/* This file is part of the Spring engine (GPL v2 or later), see LICENSE.html */


#include "System/TdfParser.h"

#include <cassert>
#include <cstring>
#include <deque>

#include "TerrainBase.h"
#include "TerrainNode.h"
#include "Textures.h"
#include "Map/SM3/Plane.h"
#include "Rendering/Textures/Bitmap.h"
#include "System/FileSystem/FileSystem.h"
#include "System/float3.h"
#if       defined(TERRAIN_USE_IL)
#include <IL/il.h>
#endif // defined(TERRAIN_USE_IL)

namespace terrain {

	void SetTexCoordGen(float* tgv)
	{
		glTexGeni(GL_S, GL_TEXTURE_GEN_MODE, GL_OBJECT_LINEAR);
		glTexGeni(GL_T, GL_TEXTURE_GEN_MODE, GL_OBJECT_LINEAR);

		Plane s(tgv[0], 0, 0, tgv[2]);
		glTexGenfv(GL_S, GL_OBJECT_PLANE, (float*)&s);
		Plane t(0, 0, tgv[1], tgv[3]);
		glTexGenfv(GL_T, GL_OBJECT_PLANE, (float*)&t);

		glEnable(GL_TEXTURE_GEN_S);
		glEnable(GL_TEXTURE_GEN_T);
	}

//-----------------------------------------------------------------------
// Texturing objects
//-----------------------------------------------------------------------

	BaseTexture::BaseTexture()
		: id(0)
		, tilesize(10.0f, 10.0f)
	{
	}

	BaseTexture::~BaseTexture()
	{
		if (id) {
			glDeleteTextures(1, &id);
			id = 0;
		}
	}

	void BaseTexture::CalcTexGenVector(float* v)
	{
		v[0] = 1.0f / (SquareSize * tilesize.x);
		v[1] = 1.0f / (SquareSize * tilesize.y);
		v[2] = v[3] = 0.0f;
	}

	void BaseTexture::SetupTexGen()
	{
		float tgv[4];
		CalcTexGenVector(tgv);

		Plane s(tgv[0], 0, 0, tgv[2]);
		glTexGenfv(GL_S, GL_OBJECT_PLANE, (float*)&s);
		Plane t(0, 0, tgv[1], tgv[3]);
		glTexGenfv(GL_T, GL_OBJECT_PLANE, (float*)&t);
	}

	TiledTexture::TiledTexture()
	{}

	TiledTexture::~TiledTexture()
	{}

	void TiledTexture::Load(const std::string& name, const std::string& section, ILoadCallback* cb, const TdfParser* tdf, bool isBumpmap)
	{
		this->name = name;

		tilesize.x = tilesize.y = atof(tdf->SGetValueDef("10", section + "\\Tilesize").c_str());

		std::string texture;
		if (isBumpmap) {
			if (!tdf->SGetValue(texture, section + "\\Bumpmap"))
				return;

			this->name += "_BM";
		} else {
			if (!tdf->SGetValue(texture, section + "\\File"))
				throw content_error("Texture " + section + " has no image file.");
		}

		if (cb) cb->PrintMsg("    loading %s %s from %s...", isBumpmap ? "bumpmap" : "texture", name.c_str(), texture.c_str());
		id = LoadTexture(texture);
	}

	TiledTexture* TiledTexture::CreateFlatBumpmap()
	{
		TiledTexture* tt = new TiledTexture;
		glGenTextures(1, &tt->id);
		glBindTexture(GL_TEXTURE_2D, tt->id);
		glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
		glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
		uchar img[3] = { 127, 127, 255 };
		glTexImage2D(GL_TEXTURE_2D,0, 3, 1, 1, 0,GL_RGB, GL_UNSIGNED_BYTE, img);
		tt->name = "_flatbm";
		return tt;
	}

	Blendmap::Blendmap()
		: generatorInfo(NULL)
		, image(NULL)
		, curAreaResult(AlphaImage::AREA_ONE)
	{
	}

	Blendmap::~Blendmap()
	{
		delete generatorInfo;
	}

	void Blendmap::Load(const std::string& name, const std::string& section, Heightmap* heightmap, ILoadCallback* cb, const TdfParser* tdf)
	{
		// Create blendmap
		this->name = name;
		tilesize.x = heightmap->w;
		tilesize.y = heightmap->h;

		// Is the blendmap generated or loaded from a file?
		std::string blendmapImg;
		tdf->GetDef(blendmapImg, std::string(), section + "\\File");
		bool generateBlendmap = blendmapImg.empty();
		if (generateBlendmap) {
			// Load blendfactor function parameters
			GeneratorInfo* gi = generatorInfo = new GeneratorInfo;
			gi->coverage = atof(tdf->SGetValueDef("1", section + "\\Coverage").c_str());
			gi->noise = atof(tdf->SGetValueDef("0", section + "\\Noise").c_str());
			gi->minSlope = atof(tdf->SGetValueDef("0", section + "\\MinSlope").c_str());
			gi->maxSlope = atof(tdf->SGetValueDef("1", section + "\\MaxSlope").c_str());
			gi->minSlopeFuzzy = atof(tdf->SGetValueDef("0", section + "\\MinSlopeFuzzy").c_str());
			gi->maxSlopeFuzzy = atof(tdf->SGetValueDef("0", section + "\\MaxSlopeFuzzy").c_str());
			gi->maxHeight = atof(tdf->SGetValueDef("1.01", section + "\\MaxHeight").c_str());
			gi->minHeight = atof(tdf->SGetValueDef("-0.01", section + "\\MinHeight").c_str());
			gi->maxHeightFuzzy = atof(tdf->SGetValueDef("0", section + "\\MaxHeightFuzzy").c_str());
			gi->minHeightFuzzy = atof(tdf->SGetValueDef("0", section + "\\MinHeightFuzzy").c_str());

			int generatorLOD = atoi(tdf->SGetValueDef("0", section + "\\GeneratorLOD").c_str());

			float hmScale = atof(tdf->SGetValueDef("1000", "map\\terrain\\HeightScale").c_str());
			float hmOffset = atof(tdf->SGetValueDef("0", "map\\terrain\\HeightOffset").c_str());

			if (cb) cb->PrintMsg("    generating %s...", name.c_str());
			Generate(heightmap, generatorLOD, hmScale, hmOffset);
		}
		else { // Load blendmap from file
			CBitmap bitmap;
			if (!bitmap.LoadGrayscale(blendmapImg))
				throw std::runtime_error("Failed to load blendmap image " + blendmapImg);

			if (cb) cb->PrintMsg("    loading blendmap %s from %s...", name.c_str(), blendmapImg.c_str());

			image = new AlphaImage;
			image->CopyFromBitmap(bitmap);
		}
	}

	static void BlendmapFilter(AlphaImage* img)
	{
		float* nd = new float[img->w*img->h];

		//3.95f*(x-.5f)^3+.5

		for (int y=0;y<img->h;y++) {
			for (int x=0;x<img->w;x++) {
				int l=x?x-1:x;
				int r=x<img->w-1?x+1:x;
				int t=y?y-1:y;
				int b=y<img->h-1?y+1:y;

				float result = 0.0f;

				result += img->at(l,t);
				result += img->at(x,t);
				result += img->at(r,t);

				result += img->at(l,y);
				//result += img->at(x,y);
				result += img->at(r,y);

				result += img->at(l,b);
				result += img->at(x,b);
				result += img->at(r,b);

				result *= (1.0f/8.0f);
				nd[y*img->w+x] = result;
			}
		}

		memcpy(img->data, nd, sizeof(float)*img->w*img->h);
		delete[] nd;
	}


	void Blendmap::Generate(Heightmap* rootHm, int lodLevel, float hmScale, float hmOffset)
	{
		const Heightmap* heightmap = rootHm->GetLevel(-lodLevel);

		// Allocate the blendmap image
		AlphaImage* bm = new AlphaImage;
		bm->Alloc(heightmap->w-1, heightmap->h-1); // texture dimensions have to be power-of-two

		Blendmap::GeneratorInfo* gi = generatorInfo;

		// Calculate blend factors using the function parameters and heightmap input:
		for (int y=0;y<bm->h;y++)
		{
			for (int x=0;x<bm->w;x++)
			{
				const float h = (heightmap->atSynced(x, y) - hmOffset) / hmScale;
				float factor=1.0f;

				if(h < gi->minHeight - gi->minHeightFuzzy) {
					bm->at(x,y) = 0.0f;
					continue;
				} else if (gi->minHeightFuzzy > 0.0f && h < gi->minHeight + gi->minHeightFuzzy)
					factor = (h - (gi->minHeight - gi->minHeightFuzzy)) / (2.0f * gi->minHeightFuzzy);

				if(h > gi->maxHeight + gi->maxHeightFuzzy) {
					bm->at (x,y) = 0.0f;
					continue;
				} else if (gi->maxHeightFuzzy > 0.0f && h > gi->maxHeight - gi->maxHeightFuzzy)
					factor *= ((gi->maxHeight + gi->maxHeightFuzzy) - h) / (2.0f * gi->maxHeightFuzzy);

                float norm_y = 0.0f;
				if (heightmap->normalData) {
					const uchar* cnorm = heightmap->GetNormal(x, y);
					norm_y = cnorm[1] / 255.0f * 2.0f - 1.0f;
					if (norm_y > 1.0f) norm_y = 1.0f;
				} else {
					Vector3 tangent, binormal;
					CalculateTangents(heightmap, x,y,tangent,binormal);
					Vector3 normal = tangent.cross(binormal);
					normal.ANormalize();
					norm_y = normal.y;
				}

				// flatness=dotproduct of surface normal with up vector
				float slope = 1.0f - math::fabs(norm_y);

				if (slope < gi->minSlope - gi->minSlopeFuzzy) {
					bm->at(x,y) = 0.0f;
					continue;
				} else if (gi->minSlopeFuzzy > 0.0f && slope < gi->minSlope + gi->minSlopeFuzzy)
					factor *= (h - (gi->minSlope - gi->minSlopeFuzzy)) / ( 2.0f * gi->minSlopeFuzzy);

				if (slope > gi->maxSlope + gi->maxSlopeFuzzy) {
					bm->at(x,y) = 0.0f;
					continue;
				} else if (gi->maxSlopeFuzzy > 0.0f && slope > gi->maxSlope - gi->maxSlopeFuzzy)
					factor *= ((gi->maxSlope + gi->maxSlopeFuzzy) - h) / (2.0f * gi->maxSlopeFuzzy);

				factor *= gi->coverage;
				factor *= (guRNG.NextFloat() < gi->noise) ? 0.0f : 1.0f;

				bm->at(x,y) = factor;
			}
		}

		BlendmapFilter(bm);
		image = bm;
	}


	void DetailBumpmap::CalcTexGenVector(float* v4)
	{
		QuadRenderData* rd = node->renderData;
		float pw = 1.0f / rd->normalMapTexWidth;

		v4[0] = pw * (rd->normalMapW - 1) / (node->end.x - node->start.x);
		v4[2] = 0.5f * pw - v4[0] * node->start.x;

		v4[1] = pw * (rd->normalMapW - 1) / (node->end.z - node->start.z);
		v4[3] = 0.5f * pw - v4[1] * node->start.z;
	}

	DetailBumpmap::~DetailBumpmap() {}


	// Util functions

	GLuint GenSphereBumpmap()
	{
		GLuint id;
		glGenTextures(1, &id);
		glBindTexture(GL_TEXTURE_2D, id);

		uchar img[3 * 64 * 64], *p = img;

		for (int y = 0; y < 64; y++) {
			for (int x = 0; x < 64; x++)
			{
				int sx = x - 32;
				int sy = y - 32;
				Vector3 n;

				if (sx*sx + sy*sy < 32*32) {
					const int sz = (int)math::sqrt(static_cast<float>(32 * 32 - sx*sx - sy*sy));
					n = Vector3(sx, sy, sz);
					n.ANormalize();
				}

				// compress it into a color
				*(p++) = (uchar)(255 * (n.x * 0.5f + 0.5f));
				*(p++) = (uchar)(255 * (n.y * 0.5f + 0.5f));
				*(p++) = (uchar)(255 * (n.z * 0.5f + 0.5f));
			}
		}

		glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
		glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
		glTexImage2D(GL_TEXTURE_2D, 0, 3, 64, 64, 0, GL_RGB, GL_UNSIGNED_BYTE, img);

		SaveImage("sphere_bm.jpg", 3, GL_UNSIGNED_BYTE, 64, 64, img);
		return id;
	}

	GLuint LoadTexture(const std::string& fn, bool isBumpmap)
	{
		CBitmap bmp;

		if (!bmp.Load(fn))
			throw content_error("Failed to load texture: " + fn);

		GLuint tex = bmp.CreateMipMapTexture();
		return tex;
	}

	void SaveImage(const char* fn, int components, GLenum type, int w, int h, void* data)
	{
		// We use the fact that DevIL has the same constants for component type as OpenGL
		/// ( GL_UNSIGNED_BYTE = IL_UNSIGNED_BYTE for example )
#if       defined(TERRAIN_USE_IL)
		// Save image
		ILuint out;
		ilGenImages(1, &out);
		ilBindImage(out);
		ILenum fmt = IL_RGB;
		if (components == 4) {
			fmt = IL_RGBA;
		} else if (components == 1) {
			fmt = IL_LUMINANCE;
		}
		ilTexImage(w, h, 1, components, fmt, type, data);
		FileSystem::Remove(fn);
		ilSaveImage((ILstring) fn);
		ilDeleteImages(1, &out);
#endif // defined(TERRAIN_USE_IL)
	}

}

