/*
 * 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 "camera.h"
#include "device.h"
#include "film.h"
#include "integrator.h"
#include "mesh.h"
#include "scene.h"
#include "tables.h"

#include "util_algorithm.h"
#include "util_debug.h"
#include "util_foreach.h"
#include "util_math.h"

CCL_NAMESPACE_BEGIN

/* Pass */

static bool compare_pass_order(const Pass& a, const Pass& b)
{
	if(a.components == b.components)
		return (a.type < b.type);
	return (a.components > b.components);
}

void Pass::add(PassType type, vector<Pass>& passes)
{
	foreach(Pass& existing_pass, passes)
		if(existing_pass.type == type)
			return;

	Pass pass;

	pass.type = type;
	pass.filter = true;
	pass.exposure = false;
	pass.divide_type = PASS_NONE;

	switch(type) {
		case PASS_NONE:
			pass.components = 0;
			break;
		case PASS_COMBINED:
			pass.components = 4;
			pass.exposure = true;
			break;
		case PASS_DEPTH:
			pass.components = 1;
			pass.filter = false;
			break;
		case PASS_MIST:
			pass.components = 1;
			break;
		case PASS_NORMAL:
			pass.components = 4;
			break;
		case PASS_UV:
			pass.components = 4;
			break;
		case PASS_MOTION:
			pass.components = 4;
			pass.divide_type = PASS_MOTION_WEIGHT;
			break;
		case PASS_MOTION_WEIGHT:
			pass.components = 1;
			break;
		case PASS_OBJECT_ID:
			pass.components = 1;
			pass.filter = false;
			break;
		case PASS_MATERIAL_ID:
			pass.components = 1;
			pass.filter = false;
			break;
		case PASS_DIFFUSE_COLOR:
			pass.components = 4;
			break;
		case PASS_GLOSSY_COLOR:
			pass.components = 4;
			break;
		case PASS_TRANSMISSION_COLOR:
			pass.components = 4;
			break;
		case PASS_SUBSURFACE_COLOR:
			pass.components = 4;
			break;
		case PASS_DIFFUSE_INDIRECT:
			pass.components = 4;
			pass.exposure = true;
			pass.divide_type = PASS_DIFFUSE_COLOR;
			break;
		case PASS_GLOSSY_INDIRECT:
			pass.components = 4;
			pass.exposure = true;
			pass.divide_type = PASS_GLOSSY_COLOR;
			break;
		case PASS_TRANSMISSION_INDIRECT:
			pass.components = 4;
			pass.exposure = true;
			pass.divide_type = PASS_TRANSMISSION_COLOR;
			break;
		case PASS_SUBSURFACE_INDIRECT:
			pass.components = 4;
			pass.exposure = true;
			pass.divide_type = PASS_SUBSURFACE_COLOR;
			break;
		case PASS_DIFFUSE_DIRECT:
			pass.components = 4;
			pass.exposure = true;
			pass.divide_type = PASS_DIFFUSE_COLOR;
			break;
		case PASS_GLOSSY_DIRECT:
			pass.components = 4;
			pass.exposure = true;
			pass.divide_type = PASS_GLOSSY_COLOR;
			break;
		case PASS_TRANSMISSION_DIRECT:
			pass.components = 4;
			pass.exposure = true;
			pass.divide_type = PASS_TRANSMISSION_COLOR;
			break;
		case PASS_SUBSURFACE_DIRECT:
			pass.components = 4;
			pass.exposure = true;
			pass.divide_type = PASS_SUBSURFACE_COLOR;
			break;

		case PASS_EMISSION:
			pass.components = 4;
			pass.exposure = true;
			break;
		case PASS_BACKGROUND:
			pass.components = 4;
			pass.exposure = true;
			break;
		case PASS_AO:
			pass.components = 4;
			break;
		case PASS_SHADOW:
			pass.components = 4;
			pass.exposure = false;
			break;
		case PASS_LIGHT:
			/* ignores */
			break;
	}

	passes.push_back(pass);

	/* order from by components, to ensure alignment so passes with size 4
	 * come first and then passes with size 1 */
	sort(passes.begin(), passes.end(), compare_pass_order);

	if(pass.divide_type != PASS_NONE)
		Pass::add(pass.divide_type, passes);
}

bool Pass::equals(const vector<Pass>& A, const vector<Pass>& B)
{
	if(A.size() != B.size())
		return false;
	
	for(int i = 0; i < A.size(); i++)
		if(A[i].type != B[i].type)
			return false;
	
	return true;
}

bool Pass::contains(const vector<Pass>& passes, PassType type)
{
	foreach(const Pass& pass, passes)
		if(pass.type == type)
			return true;
	
	return false;
}

/* Pixel Filter */

static float filter_func_box(float v, float width)
{
	return 1.0f;
}

static float filter_func_gaussian(float v, float width)
{
	v *= 2.0f/width;
	return expf(-2.0f*v*v);
}

static vector<float> filter_table(FilterType type, float width)
{
	const int filter_table_size = FILTER_TABLE_SIZE-1;
	vector<float> filter_table_cdf(filter_table_size+1);
	vector<float> filter_table(filter_table_size+1);
	float (*filter_func)(float, float) = NULL;
	int i, half_size = filter_table_size/2;

	switch(type) {
		case FILTER_BOX:
			filter_func = filter_func_box;
			break;
		case FILTER_GAUSSIAN:
			filter_func = filter_func_gaussian;
			break;
		default:
			assert(0);
	}

	/* compute cumulative distribution function */
	filter_table_cdf[0] = 0.0f;
	
	for(i = 0; i < filter_table_size; i++) {
		float x = i*width*0.5f/(filter_table_size-1);
		float y = filter_func(x, width);
		filter_table_cdf[i+1] += filter_table_cdf[i] + fabsf(y);
	}

	for(i = 0; i <= filter_table_size; i++)
		filter_table_cdf[i] /= filter_table_cdf[filter_table_size];
	
	/* create importance sampling table */
	for(i = 0; i <= half_size; i++) {
		float x = i/(float)half_size;
		int index = upper_bound(filter_table_cdf.begin(), filter_table_cdf.end(), x) - filter_table_cdf.begin();
		float t;

		if(index < filter_table_size+1) {
			t = (x - filter_table_cdf[index])/(filter_table_cdf[index+1] - filter_table_cdf[index]);
		}
		else {
			t = 0.0f;
			index = filter_table_size;
		}

		float y = ((index + t)/(filter_table_size))*width;

		filter_table[half_size+i] = 0.5f*(1.0f + y);
		filter_table[half_size-i] = 0.5f*(1.0f - y);
	}

	return filter_table;
}

/* Film */

Film::Film()
{
	exposure = 0.8f;
	Pass::add(PASS_COMBINED, passes);
	pass_alpha_threshold = 0.5f;

	filter_type = FILTER_BOX;
	filter_width = 1.0f;
	filter_table_offset = TABLE_OFFSET_INVALID;

	mist_start = 0.0f;
	mist_depth = 100.0f;
	mist_falloff = 1.0f;

	use_light_visibility = false;
	use_sample_clamp = false;

	need_update = true;
}

Film::~Film()
{
}

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

	KernelFilm *kfilm = &dscene->data.film;

	/* update __data */
	kfilm->exposure = exposure;
	kfilm->pass_flag = 0;
	kfilm->pass_stride = 0;
	kfilm->use_light_pass = use_light_visibility || use_sample_clamp;

	foreach(Pass& pass, passes) {
		kfilm->pass_flag |= pass.type;

		switch(pass.type) {
			case PASS_COMBINED:
				kfilm->pass_combined = kfilm->pass_stride;
				break;
			case PASS_DEPTH:
				kfilm->pass_depth = kfilm->pass_stride;
				break;
			case PASS_MIST:
				kfilm->pass_mist = kfilm->pass_stride;
				kfilm->use_light_pass = 1;
				break;
			case PASS_NORMAL:
				kfilm->pass_normal = kfilm->pass_stride;
				break;
			case PASS_UV:
				kfilm->pass_uv = kfilm->pass_stride;
				break;
			case PASS_MOTION:
				kfilm->pass_motion = kfilm->pass_stride;
				break;
			case PASS_MOTION_WEIGHT:
				kfilm->pass_motion_weight = kfilm->pass_stride;
				break;
			case PASS_OBJECT_ID:
				kfilm->pass_object_id = kfilm->pass_stride;
				break;
			case PASS_MATERIAL_ID:
				kfilm->pass_material_id = kfilm->pass_stride;
				break;
			case PASS_DIFFUSE_COLOR:
				kfilm->pass_diffuse_color = kfilm->pass_stride;
				kfilm->use_light_pass = 1;
				break;
			case PASS_GLOSSY_COLOR:
				kfilm->pass_glossy_color = kfilm->pass_stride;
				kfilm->use_light_pass = 1;
				break;
			case PASS_TRANSMISSION_COLOR:
				kfilm->pass_transmission_color = kfilm->pass_stride;
				kfilm->use_light_pass = 1;
				break;
			case PASS_SUBSURFACE_COLOR:
				kfilm->pass_subsurface_color = kfilm->pass_stride;
				kfilm->use_light_pass = 1;
				break;
			case PASS_DIFFUSE_INDIRECT:
				kfilm->pass_diffuse_indirect = kfilm->pass_stride;
				kfilm->use_light_pass = 1;
				break;
			case PASS_GLOSSY_INDIRECT:
				kfilm->pass_glossy_indirect = kfilm->pass_stride;
				kfilm->use_light_pass = 1;
				break;
			case PASS_TRANSMISSION_INDIRECT:
				kfilm->pass_transmission_indirect = kfilm->pass_stride;
				kfilm->use_light_pass = 1;
				break;
			case PASS_SUBSURFACE_INDIRECT:
				kfilm->pass_subsurface_indirect = kfilm->pass_stride;
				kfilm->use_light_pass = 1;
				break;
			case PASS_DIFFUSE_DIRECT:
				kfilm->pass_diffuse_direct = kfilm->pass_stride;
				kfilm->use_light_pass = 1;
				break;
			case PASS_GLOSSY_DIRECT:
				kfilm->pass_glossy_direct = kfilm->pass_stride;
				kfilm->use_light_pass = 1;
				break;
			case PASS_TRANSMISSION_DIRECT:
				kfilm->pass_transmission_direct = kfilm->pass_stride;
				kfilm->use_light_pass = 1;
				break;
			case PASS_SUBSURFACE_DIRECT:
				kfilm->pass_subsurface_direct = kfilm->pass_stride;
				kfilm->use_light_pass = 1;
				break;

			case PASS_EMISSION:
				kfilm->pass_emission = kfilm->pass_stride;
				kfilm->use_light_pass = 1;
				break;
			case PASS_BACKGROUND:
				kfilm->pass_background = kfilm->pass_stride;
				kfilm->use_light_pass = 1;
				break;
			case PASS_AO:
				kfilm->pass_ao = kfilm->pass_stride;
				kfilm->use_light_pass = 1;
				break;
			case PASS_SHADOW:
				kfilm->pass_shadow = kfilm->pass_stride;
				kfilm->use_light_pass = 1;
				break;

			case PASS_LIGHT:
				kfilm->use_light_pass = 1;
				break;
			case PASS_NONE:
				break;
		}

		kfilm->pass_stride += pass.components;
	}

	kfilm->pass_stride = align_up(kfilm->pass_stride, 4);
	kfilm->pass_alpha_threshold = pass_alpha_threshold;

	/* update filter table */
	vector<float> table = filter_table(filter_type, filter_width);
	filter_table_offset = scene->lookup_tables->add_table(dscene, table);
	kfilm->filter_table_offset = (int)filter_table_offset;

	/* mist pass parameters */
	kfilm->mist_start = mist_start;
	kfilm->mist_inv_depth = (mist_depth > 0.0f)? 1.0f/mist_depth: 0.0f;
	kfilm->mist_falloff = mist_falloff;

	need_update = false;
}

void Film::device_free(Device *device, DeviceScene *dscene, Scene *scene)
{
	if(filter_table_offset != TABLE_OFFSET_INVALID) {
		scene->lookup_tables->remove_table(filter_table_offset);
		filter_table_offset = TABLE_OFFSET_INVALID;
	}
}

bool Film::modified(const Film& film)
{
	return !(exposure == film.exposure
		&& Pass::equals(passes, film.passes)
		&& pass_alpha_threshold == film.pass_alpha_threshold
		&& use_sample_clamp == film.use_sample_clamp
		&& filter_type == film.filter_type
		&& filter_width == film.filter_width
		&& mist_start == film.mist_start
		&& mist_depth == film.mist_depth
		&& mist_falloff == film.mist_falloff);
}

void Film::tag_passes_update(Scene *scene, const vector<Pass>& passes_)
{
	if(Pass::contains(passes, PASS_UV) != Pass::contains(passes_, PASS_UV)) {
		scene->mesh_manager->tag_update(scene);

		foreach(Shader *shader, scene->shaders)
			shader->need_update_attributes = true;
	}
	else if(Pass::contains(passes, PASS_MOTION) != Pass::contains(passes_, PASS_MOTION))
		scene->mesh_manager->tag_update(scene);

	passes = passes_;
}

void Film::tag_update(Scene *scene)
{
	need_update = true;
}

CCL_NAMESPACE_END