/*************************************************************************/
/*  collision_solver_sw.cpp                                              */
/*************************************************************************/
/*                       This file is part of:                           */
/*                           GODOT ENGINE                                */
/*                    http://www.godotengine.org                         */
/*************************************************************************/
/* Copyright (c) 2007-2014 Juan Linietsky, Ariel Manzur.                 */
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/* Permission is hereby granted, free of charge, to any person obtaining */
/* a copy of this software and associated documentation files (the       */
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/* distribute, sublicense, and/or sell copies of the Software, and to    */
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/* the following conditions:                                             */
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/* The above copyright notice and this permission notice shall be        */
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/* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,       */
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/*************************************************************************/
#include "collision_solver_sw.h"
#include "collision_solver_sat.h"

#include "gjk_epa.h"
#include "collision_solver_sat.h"


#define collision_solver sat_calculate_penetration
//#define collision_solver gjk_epa_calculate_penetration


bool CollisionSolverSW::solve_static_plane(const ShapeSW *p_shape_A,const Transform& p_transform_A,const ShapeSW *p_shape_B,const Transform& p_transform_B,CallbackResult p_result_callback,void *p_userdata,bool p_swap_result) {

	const PlaneShapeSW *plane = static_cast<const PlaneShapeSW*>(p_shape_A);
	if (p_shape_B->get_type()==PhysicsServer::SHAPE_PLANE)
		return false;
	Plane p = p_transform_A.xform(plane->get_plane());

	static const int max_supports = 16;
	Vector3 supports[max_supports];
	int support_count;

	p_shape_B->get_supports(p_transform_B.basis.xform_inv(-p.normal).normalized(),max_supports,supports,support_count);

	bool found=false;

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

		supports[i] = p_transform_B.xform( supports[i] );
		if (p.distance_to(supports[i])>=0)
			continue;
		found=true;

		Vector3 support_A = p.project(supports[i]);

		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 CollisionSolverSW::solve_ray(const ShapeSW *p_shape_A,const Transform& p_transform_A,const ShapeSW *p_shape_B,const Transform& p_transform_B,CallbackResult p_result_callback,void *p_userdata,bool p_swap_result) {


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

	Vector3 from = p_transform_A.origin;
	Vector3 to = from+p_transform_A.basis.get_axis(2)*ray->get_length();
	Vector3 support_A=to;

	Transform ai = p_transform_B.affine_inverse();

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

	Vector3 p,n;
	if (!p_shape_B->intersect_segment(from,to,p,n))
		return false;

	Vector3 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 _ConcaveCollisionInfo {

	const Transform *transform_A;
	const ShapeSW *shape_A;
	const Transform *transform_B;
	CollisionSolverSW::CallbackResult result_callback;
	void *userdata;
	bool swap_result;
	bool collided;
	int aabb_tests;
	int collisions;

};

void CollisionSolverSW::concave_callback(void *p_userdata, ShapeSW *p_convex) {


	_ConcaveCollisionInfo &cinfo = *(_ConcaveCollisionInfo*)(p_userdata);
	cinfo.aabb_tests++;

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

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

}

bool CollisionSolverSW::solve_concave(const ShapeSW *p_shape_A,const Transform& p_transform_A,const ShapeSW *p_shape_B,const Transform& p_transform_B,CallbackResult p_result_callback,void *p_userdata,bool p_swap_result) {


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

	_ConcaveCollisionInfo cinfo;
	cinfo.transform_A=&p_transform_A;
	cinfo.shape_A=p_shape_A;
	cinfo.transform_B=&p_transform_B;
	cinfo.result_callback=p_result_callback;
	cinfo.userdata=p_userdata;
	cinfo.swap_result=p_swap_result;
	cinfo.collided=false;
	cinfo.collisions=0;

	cinfo.aabb_tests=0;

	Transform rel_transform = p_transform_A;
	rel_transform.origin-=p_transform_B.origin;

	//quickly compute a local AABB

	AABB local_aabb;
	for(int i=0;i<3;i++) {

	     Vector3 axis( p_transform_B.basis.get_axis(i) );
	     float axis_scale = 1.0/axis.length();
	     axis*=axis_scale;

	     float smin,smax;
	     p_shape_A->project_range(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);


	return cinfo.collided;
}


bool CollisionSolverSW::solve_static(const ShapeSW *p_shape_A,const Transform& p_transform_A,const ShapeSW *p_shape_B,const Transform& p_transform_B,CallbackResult p_result_callback,void *p_userdata,Vector3 *r_sep_axis) {


	PhysicsServer::ShapeType type_A=p_shape_A->get_type();
	PhysicsServer::ShapeType type_B=p_shape_B->get_type();
	bool concave_A=p_shape_A->is_concave();
	bool concave_B=p_shape_B->is_concave();

	bool swap = false;

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

	if (type_A==PhysicsServer::SHAPE_PLANE) {

		if (type_B==PhysicsServer::SHAPE_PLANE)
			return false;
		if (type_B==PhysicsServer::SHAPE_RAY) {
			return false;
		}

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

	} else if (type_A==PhysicsServer::SHAPE_RAY) {

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

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

	} else if (concave_B) {


		if (concave_A)
			return false;

		if (!swap)
			return solve_concave(p_shape_A,p_transform_A,p_shape_B,p_transform_B,p_result_callback,p_userdata,false);
		else
			return solve_concave(p_shape_B,p_transform_B,p_shape_A,p_transform_A,p_result_callback,p_userdata,true);



	} else {

		return collision_solver(p_shape_A, p_transform_A, p_shape_B, p_transform_B, p_result_callback,p_userdata,false,r_sep_axis);
	}


	return false;
}
