/* 
 * ***** BEGIN GPL LICENSE BLOCK *****
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version 2
 * of the License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
 *
 * The Original Code is Copyright (C) 2001-2002 by NaN Holding BV.
 * All rights reserved.
 *
 * Contributors: Matt Ebb
 *
 * ***** END GPL LICENSE BLOCK *****
 */

/** \file blender/render/intern/source/pointdensity.c
 *  \ingroup render
 */


#include <math.h>
#include <stdlib.h>
#include <stdio.h>

#include "MEM_guardedalloc.h"

#include "BLI_math.h"
#include "BLI_blenlib.h"
#include "BLI_noise.h"
#include "BLI_kdopbvh.h"
#include "BLI_utildefines.h"

#include "BLF_translation.h"

#include "BKE_DerivedMesh.h"
#include "BKE_lattice.h"
#include "BKE_main.h"
#include "BKE_particle.h"
#include "BKE_scene.h"
#include "BKE_texture.h"
#include "BKE_colortools.h"

#include "DNA_meshdata_types.h"
#include "DNA_texture_types.h"
#include "DNA_particle_types.h"

#include "render_types.h"
#include "renderdatabase.h"
#include "texture.h"
#include "pointdensity.h"

/* ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ */
/* defined in pipeline.c, is hardcopy of active dynamic allocated Render */
/* only to be used here in this file, it's for speed */
extern struct Render R;
/* ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ */


static int point_data_used(PointDensity *pd)
{
	int pd_bitflag = 0;
	
	if (pd->source == TEX_PD_PSYS) {
		if ((pd->noise_influence == TEX_PD_NOISE_VEL) || (pd->falloff_type == TEX_PD_FALLOFF_PARTICLE_VEL) || (pd->color_source == TEX_PD_COLOR_PARTVEL) || (pd->color_source == TEX_PD_COLOR_PARTSPEED))
			pd_bitflag |= POINT_DATA_VEL;
		if ((pd->noise_influence == TEX_PD_NOISE_AGE) || (pd->color_source == TEX_PD_COLOR_PARTAGE) || (pd->falloff_type == TEX_PD_FALLOFF_PARTICLE_AGE)) 
			pd_bitflag |= POINT_DATA_LIFE;
	}
		
	return pd_bitflag;
}


/* additional data stored alongside the point density BVH, 
 * accessible by point index number to retrieve other information 
 * such as particle velocity or lifetime */
static void alloc_point_data(PointDensity *pd, int total_particles, int point_data_used)
{
	int data_size = 0;
	
	if (point_data_used & POINT_DATA_VEL) {
		/* store 3 channels of velocity data */
		data_size += 3;
	}
	if (point_data_used & POINT_DATA_LIFE) {
		/* store 1 channel of lifetime data */
		data_size += 1;
	}

	if (data_size)
		pd->point_data = MEM_mallocN(sizeof(float)*data_size*total_particles, "particle point data");
}

static void pointdensity_cache_psys(Render *re, PointDensity *pd, Object *ob, ParticleSystem *psys)
{
	DerivedMesh* dm;
	ParticleKey state;
	ParticleCacheKey *cache;
	ParticleSimulationData sim= {NULL};
	ParticleData *pa=NULL;
	float cfra = BKE_scene_frame_get(re->scene);
	int i /*, childexists*/ /* UNUSED */;
	int total_particles, offset=0;
	int data_used = point_data_used(pd);
	float partco[3];
	float obview[4][4];
	
	/* init everything */
	if (!psys || !ob || !pd) return;

	mul_m4_m4m4(obview, ob->obmat, re->viewinv);
	
	/* Just to create a valid rendering context for particles */
	psys_render_set(ob, psys, re->viewmat, re->winmat, re->winx, re->winy, 0);
	
	dm = mesh_create_derived_render(re->scene, ob, CD_MASK_BAREMESH|CD_MASK_MTFACE|CD_MASK_MCOL);
	
	if ( !psys_check_enabled(ob, psys)) {
		psys_render_restore(ob, psys);
		return;
	}
	
	sim.scene= re->scene;
	sim.ob= ob;
	sim.psys= psys;

	/* in case ob->imat isn't up-to-date */
	invert_m4_m4(ob->imat, ob->obmat);
	
	total_particles = psys->totpart+psys->totchild;
	psys->lattice_deform_data = psys_create_lattice_deform_data(&sim);
	
	pd->point_tree = BLI_bvhtree_new(total_particles, 0.0, 4, 6);
	alloc_point_data(pd, total_particles, data_used);
	pd->totpoints = total_particles;
	if (data_used & POINT_DATA_VEL) offset = pd->totpoints*3;
	
#if 0 /* UNUSED */
	if (psys->totchild > 0 && !(psys->part->draw & PART_DRAW_PARENT))
		childexists = 1;
#endif

	for (i=0, pa=psys->particles; i < total_particles; i++, pa++) {

		if (psys->part->type == PART_HAIR) {
			/* hair particles */
			if (i < psys->totpart && psys->pathcache)
				cache = psys->pathcache[i];
			else if (i >= psys->totpart && psys->childcache)
				cache = psys->childcache[i - psys->totpart];
			else
				continue;

			cache += cache->steps; /* use endpoint */

			copy_v3_v3(state.co, cache->co);
			zero_v3(state.vel);
			state.time = 0.0f;
		}
		else {
			/* emitter particles */
			state.time = cfra;

			if (!psys_get_particle_state(&sim, i, &state, 0))
				continue;

			if (data_used & POINT_DATA_LIFE) {
				if (i < psys->totpart) {
					state.time = (cfra - pa->time)/pa->lifetime;
				}
				else {
					ChildParticle *cpa= (psys->child + i) - psys->totpart;
					float pa_birthtime, pa_dietime;
					
					state.time = psys_get_child_time(psys, cpa, cfra, &pa_birthtime, &pa_dietime);
				}
			}
		}

		copy_v3_v3(partco, state.co);
		
		if (pd->psys_cache_space == TEX_PD_OBJECTSPACE)
			mul_m4_v3(ob->imat, partco);
		else if (pd->psys_cache_space == TEX_PD_OBJECTLOC) {
			sub_v3_v3(partco, ob->loc);
		}
		else {
			/* TEX_PD_WORLDSPACE */
		}
		
		BLI_bvhtree_insert(pd->point_tree, i, partco, 1);
		
		if (data_used & POINT_DATA_VEL) {
			pd->point_data[i*3 + 0] = state.vel[0];
			pd->point_data[i*3 + 1] = state.vel[1];
			pd->point_data[i*3 + 2] = state.vel[2];
		}
		if (data_used & POINT_DATA_LIFE) {
			pd->point_data[offset + i] = state.time;
		}
	}
	
	BLI_bvhtree_balance(pd->point_tree);
	dm->release(dm);
	
	if (psys->lattice_deform_data) {
		end_latt_deform(psys->lattice_deform_data);
		psys->lattice_deform_data = NULL;
	}
	
	psys_render_restore(ob, psys);
}


static void pointdensity_cache_object(Render *re, PointDensity *pd, Object *ob)
{
	int i;
	DerivedMesh *dm;
	MVert *mvert = NULL;
	
	dm = mesh_create_derived_render(re->scene, ob,	CD_MASK_BAREMESH|CD_MASK_MTFACE|CD_MASK_MCOL);
	mvert= dm->getVertArray(dm);	/* local object space */
	
	pd->totpoints= dm->getNumVerts(dm);
	if (pd->totpoints == 0) return;

	pd->point_tree = BLI_bvhtree_new(pd->totpoints, 0.0, 4, 6);
	
	for (i=0; i < pd->totpoints; i++, mvert++) {
		float co[3];
		
		copy_v3_v3(co, mvert->co);

		switch (pd->ob_cache_space) {
			case TEX_PD_OBJECTSPACE:
				break;
			case TEX_PD_OBJECTLOC:
				mul_m4_v3(ob->obmat, co);
				sub_v3_v3(co, ob->loc);
				break;
			case TEX_PD_WORLDSPACE:
			default:
				mul_m4_v3(ob->obmat, co);
				break;
		}

		BLI_bvhtree_insert(pd->point_tree, i, co, 1);
	}
	
	BLI_bvhtree_balance(pd->point_tree);
	dm->release(dm);

}
void cache_pointdensity(Render *re, Tex *tex)
{
	PointDensity *pd = tex->pd;
	
	if (!pd)
		return;

	if (pd->point_tree) {
		BLI_bvhtree_free(pd->point_tree);
		pd->point_tree = NULL;
	}
	
	if (pd->source == TEX_PD_PSYS) {
		Object *ob = pd->object;
		ParticleSystem *psys;

		if (!ob || !pd->psys) return;

		psys= BLI_findlink(&ob->particlesystem, pd->psys-1);
		if (!psys) return;
		
		pointdensity_cache_psys(re, pd, ob, psys);
	}
	else if (pd->source == TEX_PD_OBJECT) {
		Object *ob = pd->object;
		if (ob && ob->type == OB_MESH)
			pointdensity_cache_object(re, pd, ob);
	}
}

static void free_pointdensity(Render *UNUSED(re), Tex *tex)
{
	PointDensity *pd = tex->pd;

	if (!pd) return;
	
	if (pd->point_tree) {
		BLI_bvhtree_free(pd->point_tree);
		pd->point_tree = NULL;
	}

	if (pd->point_data) {
		MEM_freeN(pd->point_data);
		pd->point_data = NULL;
	}
	pd->totpoints = 0;
}



void make_pointdensities(Render *re)
{
	Tex *tex;
	
	if (re->scene->r.scemode & R_BUTS_PREVIEW)
		return;
	
	re->i.infostr = IFACE_("Caching Point Densities");
	re->stats_draw(re->sdh, &re->i);

	for (tex= re->main->tex.first; tex; tex= tex->id.next) {
		if (tex->id.us && tex->type==TEX_POINTDENSITY) {
			cache_pointdensity(re, tex);
		}
	}
	
	re->i.infostr = NULL;
	re->stats_draw(re->sdh, &re->i);
}

void free_pointdensities(Render *re)
{
	Tex *tex;
	
	if (re->scene->r.scemode & R_BUTS_PREVIEW)
		return;
	
	for (tex= re->main->tex.first; tex; tex= tex->id.next) {
		if (tex->id.us && tex->type==TEX_POINTDENSITY) {
			free_pointdensity(re, tex);
		}
	}
}

typedef struct PointDensityRangeData {
	float *density;
	float squared_radius;
	const float *point_data;
	float *vec;
	float softness;
	short falloff_type;
	short noise_influence;
	float *age;
	int point_data_used;
	int offset;
	struct CurveMapping *density_curve;
	float velscale;
} PointDensityRangeData;

static void accum_density(void *userdata, int index, float squared_dist)
{
	PointDensityRangeData *pdr = (PointDensityRangeData *)userdata;
	const float dist = (pdr->squared_radius - squared_dist) / pdr->squared_radius * 0.5f;
	float density = 0.0f;
	
	if (pdr->point_data_used & POINT_DATA_VEL) {
		pdr->vec[0] += pdr->point_data[index*3 + 0]; // * density;
		pdr->vec[1] += pdr->point_data[index*3 + 1]; // * density;
		pdr->vec[2] += pdr->point_data[index*3 + 2]; // * density;
	}
	if (pdr->point_data_used & POINT_DATA_LIFE) {
		*pdr->age += pdr->point_data[pdr->offset + index]; // * density;
	}
	
	if (pdr->falloff_type == TEX_PD_FALLOFF_STD)
		density = dist;
	else if (pdr->falloff_type == TEX_PD_FALLOFF_SMOOTH)
		density = 3.0f*dist*dist - 2.0f*dist*dist*dist;
	else if (pdr->falloff_type == TEX_PD_FALLOFF_SOFT)
		density = pow(dist, pdr->softness);
	else if (pdr->falloff_type == TEX_PD_FALLOFF_CONSTANT)
		density = pdr->squared_radius;
	else if (pdr->falloff_type == TEX_PD_FALLOFF_ROOT)
		density = sqrtf(dist);
	else if (pdr->falloff_type == TEX_PD_FALLOFF_PARTICLE_AGE) {
		if (pdr->point_data_used & POINT_DATA_LIFE)
			density = dist*MIN2(pdr->point_data[pdr->offset + index], 1.0f);
		else
			density = dist;
	}
	else if (pdr->falloff_type == TEX_PD_FALLOFF_PARTICLE_VEL) {
		if (pdr->point_data_used & POINT_DATA_VEL)
			density = dist*len_v3(pdr->point_data + index*3)*pdr->velscale;
		else
			density = dist;
	}
	
	if (pdr->density_curve && dist != 0.0f) {
		curvemapping_initialize(pdr->density_curve);
		density = curvemapping_evaluateF(pdr->density_curve, 0, density/dist)*dist;
	}
	
	*pdr->density += density;
}


static void init_pointdensityrangedata(PointDensity *pd, PointDensityRangeData *pdr, 
	float *density, float *vec, float *age, struct CurveMapping *density_curve, float velscale)
{
	pdr->squared_radius = pd->radius*pd->radius;
	pdr->density = density;
	pdr->point_data = pd->point_data;
	pdr->falloff_type = pd->falloff_type;
	pdr->vec = vec;
	pdr->age = age;
	pdr->softness = pd->falloff_softness;
	pdr->noise_influence = pd->noise_influence;
	pdr->point_data_used = point_data_used(pd);
	pdr->offset = (pdr->point_data_used & POINT_DATA_VEL)?pd->totpoints*3:0;
	pdr->density_curve = density_curve;
	pdr->velscale = velscale;
}


int pointdensitytex(Tex *tex, const float texvec[3], TexResult *texres)
{
	int retval = TEX_INT;
	PointDensity *pd = tex->pd;
	PointDensityRangeData pdr;
	float density=0.0f, age=0.0f, time=0.0f;
	float vec[3] = {0.0f, 0.0f, 0.0f}, co[3];
	float col[4];
	float turb, noise_fac;
	int num=0;
	
	texres->tin = 0.0f;
	
	if ((!pd) || (!pd->point_tree))
		return 0;
		
	init_pointdensityrangedata(pd, &pdr, &density, vec, &age, 
		(pd->flag&TEX_PD_FALLOFF_CURVE ? pd->falloff_curve : NULL), pd->falloff_speed_scale*0.001f);
	noise_fac = pd->noise_fac * 0.5f;	/* better default */
	
	copy_v3_v3(co, texvec);
	
	if (point_data_used(pd)) {
		/* does a BVH lookup to find accumulated density and additional point data *
		 * stores particle velocity vector in 'vec', and particle lifetime in 'time' */
		num = BLI_bvhtree_range_query(pd->point_tree, co, pd->radius, accum_density, &pdr);
		if (num > 0) {
			age /= num;
			mul_v3_fl(vec, 1.0f/num);
		}
		
		/* reset */
		density = vec[0] = vec[1] = vec[2] = 0.0f;
	}
	
	if (pd->flag & TEX_PD_TURBULENCE) {
	
		if (pd->noise_influence == TEX_PD_NOISE_AGE) {
			turb = BLI_gTurbulence(pd->noise_size, texvec[0]+age, texvec[1]+age, texvec[2]+age, pd->noise_depth, 0, pd->noise_basis);
		}
		else if (pd->noise_influence == TEX_PD_NOISE_TIME) {
			time = R.r.cfra / (float)R.r.efra;
			turb = BLI_gTurbulence(pd->noise_size, texvec[0]+time, texvec[1]+time, texvec[2]+time, pd->noise_depth, 0, pd->noise_basis);
			//turb = BLI_turbulence(pd->noise_size, texvec[0]+time, texvec[1]+time, texvec[2]+time, pd->noise_depth);
		}
		else {
			turb = BLI_gTurbulence(pd->noise_size, texvec[0]+vec[0], texvec[1]+vec[1], texvec[2]+vec[2], pd->noise_depth, 0, pd->noise_basis);
		}

		turb -= 0.5f;	/* re-center 0.0-1.0 range around 0 to prevent offsetting result */
		
		/* now we have an offset coordinate to use for the density lookup */
		co[0] = texvec[0] + noise_fac * turb;
		co[1] = texvec[1] + noise_fac * turb;
		co[2] = texvec[2] + noise_fac * turb;
	}

	/* BVH query with the potentially perturbed coordinates */
	num = BLI_bvhtree_range_query(pd->point_tree, co, pd->radius, accum_density, &pdr);
	if (num > 0) {
		age /= num;
		mul_v3_fl(vec, 1.0f/num);
	}
	
	texres->tin = density;
	BRICONT;
	
	if (pd->color_source == TEX_PD_COLOR_CONSTANT)
		return retval;
	
	retval |= TEX_RGB;
	
	switch (pd->color_source) {
		case TEX_PD_COLOR_PARTAGE:
			if (pd->coba) {
				if (do_colorband(pd->coba, age, col)) {
					texres->talpha = true;
					copy_v3_v3(&texres->tr, col);
					texres->tin *= col[3];
					texres->ta = texres->tin;
				}
			}
			break;
		case TEX_PD_COLOR_PARTSPEED:
		{
			float speed = len_v3(vec) * pd->speed_scale;
			
			if (pd->coba) {
				if (do_colorband(pd->coba, speed, col)) {
					texres->talpha = true;
					copy_v3_v3(&texres->tr, col);
					texres->tin *= col[3];
					texres->ta = texres->tin;
				}
			}
			break;
		}
		case TEX_PD_COLOR_PARTVEL:
			texres->talpha = true;
			mul_v3_fl(vec, pd->speed_scale);
			copy_v3_v3(&texres->tr, vec);
			texres->ta = texres->tin;
			break;
		case TEX_PD_COLOR_CONSTANT:
		default:
			texres->tr = texres->tg = texres->tb = texres->ta = 1.0f;
			break;
	}
	BRICONTRGB;
	
	return retval;
	
#if 0
	if (texres->nor!=NULL) {
		texres->nor[0] = texres->nor[1] = texres->nor[2] = 0.0f;
	}
#endif
}
