/*
 * 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/curves.h"
#include "render/mesh.h"
#include "render/object.h"
#include "render/scene.h"

#include "util/util_foreach.h"
#include "util/util_map.h"
#include "util/util_progress.h"
#include "util/util_vector.h"

CCL_NAMESPACE_BEGIN

/* Curve functions */

void curvebounds(float *lower, float *upper, float3 *p, int dim)
{
	float *p0 = &p[0].x;
	float *p1 = &p[1].x;
	float *p2 = &p[2].x;
	float *p3 = &p[3].x;

	float fc = 0.71f;
	float curve_coef[4];
	curve_coef[0] = p1[dim];
	curve_coef[1] = -fc*p0[dim] + fc*p2[dim];
	curve_coef[2] = 2.0f * fc * p0[dim] + (fc - 3.0f) * p1[dim] + (3.0f - 2.0f * fc) * p2[dim] - fc * p3[dim];
	curve_coef[3] = -fc * p0[dim] + (2.0f - fc) * p1[dim] + (fc - 2.0f) * p2[dim] + fc * p3[dim];

	float discroot = curve_coef[2] * curve_coef[2] - 3 * curve_coef[3] * curve_coef[1];
	float ta = -1.0f;
	float tb = -1.0f;

	if(discroot >= 0) {
		discroot = sqrtf(discroot);
		ta = (-curve_coef[2] - discroot) / (3 * curve_coef[3]);
		tb = (-curve_coef[2] + discroot) / (3 * curve_coef[3]);
		ta = (ta > 1.0f || ta < 0.0f) ? -1.0f : ta;
		tb = (tb > 1.0f || tb < 0.0f) ? -1.0f : tb;
	}

	*upper = max(p1[dim],p2[dim]);
	*lower = min(p1[dim],p2[dim]);

	float exa = p1[dim];
	float exb = p2[dim];

	if(ta >= 0.0f) {
		float t2 = ta * ta;
		float t3 = t2 * ta;
		exa = curve_coef[3] * t3 + curve_coef[2] * t2 + curve_coef[1] * ta + curve_coef[0];
	}
	if(tb >= 0.0f) {
		float t2 = tb * tb;
		float t3 = t2 * tb;
		exb = curve_coef[3] * t3 + curve_coef[2] * t2 + curve_coef[1] * tb + curve_coef[0];
	}

	*upper = max(*upper, max(exa,exb));
	*lower = min(*lower, min(exa,exb));
}

/* Hair System Manager */

CurveSystemManager::CurveSystemManager()
{
	primitive = CURVE_LINE_SEGMENTS;
	curve_shape = CURVE_THICK;
	line_method = CURVE_CORRECTED;
	triangle_method = CURVE_CAMERA_TRIANGLES;
	resolution = 3;
	subdivisions = 3;

	minimum_width = 0.0f;
	maximum_width = 0.0f;

	use_curves = true;
	use_encasing = true;
	use_backfacing = false;
	use_tangent_normal_geometry = false;

	need_update = true;
	need_mesh_update = false;
}

CurveSystemManager::~CurveSystemManager()
{
}

void CurveSystemManager::device_update(Device *device,
                                       DeviceScene *dscene,
                                       Scene * /*scene*/,
                                       Progress& progress)
{
	if(!need_update)
		return;

	device_free(device, dscene);

	progress.set_status("Updating Hair settings", "Copying Hair settings to device");

	KernelCurves *kcurve = &dscene->data.curve;

	kcurve->curveflags = 0;

	if(use_curves) {
		if(primitive == CURVE_SEGMENTS || primitive == CURVE_RIBBONS)
			kcurve->curveflags |= CURVE_KN_INTERPOLATE;
		if(primitive == CURVE_RIBBONS)
			kcurve->curveflags |= CURVE_KN_RIBBONS;

		if(line_method == CURVE_ACCURATE)
			kcurve->curveflags |= CURVE_KN_ACCURATE;
		else if(line_method == CURVE_CORRECTED)
			kcurve->curveflags |= CURVE_KN_INTERSECTCORRECTION;

		if(use_tangent_normal_geometry)
			kcurve->curveflags |= CURVE_KN_TRUETANGENTGNORMAL;
		if(use_backfacing)
			kcurve->curveflags |= CURVE_KN_BACKFACING;
		if(use_encasing)
			kcurve->curveflags |= CURVE_KN_ENCLOSEFILTER;

		kcurve->minimum_width = minimum_width;
		kcurve->maximum_width = maximum_width;
		kcurve->subdivisions = subdivisions;
	}

	if(progress.get_cancel()) return;

	need_update = false;
}

void CurveSystemManager::device_free(Device * /*device*/,
                                     DeviceScene * /*dscene*/)
{

}

bool CurveSystemManager::modified(const CurveSystemManager& CurveSystemManager)
{
	return !(curve_shape == CurveSystemManager.curve_shape &&
		line_method == CurveSystemManager.line_method &&
		primitive == CurveSystemManager.primitive &&
		use_encasing == CurveSystemManager.use_encasing &&
		use_tangent_normal_geometry == CurveSystemManager.use_tangent_normal_geometry &&
		minimum_width == CurveSystemManager.minimum_width &&
		maximum_width == CurveSystemManager.maximum_width &&
		use_backfacing == CurveSystemManager.use_backfacing &&
		triangle_method == CurveSystemManager.triangle_method &&
		resolution == CurveSystemManager.resolution &&
		use_curves == CurveSystemManager.use_curves &&
		subdivisions == CurveSystemManager.subdivisions);
}

bool CurveSystemManager::modified_mesh(const CurveSystemManager& CurveSystemManager)
{
	return !(primitive == CurveSystemManager.primitive &&
		curve_shape == CurveSystemManager.curve_shape &&
		triangle_method == CurveSystemManager.triangle_method &&
		resolution == CurveSystemManager.resolution &&
		use_curves == CurveSystemManager.use_curves);
}

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

void CurveSystemManager::tag_update_mesh()
{
	need_mesh_update = true;
}
CCL_NAMESPACE_END

