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, 176 insertions, 0 deletions

diff --git a/intern/cycles/kernel/split/kernel_next_iteration_setup.h b/intern/cycles/kernel/split/kernel_next_iteration_setup.h
new file mode 100644
index 00000000000..343dbb06e99
--- /dev/null
+++ b/intern/cycles/kernel/split/kernel_next_iteration_setup.h
@@ -0,0 +1,176 @@
+/*
+ * 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_setup_next_iteration kernel.
+ * This is the tenth kernel in the ray tracing logic. This is the ninth
+ * of the path iteration kernels. This kernel takes care of setting up
+ * Ray for the next iteration of path-iteration and accumulating radiance
+ * corresponding to AO and direct-lighting
+ *
+ * Ray state of rays that are terminated in this kernel are changed to RAY_UPDATE_BUFFER
+ *
+ * The input and output are as follows,
+ *
+ * rng_coop ---------------------------------------------|--- kernel_next_iteration_setup -|--- Queue_index (QUEUE_HITBG_BUFF_UPDATE_TOREGEN_RAYS)
+ * throughput_coop --------------------------------------|                                 |--- Queue_data (QUEUE_HITBF_BUFF_UPDATE_TOREGEN_RAYS)
+ * PathRadiance_coop ------------------------------------|                                 |--- throughput_coop
+ * PathState_coop ---------------------------------------|                                 |--- PathRadiance_coop
+ * shader_data ------------------------------------------|                                 |--- PathState_coop
+ * ray_state --------------------------------------------|                                 |--- ray_state
+ * Queue_data (QUEUE_ACTIVE_AND_REGENERATD_RAYS) --------|                                 |--- Ray_coop
+ * Queue_index (QUEUE_HITBG_BUFF_UPDATE_TOREGEN_RAYS) ---|                                 |--- use_queues_flag
+ * Ray_coop ---------------------------------------------|                                 |
+ * kg (globals + data) ----------------------------------|                                 |
+ * LightRay_dl_coop -------------------------------------|
+ * ISLamp_coop ------------------------------------------|
+ * BSDFEval_coop ----------------------------------------|
+ * LightRay_ao_coop -------------------------------------|
+ * AOBSDF_coop ------------------------------------------|
+ * AOAlpha_coop -----------------------------------------|
+ *
+ * Note on queues,
+ * This kernel fetches rays from the queue QUEUE_ACTIVE_AND_REGENERATED_RAYS and processes only
+ * the rays of state RAY_ACTIVE.
+ * There are different points in this kernel where a ray may terminate and reach RAY_UPDATE_BUFF
+ * state. These rays are enqueued into QUEUE_HITBG_BUFF_UPDATE_TOREGEN_RAYS queue. These rays will
+ * still be present in QUEUE_ACTIVE_AND_REGENERATED_RAYS queue, but since their ray-state has been
+ * changed to RAY_UPDATE_BUFF, there is no problem.
+ *
+ * State of queues when this kernel is called :
+ * At entry,
+ * QUEUE_ACTIVE_AND_REGENERATED_RAYS will be filled with RAY_ACTIVE, RAY_REGENERATED, RAY_UPDATE_BUFFER rays.
+ * QUEUE_HITBG_BUFF_UPDATE_TOREGEN_RAYS will be filled with RAY_TO_REGENERATE and RAY_UPDATE_BUFFER rays
+ * At exit,
+ * QUEUE_ACTIVE_AND_REGENERATED_RAYS will be filled with RAY_ACTIVE, RAY_REGENERATED and more RAY_UPDATE_BUFFER rays.
+ * QUEUE_HITBG_BUFF_UPDATE_TOREGEN_RAYS will be filled with RAY_TO_REGENERATE and more RAY_UPDATE_BUFFER rays
+ */
+
+ccl_device void kernel_next_iteration_setup(
+	ccl_global char *globals,
+	ccl_constant KernelData *data,
+	ccl_global char *shader_data,               /* Required for setting up ray for next iteration */
+	ccl_global uint *rng_coop,                  /* Required for setting up ray for next iteration */
+	ccl_global float3 *throughput_coop,         /* Required for setting up ray for next iteration */
+	PathRadiance *PathRadiance_coop, /* Required for setting up ray for next iteration */
+	ccl_global Ray *Ray_coop,                   /* Required for setting up ray for next iteration */
+	ccl_global PathState *PathState_coop,       /* Required for setting up ray for next iteration */
+	ccl_global Ray *LightRay_dl_coop,           /* Required for radiance update - direct lighting */
+	ccl_global int *ISLamp_coop,                /* Required for radiance update - direct lighting */
+	ccl_global BsdfEval *BSDFEval_coop,         /* Required for radiance update - direct lighting */
+	ccl_global Ray *LightRay_ao_coop,           /* Required for radiance update - AO */
+	ccl_global float3 *AOBSDF_coop,             /* Required for radiance update - AO */
+	ccl_global float3 *AOAlpha_coop,            /* Required for radiance update - AO */
+	ccl_global char *ray_state,                 /* Denotes the state of each ray */
+	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 */
+	ccl_global char *use_queues_flag            /* flag to decide if scene_intersect kernel should use queues to fetch ray index */
+	)
+{
+
+	ccl_local unsigned int local_queue_atomics;
+	if(get_local_id(0) == 0 && get_local_id(1) == 0) {
+		local_queue_atomics = 0;
+	}
+	barrier(CLK_LOCAL_MEM_FENCE);
+
+	if(get_global_id(0) == 0 && get_global_id(1) == 0) {
+		/* If we are here, then it means that scene-intersect kernel
+		* has already been executed atleast once. From the next time,
+		* scene-intersect kernel may operate on queues to fetch ray index
+		*/
+		use_queues_flag[0] = 1;
+
+		/* Mark queue indices of QUEUE_SHADOW_RAY_CAST_AO_RAYS and QUEUE_SHADOW_RAY_CAST_DL_RAYS
+		 * queues that were made empty during the previous kernel
+		 */
+		Queue_index[QUEUE_SHADOW_RAY_CAST_AO_RAYS] = 0;
+		Queue_index[QUEUE_SHADOW_RAY_CAST_DL_RAYS] = 0;
+	}
+
+	char enqueue_flag = 0;
+	int ray_index = get_global_id(1) * get_global_size(0) + get_global_id(0);
+	ray_index = get_ray_index(ray_index, QUEUE_ACTIVE_AND_REGENERATED_RAYS, Queue_data, queuesize, 0);
+
+#ifdef __COMPUTE_DEVICE_GPU__
+	/* If we are executing on a GPU device, we exit all threads that are not required
+	 * If we are executing on a CPU device, then we need to keep all threads active
+	 * since we have barrier() calls later in the kernel. CPU devices,
+	 * expect all threads to execute barrier statement.
+	 */
+	if(ray_index == QUEUE_EMPTY_SLOT)
+		return;
+#endif
+
+#ifndef __COMPUTE_DEVICE_GPU__
+	if(ray_index != QUEUE_EMPTY_SLOT) {
+#endif
+		/* Load kernel globals structure and ShaderData structure */
+		KernelGlobals *kg = (KernelGlobals *)globals;
+		ShaderData *sd = (ShaderData *)shader_data;
+		PathRadiance *L = 0x0;
+		ccl_global PathState *state = 0x0;
+
+		/* Path radiance update for AO/Direct_lighting's shadow blocked */
+		if(IS_FLAG(ray_state, ray_index, RAY_SHADOW_RAY_CAST_DL) || IS_FLAG(ray_state, ray_index, RAY_SHADOW_RAY_CAST_AO)) {
+			state = &PathState_coop[ray_index];
+			L = &PathRadiance_coop[ray_index];
+			float3 _throughput = throughput_coop[ray_index];
+
+			if(IS_FLAG(ray_state, ray_index, RAY_SHADOW_RAY_CAST_AO)) {
+				float3 shadow = LightRay_ao_coop[ray_index].P;
+				char update_path_radiance = LightRay_ao_coop[ray_index].t;
+				if(update_path_radiance) {
+					path_radiance_accum_ao(L, _throughput, AOAlpha_coop[ray_index], AOBSDF_coop[ray_index], shadow, state->bounce);
+				}
+				REMOVE_RAY_FLAG(ray_state, ray_index, RAY_SHADOW_RAY_CAST_AO);
+			}
+
+			if(IS_FLAG(ray_state, ray_index, RAY_SHADOW_RAY_CAST_DL)) {
+				float3 shadow = LightRay_dl_coop[ray_index].P;
+				char update_path_radiance = LightRay_dl_coop[ray_index].t;
+				if(update_path_radiance) {
+					BsdfEval L_light = BSDFEval_coop[ray_index];
+					path_radiance_accum_light(L, _throughput, &L_light, shadow, 1.0f, state->bounce, ISLamp_coop[ray_index]);
+				}
+				REMOVE_RAY_FLAG(ray_state, ray_index, RAY_SHADOW_RAY_CAST_DL);
+			}
+		}
+
+		if(IS_STATE(ray_state, ray_index, RAY_ACTIVE)) {
+
+			ccl_global float3 *throughput = &throughput_coop[ray_index];
+			ccl_global Ray *ray = &Ray_coop[ray_index];
+			ccl_global RNG* rng = &rng_coop[ray_index];
+			state = &PathState_coop[ray_index];
+			L = &PathRadiance_coop[ray_index];
+
+			/* compute direct lighting and next bounce */
+			if(!kernel_path_surface_bounce(kg, rng, sd, throughput, state, L, ray)) {
+				ASSIGN_RAY_STATE(ray_state, ray_index, RAY_UPDATE_BUFFER);
+				enqueue_flag = 1;
+			}
+		}
+#ifndef __COMPUTE_DEVICE_GPU__
+	}
+#endif
+
+	/* Enqueue RAY_UPDATE_BUFFER rays */
+	enqueue_ray_index_local(ray_index, QUEUE_HITBG_BUFF_UPDATE_TOREGEN_RAYS, enqueue_flag, queuesize, &local_queue_atomics, Queue_data, Queue_index);
+}