minetest/src/mapnode.h

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

#ifndef MAPNODE_HEADER
#define MAPNODE_HEADER

#include <iostream>
#include "common_irrlicht.h"
#include "light.h"
#include "utility.h"
#include "exceptions.h"
#include "serialization.h"

// Size of node in rendering units
#define BS 10

#define MATERIALS_COUNT 256

// This is completely ignored. It doesn't create faces with anything.
#define MATERIAL_IGNORE 255
// This is the common material through which the player can walk
// and which is transparent to light
#define MATERIAL_AIR 254

/*
	Materials-todo:

	GRAVEL
	  - Dynamics of gravel: if there is a drop of more than two
	    blocks on any side, it will drop in there. Is this doable?
*/

enum Material
{
	MATERIAL_STONE=0,

	MATERIAL_GRASS,

	/*
		For water, the param is water pressure. 0...127.
		TODO: No, at least the lowest nibble is used for lighting.
		
		- Water will be a bit like light, but with different flow
		  behavior.
		- Water blocks will fall down if there is empty space below.
		- If there is water below, the pressure of the block below is
		  the pressure of the current block + 1, or higher.
		- If there is any pressure in a horizontally neighboring
		  block, a water block will try to move away from it.
		- If there is >=2 of pressure in a block below, water will
		  try to move upwards.
		- NOTE: To keep large operations fast, we have to keep a
		        cache of the water-air-surfaces, just like with light
	*/
	MATERIAL_WATER,

	MATERIAL_LIGHT,

	MATERIAL_TREE,
	MATERIAL_LEAVES,

	MATERIAL_GRASS_FOOTSTEPS,
	
	MATERIAL_MESE,
	
	// This is set to the number of the actual values in this enum
	USEFUL_MATERIAL_COUNT
};

/*
	If true, the material allows light propagation and brightness is stored
	in param.
*/
inline bool light_propagates_material(u8 m)
{
	return (m == MATERIAL_AIR || m == MATERIAL_LIGHT || m == MATERIAL_WATER);
}

/*
	If true, the material allows lossless sunlight propagation.
*/
inline bool sunlight_propagates_material(u8 m)
{
	return (m == MATERIAL_AIR);
}

/*
	On a node-node surface, the material of the node with higher solidness
	is used for drawing.
	0: Invisible
	1: Transparent
	2: Opaque
*/
inline u8 material_solidness(u8 m)
{
	if(m == MATERIAL_AIR)
		return 0;
	if(m == MATERIAL_WATER)
		return 1;
	return 2;
}

/*
	Nodes make a face if materials differ and solidness differs.
	Return value:
		0: No face
		1: Face uses m1's material
		2: Face uses m2's material
*/
inline u8 face_materials(u8 m1, u8 m2)
{
	if(m1 == MATERIAL_IGNORE || m2 == MATERIAL_IGNORE)
		return 0;
	
	bool materials_differ = (m1 != m2);
	bool solidness_differs = (material_solidness(m1) != material_solidness(m2));
	bool makes_face = materials_differ && solidness_differs;

	if(makes_face == false)
		return 0;

	if(material_solidness(m1) > material_solidness(m2))
		return 1;
	else
		return 2;
}

struct MapNode
{
	//TODO: block type to differ from material
	//      (e.g. grass edges or something)
	// block type
	u8 d;

	// Removed because light is now stored in param for air
	// f32 light;

	/*
		Misc parameter. Initialized to 0.
		- For light_propagates() blocks, this is light intensity,
		  stored logarithmically from 0 to LIGHT_MAX.
		  Sunlight is LIGHT_SUN, which is LIGHT_MAX+1.
	*/
	s8 param;

	MapNode(const MapNode & n)
	{
		*this = n;
	}
	
	MapNode(u8 data=MATERIAL_AIR, u8 a_param=0)
	{
		d = data;
		param = a_param;
	}

	bool light_propagates()
	{
		return light_propagates_material(d);
	}
	
	bool sunlight_propagates()
	{
		return sunlight_propagates_material(d);
	}
	
	u8 solidness()
	{
		return material_solidness(d);
	}

	u8 light_source()
	{
		/*
			Note that a block that isn't light_propagates() can be a light source.
		*/
		if(d == MATERIAL_LIGHT)
			return LIGHT_MAX;
		
		return 0;
	}

	u8 getLight()
	{
		// Select the brightest of [light_source, transparent_light]
		u8 light = 0;
		if(light_propagates())
			light = param & 0x0f;
		if(light_source() > light)
			light = light_source();
		return light;
	}

	void setLight(u8 a_light)
	{
		// If not transparent, can't set light
		if(light_propagates() == false)
			return;
		param = a_light;
	}

	static u32 serializedLength(u8 version)
	{
		if(!ser_ver_supported(version))
			throw VersionMismatchException("ERROR: MapNode format not supported");
			
		if(version == 0)
			return 1;
		else
			return 2;
	}
	void serialize(u8 *dest, u8 version)
	{
		if(!ser_ver_supported(version))
			throw VersionMismatchException("ERROR: MapNode format not supported");
			
		if(version == 0)
		{
			dest[0] = d;
		}
		else
		{
			dest[0] = d;
			dest[1] = param;
		}
	}
	void deSerialize(u8 *source, u8 version)
	{
		if(!ser_ver_supported(version))
			throw VersionMismatchException("ERROR: MapNode format not supported");
			
		if(version == 0)
		{
			d = source[0];
		}
		else if(version == 1)
		{
			d = source[0];
			// This version doesn't support saved lighting
			if(light_propagates() || light_source() > 0)
				param = 0;
			else
				param = source[1];
		}
		else
		{
			d = source[0];
			param = source[1];
		}
	}
};

/*
	Returns integer position of the node in given
	floating point position.
*/
inline v3s16 floatToInt(v3f p)
{
	v3s16 p2(
		(p.X + (p.X>0 ? BS/2 : -BS/2))/BS,
		(p.Y + (p.Y>0 ? BS/2 : -BS/2))/BS,
		(p.Z + (p.Z>0 ? BS/2 : -BS/2))/BS);
	return p2;
}

inline v3f intToFloat(v3s16 p)
{
	v3f p2(
		p.X * BS,
		p.Y * BS,
		p.Z * BS
	);
	return p2;
}



#endif