Fix #35207: addition to previous fix to avoid OSL getting uninitialized

ray differentials for lighting, which could cause bad texture filtering
artifacts or performance.

7 files changed, 41 insertions, 29 deletions

diff --git a/intern/cycles/kernel/kernel_camera.h b/intern/cycles/kernel/kernel_camera.h
index fe31419b11e..13f2f84691d 100644
--- a/intern/cycles/kernel/kernel_camera.h
+++ b/intern/cycles/kernel/kernel_camera.h
@@ -76,8 +76,7 @@ __device void camera_sample_perspective(KernelGlobals *kg, float raster_x, float
 	/* ray differential */
 	float3 Ddiff = transform_direction(&cameratoworld, Pcamera);
 
-	ray->dP.dx = make_float3(0.0f, 0.0f, 0.0f);
-	ray->dP.dy = make_float3(0.0f, 0.0f, 0.0f);
+	ray->dP = differential3_zero();
 
 	ray->dD.dx = normalize(Ddiff + float4_to_float3(kernel_data.cam.dx)) - normalize(Ddiff);
 	ray->dD.dy = normalize(Ddiff + float4_to_float3(kernel_data.cam.dy)) - normalize(Ddiff);
@@ -138,8 +137,7 @@ __device void camera_sample_orthographic(KernelGlobals *kg, float raster_x, floa
 	ray->dP.dx = float4_to_float3(kernel_data.cam.dx);
 	ray->dP.dy = float4_to_float3(kernel_data.cam.dy);
 
-	ray->dD.dx = make_float3(0.0f, 0.0f, 0.0f);
-	ray->dD.dy = make_float3(0.0f, 0.0f, 0.0f);
+	ray->dD = differential3_zero();
 #endif
 
 #ifdef __CAMERA_CLIPPING__
@@ -209,8 +207,7 @@ __device void camera_sample_panorama(KernelGlobals *kg, float raster_x, float ra
 
 #ifdef __RAY_DIFFERENTIALS__
 	/* ray differential */
-	ray->dP.dx = make_float3(0.0f, 0.0f, 0.0f);
-	ray->dP.dy = make_float3(0.0f, 0.0f, 0.0f);
+	ray->dP = differential3_zero();
 
 	Pcamera = transform_perspective(&rastertocamera, make_float3(raster_x + 1.0f, raster_y, 0.0f));
 	ray->dD.dx = normalize(transform_direction(&cameratoworld, panorama_to_direction(kg, Pcamera.x, Pcamera.y))) - ray->D;
diff --git a/intern/cycles/kernel/kernel_differential.h b/intern/cycles/kernel/kernel_differential.h
index 2190e04e231..c5332786f8b 100644
--- a/intern/cycles/kernel/kernel_differential.h
+++ b/intern/cycles/kernel/kernel_differential.h
@@ -86,5 +86,23 @@ __device void differential_dudv(differential *du, differential *dv, float3 dPdu,
 	dv->dy = (dP.dy.y*dPdu.x - dP.dy.x*dPdu.y)*det;
 }
 
+__device differential differential_zero()
+{
+	differential d;
+	d.dx = 0.0f;
+	d.dy = 0.0f;
+
+	return d;
+}
+
+__device differential3 differential3_zero()
+{
+	differential3 d;
+	d.dx = make_float3(0.0f, 0.0f, 0.0f);
+	d.dy = make_float3(0.0f, 0.0f, 0.0f);
+
+	return d;
+}
+
 CCL_NAMESPACE_END
 
diff --git a/intern/cycles/kernel/kernel_displace.h b/intern/cycles/kernel/kernel_displace.h
index 5f95e0c2e3b..8b95e413b3f 100644
--- a/intern/cycles/kernel/kernel_displace.h
+++ b/intern/cycles/kernel/kernel_displace.h
@@ -52,10 +52,8 @@ __device void kernel_shader_evaluate(KernelGlobals *kg, uint4 *input, float4 *ou
 #endif
 
 #ifdef __RAY_DIFFERENTIALS__
-		ray.dD.dx = make_float3(0.0f, 0.0f, 0.0f);
-		ray.dD.dy = make_float3(0.0f, 0.0f, 0.0f);
-		ray.dP.dx = make_float3(0.0f, 0.0f, 0.0f);
-		ray.dP.dy = make_float3(0.0f, 0.0f, 0.0f);
+		ray.dD = differential3_zero();
+		ray.dP = differential3_zero();
 #endif
 
 		/* setup shader data */
diff --git a/intern/cycles/kernel/kernel_emission.h b/intern/cycles/kernel/kernel_emission.h
index 0553ac7a4ee..6f7a3e71d27 100644
--- a/intern/cycles/kernel/kernel_emission.h
+++ b/intern/cycles/kernel/kernel_emission.h
@@ -36,8 +36,7 @@ __device_noinline float3 direct_emissive_eval(KernelGlobals *kg, float rando,
 #ifdef __OBJECT_MOTION__
 		ray.time = time;
 #endif
-		ray.dP.dx = make_float3(0.0f, 0.0f, 0.0f);
-		ray.dP.dy = make_float3(0.0f, 0.0f, 0.0f);
+		ray.dP = differential3_zero();
 		ray.dD = dI;
 #ifdef __CAMERA_MOTION__
 		ray.time = time;
@@ -95,9 +94,7 @@ __device_noinline bool direct_emission(KernelGlobals *kg, ShaderData *sd, int li
 		return false;
 
 	/* todo: implement */
-	differential3 dD;
-	dD.dx = make_float3(0.0f, 0.0f, 0.0f);
-	dD.dy = make_float3(0.0f, 0.0f, 0.0f);
+	differential3 dD = differential3_zero();
 
 	/* evaluate closure */
 	float3 light_eval = direct_emissive_eval(kg, rando, &ls, randu, randv, -ls.D, dD, ls.t, sd->time);
@@ -138,6 +135,9 @@ __device_noinline bool direct_emission(KernelGlobals *kg, ShaderData *sd, int li
 			ray->D = ray_offset(ls.P, ls.Ng) - ray->P;
 			ray->D = normalize_len(ray->D, &ray->t);
 		}
+
+		ray->dP = sd->dP;
+		ray->dD = differential3_zero();
 	}
 	else {
 		/* signal to not cast shadow ray */
diff --git a/intern/cycles/kernel/kernel_path.h b/intern/cycles/kernel/kernel_path.h
index 4e50b84291a..faf0ac6035c 100644
--- a/intern/cycles/kernel/kernel_path.h
+++ b/intern/cycles/kernel/kernel_path.h
@@ -414,6 +414,8 @@ __device float4 kernel_path_progressive(KernelGlobals *kg, RNG *rng, int sample,
 #ifdef __OBJECT_MOTION__
 				light_ray.time = sd.time;
 #endif
+				light_ray.dP = sd.dP;
+				light_ray.dD = differential3_zero();
 
 				if(!shadow_blocked(kg, &state, &light_ray, &ao_shadow))
 					path_radiance_accum_ao(&L, throughput, ao_bsdf, ao_shadow, state.bounce);
@@ -640,6 +642,8 @@ __device void kernel_path_indirect(KernelGlobals *kg, RNG *rng, int sample, Ray
 #ifdef __OBJECT_MOTION__
 				light_ray.time = sd.time;
 #endif
+				light_ray.dP = sd.dP;
+				light_ray.dD = differential3_zero();
 
 				if(!shadow_blocked(kg, &state, &light_ray, &ao_shadow))
 					path_radiance_accum_ao(L, throughput, ao_bsdf, ao_shadow, state.bounce);
@@ -757,6 +761,8 @@ __device_noinline void kernel_path_non_progressive_lighting(KernelGlobals *kg, R
 #ifdef __OBJECT_MOTION__
 				light_ray.time = sd->time;
 #endif
+				light_ray.dP = sd->dP;
+				light_ray.dD = differential3_zero();
 
 				if(!shadow_blocked(kg, &state, &light_ray, &ao_shadow))
 					path_radiance_accum_ao(L, throughput*num_samples_inv, ao_bsdf, ao_shadow, state.bounce);
diff --git a/intern/cycles/kernel/kernel_shader.h b/intern/cycles/kernel/kernel_shader.h
index ec532858c8d..21152efff4c 100644
--- a/intern/cycles/kernel/kernel_shader.h
+++ b/intern/cycles/kernel/kernel_shader.h
@@ -370,14 +370,10 @@ __device_noinline void shader_setup_from_sample(KernelGlobals *kg, ShaderData *s
 
 #ifdef __RAY_DIFFERENTIALS__
 	/* no ray differentials here yet */
-	sd->dP.dx = make_float3(0.0f, 0.0f, 0.0f);
-	sd->dP.dy = make_float3(0.0f, 0.0f, 0.0f);
-	sd->dI.dx = make_float3(0.0f, 0.0f, 0.0f);
-	sd->dI.dy = make_float3(0.0f, 0.0f, 0.0f);
-	sd->du.dx = 0.0f;
-	sd->du.dy = 0.0f;
-	sd->dv.dx = 0.0f;
-	sd->dv.dy = 0.0f;
+	sd->dP = differential3_zero();
+	sd->dI = differential3_zero();
+	sd->du = differential_zero();
+	sd->dv = differential_zero();
 #endif
 }
 
@@ -438,10 +434,8 @@ __device_inline void shader_setup_from_background(KernelGlobals *kg, ShaderData
 	/* differentials */
 	sd->dP = ray->dD;
 	differential_incoming(&sd->dI, sd->dP);
-	sd->du.dx = 0.0f;
-	sd->du.dy = 0.0f;
-	sd->dv.dx = 0.0f;
-	sd->dv.dy = 0.0f;
+	sd->du = differential_zero();
+	sd->dv = differential_zero();
 #endif
 }
 
diff --git a/intern/cycles/kernel/kernel_subsurface.h b/intern/cycles/kernel/kernel_subsurface.h
index f503c488a34..f7bccf71976 100644
--- a/intern/cycles/kernel/kernel_subsurface.h
+++ b/intern/cycles/kernel/kernel_subsurface.h
@@ -203,8 +203,7 @@ __device void subsurface_scatter_step(KernelGlobals *kg, ShaderData *sd, int sta
 		ray.P = p1;
 		ray.D = normalize_len(p2 - p1, &ray.t);
 		ray.dP = sd->dP;
-		ray.dD.dx = make_float3(0.0f, 0.0f, 0.0f);
-		ray.dD.dy = make_float3(0.0f, 0.0f, 0.0f);
+		ray.dD = differential3_zero();
 		ray.time = sd->time;
 
 		/* intersect with the same object. if multiple intersections are