/*
 * 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.
 */

CCL_NAMESPACE_BEGIN

/* Shadow ray cast for direct visible light. */
ccl_device void kernel_shadow_blocked_dl(KernelGlobals *kg)
{
	unsigned int dl_queue_length = kernel_split_params.queue_index[QUEUE_SHADOW_RAY_CAST_DL_RAYS];
	ccl_barrier(CCL_LOCAL_MEM_FENCE);

	int ray_index = QUEUE_EMPTY_SLOT;
	int thread_index = ccl_global_id(1) * ccl_global_size(0) + ccl_global_id(0);
	if(thread_index < dl_queue_length) {
		ray_index = get_ray_index(kg, thread_index, QUEUE_SHADOW_RAY_CAST_DL_RAYS,
		                          kernel_split_state.queue_data, kernel_split_params.queue_size, 1);
	}

#ifdef __BRANCHED_PATH__
	/* TODO(mai): move this somewhere else? */
	if(thread_index == 0) {
		/* Clear QUEUE_INACTIVE_RAYS before next kernel. */
		kernel_split_params.queue_index[QUEUE_INACTIVE_RAYS] = 0;
	}
#endif  /* __BRANCHED_PATH__ */

	if(ray_index == QUEUE_EMPTY_SLOT)
		return;

	ccl_global PathState *state = &kernel_split_state.path_state[ray_index];
	Ray ray = kernel_split_state.light_ray[ray_index];
	PathRadiance *L = &kernel_split_state.path_radiance[ray_index];
	ShaderData *sd = &kernel_split_state.sd[ray_index];
	float3 throughput = kernel_split_state.throughput[ray_index];
	RNG rng = kernel_split_state.rng[ray_index];

	BsdfEval L_light = kernel_split_state.bsdf_eval[ray_index];
	ShaderData *emission_sd = &kernel_split_state.sd_DL_shadow[ray_index];
	bool is_lamp = kernel_split_state.is_lamp[ray_index];

#  if defined(__BRANCHED_PATH__) || defined(__SHADOW_TRICKS__)
	bool use_branched = false;
	int all = 0;

	if(state->flag & PATH_RAY_SHADOW_CATCHER) {
		use_branched = true;
		all = 1;
	}
#    if defined(__BRANCHED_PATH__)
	else if(kernel_data.integrator.branched) {
		use_branched = true;

		if(IS_FLAG(kernel_split_state.ray_state, ray_index, RAY_BRANCHED_INDIRECT)) {
			all = (kernel_data.integrator.sample_all_lights_indirect);
		}
		else
		{
			all = (kernel_data.integrator.sample_all_lights_direct);
		}
	}
#    endif  /* __BRANCHED_PATH__ */

	if(use_branched) {
		kernel_branched_path_surface_connect_light(kg,
		                                           &rng,
		                                           sd,
		                                           emission_sd,
		                                           state,
		                                           throughput,
		                                           1.0f,
		                                           L,
		                                           all);
	}
	else
#  endif  /* defined(__BRANCHED_PATH__) || defined(__SHADOW_TRICKS__)*/
	{
		/* trace shadow ray */
		float3 shadow;

		if(!shadow_blocked(kg,
			               emission_sd,
			               state,
			               &ray,
			               &shadow))
		{
			/* accumulate */
			path_radiance_accum_light(L, state, throughput, &L_light, shadow, 1.0f, is_lamp);
		}
		else {
			path_radiance_accum_total_light(L, state, throughput, &L_light);
		}
	}

	kernel_split_state.rng[ray_index] = rng;
}

CCL_NAMESPACE_END