/*
Part of Minetest-c55
Copyright (C) 2011 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.
*/

/*
	A quick messy implementation of terrain rendering for a long
	distance according to map seed
*/

#include "farmesh.h"

#include "constants.h"
#include "debug.h"
#include "noise.h"
#include "map.h"
#include "client.h"
#include "tile.h" // ITextureSource
#include "clientmap.h"

#include "mapgen.h" // Shouldn't really be done this way

FarMesh::FarMesh(
		scene::ISceneNode* parent,
		scene::ISceneManager* mgr,
		s32 id,
		u64 seed,
		Client *client
):
	scene::ISceneNode(parent, mgr, id),
	m_seed(seed),
	m_camera_pos(0,0),
	m_time(0),
	m_client(client),
	m_render_range(20*MAP_BLOCKSIZE)
{
	dstream<<__FUNCTION_NAME<<std::endl;
	
	//video::IVideoDriver* driver = mgr->getVideoDriver();

	m_materials[0].setFlag(video::EMF_LIGHTING, false);
	m_materials[0].setFlag(video::EMF_BACK_FACE_CULLING, true);
	//m_materials[0].setFlag(video::EMF_BACK_FACE_CULLING, false);
	m_materials[0].setFlag(video::EMF_BILINEAR_FILTER, false);
	m_materials[0].setFlag(video::EMF_FOG_ENABLE, false);
	//m_materials[0].setFlag(video::EMF_ANTI_ALIASING, true);
	//m_materials[0].MaterialType = video::EMT_TRANSPARENT_VERTEX_ALPHA;
	m_materials[0].setFlag(video::EMF_FOG_ENABLE, true);
	
	m_materials[1].setFlag(video::EMF_LIGHTING, false);
	m_materials[1].setFlag(video::EMF_BACK_FACE_CULLING, false);
	m_materials[1].setFlag(video::EMF_BILINEAR_FILTER, false);
	m_materials[1].setFlag(video::EMF_FOG_ENABLE, false);
	m_materials[1].setTexture(0, client->tsrc()->getTextureRaw("treeprop.png"));
	m_materials[1].MaterialType = video::EMT_TRANSPARENT_ALPHA_CHANNEL_REF;
	m_materials[1].setFlag(video::EMF_FOG_ENABLE, true);

	m_box = core::aabbox3d<f32>(-BS*1000000,-BS*31000,-BS*1000000,
			BS*1000000,BS*31000,BS*1000000);

}

FarMesh::~FarMesh()
{
	dstream<<__FUNCTION_NAME<<std::endl;
}

u32 FarMesh::getMaterialCount() const
{
	return FARMESH_MATERIAL_COUNT;
}

video::SMaterial& FarMesh::getMaterial(u32 i)
{
	return m_materials[i];
}
	

void FarMesh::OnRegisterSceneNode()
{
	if(IsVisible)
	{
		//SceneManager->registerNodeForRendering(this, scene::ESNRP_TRANSPARENT);
		SceneManager->registerNodeForRendering(this, scene::ESNRP_SOLID);
		//SceneManager->registerNodeForRendering(this, scene::ESNRP_SKY_BOX);
	}

	ISceneNode::OnRegisterSceneNode();
}

#define MYROUND(x) (x > 0.0 ? (int)x : (int)x - 1)

// Temporary hack
struct HeightPoint
{
	float gh; // ground height
	float ma; // mud amount
	float have_sand;
	float tree_amount;
};
core::map<v2s16, HeightPoint> g_heights;

HeightPoint ground_height(u64 seed, v2s16 p2d)
{
	core::map<v2s16, HeightPoint>::Node *n = g_heights.find(p2d);
	if(n)
		return n->getValue();
	HeightPoint hp;
	s16 level = Mapgen::find_ground_level_from_noise(seed, p2d, 3);
	hp.gh = (level-4)*BS;
	hp.ma = (4)*BS;
	/*hp.gh = BS*base_rock_level_2d(seed, p2d);
	hp.ma = BS*get_mud_add_amount(seed, p2d);*/
	hp.have_sand = Mapgen::get_have_beach(seed, p2d);
	if(hp.gh > BS*WATER_LEVEL)
		hp.tree_amount = Mapgen::tree_amount_2d(seed, p2d);
	else
		hp.tree_amount = 0;
	// No mud has been added if mud amount is less than 1
	if(hp.ma < 1.0*BS)
		hp.ma = 0.0;
	//hp.gh -= BS*3; // Lower a bit so that it is not that much in the way
	g_heights[p2d] = hp;
	return hp;
}

void FarMesh::render()
{
	video::IVideoDriver* driver = SceneManager->getVideoDriver();

	/*if(SceneManager->getSceneNodeRenderPass() != scene::ESNRP_TRANSPARENT)
		return;*/
	if(SceneManager->getSceneNodeRenderPass() != scene::ESNRP_SOLID)
		return;
	/*if(SceneManager->getSceneNodeRenderPass() != scene::ESNRP_SKY_BOX)
		return;*/

	driver->setTransform(video::ETS_WORLD, AbsoluteTransformation);
	
	//const s16 grid_radius_i = 12;
	//const float grid_size = BS*50;
	const s16 grid_radius_i = m_render_range/MAP_BLOCKSIZE;
	const float grid_size = BS*MAP_BLOCKSIZE;
	const v2f grid_speed(-BS*0, 0);
	
	// Position of grid noise origin in world coordinates
	v2f world_grid_origin_pos_f(0,0);
	// Position of grid noise origin from the camera
	v2f grid_origin_from_camera_f = world_grid_origin_pos_f - m_camera_pos;
	// The center point of drawing in the noise
	v2f center_of_drawing_in_noise_f = -grid_origin_from_camera_f;
	// The integer center point of drawing in the noise
	v2s16 center_of_drawing_in_noise_i(
		MYROUND(center_of_drawing_in_noise_f.X / grid_size),
		MYROUND(center_of_drawing_in_noise_f.Y / grid_size)
	);
	// The world position of the integer center point of drawing in the noise
	v2f world_center_of_drawing_in_noise_f = v2f(
		center_of_drawing_in_noise_i.X * grid_size,
		center_of_drawing_in_noise_i.Y * grid_size
	) + world_grid_origin_pos_f;

	for(s16 zi=-grid_radius_i; zi<grid_radius_i; zi++)
	for(s16 xi=-grid_radius_i; xi<grid_radius_i; xi++)
	{
		/*// Don't draw very close to player
		s16 dd = 3;
		if(zi > -dd && zi < dd && xi > -dd && xi < dd)
			continue;*/

		v2s16 p_in_noise_i(
			xi+center_of_drawing_in_noise_i.X,
			zi+center_of_drawing_in_noise_i.Y
		);
		
		// If sector was drawn, don't draw it this way
		if(m_client->m_env.getClientMap().sectorWasDrawn(p_in_noise_i))
			continue;

		/*if((p_in_noise_i.X + p_in_noise_i.Y)%2==0)
			continue;*/
		/*if((p_in_noise_i.X/2 + p_in_noise_i.Y/2)%2==0)
			continue;*/

		v2f p0 = v2f(xi,zi)*grid_size + world_center_of_drawing_in_noise_f;
		
		/*double noise[4];
		double d = 100*BS;
		noise[0] = d*noise2d_perlin(
				(float)(p_in_noise_i.X+0)*grid_size/BS/100,
				(float)(p_in_noise_i.Y+0)*grid_size/BS/100,
				m_seed, 3, 0.5);
		
		noise[1] = d*noise2d_perlin(
				(float)(p_in_noise_i.X+0)*grid_size/BS/100,
				(float)(p_in_noise_i.Y+1)*grid_size/BS/100,
				m_seed, 3, 0.5);
		
		noise[2] = d*noise2d_perlin(
				(float)(p_in_noise_i.X+1)*grid_size/BS/100,
				(float)(p_in_noise_i.Y+1)*grid_size/BS/100,
				m_seed, 3, 0.5);
		
		noise[3] = d*noise2d_perlin(
				(float)(p_in_noise_i.X+1)*grid_size/BS/100,
				(float)(p_in_noise_i.Y+0)*grid_size/BS/100,
				m_seed, 3, 0.5);*/
		
		HeightPoint hps[5];
		hps[0] = ground_height(m_seed, v2s16(
				(p_in_noise_i.X+0)*grid_size/BS,
				(p_in_noise_i.Y+0)*grid_size/BS));
		hps[1] = ground_height(m_seed, v2s16(
				(p_in_noise_i.X+0)*grid_size/BS,
				(p_in_noise_i.Y+1)*grid_size/BS));
		hps[2] = ground_height(m_seed, v2s16(
				(p_in_noise_i.X+1)*grid_size/BS,
				(p_in_noise_i.Y+1)*grid_size/BS));
		hps[3] = ground_height(m_seed, v2s16(
				(p_in_noise_i.X+1)*grid_size/BS,
				(p_in_noise_i.Y+0)*grid_size/BS));
		v2s16 centerpoint(
				(p_in_noise_i.X+0)*grid_size/BS+MAP_BLOCKSIZE/2,
				(p_in_noise_i.Y+0)*grid_size/BS+MAP_BLOCKSIZE/2);
		hps[4] = ground_height(m_seed, centerpoint);
		
		float noise[5];
		float h_min = BS*65535;
		float h_max = -BS*65536;
		float ma_avg = 0;
		float h_avg = 0;
		u32 have_sand_count = 0;
		float tree_amount_avg = 0;
		for(u32 i=0; i<5; i++)
		{
			noise[i] = hps[i].gh + hps[i].ma;
			if(noise[i] < h_min)
				h_min = noise[i];
			if(noise[i] > h_max)
				h_max = noise[i];
			ma_avg += hps[i].ma;
			h_avg += noise[i];
			if(hps[i].have_sand)
				have_sand_count++;
			tree_amount_avg += hps[i].tree_amount;
		}
		ma_avg /= 5.0;
		h_avg /= 5.0;
		tree_amount_avg /= 5.0;

		float steepness = (h_max - h_min)/grid_size;
		
		float light_f = noise[0]+noise[1]-noise[2]-noise[3];
		light_f /= 100;
		if(light_f < -1.0) light_f = -1.0;
		if(light_f > 1.0) light_f = 1.0;
		//light_f += 1.0;
		//light_f /= 2.0;
		
		v2f p1 = p0 + v2f(1,1)*grid_size;
		
		bool ground_is_sand = false;
		bool ground_is_rock = false;
		bool ground_is_mud = false;
		video::SColor c;
		// Detect water
		if(h_avg < WATER_LEVEL*BS && h_max < (WATER_LEVEL+5)*BS)
		{
			//c = video::SColor(255,59,86,146);
			//c = video::SColor(255,82,120,204);
			c = video::SColor(255,74,105,170);

			/*// Set to water level
			for(u32 i=0; i<4; i++)
			{
				if(noise[i] < BS*WATER_LEVEL)
					noise[i] = BS*WATER_LEVEL;
			}*/
			light_f = 0;
		}
		// Steep cliffs
		else if(steepness > 2.0)
		{
			c = video::SColor(255,128,128,128);
			ground_is_rock = true;
		}
		// Basic ground
		else
		{
			if(ma_avg < 2.0*BS)
			{
				c = video::SColor(255,128,128,128);
				ground_is_rock = true;
			}
			else
			{
				if(h_avg <= 2.5*BS && have_sand_count >= 2)
				{
					c = video::SColor(255,210,194,156);
					ground_is_sand = true;
				}
				else
				{
					/*// Trees if there are over 0.01 trees per MapNode
					if(tree_amount_avg > 0.01)
						c = video::SColor(255,50,128,50);
					else
						c = video::SColor(255,107,134,51);*/
					c = video::SColor(255,107,134,51);
					ground_is_mud = true;
				}
			}
		}
		
		// Set to water level
		for(u32 i=0; i<4; i++)
		{
			if(noise[i] < BS*WATER_LEVEL)
				noise[i] = BS*WATER_LEVEL;
		}

		float b = m_brightness + light_f*0.1*m_brightness;
		if(b < 0) b = 0;
		if(b > 2) b = 2;
		
		c = video::SColor(255, b*c.getRed(), b*c.getGreen(), b*c.getBlue());
		
		driver->setMaterial(m_materials[0]);

		video::S3DVertex vertices[4] =
		{
			video::S3DVertex(p0.X,noise[0],p0.Y, 0,0,0, c, 0,1),
			video::S3DVertex(p0.X,noise[1],p1.Y, 0,0,0, c, 1,1),
			video::S3DVertex(p1.X,noise[2],p1.Y, 0,0,0, c, 1,0),
			video::S3DVertex(p1.X,noise[3],p0.Y, 0,0,0, c, 0,0),
		};
		u16 indices[] = {0,1,2,2,3,0};
		driver->drawVertexPrimitiveList(vertices, 4, indices, 2,
				video::EVT_STANDARD, scene::EPT_TRIANGLES, video::EIT_16BIT);

		// Add some trees if appropriate
		if(tree_amount_avg >= 0.0065 && steepness < 1.4
				&& ground_is_mud == true)
		{
			driver->setMaterial(m_materials[1]);
			
			float b = m_brightness;
			c = video::SColor(255, b*255, b*255, b*255);
			
			{
				video::S3DVertex vertices[4] =
				{
					video::S3DVertex(p0.X,noise[0],p0.Y,
							0,0,0, c, 0,1),
					video::S3DVertex(p0.X,noise[0]+BS*MAP_BLOCKSIZE,p0.Y,
							0,0,0, c, 0,0),
					video::S3DVertex(p1.X,noise[2]+BS*MAP_BLOCKSIZE,p1.Y,
							0,0,0, c, 1,0),
					video::S3DVertex(p1.X,noise[2],p1.Y,
							0,0,0, c, 1,1),
				};
				u16 indices[] = {0,1,2,2,3,0};
				driver->drawVertexPrimitiveList(vertices, 4, indices, 2,
						video::EVT_STANDARD, scene::EPT_TRIANGLES,
						video::EIT_16BIT);
			}
			{
				video::S3DVertex vertices[4] =
				{
					video::S3DVertex(p1.X,noise[3],p0.Y,
							0,0,0, c, 0,1),
					video::S3DVertex(p1.X,noise[3]+BS*MAP_BLOCKSIZE,p0.Y,
							0,0,0, c, 0,0),
					video::S3DVertex(p0.X,noise[1]+BS*MAP_BLOCKSIZE,p1.Y,
							0,0,0, c, 1,0),
					video::S3DVertex(p0.X,noise[1],p1.Y,
							0,0,0, c, 1,1),
				};
				u16 indices[] = {0,1,2,2,3,0};
				driver->drawVertexPrimitiveList(vertices, 4, indices, 2,
						video::EVT_STANDARD, scene::EPT_TRIANGLES,
						video::EIT_16BIT);
			}
		}
	}

	//driver->clearZBuffer();
}

void FarMesh::step(float dtime)
{
	m_time += dtime;
}

void FarMesh::update(v2f camera_p, float brightness, s16 render_range)
{
	m_camera_pos = camera_p;
	m_brightness = brightness;
	m_render_range = render_range;
}