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, 209 insertions, 0 deletions

diff --git a/intern/cycles/kernel/split/kernel_lamp_emission.h b/intern/cycles/kernel/split/kernel_lamp_emission.h
new file mode 100644
index 00000000000..f400a99e229
--- /dev/null
+++ b/intern/cycles/kernel/split/kernel_lamp_emission.h
@@ -0,0 +1,209 @@
+/*
+ * 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_lamp_emission
+ * This is the 3rd kernel in the ray-tracing logic. This is the second of the
+ * path-iteration kernels. This kernel takes care of the indirect lamp emission logic.
+ * This kernel operates on QUEUE_ACTIVE_AND_REGENERATED_RAYS. It processes rays of state RAY_ACTIVE
+ * and RAY_HIT_BACKGROUND.
+ * We will empty QUEUE_ACTIVE_AND_REGENERATED_RAYS queue in this kernel.
+ * The input/output of the kernel is as follows,
+ * Throughput_coop ------------------------------------|--- kernel_lamp_emission --|--- PathRadiance_coop
+ * Ray_coop -------------------------------------------|                           |--- Queue_data(QUEUE_ACTIVE_AND_REGENERATED_RAYS)
+ * PathState_coop -------------------------------------|                           |--- Queue_index(QUEUE_ACTIVE_AND_REGENERATED_RAYS)
+ * kg (globals + data) --------------------------------|                           |
+ * Intersection_coop ----------------------------------|                           |
+ * ray_state ------------------------------------------|                           |
+ * Queue_data (QUEUE_ACTIVE_AND_REGENERATED_RAYS) -----|                           |
+ * Queue_index (QUEUE_ACTIVE_AND_REGENERATED_RAYS) ----|                           |
+ * queuesize ------------------------------------------|                           |
+ * use_queues_flag ------------------------------------|                           |
+ * sw -------------------------------------------------|                           |
+ * sh -------------------------------------------------|                           |
+ * parallel_samples -----------------------------------|                           |
+ *
+ * note : shader_data is neither input nor output. Its just filled and consumed in the same, kernel_lamp_emission, kernel.
+ */
+ccl_device void kernel_lamp_emission(
+	ccl_global char *globals,
+	ccl_constant KernelData *data,
+	ccl_global char *shader_data,               /* Required for lamp emission */
+	ccl_global float3 *throughput_coop,         /* Required for lamp emission */
+	PathRadiance *PathRadiance_coop, /* Required for lamp emission */
+	ccl_global Ray *Ray_coop,                   /* Required for lamp emission */
+	ccl_global PathState *PathState_coop,       /* Required for lamp emission */
+	Intersection *Intersection_coop, /* Required for lamp emission */
+	ccl_global char *ray_state,                 /* Denotes the state of each ray */
+	int sw, int sh,
+	ccl_global int *Queue_data,                 /* Memory for queues */
+	ccl_global int *Queue_index,                /* Tracks the number of elements in queues */
+	int queuesize,                              /* Size (capacity) of queues */
+	ccl_global char *use_queues_flag,           /* used to decide if this kernel should use queues to fetch ray index */
+	int parallel_samples                        /* Number of samples to be processed in parallel */
+	)
+{
+	int x = get_global_id(0);
+	int y = get_global_id(1);
+
+	/* We will empty this queue in this kernel */
+	if(get_global_id(0) == 0 && get_global_id(1) == 0) {
+		Queue_index[QUEUE_ACTIVE_AND_REGENERATED_RAYS] = 0;
+	}
+
+	/* Fetch use_queues_flag */
+	ccl_local char local_use_queues_flag;
+	if(get_local_id(0) == 0 && get_local_id(1) == 0) {
+		local_use_queues_flag = use_queues_flag[0];
+	}
+	barrier(CLK_LOCAL_MEM_FENCE);
+
+	int ray_index;
+	if(local_use_queues_flag) {
+		int thread_index = get_global_id(1) * get_global_size(0) + get_global_id(0);
+		ray_index = get_ray_index(thread_index, QUEUE_ACTIVE_AND_REGENERATED_RAYS, Queue_data, queuesize, 1);
+
+		if(ray_index == QUEUE_EMPTY_SLOT) {
+			return;
+		}
+	} else {
+		if(x < (sw * parallel_samples) && y < sh){
+			ray_index = x + y * (sw * parallel_samples);
+		} else {
+			return;
+		}
+	}
+
+	if(IS_STATE(ray_state, ray_index, RAY_ACTIVE) || IS_STATE(ray_state, ray_index, RAY_HIT_BACKGROUND)) {
+		KernelGlobals *kg = (KernelGlobals *)globals;
+		ShaderData *sd = (ShaderData *)shader_data;
+		PathRadiance *L = &PathRadiance_coop[ray_index];
+
+		float3 throughput = throughput_coop[ray_index];
+		Ray ray = Ray_coop[ray_index];
+		PathState state = PathState_coop[ray_index];
+
+#ifdef __LAMP_MIS__
+		if(kernel_data.integrator.use_lamp_mis && !(state.flag & PATH_RAY_CAMERA)) {
+			/* ray starting from previous non-transparent bounce */
+			Ray light_ray;
+
+			light_ray.P = ray.P - state.ray_t*ray.D;
+			state.ray_t += Intersection_coop[ray_index].t;
+			light_ray.D = ray.D;
+			light_ray.t = state.ray_t;
+			light_ray.time = ray.time;
+			light_ray.dD = ray.dD;
+			light_ray.dP = ray.dP;
+			/* intersect with lamp */
+			float3 emission;
+
+			if(indirect_lamp_emission(kg, &state, &light_ray, &emission, sd)) {
+				path_radiance_accum_emission(L, throughput, emission, state.bounce);
+			}
+		}
+#endif
+		/* __VOLUME__ feature is disabled */
+#if 0
+#ifdef __VOLUME__
+		/* volume attenuation, emission, scatter */
+		if(state.volume_stack[0].shader != SHADER_NONE) {
+			Ray volume_ray = ray;
+			volume_ray.t = (hit)? isect.t: FLT_MAX;
+
+			bool heterogeneous = volume_stack_is_heterogeneous(kg, state.volume_stack);
+
+#ifdef __VOLUME_DECOUPLED__
+			int sampling_method = volume_stack_sampling_method(kg, state.volume_stack);
+			bool decoupled = kernel_volume_use_decoupled(kg, heterogeneous, true, sampling_method);
+
+			if(decoupled) {
+				/* cache steps along volume for repeated sampling */
+				VolumeSegment volume_segment;
+				ShaderData volume_sd;
+
+				shader_setup_from_volume(kg, &volume_sd, &volume_ray, state.bounce, state.transparent_bounce);
+				kernel_volume_decoupled_record(kg, &state,
+					&volume_ray, &volume_sd, &volume_segment, heterogeneous);
+
+				volume_segment.sampling_method = sampling_method;
+
+				/* emission */
+				if(volume_segment.closure_flag & SD_EMISSION)
+					path_radiance_accum_emission(&L, throughput, volume_segment.accum_emission, state.bounce);
+
+				/* scattering */
+				VolumeIntegrateResult result = VOLUME_PATH_ATTENUATED;
+
+				if(volume_segment.closure_flag & SD_SCATTER) {
+					bool all = false;
+
+					/* direct light sampling */
+					kernel_branched_path_volume_connect_light(kg, rng, &volume_sd,
+						throughput, &state, &L, 1.0f, all, &volume_ray, &volume_segment);
+
+					/* indirect sample. if we use distance sampling and take just
+					 * one sample for direct and indirect light, we could share
+					 * this computation, but makes code a bit complex */
+					float rphase = path_state_rng_1D_for_decision(kg, rng, &state, PRNG_PHASE);
+					float rscatter = path_state_rng_1D_for_decision(kg, rng, &state, PRNG_SCATTER_DISTANCE);
+
+					result = kernel_volume_decoupled_scatter(kg,
+						&state, &volume_ray, &volume_sd, &throughput,
+						rphase, rscatter, &volume_segment, NULL, true);
+				}
+
+				if(result != VOLUME_PATH_SCATTERED)
+					throughput *= volume_segment.accum_transmittance;
+
+				/* free cached steps */
+				kernel_volume_decoupled_free(kg, &volume_segment);
+
+				if(result == VOLUME_PATH_SCATTERED) {
+					if(kernel_path_volume_bounce(kg, rng, &volume_sd, &throughput, &state, &L, &ray))
+						continue;
+					else
+						break;
+				}
+			}
+			else
+#endif
+			{
+				/* integrate along volume segment with distance sampling */
+				ShaderData volume_sd;
+				VolumeIntegrateResult result = kernel_volume_integrate(
+					kg, &state, &volume_sd, &volume_ray, &L, &throughput, rng, heterogeneous);
+
+#ifdef __VOLUME_SCATTER__
+				if(result == VOLUME_PATH_SCATTERED) {
+					/* direct lighting */
+					kernel_path_volume_connect_light(kg, rng, &volume_sd, throughput, &state, &L);
+
+					/* indirect light bounce */
+					if(kernel_path_volume_bounce(kg, rng, &volume_sd, &throughput, &state, &L, &ray))
+						continue;
+					else
+						break;
+				}
+#endif
+			}
+		}
+#endif
+#endif
+	}
+}