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

#include "blender/blender_sync.h"
#include "blender/blender_util.h"

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

CCL_NAMESPACE_BEGIN

ParticleCurveData::ParticleCurveData()
{
}

ParticleCurveData::~ParticleCurveData()
{
}

static void interp_weights(float t, float data[4])
{
	/* Cardinal curve interpolation */
	float t2 = t * t;
	float t3 = t2 * t;
	float fc = 0.71f;

	data[0] = -fc          * t3  + 2.0f * fc          * t2 - fc * t;
	data[1] =  (2.0f - fc) * t3  + (fc - 3.0f)        * t2 + 1.0f;
	data[2] =  (fc - 2.0f) * t3  + (3.0f - 2.0f * fc) * t2 + fc * t;
	data[3] =  fc          * t3  - fc * t2;
}

static void curveinterp_v3_v3v3v3v3(float3 *p,
                                    float3 *v1, float3 *v2, float3 *v3, float3 *v4,
                                    const float w[4])
{
	p->x = v1->x * w[0] + v2->x * w[1] + v3->x * w[2] + v4->x * w[3];
	p->y = v1->y * w[0] + v2->y * w[1] + v3->y * w[2] + v4->y * w[3];
	p->z = v1->z * w[0] + v2->z * w[1] + v3->z * w[2] + v4->z * w[3];
}

static float shaperadius(float shape, float root, float tip, float time)
{
	float radius = 1.0f - time;

	if(shape != 0.0f) {
		if(shape < 0.0f)
			radius = powf(radius, 1.0f + shape);
		else
			radius = powf(radius, 1.0f / (1.0f - shape));
	}
	return (radius * (root - tip)) + tip;
}

/* curve functions */

static void InterpolateKeySegments(int seg,
                                   int segno,
                                   int key,
                                   int curve,
                                   float3 *keyloc,
                                   float *time,
                                   ParticleCurveData *CData)
{
	float3 ckey_loc1 = CData->curvekey_co[key];
	float3 ckey_loc2 = ckey_loc1;
	float3 ckey_loc3 = CData->curvekey_co[key+1];
	float3 ckey_loc4 = ckey_loc3;

	if(key > CData->curve_firstkey[curve])
		ckey_loc1 = CData->curvekey_co[key - 1];

	if(key < CData->curve_firstkey[curve] + CData->curve_keynum[curve] - 2)
		ckey_loc4 = CData->curvekey_co[key + 2];

	float time1 = CData->curvekey_time[key]/CData->curve_length[curve];
	float time2 = CData->curvekey_time[key + 1]/CData->curve_length[curve];

	float dfra = (time2 - time1) / (float)segno;

	if(time)
		*time = (dfra * seg) + time1;

	float t[4];

	interp_weights((float)seg / (float)segno, t);

	if(keyloc)
		curveinterp_v3_v3v3v3v3(keyloc, &ckey_loc1, &ckey_loc2, &ckey_loc3, &ckey_loc4, t);
}

static bool ObtainCacheParticleData(Mesh *mesh,
                                    BL::Mesh *b_mesh,
                                    BL::Object *b_ob,
                                    ParticleCurveData *CData,
                                    bool background)
{
	int curvenum = 0;
	int keyno = 0;

	if(!(mesh && b_mesh && b_ob && CData))
		return false;

	Transform tfm = get_transform(b_ob->matrix_world());
	Transform itfm = transform_quick_inverse(tfm);

	BL::Object::modifiers_iterator b_mod;
	for(b_ob->modifiers.begin(b_mod); b_mod != b_ob->modifiers.end(); ++b_mod) {
		if((b_mod->type() == b_mod->type_PARTICLE_SYSTEM) && (background ? b_mod->show_render() : b_mod->show_viewport())) {
			BL::ParticleSystemModifier psmd((const PointerRNA)b_mod->ptr);
			BL::ParticleSystem b_psys((const PointerRNA)psmd.particle_system().ptr);
			BL::ParticleSettings b_part((const PointerRNA)b_psys.settings().ptr);

			if((b_part.render_type() == BL::ParticleSettings::render_type_PATH) && (b_part.type() == BL::ParticleSettings::type_HAIR)) {
				int shader = clamp(b_part.material()-1, 0, mesh->used_shaders.size()-1);
				int draw_step = background ? b_part.render_step() : b_part.draw_step();
				int totparts = b_psys.particles.length();
				int totchild = background ? b_psys.child_particles.length() : (int)((float)b_psys.child_particles.length() * (float)b_part.draw_percentage() / 100.0f);
				int totcurves = totchild;

				if(b_part.child_type() == 0 || totchild == 0)
					totcurves += totparts;

				if(totcurves == 0)
					continue;

				int ren_step = (1 << draw_step) + 1;
				if(b_part.kink() == BL::ParticleSettings::kink_SPIRAL)
					ren_step += b_part.kink_extra_steps();

				PointerRNA cpsys = RNA_pointer_get(&b_part.ptr, "cycles");

				CData->psys_firstcurve.push_back_slow(curvenum);
				CData->psys_curvenum.push_back_slow(totcurves);
				CData->psys_shader.push_back_slow(shader);

				float radius = get_float(cpsys, "radius_scale") * 0.5f;

				CData->psys_rootradius.push_back_slow(radius * get_float(cpsys, "root_width"));
				CData->psys_tipradius.push_back_slow(radius * get_float(cpsys, "tip_width"));
				CData->psys_shape.push_back_slow(get_float(cpsys, "shape"));
				CData->psys_closetip.push_back_slow(get_boolean(cpsys, "use_closetip"));

				int pa_no = 0;
				if(!(b_part.child_type() == 0) && totchild != 0)
					pa_no = totparts;

				int num_add = (totparts+totchild - pa_no);
				CData->curve_firstkey.reserve(CData->curve_firstkey.size() + num_add);
				CData->curve_keynum.reserve(CData->curve_keynum.size() + num_add);
				CData->curve_length.reserve(CData->curve_length.size() + num_add);
				CData->curvekey_co.reserve(CData->curvekey_co.size() + num_add*ren_step);
				CData->curvekey_time.reserve(CData->curvekey_time.size() + num_add*ren_step);

				for(; pa_no < totparts+totchild; pa_no++) {
					int keynum = 0;
					CData->curve_firstkey.push_back_slow(keyno);

					float curve_length = 0.0f;
					float3 pcKey;
					for(int step_no = 0; step_no < ren_step; step_no++) {
						float nco[3];
						b_psys.co_hair(*b_ob, pa_no, step_no, nco);
						float3 cKey = make_float3(nco[0], nco[1], nco[2]);
						cKey = transform_point(&itfm, cKey);
						if(step_no > 0) {
							float step_length = len(cKey - pcKey);
							if(step_length == 0.0f)
								continue;
							curve_length += step_length;
						}
						CData->curvekey_co.push_back_slow(cKey);
						CData->curvekey_time.push_back_slow(curve_length);
						pcKey = cKey;
						keynum++;
					}
					keyno += keynum;

					CData->curve_keynum.push_back_slow(keynum);
					CData->curve_length.push_back_slow(curve_length);
					curvenum++;
				}
			}
		}
	}

	return true;
}

static bool ObtainCacheParticleUV(Mesh *mesh,
                                  BL::Mesh *b_mesh,
                                  BL::Object *b_ob,
                                  ParticleCurveData *CData,
                                  bool background,
                                  int uv_num)
{
	if(!(mesh && b_mesh && b_ob && CData))
		return false;

	CData->curve_uv.clear();

	BL::Object::modifiers_iterator b_mod;
	for(b_ob->modifiers.begin(b_mod); b_mod != b_ob->modifiers.end(); ++b_mod) {
		if((b_mod->type() == b_mod->type_PARTICLE_SYSTEM) && (background ? b_mod->show_render() : b_mod->show_viewport())) {
			BL::ParticleSystemModifier psmd((const PointerRNA)b_mod->ptr);
			BL::ParticleSystem b_psys((const PointerRNA)psmd.particle_system().ptr);
			BL::ParticleSettings b_part((const PointerRNA)b_psys.settings().ptr);

			if((b_part.render_type() == BL::ParticleSettings::render_type_PATH) && (b_part.type() == BL::ParticleSettings::type_HAIR)) {
				int totparts = b_psys.particles.length();
				int totchild = background ? b_psys.child_particles.length() : (int)((float)b_psys.child_particles.length() * (float)b_part.draw_percentage() / 100.0f);
				int totcurves = totchild;

				if(b_part.child_type() == 0 || totchild == 0)
					totcurves += totparts;

				if(totcurves == 0)
					continue;

				int pa_no = 0;
				if(!(b_part.child_type() == 0) && totchild != 0)
					pa_no = totparts;

				int num_add = (totparts+totchild - pa_no);
				CData->curve_uv.reserve(CData->curve_uv.size() + num_add);

				BL::ParticleSystem::particles_iterator b_pa;
				b_psys.particles.begin(b_pa);
				for(; pa_no < totparts+totchild; pa_no++) {
					/* Add UVs */
					BL::Mesh::tessface_uv_textures_iterator l;
					b_mesh->tessface_uv_textures.begin(l);

					float3 uv = make_float3(0.0f, 0.0f, 0.0f);
					if(b_mesh->tessface_uv_textures.length())
						b_psys.uv_on_emitter(psmd, *b_pa, pa_no, uv_num, &uv.x);
					CData->curve_uv.push_back_slow(uv);

					if(pa_no < totparts && b_pa != b_psys.particles.end())
						++b_pa;
				}
			}
		}
	}

	return true;
}

static bool ObtainCacheParticleVcol(Mesh *mesh,
                                    BL::Mesh *b_mesh,
                                    BL::Object *b_ob,
                                    ParticleCurveData *CData,
                                    bool background,
                                    int vcol_num)
{
	if(!(mesh && b_mesh && b_ob && CData))
		return false;

	CData->curve_vcol.clear();

	BL::Object::modifiers_iterator b_mod;
	for(b_ob->modifiers.begin(b_mod); b_mod != b_ob->modifiers.end(); ++b_mod) {
		if((b_mod->type() == b_mod->type_PARTICLE_SYSTEM) && (background ? b_mod->show_render() : b_mod->show_viewport())) {
			BL::ParticleSystemModifier psmd((const PointerRNA)b_mod->ptr);
			BL::ParticleSystem b_psys((const PointerRNA)psmd.particle_system().ptr);
			BL::ParticleSettings b_part((const PointerRNA)b_psys.settings().ptr);

			if((b_part.render_type() == BL::ParticleSettings::render_type_PATH) && (b_part.type() == BL::ParticleSettings::type_HAIR)) {
				int totparts = b_psys.particles.length();
				int totchild = background ? b_psys.child_particles.length() : (int)((float)b_psys.child_particles.length() * (float)b_part.draw_percentage() / 100.0f);
				int totcurves = totchild;

				if(b_part.child_type() == 0 || totchild == 0)
					totcurves += totparts;

				if(totcurves == 0)
					continue;

				int pa_no = 0;
				if(!(b_part.child_type() == 0) && totchild != 0)
					pa_no = totparts;

				int num_add = (totparts+totchild - pa_no);
				CData->curve_vcol.reserve(CData->curve_vcol.size() + num_add);

				BL::ParticleSystem::particles_iterator b_pa;
				b_psys.particles.begin(b_pa);
				for(; pa_no < totparts+totchild; pa_no++) {
					/* Add vertex colors */
					BL::Mesh::tessface_vertex_colors_iterator l;
					b_mesh->tessface_vertex_colors.begin(l);

					float3 vcol = make_float3(0.0f, 0.0f, 0.0f);
					if(b_mesh->tessface_vertex_colors.length())
						b_psys.mcol_on_emitter(psmd, *b_pa, pa_no, vcol_num, &vcol.x);
					CData->curve_vcol.push_back_slow(vcol);

					if(pa_no < totparts && b_pa != b_psys.particles.end())
						++b_pa;
				}
			}
		}
	}

	return true;
}

static void set_resolution(BL::Object *b_ob, BL::Scene *scene, bool render)
{
	BL::Object::modifiers_iterator b_mod;
	for(b_ob->modifiers.begin(b_mod); b_mod != b_ob->modifiers.end(); ++b_mod) {
		if((b_mod->type() == b_mod->type_PARTICLE_SYSTEM) && ((b_mod->show_viewport()) || (b_mod->show_render()))) {
			BL::ParticleSystemModifier psmd((const PointerRNA)b_mod->ptr);
			BL::ParticleSystem b_psys((const PointerRNA)psmd.particle_system().ptr);
			b_psys.set_resolution(*scene, *b_ob, (render)? 2: 1);
		}
	}
}

static void ExportCurveTrianglePlanes(Mesh *mesh, ParticleCurveData *CData,
                                      float3 RotCam, bool is_ortho)
{
	int vertexno = mesh->verts.size();
	int vertexindex = vertexno;
	int numverts = 0, numtris = 0;

	/* compute and reserve size of arrays */
	for(int sys = 0; sys < CData->psys_firstcurve.size(); sys++) {
		for(int curve = CData->psys_firstcurve[sys]; curve < CData->psys_firstcurve[sys] + CData->psys_curvenum[sys]; curve++) {
			if(CData->curve_keynum[curve] <= 1 || CData->curve_length[curve] == 0.0f)
				continue;

			numverts += 2 + (CData->curve_keynum[curve] - 1)*2;
			numtris += (CData->curve_keynum[curve] - 1)*2;
		}
	}

	mesh->reserve_mesh(mesh->verts.size() + numverts, mesh->num_triangles() + numtris);

	/* actually export */
	for(int sys = 0; sys < CData->psys_firstcurve.size(); sys++) {
		for(int curve = CData->psys_firstcurve[sys]; curve < CData->psys_firstcurve[sys] + CData->psys_curvenum[sys]; curve++) {
			if(CData->curve_keynum[curve] <= 1 || CData->curve_length[curve] == 0.0f)
				continue;

			float3 xbasis;
			float3 v1;
			float time = 0.0f;
			float3 ickey_loc = CData->curvekey_co[CData->curve_firstkey[curve]];
			float radius = shaperadius(CData->psys_shape[sys], CData->psys_rootradius[sys], CData->psys_tipradius[sys], 0.0f);
			v1 = CData->curvekey_co[CData->curve_firstkey[curve] + 1] - CData->curvekey_co[CData->curve_firstkey[curve]];
			if(is_ortho)
				xbasis = normalize(cross(RotCam, v1));
			else
				xbasis = normalize(cross(RotCam - ickey_loc, v1));
			float3 ickey_loc_shfl = ickey_loc - radius * xbasis;
			float3 ickey_loc_shfr = ickey_loc + radius * xbasis;
			mesh->add_vertex(ickey_loc_shfl);
			mesh->add_vertex(ickey_loc_shfr);
			vertexindex += 2;

			for(int curvekey = CData->curve_firstkey[curve] + 1; curvekey < CData->curve_firstkey[curve] + CData->curve_keynum[curve]; curvekey++) {
				ickey_loc = CData->curvekey_co[curvekey];

				if(curvekey == CData->curve_firstkey[curve] + CData->curve_keynum[curve] - 1)
					v1 = CData->curvekey_co[curvekey] - CData->curvekey_co[max(curvekey - 1, CData->curve_firstkey[curve])];
				else
					v1 = CData->curvekey_co[curvekey + 1] - CData->curvekey_co[curvekey - 1];

				time = CData->curvekey_time[curvekey]/CData->curve_length[curve];
				radius = shaperadius(CData->psys_shape[sys], CData->psys_rootradius[sys], CData->psys_tipradius[sys], time);

				if(curvekey == CData->curve_firstkey[curve] + CData->curve_keynum[curve] - 1)
					radius = shaperadius(CData->psys_shape[sys], CData->psys_rootradius[sys], CData->psys_tipradius[sys], 0.95f);

				if(CData->psys_closetip[sys] && (curvekey == CData->curve_firstkey[curve] + CData->curve_keynum[curve] - 1))
					radius = shaperadius(CData->psys_shape[sys], CData->psys_rootradius[sys], 0.0f, 0.95f);

				if(is_ortho)
					xbasis = normalize(cross(RotCam, v1));
				else
					xbasis = normalize(cross(RotCam - ickey_loc, v1));
				float3 ickey_loc_shfl = ickey_loc - radius * xbasis;
				float3 ickey_loc_shfr = ickey_loc + radius * xbasis;
				mesh->add_vertex(ickey_loc_shfl);
				mesh->add_vertex(ickey_loc_shfr);
				mesh->add_triangle(vertexindex-2, vertexindex, vertexindex-1, CData->psys_shader[sys], true);
				mesh->add_triangle(vertexindex+1, vertexindex-1, vertexindex, CData->psys_shader[sys], true);
				vertexindex += 2;
			}
		}
	}

	mesh->resize_mesh(mesh->verts.size(), mesh->num_triangles());
	mesh->attributes.remove(ATTR_STD_VERTEX_NORMAL);
	mesh->attributes.remove(ATTR_STD_FACE_NORMAL);
	mesh->add_face_normals();
	mesh->add_vertex_normals();
	mesh->attributes.remove(ATTR_STD_FACE_NORMAL);

	/* texture coords still needed */
}

static void ExportCurveTriangleGeometry(Mesh *mesh,
                                        ParticleCurveData *CData,
                                        int resolution)
{
	int vertexno = mesh->verts.size();
	int vertexindex = vertexno;
	int numverts = 0, numtris = 0;

	/* compute and reserve size of arrays */
	for(int sys = 0; sys < CData->psys_firstcurve.size(); sys++) {
		for(int curve = CData->psys_firstcurve[sys]; curve < CData->psys_firstcurve[sys] + CData->psys_curvenum[sys]; curve++) {
			if(CData->curve_keynum[curve] <= 1 || CData->curve_length[curve] == 0.0f)
				continue;

			numverts += (CData->curve_keynum[curve] - 1)*resolution + resolution;
			numtris += (CData->curve_keynum[curve] - 1)*2*resolution;
		}
	}

	mesh->reserve_mesh(mesh->verts.size() + numverts, mesh->num_triangles() + numtris);

	/* actually export */
	for(int sys = 0; sys < CData->psys_firstcurve.size(); sys++) {
		for(int curve = CData->psys_firstcurve[sys]; curve < CData->psys_firstcurve[sys] + CData->psys_curvenum[sys]; curve++) {
			if(CData->curve_keynum[curve] <= 1 || CData->curve_length[curve] == 0.0f)
				continue;

			float3 firstxbasis = cross(make_float3(1.0f,0.0f,0.0f),CData->curvekey_co[CData->curve_firstkey[curve]+1] - CData->curvekey_co[CData->curve_firstkey[curve]]);
			if(!is_zero(firstxbasis))
				firstxbasis = normalize(firstxbasis);
			else
				firstxbasis = normalize(cross(make_float3(0.0f,1.0f,0.0f),CData->curvekey_co[CData->curve_firstkey[curve]+1] - CData->curvekey_co[CData->curve_firstkey[curve]]));

			for(int curvekey = CData->curve_firstkey[curve]; curvekey < CData->curve_firstkey[curve] + CData->curve_keynum[curve] - 1; curvekey++) {
				float3 xbasis = firstxbasis;
				float3 v1;
				float3 v2;

				if(curvekey == CData->curve_firstkey[curve]) {
					v1 = CData->curvekey_co[min(curvekey+2,CData->curve_firstkey[curve] + CData->curve_keynum[curve] - 1)] - CData->curvekey_co[curvekey+1];
					v2 = CData->curvekey_co[curvekey+1] - CData->curvekey_co[curvekey];
				}
				else if(curvekey == CData->curve_firstkey[curve] + CData->curve_keynum[curve] - 1) {
					v1 = CData->curvekey_co[curvekey] - CData->curvekey_co[curvekey-1];
					v2 = CData->curvekey_co[curvekey-1] - CData->curvekey_co[max(curvekey-2,CData->curve_firstkey[curve])];
				}
				else {
					v1 = CData->curvekey_co[curvekey+1] - CData->curvekey_co[curvekey];
					v2 = CData->curvekey_co[curvekey] - CData->curvekey_co[curvekey-1];
				}

				xbasis = cross(v1, v2);

				if(len_squared(xbasis) >= 0.05f * len_squared(v1) * len_squared(v2)) {
					firstxbasis = normalize(xbasis);
					break;
				}
			}

			for(int curvekey = CData->curve_firstkey[curve]; curvekey < CData->curve_firstkey[curve] + CData->curve_keynum[curve] - 1; curvekey++) {
				int subv = 1;
				float3 xbasis;
				float3 ybasis;
				float3 v1;
				float3 v2;

				if(curvekey == CData->curve_firstkey[curve]) {
					subv = 0;
					v1 = CData->curvekey_co[min(curvekey+2,CData->curve_firstkey[curve] + CData->curve_keynum[curve] - 1)] - CData->curvekey_co[curvekey+1];
					v2 = CData->curvekey_co[curvekey+1] - CData->curvekey_co[curvekey];
				}
				else if(curvekey == CData->curve_firstkey[curve] + CData->curve_keynum[curve] - 1) {
					v1 = CData->curvekey_co[curvekey] - CData->curvekey_co[curvekey-1];
					v2 = CData->curvekey_co[curvekey-1] - CData->curvekey_co[max(curvekey-2,CData->curve_firstkey[curve])];
				}
				else {
					v1 = CData->curvekey_co[curvekey+1] - CData->curvekey_co[curvekey];
					v2 = CData->curvekey_co[curvekey] - CData->curvekey_co[curvekey-1];
				}

				xbasis = cross(v1, v2);

				if(len_squared(xbasis) >= 0.05f * len_squared(v1) * len_squared(v2)) {
					xbasis = normalize(xbasis);
					firstxbasis = xbasis;
				}
				else
					xbasis = firstxbasis;

				ybasis = normalize(cross(xbasis, v2));

				for(; subv <= 1; subv++) {
					float3 ickey_loc = make_float3(0.0f,0.0f,0.0f);
					float time = 0.0f;

					InterpolateKeySegments(subv, 1, curvekey, curve, &ickey_loc, &time, CData);

					float radius = shaperadius(CData->psys_shape[sys], CData->psys_rootradius[sys], CData->psys_tipradius[sys], time);

					if((curvekey == CData->curve_firstkey[curve] + CData->curve_keynum[curve] - 2) && (subv == 1))
						radius = shaperadius(CData->psys_shape[sys], CData->psys_rootradius[sys], CData->psys_tipradius[sys], 0.95f);

					if(CData->psys_closetip[sys] && (subv == 1) && (curvekey == CData->curve_firstkey[curve] + CData->curve_keynum[curve] - 2))
						radius = shaperadius(CData->psys_shape[sys], CData->psys_rootradius[sys], 0.0f, 0.95f);

					float angle = M_2PI_F / (float)resolution;
					for(int section = 0; section < resolution; section++) {
						float3 ickey_loc_shf = ickey_loc + radius * (cosf(angle * section) * xbasis + sinf(angle * section) * ybasis);
						mesh->add_vertex(ickey_loc_shf);
					}

					if(subv != 0) {
						for(int section = 0; section < resolution - 1; section++) {
							mesh->add_triangle(vertexindex - resolution + section, vertexindex + section, vertexindex - resolution + section + 1, CData->psys_shader[sys], true);
							mesh->add_triangle(vertexindex + section + 1, vertexindex - resolution + section + 1, vertexindex + section, CData->psys_shader[sys], true);
						}
						mesh->add_triangle(vertexindex-1, vertexindex + resolution - 1, vertexindex - resolution, CData->psys_shader[sys], true);
						mesh->add_triangle(vertexindex, vertexindex - resolution , vertexindex + resolution - 1, CData->psys_shader[sys], true);
					}
					vertexindex += resolution;
				}
			}
		}
	}

	mesh->resize_mesh(mesh->verts.size(), mesh->num_triangles());
	mesh->attributes.remove(ATTR_STD_VERTEX_NORMAL);
	mesh->attributes.remove(ATTR_STD_FACE_NORMAL);
	mesh->add_face_normals();
	mesh->add_vertex_normals();
	mesh->attributes.remove(ATTR_STD_FACE_NORMAL);

	/* texture coords still needed */
}

static void ExportCurveSegments(Scene *scene, Mesh *mesh, ParticleCurveData *CData)
{
	int num_keys = 0;
	int num_curves = 0;

	if(mesh->num_curves())
		return;

	Attribute *attr_intercept = NULL;

	if(mesh->need_attribute(scene, ATTR_STD_CURVE_INTERCEPT))
		attr_intercept = mesh->curve_attributes.add(ATTR_STD_CURVE_INTERCEPT);

	/* compute and reserve size of arrays */
	for(int sys = 0; sys < CData->psys_firstcurve.size(); sys++) {
		for(int curve = CData->psys_firstcurve[sys]; curve < CData->psys_firstcurve[sys] + CData->psys_curvenum[sys]; curve++) {
			if(CData->curve_keynum[curve] <= 1 || CData->curve_length[curve] == 0.0f)
				continue;

			num_keys += CData->curve_keynum[curve];
			num_curves++;
		}
	}

	if(num_curves > 0) {
		VLOG(1) << "Exporting curve segments for mesh " << mesh->name;
	}

	mesh->reserve_curves(mesh->num_curves() + num_curves, mesh->curve_keys.size() + num_keys);

	num_keys = 0;
	num_curves = 0;

	/* actually export */
	for(int sys = 0; sys < CData->psys_firstcurve.size(); sys++) {
		for(int curve = CData->psys_firstcurve[sys]; curve < CData->psys_firstcurve[sys] + CData->psys_curvenum[sys]; curve++) {
			if(CData->curve_keynum[curve] <= 1 || CData->curve_length[curve] == 0.0f)
				continue;

			size_t num_curve_keys = 0;

			for(int curvekey = CData->curve_firstkey[curve]; curvekey < CData->curve_firstkey[curve] + CData->curve_keynum[curve]; curvekey++) {
				float3 ickey_loc = CData->curvekey_co[curvekey];
				float time = CData->curvekey_time[curvekey]/CData->curve_length[curve];
				float radius = shaperadius(CData->psys_shape[sys], CData->psys_rootradius[sys], CData->psys_tipradius[sys], time);

				if(CData->psys_closetip[sys] && (curvekey == CData->curve_firstkey[curve] + CData->curve_keynum[curve] - 1))
					radius = 0.0f;

				mesh->add_curve_key(ickey_loc, radius);
				if(attr_intercept)
					attr_intercept->add(time);

				num_curve_keys++;
			}

			mesh->add_curve(num_keys, CData->psys_shader[sys]);
			num_keys += num_curve_keys;
			num_curves++;
		}
	}

	/* check allocation */
	if((mesh->curve_keys.size() != num_keys) || (mesh->num_curves() != num_curves)) {
		VLOG(1) << "Allocation failed, clearing data";
		mesh->clear();
	}
}

static void ExportCurveSegmentsMotion(Mesh *mesh, ParticleCurveData *CData, int time_index)
{
	VLOG(1) << "Exporting curve motion segments for mesh " << mesh->name
	        << ", time index " << time_index;

	/* find attribute */
	Attribute *attr_mP = mesh->curve_attributes.find(ATTR_STD_MOTION_VERTEX_POSITION);
	bool new_attribute = false;

	/* add new attribute if it doesn't exist already */
	if(!attr_mP) {
		VLOG(1) << "Creating new motion vertex position attribute";
		attr_mP = mesh->curve_attributes.add(ATTR_STD_MOTION_VERTEX_POSITION);
		new_attribute = true;
	}

	/* export motion vectors for curve keys */
	size_t numkeys = mesh->curve_keys.size();
	float4 *mP = attr_mP->data_float4() + time_index*numkeys;
	bool have_motion = false;
	int i = 0;

	for(int sys = 0; sys < CData->psys_firstcurve.size(); sys++) {
		if(CData->psys_curvenum[sys] == 0)
			continue;

		for(int curve = CData->psys_firstcurve[sys]; curve < CData->psys_firstcurve[sys] + CData->psys_curvenum[sys]; curve++) {
			if(CData->curve_keynum[curve] <= 1 || CData->curve_length[curve] == 0.0f)
				continue;

			for(int curvekey = CData->curve_firstkey[curve]; curvekey < CData->curve_firstkey[curve] + CData->curve_keynum[curve]; curvekey++) {
				if(i < mesh->curve_keys.size()) {
					float3 ickey_loc = CData->curvekey_co[curvekey];
					float time = CData->curvekey_time[curvekey]/CData->curve_length[curve];
					float radius = shaperadius(CData->psys_shape[sys], CData->psys_rootradius[sys], CData->psys_tipradius[sys], time);

					if(CData->psys_closetip[sys] && (curvekey == CData->curve_firstkey[curve] + CData->curve_keynum[curve] - 1))
						radius = 0.0f;

					/* curve motion keys store both position and radius in float4 */
					mP[i] = float3_to_float4(ickey_loc);
					mP[i].w = radius;

					/* unlike mesh coordinates, these tend to be slightly different
					 * between frames due to particle transforms into/out of object
					 * space, so we use an epsilon to detect actual changes */
					float4 curve_key = float3_to_float4(mesh->curve_keys[i]);
					curve_key.w = mesh->curve_radius[i];
					if(len_squared(mP[i] - curve_key) > 1e-5f*1e-5f)
						have_motion = true;
				}

				i++;
			}
		}
	}

	/* in case of new attribute, we verify if there really was any motion */
	if(new_attribute) {
		if(i != numkeys || !have_motion) {
			/* No motion or hair "topology" changed, remove attributes again. */
			if(i != numkeys) {
				VLOG(1) << "Hair topology changed, removing attribute.";
			}
			else {
				VLOG(1) << "No motion, removing attribute.";
			}
			mesh->curve_attributes.remove(ATTR_STD_MOTION_VERTEX_POSITION);
		}
		else if(time_index > 0) {
			VLOG(1) << "Filling in new motion vertex position for time_index "
			        << time_index;
			/* motion, fill up previous steps that we might have skipped because
			 * they had no motion, but we need them anyway now */
			for(int step = 0; step < time_index; step++) {
				float4 *mP = attr_mP->data_float4() + step*numkeys;

				for(int key = 0; key < numkeys; key++) {
					mP[key] = float3_to_float4(mesh->curve_keys[key]);
					mP[key].w = mesh->curve_radius[key];
				}
			}
		}
	}
}

static void ExportCurveTriangleUV(ParticleCurveData *CData,
                                  int vert_offset,
                                  int resol,
                                  float3 *uvdata)
{
	if(uvdata == NULL)
		return;

	float time = 0.0f;
	float prevtime = 0.0f;

	int vertexindex = vert_offset;

	for(int sys = 0; sys < CData->psys_firstcurve.size(); sys++) {
		for(int curve = CData->psys_firstcurve[sys]; curve < CData->psys_firstcurve[sys] + CData->psys_curvenum[sys]; curve++) {
			if(CData->curve_keynum[curve] <= 1 || CData->curve_length[curve] == 0.0f)
				continue;

			for(int curvekey = CData->curve_firstkey[curve]; curvekey < CData->curve_firstkey[curve] + CData->curve_keynum[curve] - 1; curvekey++) {
				time = CData->curvekey_time[curvekey]/CData->curve_length[curve];

				for(int section = 0; section < resol; section++) {
					uvdata[vertexindex] = CData->curve_uv[curve];
					uvdata[vertexindex].z = prevtime;
					vertexindex++;
					uvdata[vertexindex] = CData->curve_uv[curve];
					uvdata[vertexindex].z = time;
					vertexindex++;
					uvdata[vertexindex] = CData->curve_uv[curve];
					uvdata[vertexindex].z = prevtime;
					vertexindex++;
					uvdata[vertexindex] = CData->curve_uv[curve];
					uvdata[vertexindex].z = time;
					vertexindex++;
					uvdata[vertexindex] = CData->curve_uv[curve];
					uvdata[vertexindex].z = prevtime;
					vertexindex++;
					uvdata[vertexindex] = CData->curve_uv[curve];
					uvdata[vertexindex].z = time;
					vertexindex++;
				}

				prevtime = time;
			}
		}
	}
}

static void ExportCurveTriangleVcol(ParticleCurveData *CData,
                                    int vert_offset,
                                    int resol,
                                    uchar4 *cdata)
{
	if(cdata == NULL)
		return;

	int vertexindex = vert_offset;

	for(int sys = 0; sys < CData->psys_firstcurve.size(); sys++) {
		for(int curve = CData->psys_firstcurve[sys]; curve < CData->psys_firstcurve[sys] + CData->psys_curvenum[sys]; curve++) {
			if(CData->curve_keynum[curve] <= 1 || CData->curve_length[curve] == 0.0f)
				continue;

			for(int curvekey = CData->curve_firstkey[curve]; curvekey < CData->curve_firstkey[curve] + CData->curve_keynum[curve] - 1; curvekey++) {
				for(int section = 0; section < resol; section++) {
					cdata[vertexindex] = color_float_to_byte(color_srgb_to_scene_linear_v3(CData->curve_vcol[curve]));
					vertexindex++;
					cdata[vertexindex] = color_float_to_byte(color_srgb_to_scene_linear_v3(CData->curve_vcol[curve]));
					vertexindex++;
					cdata[vertexindex] = color_float_to_byte(color_srgb_to_scene_linear_v3(CData->curve_vcol[curve]));
					vertexindex++;
					cdata[vertexindex] = color_float_to_byte(color_srgb_to_scene_linear_v3(CData->curve_vcol[curve]));
					vertexindex++;
					cdata[vertexindex] = color_float_to_byte(color_srgb_to_scene_linear_v3(CData->curve_vcol[curve]));
					vertexindex++;
					cdata[vertexindex] = color_float_to_byte(color_srgb_to_scene_linear_v3(CData->curve_vcol[curve]));
					vertexindex++;
				}
			}
		}
	}
}

/* Hair Curve Sync */

void BlenderSync::sync_curve_settings()
{
	PointerRNA csscene = RNA_pointer_get(&b_scene.ptr, "cycles_curves");

	CurveSystemManager *curve_system_manager = scene->curve_system_manager;
	CurveSystemManager prev_curve_system_manager = *curve_system_manager;

	curve_system_manager->use_curves = get_boolean(csscene, "use_curves");
	curve_system_manager->minimum_width = get_float(csscene, "minimum_width");
	curve_system_manager->maximum_width = get_float(csscene, "maximum_width");

	curve_system_manager->primitive =
	        (CurvePrimitiveType)get_enum(csscene,
	                                     "primitive",
	                                     CURVE_NUM_PRIMITIVE_TYPES,
	                                     CURVE_LINE_SEGMENTS);
	curve_system_manager->curve_shape =
	        (CurveShapeType)get_enum(csscene,
	                                 "shape",
	                                 CURVE_NUM_SHAPE_TYPES,
	                                 CURVE_THICK);
	curve_system_manager->resolution = get_int(csscene, "resolution");
	curve_system_manager->subdivisions = get_int(csscene, "subdivisions");
	curve_system_manager->use_backfacing = !get_boolean(csscene, "cull_backfacing");

	/* Triangles */
	if(curve_system_manager->primitive == CURVE_TRIANGLES) {
		/* camera facing planes */
		if(curve_system_manager->curve_shape == CURVE_RIBBON) {
			curve_system_manager->triangle_method = CURVE_CAMERA_TRIANGLES;
			curve_system_manager->resolution = 1;
		}
		else if(curve_system_manager->curve_shape == CURVE_THICK) {
			curve_system_manager->triangle_method = CURVE_TESSELATED_TRIANGLES;
		}
	}
	/* Line Segments */
	else if(curve_system_manager->primitive == CURVE_LINE_SEGMENTS) {
		if(curve_system_manager->curve_shape == CURVE_RIBBON) {
			/* tangent shading */
			curve_system_manager->line_method = CURVE_UNCORRECTED;
			curve_system_manager->use_encasing = true;
			curve_system_manager->use_backfacing = false;
			curve_system_manager->use_tangent_normal_geometry = true;
		}
		else if(curve_system_manager->curve_shape == CURVE_THICK) {
			curve_system_manager->line_method = CURVE_ACCURATE;
			curve_system_manager->use_encasing = false;
			curve_system_manager->use_tangent_normal_geometry = false;
		}
	}
	/* Curve Segments */
	else if(curve_system_manager->primitive == CURVE_SEGMENTS) {
		if(curve_system_manager->curve_shape == CURVE_RIBBON) {
			curve_system_manager->primitive = CURVE_RIBBONS;
			curve_system_manager->use_backfacing = false;
		}
	}

	if(curve_system_manager->modified_mesh(prev_curve_system_manager)) {
		BL::BlendData::objects_iterator b_ob;

		for(b_data.objects.begin(b_ob); b_ob != b_data.objects.end(); ++b_ob) {
			if(object_is_mesh(*b_ob)) {
				BL::Object::particle_systems_iterator b_psys;
				for(b_ob->particle_systems.begin(b_psys); b_psys != b_ob->particle_systems.end(); ++b_psys) {
					if((b_psys->settings().render_type()==BL::ParticleSettings::render_type_PATH)&&(b_psys->settings().type()==BL::ParticleSettings::type_HAIR)) {
						BL::ID key = BKE_object_is_modified(*b_ob)? *b_ob: b_ob->data();
						mesh_map.set_recalc(key);
						object_map.set_recalc(*b_ob);
					}
				}
			}
		}
	}

	if(curve_system_manager->modified(prev_curve_system_manager))
		curve_system_manager->tag_update(scene);
}

void BlenderSync::sync_curves(Mesh *mesh,
                              BL::Mesh& b_mesh,
                              BL::Object& b_ob,
                              bool motion,
                              int time_index)
{
	if(!motion) {
		/* Clear stored curve data */
		mesh->curve_keys.clear();
		mesh->curve_radius.clear();
		mesh->curve_first_key.clear();
		mesh->curve_shader.clear();
		mesh->curve_attributes.clear();
	}

	/* obtain general settings */
	const bool use_curves = scene->curve_system_manager->use_curves;

	if(!(use_curves && b_ob.mode() != b_ob.mode_PARTICLE_EDIT)) {
		if(!motion)
			mesh->compute_bounds();
		return;
	}

	const int primitive = scene->curve_system_manager->primitive;
	const int triangle_method = scene->curve_system_manager->triangle_method;
	const int resolution = scene->curve_system_manager->resolution;
	const size_t vert_num = mesh->verts.size();
	const size_t tri_num = mesh->num_triangles();
	int used_res = 1;

	/* extract particle hair data - should be combined with connecting to mesh later*/

	ParticleCurveData CData;

	if(!preview)
		set_resolution(&b_ob, &b_scene, true);

	ObtainCacheParticleData(mesh, &b_mesh, &b_ob, &CData, !preview);

	/* add hair geometry to mesh */
	if(primitive == CURVE_TRIANGLES) {
		if(triangle_method == CURVE_CAMERA_TRIANGLES) {
			/* obtain camera parameters */
			float3 RotCam;
			Camera *camera = scene->camera;
			Transform &ctfm = camera->matrix;
			if(camera->type == CAMERA_ORTHOGRAPHIC) {
				RotCam = -make_float3(ctfm.x.z, ctfm.y.z, ctfm.z.z);
			}
			else {
				Transform tfm = get_transform(b_ob.matrix_world());
				Transform itfm = transform_quick_inverse(tfm);
				RotCam = transform_point(&itfm, make_float3(ctfm.x.w,
				                                            ctfm.y.w,
				                                            ctfm.z.w));
			}
			bool is_ortho = camera->type == CAMERA_ORTHOGRAPHIC;
			ExportCurveTrianglePlanes(mesh, &CData, RotCam, is_ortho);
		}
		else {
			ExportCurveTriangleGeometry(mesh, &CData, resolution);
			used_res = resolution;
		}
	}
	else {
		if(motion)
			ExportCurveSegmentsMotion(mesh, &CData, time_index);
		else
			ExportCurveSegments(scene, mesh, &CData);
	}

	/* generated coordinates from first key. we should ideally get this from
	 * blender to handle deforming objects */
	if(!motion) {
		if(mesh->need_attribute(scene, ATTR_STD_GENERATED)) {
			float3 loc, size;
			mesh_texture_space(b_mesh, loc, size);

			if(primitive == CURVE_TRIANGLES) {
				Attribute *attr_generated = mesh->attributes.add(ATTR_STD_GENERATED);
				float3 *generated = attr_generated->data_float3();

				for(size_t i = vert_num; i < mesh->verts.size(); i++)
					generated[i] = mesh->verts[i]*size - loc;
			}
			else {
				Attribute *attr_generated = mesh->curve_attributes.add(ATTR_STD_GENERATED);
				float3 *generated = attr_generated->data_float3();

				for(size_t i = 0; i < mesh->num_curves(); i++) {
					float3 co = mesh->curve_keys[mesh->get_curve(i).first_key];
					generated[i] = co*size - loc;
				}
			}
		}
	}

	/* create vertex color attributes */
	if(!motion) {
		BL::Mesh::tessface_vertex_colors_iterator l;
		int vcol_num = 0;

		for(b_mesh.tessface_vertex_colors.begin(l); l != b_mesh.tessface_vertex_colors.end(); ++l, vcol_num++) {
			if(!mesh->need_attribute(scene, ustring(l->name().c_str())))
				continue;

			ObtainCacheParticleVcol(mesh, &b_mesh, &b_ob, &CData, !preview, vcol_num);

			if(primitive == CURVE_TRIANGLES) {
				Attribute *attr_vcol = mesh->attributes.add(
					ustring(l->name().c_str()), TypeDesc::TypeColor, ATTR_ELEMENT_CORNER_BYTE);

				uchar4 *cdata = attr_vcol->data_uchar4();

				ExportCurveTriangleVcol(&CData, tri_num * 3, used_res, cdata);
			}
			else {
				Attribute *attr_vcol = mesh->curve_attributes.add(
					ustring(l->name().c_str()), TypeDesc::TypeColor, ATTR_ELEMENT_CURVE);

				float3 *fdata = attr_vcol->data_float3();

				if(fdata) {
					size_t i = 0;

					for(size_t curve = 0; curve < CData.curve_vcol.size(); curve++)
						if(!(CData.curve_keynum[curve] <= 1 || CData.curve_length[curve] == 0.0f))
							fdata[i++] = color_srgb_to_scene_linear_v3(CData.curve_vcol[curve]);
				}
			}
		}
	}

	/* create UV attributes */
	if(!motion) {
		BL::Mesh::tessface_uv_textures_iterator l;
		int uv_num = 0;

		for(b_mesh.tessface_uv_textures.begin(l); l != b_mesh.tessface_uv_textures.end(); ++l, uv_num++) {
			bool active_render = l->active_render();
			AttributeStandard std = (active_render)? ATTR_STD_UV: ATTR_STD_NONE;
			ustring name = ustring(l->name().c_str());

			/* UV map */
			if(mesh->need_attribute(scene, name) || mesh->need_attribute(scene, std)) {
				Attribute *attr_uv;

				ObtainCacheParticleUV(mesh, &b_mesh, &b_ob, &CData, !preview, uv_num);

				if(primitive == CURVE_TRIANGLES) {
					if(active_render)
						attr_uv = mesh->attributes.add(std, name);
					else
						attr_uv = mesh->attributes.add(name, TypeDesc::TypePoint, ATTR_ELEMENT_CORNER);

					float3 *uv = attr_uv->data_float3();

					ExportCurveTriangleUV(&CData, tri_num * 3, used_res, uv);
				}
				else {
					if(active_render)
						attr_uv = mesh->curve_attributes.add(std, name);
					else
						attr_uv = mesh->curve_attributes.add(name, TypeDesc::TypePoint,  ATTR_ELEMENT_CURVE);

					float3 *uv = attr_uv->data_float3();

					if(uv) {
						size_t i = 0;

						for(size_t curve = 0; curve < CData.curve_uv.size(); curve++)
							if(!(CData.curve_keynum[curve] <= 1 || CData.curve_length[curve] == 0.0f))
								uv[i++] = CData.curve_uv[curve];
					}
				}
			}
		}
	}

	if(!preview)
		set_resolution(&b_ob, &b_scene, false);

	mesh->compute_bounds();
}

CCL_NAMESPACE_END
