1 files changed, 60 insertions, 18 deletions

diff --git a/intern/cycles/kernel/kernel_path_state.h b/intern/cycles/kernel/kernel_path_state.h
index 5d92fd12201..eccee54c0e3 100644
--- a/intern/cycles/kernel/kernel_path_state.h
+++ b/intern/cycles/kernel/kernel_path_state.h
@@ -19,15 +19,17 @@ CCL_NAMESPACE_BEGIN
 ccl_device_inline void path_state_init(KernelGlobals *kg,
                                        ShaderData *stack_sd,
                                        ccl_addr_space PathState *state,
-                                       RNG *rng,
+                                       uint rng_hash,
                                        int sample,
                                        ccl_addr_space Ray *ray)
 {
 	state->flag = PATH_RAY_CAMERA|PATH_RAY_MIS_SKIP;
 
+	state->rng_hash = rng_hash;
 	state->rng_offset = PRNG_BASE_NUM;
 	state->sample = sample;
 	state->num_samples = kernel_data.integrator.aa_samples;
+	state->branch_factor = 1.0f;
 
 	state->bounce = 0;
 	state->diffuse_bounce = 0;
@@ -58,16 +60,12 @@ ccl_device_inline void path_state_init(KernelGlobals *kg,
 		/* Initialize volume stack with volume we are inside of. */
 		kernel_volume_stack_init(kg, stack_sd, state, ray, state->volume_stack);
 		/* Seed RNG for cases where we can't use stratified samples .*/
-		state->rng_congruential = lcg_init(*rng + sample*0x51633e2d);
+		state->rng_congruential = lcg_init(rng_hash + sample*0x51633e2d);
 	}
 	else {
 		state->volume_stack[0].shader = SHADER_NONE;
 	}
 #endif
-
-#ifdef __SHADOW_TRICKS__
-	state->catcher_object = OBJECT_NONE;
-#endif
 }
 
 ccl_device_inline void path_state_next(KernelGlobals *kg, ccl_addr_space PathState *state, int label)
@@ -78,12 +76,12 @@ ccl_device_inline void path_state_next(KernelGlobals *kg, ccl_addr_space PathSta
 		state->flag |= PATH_RAY_TRANSPARENT;
 		state->transparent_bounce++;
 
-		/* don't increase random number generator offset here, to avoid some
-		 * unwanted patterns, see path_state_rng_1D_for_decision */
-
 		if(!kernel_data.integrator.transparent_shadows)
 			state->flag |= PATH_RAY_MIS_SKIP;
 
+		/* random number generator next bounce */
+		state->rng_offset += PRNG_BOUNCE_NUM;
+
 		return;
 	}
 
@@ -146,7 +144,7 @@ ccl_device_inline void path_state_next(KernelGlobals *kg, ccl_addr_space PathSta
 #endif
 }
 
-ccl_device_inline uint path_state_ray_visibility(KernelGlobals *kg, PathState *state)
+ccl_device_inline uint path_state_ray_visibility(KernelGlobals *kg, ccl_addr_space PathState *state)
 {
 	uint flag = state->flag & PATH_RAY_ALL_VISIBILITY;
 
@@ -160,17 +158,28 @@ ccl_device_inline uint path_state_ray_visibility(KernelGlobals *kg, PathState *s
 	return flag;
 }
 
-ccl_device_inline float path_state_terminate_probability(KernelGlobals *kg, ccl_addr_space PathState *state, const float3 throughput)
+ccl_device_inline float path_state_continuation_probability(KernelGlobals *kg,
+                                                            ccl_addr_space PathState *state,
+                                                            const float3 throughput)
 {
 	if(state->flag & PATH_RAY_TRANSPARENT) {
-		/* transparent rays treated separately */
-		if(state->transparent_bounce >= kernel_data.integrator.transparent_max_bounce)
+		/* Transparent rays are treated separately with own max bounces. */
+		if(state->transparent_bounce >= kernel_data.integrator.transparent_max_bounce) {
 			return 0.0f;
-		else if(state->transparent_bounce <= kernel_data.integrator.transparent_min_bounce)
+		}
+		/* Do at least one bounce without RR. */
+		else if(state->transparent_bounce <= 1) {
 			return 1.0f;
+		}
+#ifdef __SHADOW_TRICKS__
+		/* Exception for shadow catcher not working correctly with RR. */
+		else if((state->flag & PATH_RAY_SHADOW_CATCHER) && (state->transparent_bounce <= 8)) {
+			return 1.0f;
+		}
+#endif
 	}
 	else {
-		/* other rays */
+		/* Test max bounces for various ray types. */
 		if((state->bounce >= kernel_data.integrator.max_bounce) ||
 		   (state->diffuse_bounce >= kernel_data.integrator.max_diffuse_bounce) ||
 		   (state->glossy_bounce >= kernel_data.integrator.max_glossy_bounce) ||
@@ -181,13 +190,21 @@ ccl_device_inline float path_state_terminate_probability(KernelGlobals *kg, ccl_
 		{
 			return 0.0f;
 		}
-		else if(state->bounce <= kernel_data.integrator.min_bounce) {
+		/* Do at least one bounce without RR. */
+		else if(state->bounce <= 1) {
 			return 1.0f;
 		}
+#ifdef __SHADOW_TRICKS__
+		/* Exception for shadow catcher not working correctly with RR. */
+		else if((state->flag & PATH_RAY_SHADOW_CATCHER) && (state->bounce <= 3)) {
+			return 1.0f;
+		}
+#endif
 	}
 
-	/* probalistic termination */
-	return average(throughput); /* todo: try using max here */
+	/* Probalistic termination: use sqrt() to roughly match typical view
+	 * transform and do path termination a bit later on average. */
+	return min(sqrtf(max3(fabs(throughput)) * state->branch_factor), 1.0f);
 }
 
 /* TODO(DingTo): Find more meaningful name for this */
@@ -200,5 +217,30 @@ ccl_device_inline void path_state_modify_bounce(ccl_addr_space PathState *state,
 		state->bounce -= 1;
 }
 
+ccl_device_inline bool path_state_ao_bounce(KernelGlobals *kg, ccl_addr_space PathState *state)
+{
+    if(state->bounce <= kernel_data.integrator.ao_bounces) {
+        return false;
+    }
+
+    int bounce = state->bounce - state->transmission_bounce - (state->glossy_bounce > 0);
+    return (bounce > kernel_data.integrator.ao_bounces);
+}
+
+ccl_device_inline void path_state_branch(ccl_addr_space PathState *state,
+                                         int branch,
+                                         int num_branches)
+{
+	state->rng_offset += PRNG_BOUNCE_NUM;
+
+	if(num_branches > 1) {
+		/* Path is splitting into a branch, adjust so that each branch
+		 * still gets a unique sample from the same sequence. */
+		state->sample = state->sample*num_branches + branch;
+		state->num_samples = state->num_samples*num_branches;
+		state->branch_factor *= num_branches;
+	}
+}
+
 CCL_NAMESPACE_END