/*
 * ***** 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.
 *
 * Contributor(s): Campbell Barton
 *
 * ***** END GPL LICENSE BLOCK *****
 *
 */

/** \file blender/modifiers/intern/MOD_warp.c
 *  \ingroup modifiers
 */

#include <string.h>

#include "MEM_guardedalloc.h"

#include "DNA_object_types.h"
#include "DNA_meshdata_types.h"

#include "BLI_math.h"
#include "BLI_utildefines.h"

#include "BKE_cdderivedmesh.h"
#include "BKE_modifier.h"
#include "BKE_deform.h"
#include "BKE_texture.h"
#include "BKE_colortools.h"

#include "depsgraph_private.h"

#include "RE_shader_ext.h"

#include "MOD_util.h"


static void initData(ModifierData *md)
{
	WarpModifierData *wmd = (WarpModifierData *) md;

	wmd->curfalloff = curvemapping_add(1, 0.0f, 0.0f, 1.0f, 1.0f);
	wmd->texture = NULL;
	wmd->strength = 1.0f;
	wmd->falloff_radius = 1.0f;
	wmd->falloff_type = eWarp_Falloff_Smooth;
	wmd->flag = 0;
}

static void copyData(ModifierData *md, ModifierData *target)
{
	WarpModifierData *wmd = (WarpModifierData *) md;
	WarpModifierData *twmd = (WarpModifierData *) target;

	modifier_copyData_generic(md, target);

	twmd->curfalloff = curvemapping_copy(wmd->curfalloff);
}

static CustomDataMask requiredDataMask(Object *UNUSED(ob), ModifierData *md)
{
	WarpModifierData *wmd = (WarpModifierData *)md;
	CustomDataMask dataMask = 0;

	/* ask for vertexgroups if we need them */
	if (wmd->defgrp_name[0]) dataMask |= (CD_MASK_MDEFORMVERT);
	dataMask |= (CD_MASK_MDEFORMVERT);

	/* ask for UV coordinates if we need them */
	if (wmd->texmapping == MOD_DISP_MAP_UV) dataMask |= (1 << CD_MTFACE);

	return dataMask;
}

static bool dependsOnTime(ModifierData *md)
{
	WarpModifierData *wmd = (WarpModifierData *)md;

	if (wmd->texture) {
		return BKE_texture_dependsOnTime(wmd->texture);
	}
	else {
		return false;
	}
}

static void freeData(ModifierData *md)
{
	WarpModifierData *wmd = (WarpModifierData *) md;
	curvemapping_free(wmd->curfalloff);
}


static bool isDisabled(ModifierData *md, int UNUSED(userRenderParams))
{
	WarpModifierData *wmd = (WarpModifierData *) md;

	return !(wmd->object_from && wmd->object_to);
}

static void foreachObjectLink(ModifierData *md, Object *ob, ObjectWalkFunc walk, void *userData)
{
	WarpModifierData *wmd = (WarpModifierData *) md;

	walk(userData, ob, &wmd->object_from);
	walk(userData, ob, &wmd->object_to);
	walk(userData, ob, &wmd->map_object);
}

static void foreachIDLink(ModifierData *md, Object *ob, IDWalkFunc walk, void *userData)
{
	WarpModifierData *wmd = (WarpModifierData *) md;

	walk(userData, ob, (ID **)&wmd->texture);

	walk(userData, ob, (ID **)&wmd->object_from);
	walk(userData, ob, (ID **)&wmd->object_to);
	walk(userData, ob, (ID **)&wmd->map_object);
}

static void foreachTexLink(ModifierData *md, Object *ob, TexWalkFunc walk, void *userData)
{
	walk(userData, ob, md, "texture");
}

static void updateDepgraph(ModifierData *md, DagForest *forest,
                           struct Main *UNUSED(bmain),
                           struct Scene *UNUSED(scene),
                           Object *UNUSED(ob), DagNode *obNode)
{
	WarpModifierData *wmd = (WarpModifierData *) md;

	if (wmd->object_from && wmd->object_to) {
		DagNode *fromNode = dag_get_node(forest, wmd->object_from);
		DagNode *toNode = dag_get_node(forest, wmd->object_to);

		dag_add_relation(forest, fromNode, obNode, DAG_RL_DATA_DATA | DAG_RL_OB_DATA, "Warp Modifier1");
		dag_add_relation(forest, toNode, obNode, DAG_RL_DATA_DATA | DAG_RL_OB_DATA, "Warp Modifier2");
	}

	if ((wmd->texmapping == MOD_DISP_MAP_OBJECT) && wmd->map_object) {
		DagNode *curNode = dag_get_node(forest, wmd->map_object);
		dag_add_relation(forest, curNode, obNode, DAG_RL_DATA_DATA | DAG_RL_OB_DATA, "Warp Modifier3");
	}
}

static void updateDepsgraph(ModifierData *md,
                            struct Main *UNUSED(bmain),
                            struct Scene *UNUSED(scene),
                            Object *UNUSED(ob),
                            struct DepsNodeHandle *node)
{
	WarpModifierData *wmd = (WarpModifierData *) md;
	if (wmd->object_from != NULL && wmd->object_to != NULL) {
		DEG_add_object_relation(node, wmd->object_from, DEG_OB_COMP_TRANSFORM, "Warp Modifier from");
		DEG_add_object_relation(node, wmd->object_to, DEG_OB_COMP_TRANSFORM, "Warp Modifier to");
	}
	if ((wmd->texmapping == MOD_DISP_MAP_OBJECT) && wmd->map_object != NULL) {
		DEG_add_object_relation(node, wmd->map_object, DEG_OB_COMP_TRANSFORM, "Warp Modifier map");
	}
}

static void warpModifier_do(WarpModifierData *wmd, Object *ob,
                            DerivedMesh *dm, float (*vertexCos)[3], int numVerts)
{
	float obinv[4][4];
	float mat_from[4][4];
	float mat_from_inv[4][4];
	float mat_to[4][4];
	float mat_unit[4][4];
	float mat_final[4][4];

	float tmat[4][4];

	const float falloff_radius_sq = SQUARE(wmd->falloff_radius);
	float strength = wmd->strength;
	float fac = 1.0f, weight;
	int i;
	int defgrp_index;
	MDeformVert *dvert, *dv = NULL;

	float (*tex_co)[3] = NULL;

	if (!(wmd->object_from && wmd->object_to))
		return;

	modifier_get_vgroup(ob, dm, wmd->defgrp_name, &dvert, &defgrp_index);
	if (dvert == NULL) {
		defgrp_index = -1;
	}

	if (wmd->curfalloff == NULL) /* should never happen, but bad lib linking could cause it */
		wmd->curfalloff = curvemapping_add(1, 0.0f, 0.0f, 1.0f, 1.0f);

	if (wmd->curfalloff) {
		curvemapping_initialize(wmd->curfalloff);
	}

	invert_m4_m4(obinv, ob->obmat);

	mul_m4_m4m4(mat_from, obinv, wmd->object_from->obmat);
	mul_m4_m4m4(mat_to, obinv, wmd->object_to->obmat);

	invert_m4_m4(tmat, mat_from); // swap?
	mul_m4_m4m4(mat_final, tmat, mat_to);

	invert_m4_m4(mat_from_inv, mat_from);

	unit_m4(mat_unit);

	if (strength < 0.0f) {
		float loc[3];
		strength = -strength;

		/* inverted location is not useful, just use the negative */
		copy_v3_v3(loc, mat_final[3]);
		invert_m4(mat_final);
		negate_v3_v3(mat_final[3], loc);

	}
	weight = strength;

	if (wmd->texture) {
		tex_co = MEM_mallocN(sizeof(*tex_co) * numVerts, "warpModifier_do tex_co");
		get_texture_coords((MappingInfoModifierData *)wmd, ob, dm, vertexCos, tex_co, numVerts);

		modifier_init_texture(wmd->modifier.scene, wmd->texture);
	}

	for (i = 0; i < numVerts; i++) {
		float *co = vertexCos[i];

		if (wmd->falloff_type == eWarp_Falloff_None ||
		    ((fac = len_squared_v3v3(co, mat_from[3])) < falloff_radius_sq &&
		     (fac = (wmd->falloff_radius - sqrtf(fac)) / wmd->falloff_radius)))
		{
			/* skip if no vert group found */
			if (defgrp_index != -1) {
				dv = &dvert[i];
				weight = defvert_find_weight(dv, defgrp_index) * strength;
				if (weight <= 0.0f) {
					continue;
				}
			}


			/* closely match PROP_SMOOTH and similar */
			switch (wmd->falloff_type) {
				case eWarp_Falloff_None:
					fac = 1.0f;
					break;
				case eWarp_Falloff_Curve:
					fac = curvemapping_evaluateF(wmd->curfalloff, 0, fac);
					break;
				case eWarp_Falloff_Sharp:
					fac = fac * fac;
					break;
				case eWarp_Falloff_Smooth:
					fac = 3.0f * fac * fac - 2.0f * fac * fac * fac;
					break;
				case eWarp_Falloff_Root:
					fac = sqrtf(fac);
					break;
				case eWarp_Falloff_Linear:
					/* pass */
					break;
				case eWarp_Falloff_Const:
					fac = 1.0f;
					break;
				case eWarp_Falloff_Sphere:
					fac = sqrtf(2 * fac - fac * fac);
					break;
				case eWarp_Falloff_InvSquare:
					fac = fac * (2.0f - fac);
					break;
			}

			fac *= weight;

			if (tex_co) {
				TexResult texres;
				texres.nor = NULL;
				BKE_texture_get_value(wmd->modifier.scene, wmd->texture, tex_co[i], &texres, false);
				fac *= texres.tin;
			}

			if (fac != 0.0f) {
				/* into the 'from' objects space */
				mul_m4_v3(mat_from_inv, co);

				if (fac == 1.0f) {
					mul_m4_v3(mat_final, co);
				}
				else {
					if (wmd->flag & MOD_WARP_VOLUME_PRESERVE) {
						/* interpolate the matrix for nicer locations */
						blend_m4_m4m4(tmat, mat_unit, mat_final, fac);
						mul_m4_v3(tmat, co);
					}
					else {
						float tvec[3];
						mul_v3_m4v3(tvec, mat_final, co);
						interp_v3_v3v3(co, co, tvec, fac);
					}
				}

				/* out of the 'from' objects space */
				mul_m4_v3(mat_from, co);
			}
		}
	}

	if (tex_co)
		MEM_freeN(tex_co);

}

static int warp_needs_dm(WarpModifierData *wmd)
{
	return wmd->texture || wmd->defgrp_name[0];
}

static void deformVerts(ModifierData *md, Object *ob, DerivedMesh *derivedData,
                        float (*vertexCos)[3], int numVerts, ModifierApplyFlag UNUSED(flag))
{
	DerivedMesh *dm = NULL;
	int use_dm = warp_needs_dm((WarpModifierData *)md);

	if (use_dm) {
		dm = get_cddm(ob, NULL, derivedData, vertexCos, false);
	}

	warpModifier_do((WarpModifierData *)md, ob, dm, vertexCos, numVerts);

	if (use_dm) {
		if (dm != derivedData) dm->release(dm);
	}
}

static void deformVertsEM(ModifierData *md, Object *ob, struct BMEditMesh *em,
                          DerivedMesh *derivedData, float (*vertexCos)[3], int numVerts)
{
	DerivedMesh *dm = derivedData;
	int use_dm = warp_needs_dm((WarpModifierData *)md);

	if (use_dm) {
		if (!derivedData)
			dm = CDDM_from_editbmesh(em, false, false);
	}

	deformVerts(md, ob, dm, vertexCos, numVerts, 0);

	if (use_dm) {
		if (!derivedData) dm->release(dm);
	}
}


ModifierTypeInfo modifierType_Warp = {
	/* name */              "Warp",
	/* structName */        "WarpModifierData",
	/* structSize */        sizeof(WarpModifierData),
	/* type */              eModifierTypeType_OnlyDeform,
	/* flags */             eModifierTypeFlag_AcceptsCVs |
	                        eModifierTypeFlag_SupportsEditmode,
	/* copyData */          copyData,
	/* deformVerts */       deformVerts,
	/* deformMatrices */    NULL,
	/* deformVertsEM */     deformVertsEM,
	/* deformMatricesEM */  NULL,
	/* applyModifier */     NULL,
	/* applyModifierEM */   NULL,
	/* initData */          initData,
	/* requiredDataMask */  requiredDataMask,
	/* freeData */          freeData,
	/* isDisabled */        isDisabled,
	/* updateDepgraph */    updateDepgraph,
	/* updateDepsgraph */   updateDepsgraph,
	/* dependsOnTime */     dependsOnTime,
	/* dependsOnNormals */  NULL,
	/* foreachObjectLink */ foreachObjectLink,
	/* foreachIDLink */     foreachIDLink,
	/* foreachTexLink */    foreachTexLink,
};