/*
 * ***** 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) 2009 Blender Foundation.
 * All rights reserved.
 *
 * The Original Code is: all of this file.
 *
 * Contributor(s): André Pinto.
 *
 * ***** END GPL LICENSE BLOCK *****
 */

/** \file blender/render/intern/raytrace/rayobject.cpp
 *  \ingroup render
 */


#include <assert.h>

#include "MEM_guardedalloc.h"

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

#include "DNA_material_types.h"

#include "rayintersection.h"
#include "rayobject.h"
#include "raycounter.h"
#include "render_types.h"
#include "renderdatabase.h"

/* RayFace
 *
 * note we force always inline here, because compiler refuses to otherwise
 * because function is too long. Since this is code that is called billions
 * of times we really do want to inline. */

MALWAYS_INLINE RayObject *rayface_from_coords(RayFace *rayface, void *ob, void *face,
                                              float *v1, float *v2, float *v3, float *v4)
{
	rayface->ob = ob;
	rayface->face = face;

	copy_v3_v3(rayface->v1, v1);
	copy_v3_v3(rayface->v2, v2);
	copy_v3_v3(rayface->v3, v3);

	if (v4) {
		copy_v3_v3(rayface->v4, v4);
		rayface->quad = 1;
	}
	else {
		rayface->quad = 0;
	}

	return RE_rayobject_unalignRayFace(rayface);
}

MALWAYS_INLINE void rayface_from_vlak(RayFace *rayface, ObjectInstanceRen *obi, VlakRen *vlr)
{
	rayface_from_coords(rayface, obi, vlr, vlr->v1->co, vlr->v2->co, vlr->v3->co, vlr->v4 ? vlr->v4->co : NULL);

	if (obi->transform_primitives) {
		mul_m4_v3(obi->mat, rayface->v1);
		mul_m4_v3(obi->mat, rayface->v2);
		mul_m4_v3(obi->mat, rayface->v3);

		if (RE_rayface_isQuad(rayface))
			mul_m4_v3(obi->mat, rayface->v4);
	}
}

RayObject *RE_rayface_from_vlak(RayFace *rayface, ObjectInstanceRen *obi, VlakRen *vlr)
{
	return rayface_from_coords(rayface, obi, vlr, vlr->v1->co, vlr->v2->co, vlr->v3->co, vlr->v4 ? vlr->v4->co : NULL);
}

RayObject *RE_rayface_from_coords(RayFace *rayface, void *ob, void *face, float *v1, float *v2, float *v3, float *v4)
{
	return rayface_from_coords(rayface, ob, face, v1, v2, v3, v4);
}

/* VlakPrimitive */

RayObject *RE_vlakprimitive_from_vlak(VlakPrimitive *face, struct ObjectInstanceRen *obi, struct VlakRen *vlr)
{
	face->ob = obi;
	face->face = vlr;

	return RE_rayobject_unalignVlakPrimitive(face);
}

/* Checks for ignoring faces or materials */

MALWAYS_INLINE int vlr_check_intersect(Isect *is, ObjectInstanceRen *obi, VlakRen *vlr)
{
	/* for baking selected to active non-traceable materials might still
	 * be in the raytree */
	if (!(vlr->flag & R_TRACEBLE))
		return 0;

	/* I know... cpu cycle waste, might do smarter once */
	if (is->mode == RE_RAY_MIRROR)
		return !(vlr->mat->mode & MA_ONLYCAST);
	else
		return (vlr->mat->mode2 & MA_CASTSHADOW) && (is->lay & obi->lay);
}

MALWAYS_INLINE int vlr_check_intersect_solid(Isect *UNUSED(is), ObjectInstanceRen *UNUSED(obi), VlakRen *vlr)
{
	/* solid material types only */
	if (vlr->mat->material_type == MA_TYPE_SURFACE)
		return 1;
	else
		return 0;
}

MALWAYS_INLINE int vlr_check_bake(Isect *is, ObjectInstanceRen *obi, VlakRen *UNUSED(vlr))
{
	return (obi->obr->ob != is->userdata) && (obi->obr->ob->flag & SELECT);
}

/* Ray Triangle/Quad Intersection */

static bool isect_ray_tri_watertight_no_sign_check_v3(
        const float ray_origin[3], const struct IsectRayPrecalc *isect_precalc,
        const float v0[3], const float v1[3], const float v2[3],
        float *r_lambda, float r_uv[2])
{
	const int kx = isect_precalc->kx;
	const int ky = isect_precalc->ky;
	const int kz = isect_precalc->kz;
	const float sx = isect_precalc->sx;
	const float sy = isect_precalc->sy;
	const float sz = isect_precalc->sz;

	/* Calculate vertices relative to ray origin. */
	const float a[3] = {v0[0] - ray_origin[0], v0[1] - ray_origin[1], v0[2] - ray_origin[2]};
	const float b[3] = {v1[0] - ray_origin[0], v1[1] - ray_origin[1], v1[2] - ray_origin[2]};
	const float c[3] = {v2[0] - ray_origin[0], v2[1] - ray_origin[1], v2[2] - ray_origin[2]};

	const float a_kx = a[kx], a_ky = a[ky], a_kz = a[kz];
	const float b_kx = b[kx], b_ky = b[ky], b_kz = b[kz];
	const float c_kx = c[kx], c_ky = c[ky], c_kz = c[kz];

	/* Perform shear and scale of vertices. */
	const float ax = a_kx - sx * a_kz;
	const float ay = a_ky - sy * a_kz;
	const float bx = b_kx - sx * b_kz;
	const float by = b_ky - sy * b_kz;
	const float cx = c_kx - sx * c_kz;
	const float cy = c_ky - sy * c_kz;

	/* Calculate scaled barycentric coordinates. */
	const float u = cx * by - cy * bx;
	const float v = ax * cy - ay * cx;
	const float w = bx * ay - by * ax;
	float det;

	if ((u < 0.0f || v < 0.0f || w < 0.0f) &&
	    (u > 0.0f || v > 0.0f || w > 0.0f))
	{
		return false;
	}

	/* Calculate determinant. */
	det = u + v + w;
	if (UNLIKELY(det == 0.0f)) {
		return false;
	}
	else {
		/* Calculate scaled z-coordinates of vertices and use them to calculate
		 * the hit distance.
		 */
		const float t = (u * a_kz + v * b_kz + w * c_kz) * sz;
		/* Normalize u, v and t. */
		const float inv_det = 1.0f / det;
		if (r_uv) {
			r_uv[0] = u * inv_det;
			r_uv[1] = v * inv_det;
		}
		*r_lambda = t * inv_det;
		return true;
	}
}

MALWAYS_INLINE int isec_tri_quad(const float start[3],
                                 const struct IsectRayPrecalc *isect_precalc,
                                 const RayFace *face,
                                 float r_uv[2], float *r_lambda)
{
	float uv[2], l;

	if (isect_ray_tri_watertight_v3(start, isect_precalc, face->v1, face->v2, face->v3, &l, uv)) {
		/* check if intersection is within ray length */
		if (l > -RE_RAYTRACE_EPSILON && l < *r_lambda) {
			r_uv[0] = -uv[0];
			r_uv[1] = -uv[1];
			*r_lambda = l;
			return 1;
		}
	}

	/* intersect second triangle in quad */
	if (RE_rayface_isQuad(face)) {
		if (isect_ray_tri_watertight_v3(start, isect_precalc, face->v1, face->v3, face->v4, &l, uv)) {
			/* check if intersection is within ray length */
			if (l > -RE_RAYTRACE_EPSILON && l < *r_lambda) {
				r_uv[0] = -uv[0];
				r_uv[1] = -uv[1];
				*r_lambda = l;
				return 2;
			}
		}
	}

	return 0;
}

/* Simpler yes/no Ray Triangle/Quad Intersection */

MALWAYS_INLINE int isec_tri_quad_neighbour(const float start[3],
                                           const float dir[3],
                                           const RayFace *face)
{
	float r[3];
	struct IsectRayPrecalc isect_precalc;
	float uv[2], l;

	negate_v3_v3(r, dir); /* note, different than above function */

	isect_ray_tri_watertight_v3_precalc(&isect_precalc, r);

	if (isect_ray_tri_watertight_no_sign_check_v3(start, &isect_precalc, face->v1, face->v2, face->v3, &l, uv)) {
		return 1;
	}

	/* intersect second triangle in quad */
	if (RE_rayface_isQuad(face)) {
		if (isect_ray_tri_watertight_no_sign_check_v3(start, &isect_precalc, face->v1, face->v3, face->v4, &l, uv)) {
			return 2;
		}
	}

	return 0;
}

/* RayFace intersection with checks and neighbor verifaction included,
 * Isect is modified if the face is hit. */

MALWAYS_INLINE int intersect_rayface(RayObject *hit_obj, RayFace *face, Isect *is)
{
	float dist, uv[2];
	int ok = 0;
	
	/* avoid self-intersection */
	if (is->orig.ob == face->ob && is->orig.face == face->face)
		return 0;
		
	/* check if we should intersect this face */
	if (is->check == RE_CHECK_VLR_RENDER) {
		if (vlr_check_intersect(is, (ObjectInstanceRen *)face->ob, (VlakRen *)face->face) == 0)
			return 0;
	}
	else if (is->check == RE_CHECK_VLR_NON_SOLID_MATERIAL) {
		if (vlr_check_intersect(is, (ObjectInstanceRen *)face->ob, (VlakRen *)face->face) == 0)
			return 0;
		if (vlr_check_intersect_solid(is, (ObjectInstanceRen *)face->ob, (VlakRen *)face->face) == 0)
			return 0;
	}
	else if (is->check == RE_CHECK_VLR_BAKE) {
		if (vlr_check_bake(is, (ObjectInstanceRen *)face->ob, (VlakRen *)face->face) == 0)
			return 0;
	}

	/* ray counter */
	RE_RC_COUNT(is->raycounter->faces.test);

	dist = is->dist;
	ok = isec_tri_quad(is->start, &is->isect_precalc, face, uv, &dist);

	if (ok) {
	
		/* when a shadow ray leaves a face, it can be little outside the edges
		 * of it, causing intersection to be detected in its neighbor face */
		if (is->skip & RE_SKIP_VLR_NEIGHBOUR) {
			if (dist < 0.1f && is->orig.ob == face->ob) {
				VlakRen *a = (VlakRen *)is->orig.face;
				VlakRen *b = (VlakRen *)face->face;
				ObjectRen *obr = ((ObjectInstanceRen *)face->ob)->obr;

				VertRen **va, **vb;
				int *org_idx_a, *org_idx_b;
				int i, j;
				bool is_neighbor = false;

				/* "same" vertex means either the actual same VertRen, or the same 'final org index', if available
				 * (autosmooth only, currently). */
				for (i = 0, va = &a->v1; !is_neighbor && i < 4 && *va; ++i, ++va) {
					org_idx_a = RE_vertren_get_origindex(obr, *va, false);
					for (j = 0, vb = &b->v1; !is_neighbor && j < 4 && *vb; ++j, ++vb) {
						if (*va == *vb) {
							is_neighbor = true;
						}
						else if (org_idx_a) {
							org_idx_b = RE_vertren_get_origindex(obr, *vb, 0);
							if (org_idx_b && *org_idx_a == *org_idx_b) {
								is_neighbor = true;
							}
						}
					}
				}

				/* So there's a shared edge or vertex, let's intersect ray with self, if that's true
				 * we can safely return 1, otherwise we assume the intersection is invalid, 0 */
				if (is_neighbor) {
					/* create RayFace from original face, transformed if necessary */
					RayFace origface;
					ObjectInstanceRen *ob = (ObjectInstanceRen *)is->orig.ob;
					rayface_from_vlak(&origface, ob, (VlakRen *)is->orig.face);

					if (!isec_tri_quad_neighbour(is->start, is->dir, &origface)) {
						return 0;
					}
				}
			}
		}

		RE_RC_COUNT(is->raycounter->faces.hit);

		is->isect = ok;  // which half of the quad
		is->dist = dist;
		is->u = uv[0]; is->v = uv[1];

		is->hit.ob   = face->ob;
		is->hit.face = face->face;
#ifdef RT_USE_LAST_HIT
		is->last_hit = hit_obj;
#endif
		return 1;
	}

	return 0;
}

/* Intersection */

int RE_rayobject_raycast(RayObject *r, Isect *isec)
{
	int i;

	/* Pre-calculate orientation for watertight intersection checks. */
	isect_ray_tri_watertight_v3_precalc(&isec->isect_precalc, isec->dir);

	RE_RC_COUNT(isec->raycounter->raycast.test);

	/* setup vars used on raycast */
	for (i = 0; i < 3; i++) {
		isec->idot_axis[i]          = 1.0f / isec->dir[i];
		
		isec->bv_index[2 * i]       = isec->idot_axis[i] < 0.0f ? 1 : 0;
		isec->bv_index[2 * i + 1]   = 1 - isec->bv_index[2 * i];
		
		isec->bv_index[2 * i]       = i + 3 * isec->bv_index[2 * i];
		isec->bv_index[2 * i + 1]   = i + 3 * isec->bv_index[2 * i + 1];
	}

#ifdef RT_USE_LAST_HIT	
	/* last hit heuristic */
	if (isec->mode == RE_RAY_SHADOW && isec->last_hit) {
		RE_RC_COUNT(isec->raycounter->rayshadow_last_hit.test);
		
		if (RE_rayobject_intersect(isec->last_hit, isec)) {
			RE_RC_COUNT(isec->raycounter->raycast.hit);
			RE_RC_COUNT(isec->raycounter->rayshadow_last_hit.hit);
			return 1;
		}
	}
#endif

#ifdef RT_USE_HINT
	isec->hit_hint = 0;
#endif

	if (RE_rayobject_intersect(r, isec)) {
		RE_RC_COUNT(isec->raycounter->raycast.hit);

#ifdef RT_USE_HINT
		isec->hint = isec->hit_hint;
#endif
		return 1;
	}

	return 0;
}

int RE_rayobject_intersect(RayObject *r, Isect *i)
{
	if (RE_rayobject_isRayFace(r)) {
		return intersect_rayface(r, (RayFace *) RE_rayobject_align(r), i);
	}
	else if (RE_rayobject_isVlakPrimitive(r)) {
		//TODO optimize (useless copy to RayFace to avoid duplicate code)
		VlakPrimitive *face = (VlakPrimitive *) RE_rayobject_align(r);
		RayFace nface;
		rayface_from_vlak(&nface, face->ob, face->face);

		return intersect_rayface(r, &nface, i);
	}
	else if (RE_rayobject_isRayAPI(r)) {
		r = RE_rayobject_align(r);
		return r->api->raycast(r, i);
	}
	else {
		assert(0);
		return 0;
	}
}

/* Building */

void RE_rayobject_add(RayObject *r, RayObject *o)
{
	r = RE_rayobject_align(r);
	return r->api->add(r, o);
}

void RE_rayobject_done(RayObject *r)
{
	r = RE_rayobject_align(r);
	r->api->done(r);
}

void RE_rayobject_free(RayObject *r)
{
	r = RE_rayobject_align(r);
	r->api->free(r);
}

float RE_rayobject_cost(RayObject *r)
{
	if (RE_rayobject_isRayFace(r) || RE_rayobject_isVlakPrimitive(r)) {
		return 1.0f;
	}
	else if (RE_rayobject_isRayAPI(r)) {
		r = RE_rayobject_align(r);
		return r->api->cost(r);
	}
	else {
		assert(0);
		return 1.0f;
	}
}

/* Bounding Boxes */

void RE_rayobject_merge_bb(RayObject *r, float min[3], float max[3])
{
	if (RE_rayobject_isRayFace(r)) {
		RayFace *face = (RayFace *) RE_rayobject_align(r);
		
		DO_MINMAX(face->v1, min, max);
		DO_MINMAX(face->v2, min, max);
		DO_MINMAX(face->v3, min, max);
		if (RE_rayface_isQuad(face)) DO_MINMAX(face->v4, min, max);
	}
	else if (RE_rayobject_isVlakPrimitive(r)) {
		VlakPrimitive *face = (VlakPrimitive *) RE_rayobject_align(r);
		RayFace nface;
		rayface_from_vlak(&nface, face->ob, face->face);

		DO_MINMAX(nface.v1, min, max);
		DO_MINMAX(nface.v2, min, max);
		DO_MINMAX(nface.v3, min, max);
		if (RE_rayface_isQuad(&nface)) DO_MINMAX(nface.v4, min, max);
	}
	else if (RE_rayobject_isRayAPI(r)) {
		r = RE_rayobject_align(r);
		r->api->bb(r, min, max);
	}
	else
		assert(0);
}

/* Hints */

void RE_rayobject_hint_bb(RayObject *r, RayHint *hint, float *min, float *max)
{
	if (RE_rayobject_isRayFace(r) || RE_rayobject_isVlakPrimitive(r)) {
		return;
	}
	else if (RE_rayobject_isRayAPI(r)) {
		r = RE_rayobject_align(r);
		return r->api->hint_bb(r, hint, min, max);
	}
	else
		assert(0);
}

/* RayObjectControl */

int RE_rayobjectcontrol_test_break(RayObjectControl *control)
{
	if (control->test_break)
		return control->test_break(control->data);

	return 0;
}

void RE_rayobject_set_control(RayObject *r, void *data, RE_rayobjectcontrol_test_break_callback test_break)
{
	if (RE_rayobject_isRayAPI(r)) {
		r = RE_rayobject_align(r);
		r->control.data = data;
		r->control.test_break = test_break;
	}
}