/*************************************************************************/
/*  collision_solver_2d_sw.cpp                                           */
/*************************************************************************/
/*                       This file is part of:                           */
/*                           GODOT ENGINE                                */
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/* Copyright (c) 2007-2017 Juan Linietsky, Ariel Manzur.                 */
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#include "collision_solver_2d_sw.h"
#include "collision_solver_2d_sat.h"


#define collision_solver sat_2d_calculate_penetration
//#define collision_solver gjk_epa_calculate_penetration


bool CollisionSolver2DSW::solve_static_line(const Shape2DSW *p_shape_A,const Matrix32& p_transform_A,const Shape2DSW *p_shape_B,const Matrix32& p_transform_B,CallbackResult p_result_callback,void *p_userdata,bool p_swap_result) {


	const LineShape2DSW *line = static_cast<const LineShape2DSW*>(p_shape_A);
	if (p_shape_B->get_type()==Physics2DServer::SHAPE_LINE)
		return false;


	Vector2 n = p_transform_A.basis_xform(line->get_normal()).normalized();
	Vector2 p = p_transform_A.xform(line->get_normal()*line->get_d());
	real_t d = n.dot(p);

	Vector2 supports[2];
	int support_count;

	p_shape_B->get_supports(p_transform_A.affine_inverse().basis_xform(-n).normalized(),supports,support_count);

	bool found=false;


	for(int i=0;i<support_count;i++) {

		supports[i] = p_transform_B.xform( supports[i] );
		real_t pd = n.dot(supports[i]);
		if (pd>=d)
			continue;
		found=true;

		Vector2 support_A = supports[i] - n*(pd-d);

		if (p_result_callback) {
			if (p_swap_result)
				p_result_callback(supports[i],support_A,p_userdata);
			else
				p_result_callback(support_A,supports[i],p_userdata);
		}

	}


	return found;
}

bool CollisionSolver2DSW::solve_raycast(const Shape2DSW *p_shape_A,const Matrix32& p_transform_A,const Shape2DSW *p_shape_B,const Matrix32& p_transform_B,CallbackResult p_result_callback,void *p_userdata,bool p_swap_result,Vector2 *sep_axis) {



	const RayShape2DSW *ray = static_cast<const RayShape2DSW*>(p_shape_A);
	if (p_shape_B->get_type()==Physics2DServer::SHAPE_RAY)
		return false;

	Vector2 from = p_transform_A.get_origin();
	Vector2 to = from+p_transform_A[1]*ray->get_length();
	Vector2 support_A=to;

	Matrix32 invb = p_transform_B.affine_inverse();
	from = invb.xform(from);
	to = invb.xform(to);

	Vector2 p,n;
	if (!p_shape_B->intersect_segment(from,to,p,n)) {

		if (sep_axis)
			*sep_axis=p_transform_A[1].normalized();
		return false;
	}


	Vector2 support_B=p_transform_B.xform(p);

	if (p_result_callback) {
		if (p_swap_result)
			p_result_callback(support_B,support_A,p_userdata);
		else
			p_result_callback(support_A,support_B,p_userdata);
	}
	return true;

}

/*
bool CollisionSolver2DSW::solve_ray(const Shape2DSW *p_shape_A,const Matrix32& p_transform_A,const Shape2DSW *p_shape_B,const Matrix32& p_transform_B,const Matrix32& p_inverse_B,CallbackResult p_result_callback,void *p_userdata,bool p_swap_result) {


	const RayShape2DSW *ray = static_cast<const RayShape2DSW*>(p_shape_A);

	Vector2 from = p_transform_A.origin;
	Vector2 to = from+p_transform_A.basis.get_axis(2)*ray->get_length();
	Vector2 support_A=to;

	from = p_inverse_B.xform(from);
	to = p_inverse_B.xform(to);

	Vector2 p,n;
	if (!p_shape_B->intersect_segment(from,to,&p,&n))
		return false;

	Vector2 support_B=p_transform_B.xform(p);

	if (p_result_callback) {
		if (p_swap_result)
			p_result_callback(support_B,support_A,p_userdata);
		else
			p_result_callback(support_A,support_B,p_userdata);
	}
	return true;
}
*/

struct _ConcaveCollisionInfo2D {

	const Matrix32 *transform_A;
	const Shape2DSW *shape_A;
	const Matrix32 *transform_B;
	Vector2 motion_A;
	Vector2 motion_B;
	real_t margin_A;
	real_t margin_B;
	CollisionSolver2DSW::CallbackResult result_callback;
	void *userdata;
	bool swap_result;
	bool collided;
	int aabb_tests;
	int collisions;
	Vector2 *sep_axis;

};

void CollisionSolver2DSW::concave_callback(void *p_userdata, Shape2DSW *p_convex) {



	_ConcaveCollisionInfo2D &cinfo = *(_ConcaveCollisionInfo2D*)(p_userdata);
	cinfo.aabb_tests++;
	if (!cinfo.result_callback && cinfo.collided)
		return; //already collided and no contacts requested, don't test anymore

	bool collided = collision_solver(cinfo.shape_A, *cinfo.transform_A, cinfo.motion_A, p_convex,*cinfo.transform_B, cinfo.motion_B, cinfo.result_callback, cinfo.userdata, cinfo.swap_result,cinfo.sep_axis,cinfo.margin_A,cinfo.margin_B );
	if (!collided)
		return;


	cinfo.collided=true;
	cinfo.collisions++;

}

bool CollisionSolver2DSW::solve_concave(const Shape2DSW *p_shape_A,const Matrix32& p_transform_A,const Vector2& p_motion_A,const Shape2DSW *p_shape_B,const Matrix32& p_transform_B,const Vector2& p_motion_B,CallbackResult p_result_callback,void *p_userdata,bool p_swap_result,Vector2 *sep_axis,float p_margin_A,float p_margin_B) {


	const ConcaveShape2DSW *concave_B=static_cast<const ConcaveShape2DSW*>(p_shape_B);

	_ConcaveCollisionInfo2D cinfo;
	cinfo.transform_A=&p_transform_A;
	cinfo.shape_A=p_shape_A;
	cinfo.transform_B=&p_transform_B;
	cinfo.motion_A=p_motion_A;
	cinfo.result_callback=p_result_callback;
	cinfo.userdata=p_userdata;
	cinfo.swap_result=p_swap_result;
	cinfo.collided=false;
	cinfo.collisions=0;
	cinfo.sep_axis=sep_axis;
	cinfo.margin_A=p_margin_A;
	cinfo.margin_B=p_margin_B;

	cinfo.aabb_tests=0;

	Matrix32 rel_transform = p_transform_A;
	rel_transform.elements[2]-=p_transform_B.elements[2];

	//quickly compute a local Rect2

	Rect2 local_aabb;
	for(int i=0;i<2;i++) {

	     Vector2 axis( p_transform_B.elements[i] );
	     float axis_scale = 1.0/axis.length();
	     axis*=axis_scale;

	     float smin,smax;
	     p_shape_A->project_rangev(axis,rel_transform,smin,smax);
	     smin*=axis_scale;
	     smax*=axis_scale;

	     local_aabb.pos[i]=smin;
	     local_aabb.size[i]=smax-smin;
	}

	concave_B->cull(local_aabb,concave_callback,&cinfo);


//	print_line("Rect2 TESTS: "+itos(cinfo.aabb_tests));
	return cinfo.collided;
}


bool CollisionSolver2DSW::solve(const Shape2DSW *p_shape_A,const Matrix32& p_transform_A,const Vector2& p_motion_A,const Shape2DSW *p_shape_B,const Matrix32& p_transform_B,const Vector2& p_motion_B,CallbackResult p_result_callback,void *p_userdata,Vector2 *sep_axis,float p_margin_A,float p_margin_B) {




	Physics2DServer::ShapeType type_A=p_shape_A->get_type();
	Physics2DServer::ShapeType type_B=p_shape_B->get_type();
	bool concave_A=p_shape_A->is_concave();
	bool concave_B=p_shape_B->is_concave();
	real_t margin_A=p_margin_A,margin_B=p_margin_B;

	bool swap = false;

	if (type_A>type_B) {
		SWAP(type_A,type_B);
		SWAP(concave_A,concave_B);
		SWAP(margin_A,margin_B);
		swap=true;
	}

	if (type_A==Physics2DServer::SHAPE_LINE) {

		if (type_B==Physics2DServer::SHAPE_LINE || type_B==Physics2DServer::SHAPE_RAY) {
			return false;
		//if (type_B==Physics2DServer::SHAPE_RAY) {
		//	return false;
		}

		if (swap) {
			return solve_static_line(p_shape_B,p_transform_B,p_shape_A,p_transform_A,p_result_callback,p_userdata,true);
		} else {
			return solve_static_line(p_shape_A,p_transform_A,p_shape_B,p_transform_B,p_result_callback,p_userdata,false);
		}

	/*} else if (type_A==Physics2DServer::SHAPE_RAY) {

		if (type_B==Physics2DServer::SHAPE_RAY)
			return false;

		if (swap) {
			return solve_ray(p_shape_B,p_transform_B,p_shape_A,p_transform_A,p_inverse_A,p_result_callback,p_userdata,true);
		} else {
			return solve_ray(p_shape_A,p_transform_A,p_shape_B,p_transform_B,p_inverse_B,p_result_callback,p_userdata,false);
		}
*/
	} else if (type_A==Physics2DServer::SHAPE_RAY) {

		if (type_B==Physics2DServer::SHAPE_RAY) {

			return false; //no ray-ray
		}


		if (swap) {
			return solve_raycast(p_shape_B,p_transform_B,p_shape_A,p_transform_A,p_result_callback,p_userdata,true,sep_axis);
		} else {
			return solve_raycast(p_shape_A,p_transform_A,p_shape_B,p_transform_B,p_result_callback,p_userdata,false,sep_axis);
		}


	} else if (concave_B) {


		if (concave_A)
			return false;

		if (!swap)
			return solve_concave(p_shape_A,p_transform_A,p_motion_A,p_shape_B,p_transform_B,p_motion_B,p_result_callback,p_userdata,false,sep_axis,margin_A,margin_B);
		else
			return solve_concave(p_shape_B,p_transform_B,p_motion_B,p_shape_A,p_transform_A,p_motion_A,p_result_callback,p_userdata,true,sep_axis,margin_A,margin_B);



	} else {


		return collision_solver(p_shape_A, p_transform_A,p_motion_A, p_shape_B, p_transform_B, p_motion_B,p_result_callback,p_userdata,false,sep_axis,margin_A,margin_B);
	}


	return false;
}

