src/content_mapnode.cpp

/*
Minetest
Copyright (C) 2010-2013 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 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.
*/

#include "mapblock_mesh.h"
#include "client.h"
#include "mapblock.h"
#include "map.h"
#include "profiler.h"
#include "shader.h"
#include "mesh.h"
#include "minimap.h"
#include "content_mapblock.h"
#include "util/directiontables.h"
#include "client/renderingengine.h"
#include <array>

/*
	MeshMakeData
*/

MeshMakeData::MeshMakeData(Client *client, bool use_shaders,
		bool use_tangent_vertices):
	m_client(client),
	m_use_shaders(use_shaders),
	m_use_tangent_vertices(use_tangent_vertices)
{}

void MeshMakeData::fillBlockDataBegin(const v3s16 &blockpos)
{
	m_blockpos = blockpos;

	v3s16 blockpos_nodes = m_blockpos*MAP_BLOCKSIZE;

	m_vmanip.clear();
	VoxelArea voxel_area(blockpos_nodes - v3s16(1,1,1) * MAP_BLOCKSIZE,
			blockpos_nodes + v3s16(1,1,1) * MAP_BLOCKSIZE*2-v3s16(1,1,1));
	m_vmanip.addArea(voxel_area);
}

void MeshMakeData::fillBlockData(const v3s16 &block_offset, MapNode *data)
{
	v3s16 data_size(MAP_BLOCKSIZE, MAP_BLOCKSIZE, MAP_BLOCKSIZE);
	VoxelArea data_area(v3s16(0,0,0), data_size - v3s16(1,1,1));

	v3s16 bp = m_blockpos + block_offset;
	v3s16 blockpos_nodes = bp * MAP_BLOCKSIZE;
	m_vmanip.copyFrom(data, data_area, v3s16(0,0,0), blockpos_nodes, data_size);
}

void MeshMakeData::fill(MapBlock *block)
{
	fillBlockDataBegin(block->getPos());

	fillBlockData(v3s16(0,0,0), block->getData());

	// Get map for reading neighbor blocks
	Map *map = block->getParent();

	for (const v3s16 &dir : g_26dirs) {
		v3s16 bp = m_blockpos + dir;
		MapBlock *b = map->getBlockNoCreateNoEx(bp);
		if(b)
			fillBlockData(dir, b->getData());
	}
}

void MeshMakeData::fillSingleNode(MapNode *node)
{
	m_blockpos = v3s16(0,0,0);

	v3s16 blockpos_nodes = v3s16(0,0,0);
	VoxelArea area(blockpos_nodes-v3s16(1,1,1)*MAP_BLOCKSIZE,
			blockpos_nodes+v3s16(1,1,1)*MAP_BLOCKSIZE*2-v3s16(1,1,1));
	s32 volume = area.getVolume();
	s32 our_node_index = area.index(1,1,1);

	// Allocate this block + neighbors
	m_vmanip.clear();
	m_vmanip.addArea(area);

	// Fill in data
	MapNode *data = new MapNode[volume];
	for(s32 i = 0; i < volume; i++)
	{
		if (i == our_node_index)
			data[i] = *node;
		else
			data[i] = MapNode(CONTENT_AIR, LIGHT_MAX, 0);
	}
	m_vmanip.copyFrom(data, area, area.MinEdge, area.MinEdge, area.getExtent());
	delete[] data;
}

void MeshMakeData::setCrack(int crack_level, v3s16 crack_pos)
{
	if (crack_level >= 0)
		m_crack_pos_relative = crack_pos - m_blockpos*MAP_BLOCKSIZE;
}

void MeshMakeData::setSmoothLighting(bool smooth_lighting)
{
	m_smooth_lighting = smooth_lighting;
}

/*
	Light and vertex color functions
*/

/*
	Calculate non-smooth lighting at interior of node.
	Single light bank.
*/
static u8 getInteriorLight(enum LightBank bank, MapNode n, s32 increment,
		INodeDefManager *ndef)
{
	u8 light = n.getLight(bank, ndef);

	while(increment > 0)
	{
		light = undiminish_light(light);
		--increment;
	}
	while(increment < 0)
	{
		light = diminish_light(light);
		++increment;
	}

	return decode_light(light);
}

/*
	Calculate non-smooth lighting at interior of node.
	Both light banks.
*/
u16 getInteriorLight(MapNode n, s32 increment, INodeDefManager *ndef)
{
	u16 day = getInteriorLight(LIGHTBANK_DAY, n, increment, ndef);
	u16 night = getInteriorLight(LIGHTBANK_NIGHT, n, increment, ndef);
	return day | (night << 8);
}

/*
	Calculate non-smooth lighting at face of node.
	Single light bank.
*/
static u8 getFaceLight(enum LightBank bank, MapNode n, MapNode n2,
		v3s16 face_dir, INodeDefManager *ndef)
{
	u8 light;
	u8 l1 = n.getLight(bank, ndef);
	u8 l2 = n2.getLight(bank, ndef);
	if(l1 > l2)
		light = l1;
	else
		light = l2;

	// Boost light level for light sources
	u8 light_source = MYMAX(ndef->get(n).light_source,
			ndef->get(n2).light_source);
	if(light_source > light)
		light = light_source;

	return decode_light(light);
}

/*
	Calculate non-smooth lighting at face of node.
	Both light banks.
*/
u16 getFaceLight(MapNode n, MapNode n2, v3s16 face_dir, INodeDefManager *ndef)
{
	u16 day = getFaceLight(LIGHTBANK_DAY, n, n2, face_dir, ndef);
	u16 night = getFaceLight(LIGHTBANK_NIGHT, n, n2, face_dir, ndef);
	return day | (night << 8);
}

/*
	Calculate smooth lighting at the XYZ- corner of p.
	Both light banks
*/
static u16 getSmoothLightCombined(const v3s16 &p,
	const std::array<v3s16,8> &dirs, MeshMakeData *data, bool node_solid)
{
	INodeDefManager *ndef = data->m_client->ndef();

	u16 ambient_occlusion = 0;
	u16 light_count = 0;
	u8 light_source_max = 0;
	u16 light_day = 0;
	u16 light_night = 0;

	auto add_node = [&] (int i) -> const ContentFeatures& {
		MapNode n = data->m_vmanip.getNodeNoExNoEmerge(p + dirs[i]);
		const ContentFeatures &f = ndef->get(n);
		if (f.light_source > light_source_max)
			light_source_max = f.light_source;
		// Check f.solidness because fast-style leaves look better this way
		if (f.param_type == CPT_LIGHT && f.solidness != 2) {
			light_day += decode_light(n.getLightNoChecks(LIGHTBANK_DAY, &f));
			light_night += decode_light(n.getLightNoChecks(LIGHTBANK_NIGHT, &f));
			light_count++;
		} else {
			ambient_occlusion++;
		}
		return f;
	};

	if (node_solid) {
		ambient_occlusion = 3;
		bool corner_obstructed = true;
		for (int i = 0; i < 2; ++i) {
			if (add_node(i).light_propagates)
				corner_obstructed = false;
		}
		add_node(2);
		add_node(3);
		if (corner_obstructed)
			ambient_occlusion++;
		else
			add_node(4);
	} else {
		std::array<bool, 4> obstructed = {{ 1, 1, 1, 1 }};
		add_node(0);
		bool opaque1 = !add_node(1).light_propagates;
		bool opaque2 = !add_node(2).light_propagates;
		bool opaque3 = !add_node(3).light_propagates;
		obstructed[0] = opaque1 && opaque2;
		obstructed[1] = opaque1 && opaque3;
		obstructed[2] = opaque2 && opaque3;
		for (int k = 0; k < 4; ++k) {
			if (obstructed[k])
				ambient_occlusion++;
			else if (add_node(k + 4).light_propagates)
				obstructed[3] = false;
		}
	}

	if (light_count == 0) {
		light_day = light_night = 0;
	} else {
		light_day /= light_count;
		light_night /= light_count;
	}

	// Boost brightness around light sources
	bool skip_ambient_occlusion_day = false;
	if (decode_light(light_source_max) >= light_day) {
		light_day = decode_light(light_source_max);
		skip_ambient_occlusion_day = true;
	}

	bool skip_ambient_occlusion_night = false;
	if(decode_light(light_source_max) >= light_night) {
		light_night = decode_light(light_source_max);
		skip_ambient_occlusion_night = true;
	}

	if (ambient_occlusion > 4) {
		static thread_local const float ao_gamma = rangelim(
			g_settings->getFloat("ambient_occlusion_gamma"), 0.25, 4.0);

		// Table of gamma space multiply factors.
		static const float light_amount[3] = {
			powf(0.75, 1.0 / ao_gamma),
			powf(0.5,  1.0 / ao_gamma),
			powf(0.25, 1.0 / ao_gamma)
		};

		//calculate table index for gamma space multiplier
		ambient_occlusion -= 5;

		if (!skip_ambient_occlusion_day)
			light_day = rangelim(core::round32(
					light_day * light_amount[ambient_occlusion]), 0, 255);
		if (!skip_ambient_occlusion_night)
			light_night = rangelim(core::round32(
					light_night * light_amount[ambient_occlusion]), 0, 255);
	}

	return light_day | (light_night << 8);
}

/*
	Calculate smooth lighting at the given corner of p.
	Both light banks.
	Node at p is solid, and thus the lighting is face-dependent.
*/
u16 getSmoothLightSolid(const v3s16 &p, const v3s16 &face_dir, const v3s16 &corner, MeshMakeData *data)
{
	v3s16 neighbor_offset1, neighbor_offset2;

	/*
	 * face_dir, neighbor_offset1 and neighbor_offset2 define an
	 * orthonormal basis which is used to define the offsets of the 8
	 * surrounding nodes and to differentiate the "distance" (by going only
	 * along directly neighboring nodes) relative to the node at p.
	 * Apart from the node at p, only the 4 nodes which contain face_dir
	 * can contribute light.
	 */
	if (face_dir.X != 0) {
		neighbor_offset1 = v3s16(0, corner.Y, 0);
		neighbor_offset2 = v3s16(0, 0, corner.Z);
	} else if (face_dir.Y != 0) {
		neighbor_offset1 = v3s16(0, 0, corner.Z);
		neighbor_offset2 = v3s16(corner.X, 0, 0);
	} else if (face_dir.Z != 0) {
		neighbor_offset1 = v3s16(corner.X,0,0);
		neighbor_offset2 = v3s16(0,corner.Y,0);
	}

	const std::array<v3s16,8> dirs = {{
		// Always shine light
		neighbor_offset1 + face_dir,
		neighbor_offset2 + face_dir,
		v3s16(0,0,0),
		face_dir,

		// Can be obstructed
		neighbor_offset1 + neighbor_offset2 + face_dir,

		// Do not shine light, only for ambient occlusion
		neighbor_offset1,
		neighbor_offset2,
		neighbor_offset1 + neighbor_offset2
	}};
	return getSmoothLightCombined(p, dirs, data, true);
}

/*
	Calculate smooth lighting at the given corner of p.
	Both light banks.
	Node at p is not solid, and the lighting is not face-dependent.
*/
u16 getSmoothLightTransparent(const v3s16 &p, const v3s16 &corner, MeshMakeData *data)
{
	const std::array<v3s16,8> dirs = {{
		// Always shine light
		v3s16(0,0,0),
		v3s16(corner.X,0,0),
		v3s16(0,corner.Y,0),
		v3s16(0,0,corner.Z),

		// Can be obstructed
		v3s16(corner.X,corner.Y,0),
		v3s16(corner.X,0,corner.Z),
		v3s16(0,corner.Y,corner.Z),
		v3s16(corner.X,corner.Y,corner.Z)
	}};
	return getSmoothLightCombined(p, dirs, data, false);
}

void get_sunlight_color(video::SColorf *sunlight, u32 daynight_ratio){
	f32 rg = daynight_ratio / 1000.0f - 0.04f;
	f32 b = (0.98f * daynight_ratio) / 1000.0f + 0.078f;
	sunlight->r = rg;
	sunlight->g = rg;
	sunlight->b = b;
}

void final_color_blend(video::SColor *result,
		u16 light, u32 daynight_ratio)
{
	video::SColorf dayLight;
	get_sunlight_color(&dayLight, daynight_ratio);
	final_color_blend(result,
		encode_light(light, 0), dayLight);
}

void final_color_blend(video::SColor *result,
		const video::SColor &data, const video::SColorf &dayLight)
{
	static const video::SColorf artificialColor(1.04f, 1.04f, 1.04f);

	video::SColorf c(data);
	f32 n = 1 - c.a;

	f32 r = c.r * (c.a * dayLight.r + n * artificialColor.r) * 2.0f;
	f32 g = c.g * (c.a * dayLight.g + n * artificialColor.g) * 2.0f;
	f32 b = c.b * (c.a * dayLight.b + n * artificialColor.b) * 2.0f;

	// Emphase blue a bit in darker places
	// Each entry of this array represents a range of 8 blue levels
	static const u8 emphase_blue_when_dark[32] = {
		1, 4, 6, 6, 6, 5, 4, 3, 2, 1, 0, 0, 0, 0, 0, 0,
		0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
	};

	b += emphase_blue_when_dark[irr::core::clamp((s32) ((r + g + b) / 3 * 255),
		0, 255) / 8] / 255.0f;

	result->setRed(core::clamp((s32) (r * 255.0f), 0, 255));
	result->setGreen(core::clamp((s32) (g * 255.0f), 0, 255));
	result->setBlue(core::clamp((s32) (b * 255.0f), 0, 255));
}

/*
	Mesh generation helpers
*/

/*
	vertex_dirs: v3s16[4]
*/
static void getNodeVertexDirs(v3s16 dir, v3s16 *vertex_dirs)
{
	/*
		If looked from outside the node towards the face, the corners are:
		0: bottom-right
		1: bottom-left
		2: top-left
		3: top-right
	*/
	if (dir == v3s16(0, 0, 1)) {
		// If looking towards z+, this is the face that is behind
		// the center point, facing towards z+.
		vertex_dirs[0] = v3s16(-1,-1, 1);
		vertex_dirs[1] = v3s16( 1,-1, 1);
		vertex_dirs[2] = v3s16( 1, 1, 1);
		vertex_dirs[3] = v3s16(-1, 1, 1);
	} else if (dir == v3s16(0, 0, -1)) {
		// faces towards Z-
		vertex_dirs[0] = v3s16( 1,-1,-1);
		vertex_dirs[1] = v3s16(-1,-1,-1);
		vertex_dirs[2] = v3s16(-1, 1,-1);
		vertex_dirs[3] = v3s16( 1, 1,-1);
	} else if (dir == v3s16(1, 0, 0)) {
		// faces towards X+
		vertex_dirs[0] = v3s16( 1,-1, 1);
		vertex_dirs[1] = v3s16( 1,-1,-1);
		vertex_dirs[2] = v3s16( 1, 1,-1);
		vertex_dirs[3] = v3s16( 1, 1, 1);
	} else if (dir == v3s16(-1, 0, 0)) {
		// faces towards X-
		vertex_dirs[0] = v3s16(-1,-1,-1);
		vertex_dirs[1] = v3s16(-1,-1, 1);
		vertex_dirs[2] = v3s16(-1, 1, 1);
		vertex_dirs[3] = v3s16(-1, 1,-1);
	} else if (dir == v3s16(0, 1, 0)) {
		// faces towards Y+ (assume Z- as "down" in texture)
		vertex_dirs[0] = v3s16( 1, 1,-1);
		vertex_dirs[1] = v3s16(-1, 1,-1);
		vertex_dirs[2] = v3s16(-1, 1, 1);
		vertex_dirs[3] = v3s16( 1, 1, 1);
	} else if (dir == v3s16(0, -1, 0)) {
		// faces towards Y- (assume Z+ as "down" in texture)
		vertex_dirs[0] = v3s16( 1,-1, 1);
		vertex_dirs[1] = v3s16(-1,-1, 1);
		vertex_dirs[2] = v3s16(-1,-1,-1);
		vertex_dirs[3] = v3s16( 1,-1,-1);
	}
}

static void getNodeTextureCoords(v3f base, const v3f &scale, v3s16 dir, float *u, float *v)
{
	if (dir.X > 0 || dir.Y > 0 || dir.Z < 0)
		base -= scale;
	if (dir == v3s16(0,0,1)) {
		*u = -base.X - 1;
		*v = -base.Y - 1;
	} else if (dir == v3s16(0,0,-1)) {
		*u = base.X + 1;
		*v = -base.Y - 2;
	} else if (dir == v3s16(1,0,0)) {
		*u = base.Z + 1;
		*v = -base.Y - 2;
	} else if (dir == v3s16(-1,0,0)) {
		*u = -base.Z - 1;
		*v = -base.Y - 1;
	} else if (dir == v3s16(0,1,0)) {
		*u = base.X + 1;
		*v = -base.Z - 2;
	} else if (dir == v3s16(0,-1,0)) {
		*u = base.X;
		*v = base.Z;
	}
}

struct FastFace
{
	TileLayer layer;
	video::S3DVertex vertices[4]; // Precalculated vertices
	/*!
	 * The face is divided into two triangles. If this is true,
	 * vertices 0 and 2 are connected, othervise vertices 1 and 3
	 * are connected.
	 */
	bool vertex_0_2_connected;
	u8 layernum;
	bool world_aligned;
};

static void makeFastFace(const TileSpec &tile, u16 li0, u16 li1, u16 li2, u16 li3,
	v3f tp, v3f p, v3s16 dir, v3f scale, std::vector<FastFace> &dest)
{
	// Position is at the center of the cube.
	v3f pos = p * BS;

	float x0 = 0.0f;
	float y0 = 0.0f;
	float w = 1.0f;
	float h = 1.0f;

	v3f vertex_pos[4];
	v3s16 vertex_dirs[4];
	getNodeVertexDirs(dir, vertex_dirs);
	if (tile.world_aligned)
		getNodeTextureCoords(tp, scale, dir, &x0, &y0);

	v3s16 t;
	u16 t1;
	switch (tile.rotation) {
	case 0:
		break;
	case 1: //R90
		t = vertex_dirs[0];
		vertex_dirs[0] = vertex_dirs[3];
		vertex_dirs[3] = vertex_dirs[2];
		vertex_dirs[2] = vertex_dirs[1];
		vertex_dirs[1] = t;
		t1  = li0;
		li0 = li3;
		li3 = li2;
		li2 = li1;
		li1 = t1;
		break;
	case 2: //R180
		t = vertex_dirs[0];
		vertex_dirs[0] = vertex_dirs[2];
		vertex_dirs[2] = t;
		t = vertex_dirs[1];
		vertex_dirs[1] = vertex_dirs[3];
		vertex_dirs[3] = t;
		t1  = li0;
		li0 = li2;
		li2 = t1;
		t1  = li1;
		li1 = li3;
		li3 = t1;
		break;
	case 3: //R270
		t = vertex_dirs[0];
		vertex_dirs[0] = vertex_dirs[1];
		vertex_dirs[1] = vertex_dirs[2];
		vertex_dirs[2] = vertex_dirs[3];
		vertex_dirs[3] = t;
		t1  = li0;
		li0 = li1;
		li1 = li2;
		li2 = li3;
		li3 = t1;
		break;
	case 4: //FXR90
		t = vertex_dirs[0];
		vertex_dirs[0] = vertex_dirs[3];
		vertex_dirs[3] = vertex_dirs[2];
		vertex_dirs[2] = vertex_dirs[1];
		vertex_dirs[1] = t;
		t1  = li0;
		li0 = li3;
		li3 = li2;
		li2 = li1;
		li1 = t1;
		y0 += h;
		h *= -1;
		break;
	case 5: //FXR270
		t = vertex_dirs[0];
		vertex_dirs[0] = vertex_dirs[1];
		vertex_dirs[1] = vertex_dirs[2];
		vertex_dirs[2] = vertex_dirs[3];
		vertex_dirs[3] = t;
		t1  = li0;
		li0 = li1;
		li1 = li2;
		li2 = li3;
		li3 = t1;
		y0 += h;
		h *= -1;
		break;
	case 6: //FYR90
		t = vertex_dirs[0];
		vertex_dirs[0] = vertex_dirs[3];
		vertex_dirs[3] = vertex_dirs[2];
		vertex_dirs[2] = vertex_dirs[1];
		vertex_dirs[1] = t;
		t1  = li0;
		li0 = li3;
		li3 = li2;
		li2 = li1;
		li1 = t1;
		x0 += w;
		w *= -1;
		break;
	case 7: //FYR270
		t = vertex_dirs[0];
		vertex_dirs[0] = vertex_dirs[1];
		vertex_dirs[1] = vertex_dirs[2];
		vertex_dirs[2] = vertex_dirs[3];
		vertex_dirs[3] = t;
		t1  = li0;
		li0 = li1;
		li1 = li2;
		li2 = li3;
		li3 = t1;
		x0 += w;
		w *= -1;
		break;
	case 8: //FX
		y0 += h;
		h *= -1;
		break;
	case 9: //FY
		x0 += w;
		w *= -1;
		break;
	default:
		break;
	}

	for (u16 i = 0; i < 4; i++) {
		vertex_pos[i] = v3f(
				BS / 2 * vertex_dirs[i].X,
				BS / 2 * vertex_dirs[i].Y,
				BS / 2 * vertex_dirs[i].Z
		);
	}

	for (v3f &vpos : vertex_pos) {
		vpos.X *= scale.X;
		vpos.Y *= scale.Y;
		vpos.Z *= scale.Z;
		vpos += pos;
	}

	f32 abs_scale = 1.0f;
	if      (scale.X < 0.999f || scale.X > 1.001f) abs_scale = scale.X;
	else if (scale.Y < 0.999f || scale.Y > 1.001f) abs_scale = scale.Y;
	else if (scale.Z < 0.999f || scale.Z > 1.001f) abs_scale = scale.Z;

	v3f normal(dir.X, dir.Y, dir.Z);

	u16 li[4] = { li0, li1, li2, li3 };
	u16 day[4];
	u16 night[4];

	for (u8 i = 0; i < 4; i++) {
		day[i] = li[i] >> 8;
		night[i] = li[i] & 0xFF;
	}

	bool vertex_0_2_connected = abs(day[0] - day[2]) + abs(night[0] - night[2])
			< abs(day[1] - day[3]) + abs(night[1] - night[3]);

	v2f32 f[4] = {
		core::vector2d<f32>(x0 + w * abs_scale, y0 + h),
		core::vector2d<f32>(x0, y0 + h),
		core::vector2d<f32>(x0, y0),
		core::vector2d<f32>(x0 + w * abs_scale, y0) };

	for (int layernum = 0; layernum < MAX_TILE_LAYERS; layernum++) {
		const TileLayer *layer = &tile.layers[layernum];
		if (layer->texture_id == 0)
			continue;

		// equivalent to dest.push_back(FastFace()) but faster
		dest.emplace_back();
		FastFace& face = *dest.rbegin();

		for (u8 i = 0; i < 4; i++) {
			video::SColor c = encode_light(li[i], tile.emissive_light);
			if (!tile.emissive_light)
				applyFacesShading(c, normal);

			face.vertices[i] = video::S3DVertex(vertex_pos[i], normal, c, f[i]);
		}

		/*
		 Revert triangles for nicer looking gradient if the
		 brightness of vertices 1 and 3 differ less than
		 the brightness of vertices 0 and 2.
		 */
		face.vertex_0_2_connected = vertex_0_2_connected;

		face.layer = *layer;
		face.layernum = layernum;

		face.world_aligned = tile.world_aligned;
	}
}

/*
	Nodes make a face if contents differ and solidness differs.
	Return value:
		0: No face
		1: Face uses m1's content
		2: Face uses m2's content
	equivalent: Whether the blocks share the same face (eg. water and glass)

	TODO: Add 3: Both faces drawn with backface culling, remove equivalent
*/
static u8 face_contents(content_t m1, content_t m2, bool *equivalent,
		INodeDefManager *ndef)
{
	*equivalent = false;

	if (m1 == m2 || m1 == CONTENT_IGNORE || m2 == CONTENT_IGNORE)
		return 0;

	const ContentFeatures &f1 = ndef->get(m1);
	const ContentFeatures &f2 = ndef->get(m2);

	// Contents don't differ for different forms of same liquid
	if (f1.sameLiquid(f2))
		return 0;

	u8 c1 = f1.solidness;
	u8 c2 = f2.solidness;

	if (c1 == c2)
		return 0;

	if (c1 == 0)
		c1 = f1.visual_solidness;
	else if (c2 == 0)
		c2 = f2.visual_solidness;

	if (c1 == c2) {
		*equivalent = true;
		// If same solidness, liquid takes precense
		if (f1.isLiquid())
			return 1;
		if (f2.isLiquid())
			return 2;
	}

	if (c1 > c2)
		return 1;

	return 2;
}

/*
	Gets nth node tile (0 <= n <= 5).
*/
void getNodeTileN(MapNode mn, v3s16 p, u8 tileindex, MeshMakeData *data, TileSpec &tile)
{
	INodeDefManager *ndef = data->m_client->ndef();
	const ContentFeatures &f = ndef->get(mn);
	tile = f.tiles[tileindex];
	bool has_crack = p == data->m_crack_pos_relative;
	for (TileLayer &layer : tile.layers) {
		if (layer.texture_id == 0)
			continue;
		if (!layer.has_color)
			mn.getColor(f, &(layer.color));
		// Apply temporary crack
		if (has_crack)
			layer.material_flags |= MATERIAL_FLAG_CRACK;
	}
}

/*
	Gets node tile given a face direction.
*/
void getNodeTile(MapNode mn, v3s16 p, v3s16 dir, MeshMakeData *data, TileSpec &tile)
{
	INodeDefManager *ndef = data->m_client->ndef();

	// Direction must be (1,0,0), (-1,0,0), (0,1,0), (0,-1,0),
	// (0,0,1), (0,0,-1) or (0,0,0)
	assert(dir.X * dir.X + dir.Y * dir.Y + dir.Z * dir.Z <= 1);

	// Convert direction to single integer for table lookup
	//  0 = (0,0,0)
	//  1 = (1,0,0)
	//  2 = (0,1,0)
	//  3 = (0,0,1)
	//  4 = invalid, treat as (0,0,0)
	//  5 = (0,0,-1)
	//  6 = (0,-1,0)
	//  7 = (-1,0,0)
	u8 dir_i = ((dir.X + 2 * dir.Y + 3 * dir.Z) & 7) * 2;

	// Get rotation for things like chests
	u8 facedir = mn.getFaceDir(ndef);

	static const u16 dir_to_tile[24 * 16] =
	{
		// 0     +X    +Y    +Z           -Z    -Y    -X   ->   value=tile,rotation
		   0,0,  2,0 , 0,0 , 4,0 ,  0,0,  5,0 , 1,0 , 3,0 ,  // rotate around y+ 0 - 3
		   0,0,  4,0 , 0,3 , 3,0 ,  0,0,  2,0 , 1,1 , 5,0 ,
		   0,0,  3,0 , 0,2 , 5,0 ,  0,0,  4,0 , 1,2 , 2,0 ,
		   0,0,  5,0 , 0,1 , 2,0 ,  0,0,  3,0 , 1,3 , 4,0 ,

		   0,0,  2,3 , 5,0 , 0,2 ,  0,0,  1,0 , 4,2 , 3,1 ,  // rotate around z+ 4 - 7
		   0,0,  4,3 , 2,0 , 0,1 ,  0,0,  1,1 , 3,2 , 5,1 ,
		   0,0,  3,3 , 4,0 , 0,0 ,  0,0,  1,2 , 5,2 , 2,1 ,
		   0,0,  5,3 , 3,0 , 0,3 ,  0,0,  1,3 , 2,2 , 4,1 ,

		   0,0,  2,1 , 4,2 , 1,2 ,  0,0,  0,0 , 5,0 , 3,3 ,  // rotate around z- 8 - 11
		   0,0,  4,1 , 3,2 , 1,3 ,  0,0,  0,3 , 2,0 , 5,3 ,
		   0,0,  3,1 , 5,2 , 1,0 ,  0,0,  0,2 , 4,0 , 2,3 ,
		   0,0,  5,1 , 2,2 , 1,1 ,  0,0,  0,1 , 3,0 , 4,3 ,

		   0,0,  0,3 , 3,3 , 4,1 ,  0,0,  5,3 , 2,3 , 1,3 ,  // rotate around x+ 12 - 15
		   0,0,  0,2 , 5,3 , 3,1 ,  0,0,  2,3 , 4,3 , 1,0 ,
		   0,0,  0,1 , 2,3 , 5,1 ,  0,0,  4,3 , 3,3 , 1,1 ,
		   0,0,  0,0 , 4,3 , 2,1 ,  0,0,  3,3 , 5,3 , 1,2 ,

		   0,0,  1,1 , 2,1 , 4,3 ,  0,0,  5,1 , 3,1 , 0,1 ,  // rotate around x- 16 - 19
		   0,0,  1,2 , 4,1 , 3,3 ,  0,0,  2,1 , 5,1 , 0,0 ,
		   0,0,  1,3 , 3,1 , 5,3 ,  0,0,  4,1 , 2,1 , 0,3 ,
		   0,0,  1,0 , 5,1 , 2,3 ,  0,0,  3,1 , 4,1 , 0,2 ,

		   0,0,  3,2 , 1,2 , 4,2 ,  0,0,  5,2 , 0,2 , 2,2 ,  // rotate around y- 20 - 23
		   0,0,  5,2 , 1,3 , 3,2 ,  0,0,  2,2 , 0,1 , 4,2 ,
		   0,0,  2,2 , 1,0 , 5,2 ,  0,0,  4,2 , 0,0 , 3,2 ,
		   0,0,  4,2 , 1,1 , 2,2 ,  0,0,  3,2 , 0,3 , 5,2

	};
	u16 tile_index = facedir * 16 + dir_i;
	getNodeTileN(mn, p, dir_to_tile[tile_index], data, tile);
	tile.rotation = tile.world_aligned ? 0 : dir_to_tile[tile_index + 1];
}

static void getTileInfo(
		// Input:
		MeshMakeData *data,
		const v3s16 &p,
		const v3s16 &face_dir,
		// Output:
		bool &makes_face,
		v3s16 &p_corrected,
		v3s16 &face_dir_corrected,
		u16 *lights,
		TileSpec &tile
	)
{
	VoxelManipulator &vmanip = data->m_vmanip;
	INodeDefManager *ndef = data->m_client->ndef();
	v3s16 blockpos_nodes = data->m_blockpos * MAP_BLOCKSIZE;

	const MapNode &n0 = vmanip.getNodeRefUnsafe(blockpos_nodes + p);

	// Don't even try to get n1 if n0 is already CONTENT_IGNORE
	if (n0.getContent() == CONTENT_IGNORE) {
		makes_face = false;
		return;
	}

	const MapNode &n1 = vmanip.getNodeRefUnsafeCheckFlags(blockpos_nodes + p + face_dir);

	if (n1.getContent() == CONTENT_IGNORE) {
		makes_face = false;
		return;
	Commit message (Collapse)	Author	Age
*	Add option to set water opaque (mainly for stylistic choice)	Perttu Ahola	2011-11-03
\|
*	Improve rendering and fix tiling in mesh generation	Perttu Ahola	2011-10-18
\|
*	Automate texture listing for texture atlas making	Perttu Ahola	2011-10-18
\|
*	Header file tweaking; mainly for speed	Perttu Ahola	2011-10-12
\|
*	Merge remote-tracking branch 'marktraceur/master'	Perttu Ahola	2011-09-26
\|\
\| *	Fixed merge issues with saplings, ready to pull now!	Mark Holmquist	2011-09-23
\| \|
\| *	Adding (most) of the sapling functionality. It has yet to work, since ↵	Mark Holmquist	2011-09-23
\| \| \| \| \| \| \| \|	MEET_OTHER was not implemented at the time of this commit. Hopefully it will work when merged with celeron's latest.
* \|	Merge branch 'view_bobbing_and_vielded_tool'	Perttu Ahola	2011-09-26
\|\ \
\| * \|	Wielded tool updates, leaves and glass work now	Kahrl	2011-09-19
\| \| \|
\| * \|	Removed unused camera_position and camera_direction fields from Client. ↵	Kahrl	2011-09-07
\| \| \| \| \| \| \| \| \| \| \| \|	Moved ClientEnvironment::drawPostFx to ClientMap::renderPostFx -- this will make the camera management classes easier to write, as ClientMap already knows the camera position but ClientEnvironment doesn't and has to be told about it. This also eliminates the need for Client::getEnv(). Made the post effect color a content feature defined in content_mapnode.h.
* \| \|	added locking chests - clean patch	darkrose	2011-09-22
\| \|/ \|/\|
* \|	Removed Spaces	sfan5	2011-09-11
\| \|
* \|	Added Apple Trees	sfan5	2011-09-11
\|/
*	Add note about trans_table_19.	Perttu Ahola	2011-09-07
\|
*	Fix some texture stuff: remove item_fence.png, use fence.png, remove ↵	Perttu Ahola	2011-09-06
\| \| \| \|	inexisting cactus.png from texture atlas (replace with nothing because cactus is rare)
*	Lava is now better visible inside water. (a crappy hack)	Perttu Ahola	2011-08-23
\|
*	Viscous fluids	Giuseppe Bilotta	2011-08-16
\|
*	Non-vertex-alpha texture material for lava	Perttu Ahola	2011-08-15
\|
*	Added #define WATER_ALPHA in content_mapnode.cpp	Perttu Ahola	2011-08-15
\|
*	tuned lava/universal damage code	Perttu Ahola	2011-08-15
\|
*	lava!	Perttu Ahola	2011-08-15
\|
*	* less clumsy ladder texture, based on rails	Nils Dagsson Moskopp	2011-08-01
\|
*	Ladders implemented!	Mark Holmquist	2011-08-01
\|
*	Added ladders--they don't have any use yet, though	Mark Holmquist	2011-08-01
\|
*	Added MaterialItem conversion from old content type namespace to new	Perttu Ahola	2011-07-31
\|
*	Fixed handling of inventory in creative mode (normal inventory is not ↵	Perttu Ahola	2011-07-30
\| \| \| \|	trashed anymore), fixed mese pick speed, added some forgotten stuff
*	Fixed issue #15: Glass blocks a lot of light	Perttu Ahola	2011-07-23
\|
*	merged jungle and bluish shadows	Perttu Ahola	2011-07-23
\|\
\| *	Jungle biome/whatever thing	Perttu Ahola	2011-07-23
\| \|
* \|	merged the content type extension and delta	Perttu Ahola	2011-07-23
\|\\|
\| *	Merge branch 'upstream/master'	Nils Dagsson Moskopp	2011-07-14
\| \|\ \| \| \| \| \| \| \| \| \| \| \| \| \| \| \|	Conflicts: data/oerkki1.png src/client.cpp
\| * \|	* possibly improved water flow, by flyx86	Nils Dagsson Moskopp	2011-07-14
\| \| \| \| \| \| \| \| \| \| \| \| \| \| \| \| \| \|	- When flowing liquid starts to flow down, it stops contributing to its neighboring nodes' liquid level (possibly transforming it back to air) - Flowing liquid turns into a source if there are at least 2 adjacent liquid source nodes - If a new liquid flow reaches existing flowing liquid, the existing liquid is now updated properly.
\| * \|	Merge branch 'master' of https://github.com/erlehmann/minetest-delta.git ↵	Sebastian Rühl	2011-06-26
\| \| \| \| \| \| \| \| \| \| \| \| \| \| \| \| \| \| \| \| \| \| \| \| \| \| \| \| \| \| \| \| \| \| \| \| \| \| \| \| \| \| \| \| \| \| \| \| \| \| \| \| \| \| \| \| \| \| \| \| \| \| \|	into upstream_merge Conflicts: .gitignore CMakeLists.txt data/heart.png src/CMakeLists.txt src/game.cpp src/guiMainMenu.cpp src/inventory.cpp src/map.cpp src/mapblock.cpp src/mapnode.cpp src/mapnode.h src/materials.cpp src/server.cpp Signed-off-by: Sebastian Rühl <bahamada_basti@yahoo.de>
* \| \|	extended content-type range	Perttu Ahola	2011-07-23
\| \|/ \|/\|
* \|	initial steps in doing content type extension	Perttu Ahola	2011-07-02
\|/
*	New map generator added (and SQLite, messed up the commits at that time...) ↵	Perttu Ahola	2011-06-25
\| \| \| \|	(import from temporary git repo)
*	Created and moved stuff to content_nodemeta.{h,cpp}	Perttu Ahola	2011-06-18
\|
*	Moved some mapnode content stuff from mapnode.{h,cpp} and digging property ↵	Perttu Ahola	2011-06-17
	stuff from material.cpp to content_mapnode.{h,cpp}