/*
 * Copyright 2011-2013 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 "device/device.h"
#include "render/integrator.h"
#include "render/film.h"
#include "render/light.h"
#include "render/scene.h"
#include "render/shader.h"
#include "render/sobol.h"

#include "util/util_foreach.h"
#include "util/util_hash.h"

CCL_NAMESPACE_BEGIN

NODE_DEFINE(Integrator)
{
	NodeType *type = NodeType::add("integrator", create);

	SOCKET_INT(min_bounce, "Min Bounce", 2);
	SOCKET_INT(max_bounce, "Max Bounce", 7);

	SOCKET_INT(max_diffuse_bounce, "Max Diffuse Bounce", 7);
	SOCKET_INT(max_glossy_bounce, "Max Glossy Bounce", 7);
	SOCKET_INT(max_transmission_bounce, "Max Transmission Bounce", 7);
	SOCKET_INT(max_volume_bounce, "Max Volume Bounce", 7);

	SOCKET_INT(transparent_min_bounce, "Transparent Min Bounce", 2);
	SOCKET_INT(transparent_max_bounce, "Transparent Max Bounce", 7);
	SOCKET_BOOLEAN(transparent_shadows, "Transparent Shadows", false);

	SOCKET_INT(ao_bounces, "AO Bounces", 0);

	SOCKET_INT(volume_max_steps, "Volume Max Steps", 1024);
	SOCKET_FLOAT(volume_step_size, "Volume Step Size", 0.1f);

	SOCKET_BOOLEAN(caustics_reflective, "Reflective Caustics", true);
	SOCKET_BOOLEAN(caustics_refractive, "Refractive Caustics", true);
	SOCKET_FLOAT(filter_glossy, "Filter Glossy", 0.0f);
	SOCKET_INT(seed, "Seed", 0);
	SOCKET_FLOAT(sample_clamp_direct, "Sample Clamp Direct", 0.0f);
	SOCKET_FLOAT(sample_clamp_indirect, "Sample Clamp Indirect", 0.0f);
	SOCKET_BOOLEAN(motion_blur, "Motion Blur", false);

	SOCKET_INT(aa_samples, "AA Samples", 0);
	SOCKET_INT(diffuse_samples, "Diffuse Samples", 1);
	SOCKET_INT(glossy_samples, "Glossy Samples", 1);
	SOCKET_INT(transmission_samples, "Transmission Samples", 1);
	SOCKET_INT(ao_samples, "AO Samples", 1);
	SOCKET_INT(mesh_light_samples, "Mesh Light Samples", 1);
	SOCKET_INT(subsurface_samples, "Subsurface Samples", 1);
	SOCKET_INT(volume_samples, "Volume Samples", 1);
	SOCKET_INT(start_sample, "Start Sample", 0);

	SOCKET_BOOLEAN(sample_all_lights_direct, "Sample All Lights Direct", true);
	SOCKET_BOOLEAN(sample_all_lights_indirect, "Sample All Lights Indirect", true);
	SOCKET_FLOAT(light_sampling_threshold, "Light Sampling Threshold", 0.05f);

	static NodeEnum method_enum;
	method_enum.insert("path", PATH);
	method_enum.insert("branched_path", BRANCHED_PATH);
	SOCKET_ENUM(method, "Method", method_enum, PATH);

	static NodeEnum sampling_pattern_enum;
	sampling_pattern_enum.insert("sobol", SAMPLING_PATTERN_SOBOL);
	sampling_pattern_enum.insert("cmj", SAMPLING_PATTERN_CMJ);
	SOCKET_ENUM(sampling_pattern, "Sampling Pattern", sampling_pattern_enum, SAMPLING_PATTERN_SOBOL);

	return type;
}

Integrator::Integrator()
: Node(node_type)
{
	need_update = true;
}

Integrator::~Integrator()
{
}

void Integrator::device_update(Device *device, DeviceScene *dscene, Scene *scene)
{
	if(!need_update)
		return;

	device_free(device, dscene);

	KernelIntegrator *kintegrator = &dscene->data.integrator;

	/* integrator parameters */
	kintegrator->max_bounce = max_bounce + 1;
	kintegrator->min_bounce = min_bounce + 1;

	kintegrator->max_diffuse_bounce = max_diffuse_bounce + 1;
	kintegrator->max_glossy_bounce = max_glossy_bounce + 1;
	kintegrator->max_transmission_bounce = max_transmission_bounce + 1;
	kintegrator->max_volume_bounce = max_volume_bounce + 1;

	kintegrator->transparent_max_bounce = transparent_max_bounce + 1;
	kintegrator->transparent_min_bounce = transparent_min_bounce + 1;

	if(ao_bounces == 0) {
		kintegrator->ao_bounces = INT_MAX;
	}
	else {
		kintegrator->ao_bounces = ao_bounces - 1;
	}

	/* Transparent Shadows
	 * We only need to enable transparent shadows, if we actually have 
	 * transparent shaders in the scene. Otherwise we can disable it
	 * to improve performance a bit. */
	if(transparent_shadows) {
		kintegrator->transparent_shadows = false;
		foreach(Shader *shader, scene->shaders) {
			/* keep this in sync with SD_HAS_TRANSPARENT_SHADOW in shader.cpp */
			if((shader->has_surface_transparent && shader->use_transparent_shadow) || shader->has_volume) {
				kintegrator->transparent_shadows = true;
				break;
			}
		}
	}
	else {
		kintegrator->transparent_shadows = false;
	}

	kintegrator->volume_max_steps = volume_max_steps;
	kintegrator->volume_step_size = volume_step_size;

	kintegrator->caustics_reflective = caustics_reflective;
	kintegrator->caustics_refractive = caustics_refractive;
	kintegrator->filter_glossy = (filter_glossy == 0.0f)? FLT_MAX: 1.0f/filter_glossy;

	kintegrator->seed = hash_int(seed);

	kintegrator->use_ambient_occlusion =
		((Pass::contains(scene->film->passes, PASS_AO)) || dscene->data.background.ao_factor != 0.0f);
	
	kintegrator->sample_clamp_direct = (sample_clamp_direct == 0.0f)? FLT_MAX: sample_clamp_direct*3.0f;
	kintegrator->sample_clamp_indirect = (sample_clamp_indirect == 0.0f)? FLT_MAX: sample_clamp_indirect*3.0f;

	kintegrator->branched = (method == BRANCHED_PATH);
	kintegrator->diffuse_samples = diffuse_samples;
	kintegrator->glossy_samples = glossy_samples;
	kintegrator->transmission_samples = transmission_samples;
	kintegrator->ao_samples = ao_samples;
	kintegrator->mesh_light_samples = mesh_light_samples;
	kintegrator->subsurface_samples = subsurface_samples;
	kintegrator->volume_samples = volume_samples;
	kintegrator->start_sample = start_sample;

	if(method == BRANCHED_PATH) {
		kintegrator->sample_all_lights_direct = sample_all_lights_direct;
		kintegrator->sample_all_lights_indirect = sample_all_lights_indirect;
	}
	else {
		kintegrator->sample_all_lights_direct = false;
		kintegrator->sample_all_lights_indirect = false;
	}

	kintegrator->sampling_pattern = sampling_pattern;
	kintegrator->aa_samples = aa_samples;

	if(light_sampling_threshold > 0.0f) {
		kintegrator->light_inv_rr_threshold = 1.0f / light_sampling_threshold;
	}
	else {
		kintegrator->light_inv_rr_threshold = 0.0f;
	}

	/* sobol directions table */
	int max_samples = 1;

	if(method == BRANCHED_PATH) {
		foreach(Light *light, scene->lights)
			max_samples = max(max_samples, light->samples);

		max_samples = max(max_samples, max(diffuse_samples, max(glossy_samples, transmission_samples)));
		max_samples = max(max_samples, max(ao_samples, max(mesh_light_samples, subsurface_samples)));
		max_samples = max(max_samples, volume_samples);
	}

	max_samples *= (max_bounce + transparent_max_bounce + 3 + BSSRDF_MAX_HITS);

	int dimensions = PRNG_BASE_NUM + max_samples*PRNG_BOUNCE_NUM;
	dimensions = min(dimensions, SOBOL_MAX_DIMENSIONS);

	uint *directions = dscene->sobol_directions.resize(SOBOL_BITS*dimensions);

	sobol_generate_direction_vectors((uint(*)[SOBOL_BITS])directions, dimensions);

	device->tex_alloc("__sobol_directions", dscene->sobol_directions);

	/* Clamping. */
	bool use_sample_clamp = (sample_clamp_direct != 0.0f ||
	                         sample_clamp_indirect != 0.0f);
	if(use_sample_clamp != scene->film->use_sample_clamp) {
		scene->film->use_sample_clamp = use_sample_clamp;
		scene->film->tag_update(scene);
	}

	need_update = false;
}

void Integrator::device_free(Device *device, DeviceScene *dscene)
{
	device->tex_free(dscene->sobol_directions);
	dscene->sobol_directions.clear();
}

bool Integrator::modified(const Integrator& integrator)
{
	return !Node::equals(integrator);
}

void Integrator::tag_update(Scene *scene)
{
	foreach(Shader *shader, scene->shaders) {
		if(shader->has_integrator_dependency) {
			scene->shader_manager->need_update = true;
			break;
		}
	}
	need_update = true;
}

CCL_NAMESPACE_END

