Fix #34226: cycles shadow pass got incorrectly influenced by world multiple

importance sampleing.

5 files changed, 20 insertions, 12 deletions

diff --git a/intern/cycles/device/device_cuda.cpp b/intern/cycles/device/device_cuda.cpp
index 0c590645808..399414d5966 100644
--- a/intern/cycles/device/device_cuda.cpp
+++ b/intern/cycles/device/device_cuda.cpp
@@ -109,11 +109,11 @@ public:
 		}
 	}
 
-#ifdef NDEBUG
+/*#ifdef NDEBUG
 #define cuda_abort()
 #else
 #define cuda_abort() abort()
-#endif
+#endif*/
 
 #define cuda_assert(stmt) \
 	{ \
diff --git a/intern/cycles/kernel/kernel_emission.h b/intern/cycles/kernel/kernel_emission.h
index 3b27a1f49c9..9787af535bb 100644
--- a/intern/cycles/kernel/kernel_emission.h
+++ b/intern/cycles/kernel/kernel_emission.h
@@ -141,7 +141,7 @@ __device_noinline bool direct_emission(KernelGlobals *kg, ShaderData *sd, int li
 	}
 
 	/* return if it's a lamp for shadow pass */
-	*is_lamp = (ls.prim == ~0);
+	*is_lamp = (ls.prim == ~0 && ls.type != LIGHT_BACKGROUND);
 
 	return true;
 }
diff --git a/intern/cycles/kernel/kernel_passes.h b/intern/cycles/kernel/kernel_passes.h
index 727639386ed..57dbdc2ffc1 100644
--- a/intern/cycles/kernel/kernel_passes.h
+++ b/intern/cycles/kernel/kernel_passes.h
@@ -125,14 +125,7 @@ __device_inline void kernel_write_light_passes(KernelGlobals *kg, __global float
 		kernel_write_pass_float3(buffer + kernel_data.film.pass_transmission_color, sample, L->color_transmission);
 	if(flag & PASS_SHADOW) {
 		float4 shadow = L->shadow;
-
-		/* bit of an ugly hack to compensate for emitting triangles influencing
-		 * amount of samples we get for this pass */
-		if(kernel_data.integrator.progressive && kernel_data.integrator.pdf_triangles != 0.0f)
-			shadow.w = 0.5f;
-		else
-			shadow.w = 1.0f;
-
+		shadow.w = kernel_data.film.pass_shadow_scale;
 		kernel_write_pass_float4(buffer + kernel_data.film.pass_shadow, sample, shadow);
 	}
 #endif
diff --git a/intern/cycles/kernel/kernel_types.h b/intern/cycles/kernel/kernel_types.h
index 773ea0c43fb..ddbda9240fb 100644
--- a/intern/cycles/kernel/kernel_types.h
+++ b/intern/cycles/kernel/kernel_types.h
@@ -610,9 +610,9 @@ typedef struct KernelFilm {
 	int pass_ao;
 
 	int pass_shadow;
+	float pass_shadow_scale;
 	int pass_pad1;
 	int pass_pad2;
-	int pass_pad3;
 } KernelFilm;
 
 typedef struct KernelBackground {
diff --git a/intern/cycles/render/light.cpp b/intern/cycles/render/light.cpp
index e7fb9514371..ccc6c5142bd 100644
--- a/intern/cycles/render/light.cpp
+++ b/intern/cycles/render/light.cpp
@@ -143,6 +143,7 @@ void LightManager::device_update_distribution(Device *device, DeviceScene *dscen
 
 	/* count */
 	size_t num_lights = scene->lights.size();
+	size_t num_background_lights = 0;
 	size_t num_triangles = 0;
 	size_t num_curve_segments = 0;
 
@@ -306,6 +307,8 @@ void LightManager::device_update_distribution(Device *device, DeviceScene *dscen
 
 		if(light->size > 0.0f && light->use_mis)
 			use_lamp_mis = true;
+		if(light->type == LIGHT_BACKGROUND)
+			num_background_lights++;
 	}
 
 	/* normalize cumulative distribution functions */
@@ -324,6 +327,7 @@ void LightManager::device_update_distribution(Device *device, DeviceScene *dscen
 
 	/* update device */
 	KernelIntegrator *kintegrator = &dscene->data.integrator;
+	KernelFilm *kfilm = &dscene->data.film;
 	kintegrator->use_direct_light = (totarea > 0.0f);
 
 	if(kintegrator->use_direct_light) {
@@ -354,6 +358,16 @@ void LightManager::device_update_distribution(Device *device, DeviceScene *dscen
 
 		kintegrator->use_lamp_mis = use_lamp_mis;
 
+		/* bit of an ugly hack to compensate for emitting triangles influencing
+		 * amount of samples we get for this pass */
+		if(scene->integrator->progressive && kintegrator->pdf_triangles != 0.0f)
+			kfilm->pass_shadow_scale = 0.5f;
+		else
+			kfilm->pass_shadow_scale = 1.0f;
+
+		if(num_background_lights < num_lights)
+			kfilm->pass_shadow_scale *= (float)(num_lights - num_background_lights)/(float)num_lights;
+
 		/* CDF */
 		device->tex_alloc("__light_distribution", dscene->light_distribution);
 	}
@@ -366,6 +380,7 @@ void LightManager::device_update_distribution(Device *device, DeviceScene *dscen
 		kintegrator->pdf_lights = 0.0f;
 		kintegrator->inv_pdf_lights = 0.0f;
 		kintegrator->use_lamp_mis = false;
+		kfilm->pass_shadow_scale = 1.0f;
 	}
 }