Cycles: OpenCL split kernel refactor

This does a few things at once:

- Refactors host side split kernel logic into a new device
  agnostic class `DeviceSplitKernel`.
- Removes tile splitting, a new work pool implementation takes its place and
  allows as many threads as will fit in memory regardless of tile size, which
  can give performance gains.
- Refactors split state buffers into one buffer, as well as reduces the
  number of arguments passed to kernels. Means there's less code to deal
  with overall.
- Moves kernel logic out of OpenCL kernel files so they can later be used by
  other device types.
- Replaced OpenCL specific APIs with new generic versions
- Tiles can now be seen updating during rendering

1 files changed, 102 insertions, 0 deletions

diff --git a/intern/cycles/kernel/split/kernel_queue_enqueue.h b/intern/cycles/kernel/split/kernel_queue_enqueue.h
new file mode 100644
index 00000000000..66aad705bd4
--- /dev/null
+++ b/intern/cycles/kernel/split/kernel_queue_enqueue.h
@@ -0,0 +1,102 @@
+/*
+ * Copyright 2011-2016 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.
+ */
+
+CCL_NAMESPACE_BEGIN
+
+/*
+ * The kernel "kernel_queue_enqueue" enqueues rays of
+ * different ray state into their appropriate Queues;
+ * 1. Rays that have been determined to hit the background from the
+ * "kernel_scene_intersect" kernel
+ * are enqueued in QUEUE_HITBG_BUFF_UPDATE_TOREGEN_RAYS;
+ * 2. Rays that have been determined to be actively participating in path-iteration will be enqueued into QUEUE_ACTIVE_AND_REGENERATED_RAYS.
+ *
+ * The input and output of the kernel is as follows,
+ *
+ * ray_state -------------------------------------------|--- kernel_queue_enqueue --|--- Queue_data (QUEUE_ACTIVE_AND_REGENERATED_RAYS & QUEUE_HITBF_BUFF_UPDATE_TOREGEN_RAYS)
+ * Queue_index(QUEUE_ACTIVE_AND_REGENERATED_RAYS) ------|                           |--- Queue_index (QUEUE_ACTIVE_AND_REGENERATED_RAYS & QUEUE_HITBF_BUFF_UPDATE_TOREGEN_RAYS)
+ * Queue_index(QUEUE_HITBG_BUFF_UPDATE_TOREGEN_RAYS) ---|                           |
+ * queuesize -------------------------------------------|                           |
+ *
+ * Note on Queues :
+ * State of queues during the first time this kernel is called :
+ * At entry,
+ * Both QUEUE_ACTIVE_AND_REGENERATED_RAYS and QUEUE_HITBG_BUFF_UPDATE_TOREGEN_RAYS will be empty.
+ * At exit,
+ * QUEUE_ACTIVE_AND_REGENERATED_RAYS will be filled with RAY_ACTIVE rays
+ * QUEUE_HITBF_BUFF_UPDATE_TOREGEN_RAYS will be filled with RAY_HIT_BACKGROUND rays.
+ *
+ * State of queue during other times this kernel is called :
+ * At entry,
+ * QUEUE_ACTIVE_AND_REGENERATED_RAYS will be empty.
+ * QUEUE_HITBG_BUFF_UPDATE_TOREGEN_RAYS will contain RAY_TO_REGENERATE and RAY_UPDATE_BUFFER rays.
+ * At exit,
+ * QUEUE_ACTIVE_AND_REGENERATED_RAYS will be filled with RAY_ACTIVE rays.
+ * QUEUE_HITBG_BUFF_UPDATE_TOREGEN_RAYS will be filled with RAY_TO_REGENERATE, RAY_UPDATE_BUFFER, RAY_HIT_BACKGROUND rays.
+ */
+ccl_device void kernel_queue_enqueue(KernelGlobals *kg)
+{
+	/* We have only 2 cases (Hit/Not-Hit) */
+	ccl_local unsigned int local_queue_atomics[2];
+
+	int lidx = ccl_local_id(1) * ccl_local_size(0) + ccl_local_id(0);
+	int ray_index = ccl_global_id(1) * ccl_global_size(0) + ccl_global_id(0);
+
+	if(lidx == 0) {
+		local_queue_atomics[0] = 0;
+		local_queue_atomics[1] = 0;
+	}
+	ccl_barrier(CCL_LOCAL_MEM_FENCE);
+
+	int queue_number = -1;
+
+	if(IS_STATE(kernel_split_state.ray_state, ray_index, RAY_HIT_BACKGROUND)) {
+		queue_number = QUEUE_HITBG_BUFF_UPDATE_TOREGEN_RAYS;
+	}
+	else if(IS_STATE(kernel_split_state.ray_state, ray_index, RAY_ACTIVE)) {
+		queue_number = QUEUE_ACTIVE_AND_REGENERATED_RAYS;
+	}
+
+	unsigned int my_lqidx;
+	if(queue_number != -1) {
+		my_lqidx = get_local_queue_index(queue_number, local_queue_atomics);
+	}
+	ccl_barrier(CCL_LOCAL_MEM_FENCE);
+
+	if(lidx == 0) {
+		local_queue_atomics[QUEUE_ACTIVE_AND_REGENERATED_RAYS] =
+		        get_global_per_queue_offset(QUEUE_ACTIVE_AND_REGENERATED_RAYS,
+		                                    local_queue_atomics,
+		                                    kernel_split_params.queue_index);
+		local_queue_atomics[QUEUE_HITBG_BUFF_UPDATE_TOREGEN_RAYS] =
+		        get_global_per_queue_offset(QUEUE_HITBG_BUFF_UPDATE_TOREGEN_RAYS,
+		                                    local_queue_atomics,
+		                                    kernel_split_params.queue_index);
+	}
+	ccl_barrier(CCL_LOCAL_MEM_FENCE);
+
+	unsigned int my_gqidx;
+	if(queue_number != -1) {
+		my_gqidx = get_global_queue_index(queue_number,
+		                                  kernel_split_params.queue_size,
+		                                  my_lqidx,
+		                                  local_queue_atomics);
+		kernel_split_state.queue_data[my_gqidx] = ray_index;
+	}
+}
+
+CCL_NAMESPACE_END
+