Cycles: Restructure kernel files organization

Since the kernel split work we're now having quite a few of new files, majority
of which are related on the kernel entry points. Keeping those files in the
root kernel folder will eventually make it really hard to follow which files are
actual implementation of Cycles kernel.

Those files are now moved to kernel/kernels/<device_type>. This way adding extra
entry points will be less noisy. It is also nice to have all device-specific
files grouped together.

Another change is in the way how split kernel invokes logic. Previously all the
logic was implemented directly in the .cl files, which makes it a bit tricky to
re-use the logic across other devices. Since we'll likely be looking into doing
same split work for CUDA devices eventually it makes sense to move logic from
.cl files to header files. Those files are stored in kernel/split. This does not
mean the header files will not give error messages when tried to be included
from other devices and their arguments will likely be changed, but having such
separation is a good start anyway.

There should be no functional changes.

Reviewers: juicyfruit, dingto

Differential Revision: https://developer.blender.org/D1314

1 files changed, 126 insertions, 0 deletions

diff --git a/intern/cycles/kernel/split/kernel_shadow_blocked.h b/intern/cycles/kernel/split/kernel_shadow_blocked.h
new file mode 100644
index 00000000000..71fab19518c
--- /dev/null
+++ b/intern/cycles/kernel/split/kernel_shadow_blocked.h
@@ -0,0 +1,126 @@
+/*
+ * Copyright 2011-2015 Blender Foundation
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include "kernel_split_common.h"
+
+/*
+ * Note on kernel_shadow_blocked kernel.
+ * This is the ninth kernel in the ray tracing logic. This is the eighth
+ * of the path iteration kernels. This kernel takes care of "shadow ray cast"
+ * logic of the direct lighting and AO  part of ray tracing.
+ *
+ * The input and output are as follows,
+ *
+ * PathState_coop ----------------------------------|--- kernel_shadow_blocked --|
+ * LightRay_dl_coop --------------------------------|                            |--- LightRay_dl_coop
+ * LightRay_ao_coop --------------------------------|                            |--- LightRay_ao_coop
+ * ray_state ---------------------------------------|                            |--- ray_state
+ * Queue_data(QUEUE_SHADOW_RAY_CAST_AO_RAYS &       |                            |--- Queue_data (QUEUE_SHADOW_RAY_CAST_AO_RAYS & QUEUE_SHADOW_RAY_CAST_AO_RAYS)
+	      QUEUE_SHADOW_RAY_CAST_DL_RAYS) -------|                            |
+ * Queue_index(QUEUE_SHADOW_RAY_CAST_AO_RAYS&
+	      QUEUE_SHADOW_RAY_CAST_DL_RAYS) -------|                            |
+ * kg (globals + data) -----------------------------|                            |
+ * queuesize ---------------------------------------|                            |
+ *
+ * Note on shader_shadow : shader_shadow is neither input nor output to this kernel. shader_shadow is filled and consumed in this kernel itself.
+ * Note on queues :
+ * The kernel fetches from QUEUE_SHADOW_RAY_CAST_AO_RAYS and QUEUE_SHADOW_RAY_CAST_DL_RAYS queues. We will empty
+ * these queues this kernel.
+ * State of queues when this kernel is called :
+ * state of queues QUEUE_ACTIVE_AND_REGENERATED_RAYS and QUEUE_HITBG_BUFF_UPDATE_TOREGEN_RAYS will be same
+ * before and after this kernel call.
+ * QUEUE_SHADOW_RAY_CAST_AO_RAYS & QUEUE_SHADOW_RAY_CAST_DL_RAYS will be filled with rays marked with flags RAY_SHADOW_RAY_CAST_AO
+ * and RAY_SHADOW_RAY_CAST_DL respectively, during kernel entry.
+ * QUEUE_SHADOW_RAY_CAST_AO_RAYS and QUEUE_SHADOW_RAY_CAST_DL_RAYS will be empty at kernel exit.
+ */
+
+ccl_device void kernel_shadow_blocked(
+	ccl_global char *globals,
+	ccl_constant KernelData *data,
+	ccl_global char *shader_shadow,             /* Required for shadow blocked */
+	ccl_global PathState *PathState_coop,       /* Required for shadow blocked */
+	ccl_global Ray *LightRay_dl_coop,           /* Required for direct lighting's shadow blocked */
+	ccl_global Ray *LightRay_ao_coop,           /* Required for AO's shadow blocked */
+	Intersection *Intersection_coop_AO,
+	Intersection *Intersection_coop_DL,
+	ccl_global char *ray_state,
+	ccl_global int *Queue_data,                 /* Queue memory */
+	ccl_global int *Queue_index,                /* Tracks the number of elements in each queue */
+	int queuesize,                              /* Size (capacity) of each queue */
+	int total_num_rays
+	)
+{
+#if 0
+	/* we will make the Queue_index entries '0' in the next kernel */
+	if(get_global_id(0) == 0 && get_global_id(1) == 0) {
+		/* We empty this queue here */
+		Queue_index[QUEUE_SHADOW_RAY_CAST_AO_RAYS] = 0;
+		Queue_index[QUEUE_SHADOW_RAY_CAST_DL_RAYS] = 0;
+	}
+#endif
+
+	int lidx = get_local_id(1) * get_local_id(0) + get_local_id(0);
+
+	ccl_local unsigned int ao_queue_length;
+	ccl_local unsigned int dl_queue_length;
+	if(lidx == 0) {
+		ao_queue_length = Queue_index[QUEUE_SHADOW_RAY_CAST_AO_RAYS];
+		dl_queue_length = Queue_index[QUEUE_SHADOW_RAY_CAST_DL_RAYS];
+	}
+	barrier(CLK_LOCAL_MEM_FENCE);
+
+	/* flag determining if the current ray is to process shadow ray for AO or DL */
+	char shadow_blocked_type = -1;
+	/* flag determining if we need to update L */
+	char update_path_radiance = 0;
+
+	int ray_index = QUEUE_EMPTY_SLOT;
+	int thread_index = get_global_id(1) * get_global_size(0) + get_global_id(0);
+	if(thread_index < ao_queue_length + dl_queue_length) {
+		if(thread_index < ao_queue_length) {
+			ray_index = get_ray_index(thread_index, QUEUE_SHADOW_RAY_CAST_AO_RAYS, Queue_data, queuesize, 1);
+			shadow_blocked_type = RAY_SHADOW_RAY_CAST_AO;
+		} else {
+			ray_index = get_ray_index(thread_index - ao_queue_length, QUEUE_SHADOW_RAY_CAST_DL_RAYS, Queue_data, queuesize, 1);
+			shadow_blocked_type = RAY_SHADOW_RAY_CAST_DL;
+		}
+	}
+
+	if(ray_index == QUEUE_EMPTY_SLOT)
+		return;
+
+	if(IS_FLAG(ray_state, ray_index, RAY_SHADOW_RAY_CAST_DL) || IS_FLAG(ray_state, ray_index, RAY_SHADOW_RAY_CAST_AO)) {
+		/* Load kernel global structure */
+		KernelGlobals *kg = (KernelGlobals *)globals;
+		ShaderData *sd_shadow  = (ShaderData *)shader_shadow;
+
+		ccl_global PathState *state = &PathState_coop[ray_index];
+		ccl_global Ray *light_ray_dl_global = &LightRay_dl_coop[ray_index];
+		ccl_global Ray *light_ray_ao_global = &LightRay_ao_coop[ray_index];
+		Intersection *isect_ao_global = &Intersection_coop_AO[ray_index];
+		Intersection *isect_dl_global = &Intersection_coop_DL[ray_index];
+
+		ccl_global Ray *light_ray_global = shadow_blocked_type == RAY_SHADOW_RAY_CAST_AO ? light_ray_ao_global : light_ray_dl_global;
+		Intersection *isect_global = RAY_SHADOW_RAY_CAST_AO ? isect_ao_global : isect_dl_global;
+
+		float3 shadow;
+		update_path_radiance = !(shadow_blocked(kg, state, light_ray_global, &shadow, sd_shadow, isect_global));
+
+		/* We use light_ray_global's P and t to store shadow and update_path_radiance */
+		light_ray_global->P = shadow;
+		light_ray_global->t = update_path_radiance;
+	}
+}