current_params->refraction_ior;
+                const MediumParams* current_params = medium_stack.current_params();
+                if (current_params && result.medium_data.priority <= current_params->priority) {
+                    result.medium_data.refraction_ior = current_params->refraction_ior;
+                }
             }
+            closure = nullptr;
+            break;
         }
-        closure = nullptr;
-        break;
-    }
         default: closure = nullptr; break;
         }
         if (closure == nullptr && stack_idx > 0) {
@@ -2194,7 +2190,7 @@ BSDF::sample_vrtl(const Vec3& wo, float rx, float ry, float rz) const
     return dispatch([&](auto bsdf) { return bsdf.sample(wo, rx, ry, rz); });
 }
 
-Medium::Sample Medium::sample_vrtl(const Ray &ray, Sampler &sampler, Intersection& hit) const
+Medium::Sample Medium::sample_vrtl(Ray& ray, Sampler &sampler, Intersection& hit) const
 {
     return dispatch([&](const auto& medium) { return medium.sample(ray, sampler, hit); });
 }

src/testrender/shading.h

@@ -230,7 +230,7 @@ struct MxMediumVdfParams {
 
 struct MediumParams {
     Color3 sigma_t       = Color3(0.0f); // extinction coefficient
-    Color3 sigma_s       = Color3(0.0f); //scattering 
+    Color3 sigma_s       = Color3(0.0f); // scattering 
     float medium_g       = 0.0f;  // volumetric anisotropy
     float refraction_ior = 1.0f;
     int priority         = 0;
@@ -244,6 +244,10 @@ struct MediumParams {
         return priority == 0;
     }
 
+    OSL_HOSTDEVICE float avg_sigma_t() const {
+        return (sigma_t.x + sigma_t.y + sigma_t.z) / 3;
+    }
+
     OSL_HOSTDEVICE bool operator==(const MediumParams &rhs) const {
         return refraction_ior == rhs.refraction_ior &&
             medium_g == rhs.medium_g &&
@@ -377,16 +381,16 @@ struct has_equal<T, std::void_t<decltype(std::declval<const T&>() == std::declva
 
 struct Medium : public AbstractMedium {
     struct Sample {
-        OSL_HOSTDEVICE Sample()
-            : scatter(false), t(0.0f), transmittance(0.0f), weight(0.0f)
+        OSL_HOSTDEVICE Sample() : 
+            scatter(false), t(0.0f), transmittance(0.0f), weight(0.0f)
         {
         }
-        OSL_HOSTDEVICE Sample(const Sample& o)
-            : scatter(o.scatter), t(o.t), transmittance(o.transmittance), weight(o.weight)
+        OSL_HOSTDEVICE Sample(const Sample& o) : 
+            scatter(o.scatter), t(o.t), transmittance(o.transmittance), weight(o.weight)
         {
         }
-        OSL_HOSTDEVICE Sample(bool scatter, float t, Color3 transmittance, Color3 weight)
-            : scatter(scatter), t(t), transmittance(transmittance), weight(weight)
+        OSL_HOSTDEVICE Sample(bool scatter, float t, Color3 transmittance, Color3 weight) : 
+            scatter(scatter), t(t), transmittance(transmittance), weight(weight)
         {
         }
         bool scatter; 
@@ -396,7 +400,7 @@ struct Medium : public AbstractMedium {
     };
 
     template<typename LOBE>
-    OSL_HOSTDEVICE Medium(LOBE* lobe) : AbstractMedium(lobe)
+    OSL_HOSTDEVICE Medium(LOBE* lobe) : AbstractMedium(lobe), phase_func(nullptr)
     {
     }
 
@@ -410,11 +414,11 @@ struct Medium : public AbstractMedium {
         return {};
     }
 
-    OSL_HOSTDEVICE Sample sample(const Ray &ray, Sampler &sampler, Intersection& hit) const {
+    OSL_HOSTDEVICE Sample sample(Ray &r, Sampler &sampler, Intersection& hit) const {
         return {};
     }
 
-    OSL_HOSTDEVICE Sample sample_vrtl(const Ray &ray, Sampler &sampler, Intersection& hit) const;
+    OSL_HOSTDEVICE Sample sample_vrtl(Ray &r, Sampler &sampler, Intersection& hit) const;
 
     OSL_HOSTDEVICE const MediumParams* get_params_vrtl() const;
 
@@ -554,7 +558,7 @@ struct MediumStack {
     }
 
     OSL_HOSTDEVICE const MediumParams* current_params() const {
-        if (depth > 0) {
+        if (depth > 0 && mediums[0]) {
             const MediumParams* params = mediums[0]->get_params_vrtl();
             if (params) {
                 return params;
@@ -567,21 +571,77 @@ struct MediumStack {
 
     OSL_HOSTDEVICE int size() const { return depth; }
 
+    OSL_HOSTDEVICE bool integrate(Ray& r, Sampler& sampler, Intersection& hit, Color3& path_weight, Color3& path_radiance, float& bsdf_pdf) const 
+    {
+        if (depth <= 0) {
+            return false;
+        }
+        
+        Medium::Sample combined_sample{ false, 1.0f, Color3(1.0f), Color3(1.0f) };
+        
+        for (int i = 0; i < depth; ++i) {
+            Medium::Sample s = mediums[i]->sample_vrtl(r, sampler, hit);
+            
+            combined_sample.transmittance *= s.transmittance;
+            combined_sample.weight *= s.weight;
+            
+            combined_sample.scatter = s.scatter || combined_sample.scatter;
+            combined_sample.t = s.t < combined_sample.t ? s.t : combined_sample.t;
+        }
+
+        if (!(combined_sample.transmittance.x > 0 || combined_sample.transmittance.y > 0 || combined_sample.transmittance.z > 0)) {
+            return false;
+        }
+
+        path_weight *= combined_sample.transmittance;
+
+        Vec3 rand_phase = sampler.get();
+        if (combined_sample.scatter) {
+            if (!mediums[0]->phase_func) {
+                return false;
+            }
+            BSDF::Sample phase_sample = mediums[0]->phase_func->sample_vrtl(-r.direction, 
+                                                        rand_phase.x, 
+                                                        rand_phase.y, 
+                                                        rand_phase.z);
+            if (phase_sample.pdf <= 0.0f) {
+                return false;
+            }
+
+            path_weight *= phase_sample.weight;
+            r.direction = phase_sample.wi;
+            bsdf_pdf = phase_sample.pdf;
+            return true;
+        }
+        
+        return false;
+    }
+
     template<typename Medium_Type, typename... Medium_Args>
     OSL_HOSTDEVICE bool add_medium(Medium_Args&&... args) {
 
-        Medium_Type* new_medium = Medium_Type::create(pool + num_bytes, std::forward<Medium_Args>(args)...);
-
         if (depth >= MaxEntries)
             return false;
 
         if (num_bytes + sizeof(Medium_Type) > MaxSize)
             return false;
 
+        Medium_Type* new_medium = Medium_Type::create(pool + num_bytes, std::forward<Medium_Args>(args)...);
+        
+        if (!new_medium) {
+            return false;
+        }
+
+        const MediumParams* new_params = new_medium->get_params_vrtl();
         int insert_pos = depth;
 
         for (int i = 0; i < depth; ++i) {
-            if (new_medium->get_params_vrtl()->priority > mediums[i]->get_params_vrtl()->priority) {
+            if (!mediums[i]) {
+                continue;
+            }
+            
+            const MediumParams* existing_params = mediums[i]->get_params_vrtl();
+            if (existing_params && new_params->priority > existing_params->priority) {
                 insert_pos = i;
                 break;
             } 
@@ -601,12 +661,6 @@ struct MediumStack {
     OSL_HOSTDEVICE void pop_medium()
     {
         if (depth > 0) {
-            mediums[0]->~Medium();
-            
-            for (int i = 1; i < depth; ++i) {
-                mediums[i - 1] = mediums[i];
-            }
-            
             depth--;
         }
     }
@@ -615,6 +669,7 @@ struct MediumStack {
         const MediumParams* current = current_params();
         return (current && ((params.priority < current->priority) || (params.is_special_priority() && current->is_special_priority() && depth > 1)));
     }
+
 private:
     /// Never try to copy this struct because it would invalidate the medium pointers
     OSL_HOSTDEVICE MediumStack(const MediumStack& c);
@@ -624,6 +679,7 @@ struct MediumStack {
     enum { MaxSize = 256 * sizeof(float) };
 
     Medium* mediums[MaxEntries];
+    float cdf[MaxEntries];
     char pool[MaxSize];
     int depth, num_bytes;
 };

src/testrender/simpleraytracer.cpp

@@ -994,36 +994,8 @@ SimpleRaytracer::subpixel_radiance(float x, float y, Sampler& sampler,
             break;
         }
 
-        const Medium* medium = medium_stack.current(); 
-        bool in_medium = medium_stack.in_medium();
-
-        if (in_medium && medium) {
-            Medium::Sample medium_sample = medium->sample_vrtl(r, sampler, hit);
-            
-            path_weight *= medium_sample.transmittance;
-            
-            if (!(path_weight.x > 0 || path_weight.y > 0 || path_weight.z > 0)) {
-                break;
-            }
-            
-            if (medium_sample.scatter) {
-                r.origin = r.point(medium_sample.t);
-
-                Vec3 rand_phase = sampler.get();
-                BSDF::Sample phase_sample = medium->phase_func->sample_vrtl(-r.direction, 
-                                                            rand_phase.x, 
-                                                            rand_phase.y, 
-                                                            rand_phase.z);
-                if (phase_sample.pdf <= 0.0f) {
-                    break;
-                }
-
-                path_weight *= phase_sample.weight;
-                r.direction = phase_sample.wi;
-                bsdf_pdf = phase_sample.pdf;
-                continue;
-            }
-            
+        if (medium_stack.integrate(r, sampler, hit, path_weight, path_radiance, bsdf_pdf)) {
+            continue;
         }
 
         // construct a shader globals for the hit point
@@ -1191,7 +1163,7 @@ SimpleRaytracer::subpixel_radiance(float x, float y, Sampler& sampler,
         r.spread    = std::max(r.spread, p.roughness);
         r.roughness = p.roughness;
 
-        if (sg.backfacing) {
+        if (sg.backfacing) { // if exiting
             medium_stack.pop_medium();
         }
 

testsuite/render-mx-medium-vdf/glossy.osl …ite/render-mx-anisotropic-vdf/glossy.osltestsuite/render-mx-medium-vdf/glossy.osl renamed to testsuite/render-mx-anisotropic-vdf/glossy.osl testsuite/render-mx-medium-vdf/glossy.osl renamed to testsuite/render-mx-anisotropic-vdf/glossy.osl

@@ -22,14 +22,20 @@ glossy
     float anisotropy = 0.0
         [[  string description = "Anisotropy of the surface",
             float UImin = 0, float UImax = 1 ]],
+    float transmission_depth = 1.0
+        [[  string description = "Mean free path (0.0 is black, infinity is transparent)",
+            float UImin = 0, float UImax = 100 ]],
+    float medium_anisotropy = 1.0
+        [[  string description = "Anisotropy of the medium",
+            float UImin = 0, float UImax = 100 ]],
     int priority = 0
-        [[  string description = "Priority of the medium. Zero is a special 'off' priority",
+        [[  string description = "Priority for overlapping mediums. Zero is a special 'off' priority",
             float UImin = 0, float UImax = 8 ]], // Same as MaxEntries in MediumStack
   )
 {
     float alpha = roughness * roughness;
     float alpha_x = alpha * (1.0 - anisotropy);
     float alpha_y = alpha;
     vector U = normalize(cross(N, dPdv));
-    Ci = dielectric_bsdf(N, U, Cr, Ct, alpha_x, alpha_y, ior, "ggx") + medium_vdf(Cr, 1.0, color(0.5), 0.0, ior, priority);
+    Ci = dielectric_bsdf(N, U, Cr, Ct, alpha_x, alpha_y, ior, "ggx") + medium_vdf(color(0.5), transmission_depth, Cr, 0.0, ior, priority);
 }

testsuite/render-mx-anisotropic-vdf/run.py

@@ -7,6 +7,4 @@
 failthresh = 0.01
 failpercent = 1
 outputs = [ "out.exr" ]
-command = testrender("-r 256 256 -aa 16 scene.xml out.exr")
-
-# Note: we pick this test arbitrarily as the one to verify llvm_opt=12 works
+command = testrender("-r 196 196 -aa 48 scene.xml out.exr")