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/*
Minetest
Copyright (C) 2016 juhdanad, Daniel Juhasz <juhdanad@gmail.com>

This program is free software; you can redistribute it and/or modify
it under the terms of the GNU Lesser General Public License as published by
the Free Software Foundation; either version 2.1 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 Lesser General Public License for more details.

You should have received a copy of the GNU Lesser 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.
*/

#pragma once

#include "voxelalgorithms.h"
#include "util/pointedthing.h"

//! Sorts PointedThings based on their distance.
struct RaycastSort
{
	bool operator() (const PointedThing &pt1, const PointedThing &pt2) const;
};

//! Describes the state of a raycast.
class RaycastState
{
public:
	/*!
	 * Creates a raycast.
	 * @param objects_pointable if false, only nodes will be found
	 * @param liquids pointable if false, liquid nodes won't be found
	 */
	RaycastState(const core::line3d<f32> &shootline, bool objects_pointable,
		bool liquids_pointable);

	//! Shootline of the raycast.
	core::line3d<f32> m_shootline;
	//! Iterator to store the progress of the raycast.
	voxalgo::VoxelLineIterator m_iterator;
	//! Previous tested node during the raycast.
	v3s16 m_previous_node;

	/*!
	 * This priority queue stores the found pointed things
	 * waiting to be returned.
	 */
	std::priority_queue<PointedThing, std::vector<PointedThing>, RaycastSort> m_found;

	bool m_objects_pointable;
	bool m_liquids_pointable;

	//! The code needs to search these nodes around the center node.
	core::aabbox3d<s16> m_search_range { 0, 0, 0, 0, 0, 0 };

	//! If true, the Environment will initialize this state.
	bool m_initialization_needed = true;
};

/*!
 * Checks if a line and a box intersects.
 * @param[in]  box              box to test collision
 * @param[in]  start            starting point of the line
 * @param[in]  dir              direction and length of the line
 * @param[out] collision_point  first point of the collision
 * @param[out] collision_normal normal vector at the collision, points
 * outwards of the surface. If start is in the box, zero vector.
 * @returns true if a collision point was found
 */
bool boxLineCollision(const aabb3f &box, const v3f &start, const v3f &dir,
	v3f *collision_point, v3s16 *collision_normal);
id='n285' href='#n285'>285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385
/*
Minetest-c55
Copyright (C) 2010 celeron55, Perttu Ahola <celeron55@gmail.com>

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.
*/

/*
(c) 2010 Perttu Ahola <celeron55@gmail.com>
*/

#include "utility.h"
#include "irrlichtwrapper.h"
#include "gettime.h"

TimeTaker::TimeTaker(const char *name, u32 *result)
{
	m_name = name;
	m_result = result;
	m_running = true;
	m_time1 = getTimeMs();
}

u32 TimeTaker::stop(bool quiet)
{
	if(m_running)
	{
		u32 time2 = getTimeMs();
		u32 dtime = time2 - m_time1;
		if(m_result != NULL)
		{
			(*m_result) += dtime;
		}
		else
		{
			if(quiet == false)
				std::cout<<m_name<<" took "<<dtime<<"ms"<<std::endl;
		}
		m_running = false;
		return dtime;
	}
	return 0;
}

const v3s16 g_26dirs[26] =
{
	// +right, +top, +back
	v3s16( 0, 0, 1), // back
	v3s16( 0, 1, 0), // top
	v3s16( 1, 0, 0), // right
	v3s16( 0, 0,-1), // front
	v3s16( 0,-1, 0), // bottom
	v3s16(-1, 0, 0), // left
	// 6
	v3s16(-1, 1, 0), // top left
	v3s16( 1, 1, 0), // top right
	v3s16( 0, 1, 1), // top back
	v3s16( 0, 1,-1), // top front
	v3s16(-1, 0, 1), // back left
	v3s16( 1, 0, 1), // back right
	v3s16(-1, 0,-1), // front left
	v3s16( 1, 0,-1), // front right
	v3s16(-1,-1, 0), // bottom left
	v3s16( 1,-1, 0), // bottom right
	v3s16( 0,-1, 1), // bottom back
	v3s16( 0,-1,-1), // bottom front
	// 18
	v3s16(-1, 1, 1), // top back-left
	v3s16( 1, 1, 1), // top back-right
	v3s16(-1, 1,-1), // top front-left
	v3s16( 1, 1,-1), // top front-right
	v3s16(-1,-1, 1), // bottom back-left
	v3s16( 1,-1, 1), // bottom back-right
	v3s16(-1,-1,-1), // bottom front-left
	v3s16( 1,-1,-1), // bottom front-right
	// 26
};

static unsigned long next = 1;

/* RAND_MAX assumed to be 32767 */
int myrand(void)
{
   next = next * 1103515245 + 12345;
   return((unsigned)(next/65536) % 32768);
}

void mysrand(unsigned seed)
{
   next = seed;
}

// Float with distance
struct DFloat
{
	float v;
	u32 d;
};

float PointAttributeList::getInterpolatedFloat(v3s16 p)
{
	const u32 near_wanted_count = 5;
	// Last is nearest, first is farthest
	core::list<DFloat> near_list;

	for(core::list<PointWithAttr>::Iterator
			i = m_points.begin();
			i != m_points.end(); i++)
	{
		PointWithAttr &pwa = *i;
		u32 d = pwa.p.getDistanceFrom(p);
		
		DFloat df;
		df.v = pwa.attr.getFloat();
		df.d = d;
				
		// If near list is empty, add directly and continue
		if(near_list.size() == 0)
		{
			near_list.push_back(df);
			continue;
		}
		
		// Get distance of farthest in near list
		u32 near_d = 100000;
		if(near_list.size() > 0)
		{
			core::list<DFloat>::Iterator i = near_list.begin();
			near_d = i->d;
		}
		
		/*
			If point is closer than the farthest in the near list or
			there are not yet enough points on the list
		*/
		if(d < near_d || near_list.size() < near_wanted_count)
		{
			// Find the right place in the near list and put it there
			
			// Go from farthest to near in the near list
			core::list<DFloat>::Iterator i = near_list.begin();
			for(; i != near_list.end(); i++)
			{
				// Stop when i is at the first nearer node
				if(i->d < d)
					break;
			}
			// Add df to before i
			if(i == near_list.end())
				near_list.push_back(df);
			else
				near_list.insert_before(i, df);

			// Keep near list at right size
			if(near_list.size() > near_wanted_count)
			{
				core::list<DFloat>::Iterator j = near_list.begin();
				near_list.erase(j);
			}
		}
	}
	
	// Return if no values found
	if(near_list.size() == 0)
		return 0.0;
	
	/*
20:58:29 < tejeez> joka pisteelle a += arvo / etäisyys^6; b += 1 / etäisyys^6; ja 
lopuks sit otetaan a/b
	*/
	
	float a = 0;
	float b = 0;
	for(core::list<DFloat>::Iterator i = near_list.begin();
			i != near_list.end(); i++)
	{
		if(i->d == 0)
			return i->v;
		
		//float dd = pow((float)i->d, 6);
		float dd = pow((float)i->d, 5);
		float v = i->v;
		//dstream<<"dd="<<dd<<", v="<<v<<std::endl;
		a += v / dd;
		b += 1 / dd;
	}

	return a / b;
}

#if 0
float PointAttributeList::getInterpolatedFloat(v3s16 p)
{
	const u32 near_wanted_count = 2;
	const u32 nearest_wanted_count = 2;
	// Last is near
	core::list<DFloat> near;

	for(core::list<PointWithAttr>::Iterator
			i = m_points.begin();
			i != m_points.end(); i++)
	{
		PointWithAttr &pwa = *i;
		u32 d = pwa.p.getDistanceFrom(p);
		
		DFloat df;
		df.v = pwa.attr.getFloat();
		df.d = d;
				
		// If near list is empty, add directly and continue
		if(near_list.size() == 0)
		{
			near_list.push_back(df);
			continue;
		}
		
		// Get distance of farthest in near list
		u32 near_d = 100000;
		if(near_list.size() > 0)
		{
			core::list<DFloat>::Iterator i = near_list.begin();
			near_d = i->d;
		}
		
		/*
			If point is closer than the farthest in the near list or
			there are not yet enough points on the list
		*/
		if(d < near_d || near_list.size() < near_wanted_count)
		{
			// Find the right place in the near list and put it there
			
			// Go from farthest to near in the near list
			core::list<DFloat>::Iterator i = near_list.begin();
			for(; i != near_list.end(); i++)
			{
				// Stop when i is at the first nearer node
				if(i->d < d)
					break;
			}
			// Add df to before i
			if(i == near_list.end())
				near_list.push_back(df);
			else
				near_list.insert_before(i, df);

			// Keep near list at right size
			if(near_list.size() > near_wanted_count)
			{
				core::list<DFloat>::Iterator j = near_list.begin();
				near_list.erase(j);
			}
		}
	}
	
	// Return if no values found
	if(near_list.size() == 0)
		return 0.0;
	
	/*
		Get nearest ones
	*/

	u32 nearest_count = nearest_wanted_count;
	if(nearest_count > near_list.size())
		nearest_count = near_list.size();
	core::list<DFloat> nearest;
	{
		core::list<DFloat>::Iterator i = near_list.getLast();
		for(u32 j=0; j<nearest_count; j++)
		{
			nearest.push_front(*i);
			i--;
		}
	}

	/*
		TODO: Try this:
20:58:29 < tejeez> joka pisteelle a += arvo / etäisyys^6; b += 1 / etäisyys^6; ja 
lopuks sit otetaan a/b
	*/

	/*
		Get total distance to nearest points
	*/
	
	float nearest_d_sum = 0;
	for(core::list<DFloat>::Iterator i = nearest.begin();
			i != nearest.end(); i++)
	{
		nearest_d_sum += (float)i->d;
	}

	/*
		Interpolate a value between the first ones
	*/

	dstream<<"nearest.size()="<<nearest.size()<<std::endl;

	float interpolated = 0;
	
	for(core::list<DFloat>::Iterator i = nearest.begin();
			i != nearest.end(); i++)
	{
		float weight;
		if(nearest_d_sum > 0.001)
			weight = (float)i->d / nearest_d_sum;
		else
			weight = 1. / nearest.size();
		/*dstream<<"i->d="<<i->d<<" nearest_d_sum="<<nearest_d_sum
				<<" weight="<<weight<<std::endl;*/
		interpolated += weight * i->v;
	}

	return interpolated;
}
#endif

/*
	blockpos: position of block in block coordinates
	camera_pos: position of camera in nodes
	camera_dir: an unit vector pointing to camera direction
	range: viewing range
*/
bool isBlockInSight(v3s16 blockpos_b, v3f camera_pos, v3f camera_dir, f32 range)
{
	v3s16 blockpos_nodes = blockpos_b * MAP_BLOCKSIZE;
	
	// Block center position
	v3f blockpos(
			((float)blockpos_nodes.X + MAP_BLOCKSIZE/2) * BS,
			((float)blockpos_nodes.Y + MAP_BLOCKSIZE/2) * BS,
			((float)blockpos_nodes.Z + MAP_BLOCKSIZE/2) * BS
	);

	// Block position relative to camera
	v3f blockpos_relative = blockpos - camera_pos;

	// Distance in camera direction (+=front, -=back)
	f32 dforward = blockpos_relative.dotProduct(camera_dir);

	// Total distance
	f32 d = blockpos_relative.getLength();
	
	// If block is far away, it's not in sight
	if(d > range * BS)
		return false;

	// Maximum radius of a block
	f32 block_max_radius = 0.5*1.44*1.44*MAP_BLOCKSIZE*BS;
	
	// If block is (nearly) touching the camera, don't
	// bother validating further (that is, render it anyway)
	if(d > block_max_radius * 1.5)
	{
		// Cosine of the angle between the camera direction
		// and the block direction (camera_dir is an unit vector)
		f32 cosangle = dforward / d;
		
		// Compensate for the size of the block
		// (as the block has to be shown even if it's a bit off FOV)
		// This is an estimate.
		cosangle += block_max_radius / dforward;

		// If block is not in the field of view, skip it
		//if(cosangle < cos(FOV_ANGLE/2))
		if(cosangle < cos(FOV_ANGLE/2. * 4./3.))
			return false;
	}

	return true;
}