#include <SDL2/SDL.h>
#include <GL/glew.h>
#include <SDL2/SDL_opengl.h>
#include <glm/glm.hpp>
#include <glm/gtc/matrix_transform.hpp>
#include <glm/gtc/type_ptr.hpp>

#include <iostream>
#include <vector>
#include <cmath>
#include <cstring>
#include <unordered_map>
#include <memory>
#include <algorithm>
#include <climits>

// Build:
//   mkdir build && cd build && cmake .. && make -j$(nproc)
//   ./minicraft

static const int   SCREEN_W    = 1280;
static const int   SCREEN_H    = 720;
static const int   CHUNK_SIZE  = 16;
static const int   WORLD_H     = 64;
static const int   RENDER_DIST = 6;
static const float MOVE_SPEED  = 6.0f;
static const float MOUSE_SENS  = 0.12f;
static const float GRAVITY     = -22.0f;
static const float JUMP_VEL    = 9.0f;
static const float HW          = 0.3f;
static const float PH          = 1.8f;

enum BlockType : uint8_t { AIR=0, GRASS, DIRT, STONE, WOOD, LEAVES, SAND, SNOW, WATER };

struct BlockColor { float r,g,b; };
static const BlockColor BLOCK_COLORS[] = {
    {0,0,0},
    {0.40f,0.72f,0.24f},
    {0.55f,0.40f,0.22f},
    {0.50f,0.50f,0.50f},
    {0.45f,0.30f,0.15f},
    {0.22f,0.55f,0.18f},
    {0.88f,0.83f,0.52f},
    {0.92f,0.95f,0.98f},
    {0.18f,0.42f,0.88f},
};
static const float FACE_SHADE[] = {1.0f, 0.5f, 0.8f, 0.7f, 0.65f, 0.65f};

// Perlin noise
static int P[512];
static void initNoise(int seed){
    int perm[256]; for(int i=0;i<256;i++) perm[i]=i;
    unsigned rng=(unsigned)seed;
    for(int i=255;i>0;i--){ rng=rng*1664525u+1013904223u; int j=(rng>>16)%(i+1); std::swap(perm[i],perm[j]); }
    for(int i=0;i<512;i++) P[i]=perm[i&255];
}
static float fade(float t){return t*t*t*(t*(t*6-15)+10);}
static float lerp(float a,float b,float t){return a+t*(b-a);}
static float grad(int h,float x,float y){h&=3;float u=(h<2)?x:y,v=(h<2)?y:x;return((h&1)?-u:u)+((h&2)?-v:v);}
static float noise2(float x,float y){
    int xi=(int)floorf(x)&255,yi=(int)floorf(y)&255;
    float xf=x-floorf(x),yf=y-floorf(y),u=fade(xf),v=fade(yf);
    int aa=P[P[xi]+yi],ab=P[P[xi]+yi+1],ba=P[P[xi+1]+yi],bb=P[P[xi+1]+yi+1];
    return lerp(lerp(grad(aa,xf,yf),grad(ba,xf-1,yf),u),lerp(grad(ab,xf,yf-1),grad(bb,xf-1,yf-1),u),v);
}
static float fbm(float x,float y,int oct=6){
    float val=0,amp=1,freq=1,max=0;
    for(int i=0;i<oct;i++){val+=noise2(x*freq,y*freq)*amp;max+=amp;amp*=0.5f;freq*=2.0f;}
    return val/max;
}

struct Chunk {
    int cx,cz;
    uint8_t blocks[CHUNK_SIZE][WORLD_H][CHUNK_SIZE];
    GLuint VAO=0,VBO=0,EBO=0;
    int indexCount=0;
    bool meshDirty=true,generated=false;
    Chunk(int cx,int cz):cx(cx),cz(cz){memset(blocks,AIR,sizeof(blocks));}
    ~Chunk(){if(VAO){glDeleteVertexArrays(1,&VAO);glDeleteBuffers(1,&VBO);glDeleteBuffers(1,&EBO);}}
};

struct ChunkKey{int x,z;bool operator==(const ChunkKey& o)const{return x==o.x&&z==o.z;}};
struct ChunkKeyHash{size_t operator()(const ChunkKey& k)const{return std::hash<long long>()((long long)k.x<<32|(unsigned)k.z);}};
using ChunkMap=std::unordered_map<ChunkKey,std::unique_ptr<Chunk>,ChunkKeyHash>;
static ChunkMap CHUNKS;

static void generateChunk(Chunk& c){
    int wx0=c.cx*CHUNK_SIZE,wz0=c.cz*CHUNK_SIZE;
    for(int x=0;x<CHUNK_SIZE;x++)
    for(int z=0;z<CHUNK_SIZE;z++){
        float wx=(wx0+x)*0.008f,wz=(wz0+z)*0.008f;
        float cont=fbm(wx*0.4f,wz*0.4f,4);
        float detail=fbm(wx*2.0f+5.3f,wz*2.0f+1.7f,5);
        float ridge=1.0f-fabsf(fbm(wx*0.8f+3.1f,wz*0.8f+8.9f,4));
        float h=12.0f+cont*18.0f+detail*6.0f+ridge*14.0f*std::max(0.0f,cont);
        int top=(int)h;
        top=std::max(2,std::min(WORLD_H-2,top));
        bool isSand=(top<16),isSnow=(top>38);
        for(int y=0;y<WORLD_H;y++){
            if(y==0)          c.blocks[x][y][z]=STONE;
            else if(y<top-4)  c.blocks[x][y][z]=STONE;
            else if(y<top)    c.blocks[x][y][z]=isSand?SAND:DIRT;
            else if(y==top){
                if(isSand)    c.blocks[x][y][z]=SAND;
                else if(isSnow) c.blocks[x][y][z]=SNOW;
                else          c.blocks[x][y][z]=GRASS;
            } else if(y<=14)  c.blocks[x][y][z]=WATER;
            else              c.blocks[x][y][z]=AIR;
        }
        if(!isSand&&!isSnow&&top>=16&&top<36&&top+6<WORLD_H){
            unsigned col=(unsigned)((wx0+x)*73856093u^(unsigned)(wz0+z)*19349663u);
            if((col&0xFF)<18){
                int trunk=top+1;
                for(int t=trunk;t<trunk+4&&t<WORLD_H;t++) c.blocks[x][t][z]=WOOD;
                for(int dx=-2;dx<=2;dx++)
                for(int dz=-2;dz<=2;dz++)
                for(int dy=trunk+2;dy<=trunk+5;dy++){
                    int nx=x+dx,nz=z+dz;
                    if(nx>=0&&nx<CHUNK_SIZE&&nz>=0&&nz<CHUNK_SIZE&&dy<WORLD_H)
                        if(c.blocks[nx][dy][nz]==AIR) c.blocks[nx][dy][nz]=LEAVES;
                }
            }
        }
    }
    c.generated=true;
}

static uint8_t getBlock(int wx,int wy,int wz){
    if(wy<0) return STONE;
    if(wy>=WORLD_H) return AIR;
    int cx=(int)floorf((float)wx/CHUNK_SIZE),cz=(int)floorf((float)wz/CHUNK_SIZE);
    auto it=CHUNKS.find({cx,cz});
    if(it==CHUNKS.end()) return STONE;
    int lx=wx-cx*CHUNK_SIZE,lz=wz-cz*CHUNK_SIZE;
    return it->second->blocks[lx][wy][lz];
}

static void setBlock(int wx,int wy,int wz,uint8_t val){
    if(wy<0||wy>=WORLD_H) return;
    int cx=(int)floorf((float)wx/CHUNK_SIZE),cz=(int)floorf((float)wz/CHUNK_SIZE);
    auto it=CHUNKS.find({cx,cz});
    if(it==CHUNKS.end()) return;
    int lx=wx-cx*CHUNK_SIZE,lz=wz-cz*CHUNK_SIZE;
    it->second->blocks[lx][wy][lz]=val;
    it->second->meshDirty=true;
    if(lx==0){auto n=CHUNKS.find({cx-1,cz});if(n!=CHUNKS.end())n->second->meshDirty=true;}
    if(lx==CHUNK_SIZE-1){auto n=CHUNKS.find({cx+1,cz});if(n!=CHUNKS.end())n->second->meshDirty=true;}
    if(lz==0){auto n=CHUNKS.find({cx,cz-1});if(n!=CHUNKS.end())n->second->meshDirty=true;}
    if(lz==CHUNK_SIZE-1){auto n=CHUNKS.find({cx,cz+1});if(n!=CHUNKS.end())n->second->meshDirty=true;}
}

struct Vertex{float x,y,z,r,g,b;};

static bool shouldDrawFace(uint8_t cur,int wx,int wy,int wz){
    uint8_t nb=getBlock(wx,wy,wz);
    if(nb==AIR) return true;
    if(nb==WATER||nb==LEAVES) return cur!=nb;
    return false;
}

static void addFace(std::vector<Vertex>& verts,std::vector<GLuint>& idx,
    glm::vec3 v0,glm::vec3 v1,glm::vec3 v2,glm::vec3 v3,float r,float g,float b,float shade){
    GLuint base=(GLuint)verts.size();
    float sr=r*shade,sg=g*shade,sb=b*shade;
    verts.push_back({v0.x,v0.y,v0.z,sr,sg,sb});
    verts.push_back({v1.x,v1.y,v1.z,sr,sg,sb});
    verts.push_back({v2.x,v2.y,v2.z,sr,sg,sb});
    verts.push_back({v3.x,v3.y,v3.z,sr,sg,sb});
    idx.insert(idx.end(),{base,base+1,base+2,base,base+2,base+3});
}

static void buildChunkMesh(Chunk& c){
    std::vector<Vertex> verts; std::vector<GLuint> idx;
    int wx0=c.cx*CHUNK_SIZE,wz0=c.cz*CHUNK_SIZE;
    for(int x=0;x<CHUNK_SIZE;x++)
    for(int y=0;y<WORLD_H;y++)
    for(int z=0;z<CHUNK_SIZE;z++){
        uint8_t b=c.blocks[x][y][z]; if(b==AIR) continue;
        float r=BLOCK_COLORS[b].r,g=BLOCK_COLORS[b].g,bl=BLOCK_COLORS[b].b;
        float bx=wx0+x,by=y,bz=wz0+z;
        int wx=wx0+x,wz=wz0+z;
        if(shouldDrawFace(b,wx,y+1,wz)) addFace(verts,idx,{bx,by+1,bz+1},{bx+1,by+1,bz+1},{bx+1,by+1,bz},{bx,by+1,bz},r,g,bl,FACE_SHADE[0]);
        if(shouldDrawFace(b,wx,y-1,wz)) addFace(verts,idx,{bx,by,bz},{bx+1,by,bz},{bx+1,by,bz+1},{bx,by,bz+1},r,g,bl,FACE_SHADE[1]);
        if(shouldDrawFace(b,wx,y,wz+1)) addFace(verts,idx,{bx,by,bz+1},{bx+1,by,bz+1},{bx+1,by+1,bz+1},{bx,by+1,bz+1},r,g,bl,FACE_SHADE[2]);
        if(shouldDrawFace(b,wx,y,wz-1)) addFace(verts,idx,{bx+1,by,bz},{bx,by,bz},{bx,by+1,bz},{bx+1,by+1,bz},r,g,bl,FACE_SHADE[3]);
        if(shouldDrawFace(b,wx-1,y,wz)) addFace(verts,idx,{bx,by,bz},{bx,by,bz+1},{bx,by+1,bz+1},{bx,by+1,bz},r,g,bl,FACE_SHADE[4]);
        if(shouldDrawFace(b,wx+1,y,wz)) addFace(verts,idx,{bx+1,by,bz+1},{bx+1,by,bz},{bx+1,by+1,bz},{bx+1,by+1,bz+1},r,g,bl,FACE_SHADE[5]);
    }
    if(!c.VAO){glGenVertexArrays(1,&c.VAO);glGenBuffers(1,&c.VBO);glGenBuffers(1,&c.EBO);}
    glBindVertexArray(c.VAO);
    glBindBuffer(GL_ARRAY_BUFFER,c.VBO);
    glBufferData(GL_ARRAY_BUFFER,verts.size()*sizeof(Vertex),verts.data(),GL_DYNAMIC_DRAW);
    glBindBuffer(GL_ELEMENT_ARRAY_BUFFER,c.EBO);
    glBufferData(GL_ELEMENT_ARRAY_BUFFER,idx.size()*sizeof(GLuint),idx.data(),GL_DYNAMIC_DRAW);
    glVertexAttribPointer(0,3,GL_FLOAT,GL_FALSE,sizeof(Vertex),(void*)0);
    glEnableVertexAttribArray(0);
    glVertexAttribPointer(1,3,GL_FLOAT,GL_FALSE,sizeof(Vertex),(void*)(3*sizeof(float)));
    glEnableVertexAttribArray(1);
    c.indexCount=(int)idx.size();
    c.meshDirty=false;
}

static const char* VS_SRC=R"(
#version 330 core
layout(location=0) in vec3 aPos;
layout(location=1) in vec3 aColor;
out vec3 vColor; out float vFog;
uniform mat4 uMVP; uniform vec3 uCamPos;
void main(){
    gl_Position=uMVP*vec4(aPos,1.0);
    vColor=aColor;
    float dist=length(aPos-uCamPos);
    vFog=clamp((dist-60.0)/40.0,0.0,1.0);
})";
static const char* FS_SRC=R"(
#version 330 core
in vec3 vColor; in float vFog;
out vec4 fragColor;
void main(){
    vec3 fogColor=vec3(0.53,0.81,0.98);
    fragColor=vec4(mix(vColor,fogColor,vFog),1.0);
})";

static GLuint compileShader(GLenum type,const char* src){
    GLuint s=glCreateShader(type); glShaderSource(s,1,&src,nullptr); glCompileShader(s);
    GLint ok; glGetShaderiv(s,GL_COMPILE_STATUS,&ok);
    if(!ok){char buf[512];glGetShaderInfoLog(s,512,nullptr,buf);std::cerr<<"Shader: "<<buf<<"\n";}
    return s;
}
static GLuint buildProgram(){
    GLuint vs=compileShader(GL_VERTEX_SHADER,VS_SRC),fs=compileShader(GL_FRAGMENT_SHADER,FS_SRC);
    GLuint p=glCreateProgram(); glAttachShader(p,vs); glAttachShader(p,fs); glLinkProgram(p);
    glDeleteShader(vs); glDeleteShader(fs); return p;
}

struct Camera{
    glm::vec3 pos{0,40,0}; float yaw=0,pitch=0;
    glm::vec3 vel{0,0,0}; bool onGround=false;
    glm::vec3 forward()const{float y=glm::radians(yaw),p=glm::radians(pitch);return glm::normalize(glm::vec3(cosf(p)*cosf(y),sinf(p),cosf(p)*sinf(y)));}
    glm::vec3 right()const{return glm::normalize(glm::cross(forward(),{0,1,0}));}
    glm::mat4 view()const{return glm::lookAt(pos,pos+forward(),{0,1,0});}
};

static bool solidAt(float fx,float fy,float fz){
    int x=(int)floorf(fx),y=(int)floorf(fy),z=(int)floorf(fz);
    if(y<0) return true;
    if(y>=WORLD_H) return false;
    uint8_t b=getBlock(x,y,z);
    return b!=AIR&&b!=WATER&&b!=LEAVES;
}
static bool aabbSolid(float px,float py,float pz){
    int x0=(int)floorf(px-HW),x1=(int)floorf(px+HW);
    int y0=(int)floorf(py-PH),y1=(int)floorf(py+0.05f);
    int z0=(int)floorf(pz-HW),z1=(int)floorf(pz+HW);
    for(int x=x0;x<=x1;x++) for(int y=y0;y<=y1;y++) for(int z=z0;z<=z1;z++)
        if(solidAt((float)x,(float)y,(float)z)) return true;
    return false;
}
static void moveCamera(Camera& cam,const glm::vec3& move,float dt){
    cam.pos.x+=move.x*dt; if(aabbSolid(cam.pos.x,cam.pos.y,cam.pos.z)) cam.pos.x-=move.x*dt;
    cam.pos.z+=move.z*dt; if(aabbSolid(cam.pos.x,cam.pos.y,cam.pos.z)) cam.pos.z-=move.z*dt;
    cam.vel.y+=GRAVITY*dt; cam.pos.y+=cam.vel.y*dt;
    if(cam.vel.y<0){
        if(aabbSolid(cam.pos.x,cam.pos.y,cam.pos.z)){
            cam.pos.y=floorf(cam.pos.y-PH)+1.0f+PH+0.001f;
            cam.vel.y=0; cam.onGround=true;
        } else cam.onGround=false;
    } else {
        if(aabbSolid(cam.pos.x,cam.pos.y,cam.pos.z)){
            cam.pos.y=floorf(cam.pos.y+0.05f)-0.05f-0.001f; cam.vel.y=0;
        }
        cam.onGround=false;
    }
}

static bool raycast(const Camera& cam,glm::ivec3& hit,glm::ivec3& prev){
    glm::vec3 dir=cam.forward(),p=cam.pos;
    glm::ivec3 last{(int)floorf(p.x),(int)floorf(p.y),(int)floorf(p.z)};
    for(float t=0;t<8.0f;t+=0.05f){
        glm::vec3 rp=p+dir*t;
        glm::ivec3 bp{(int)floorf(rp.x),(int)floorf(rp.y),(int)floorf(rp.z)};
        if(bp.y<0||bp.y>=WORLD_H){last=bp;continue;}
        uint8_t b=getBlock(bp.x,bp.y,bp.z);
        if(b!=AIR&&b!=WATER){hit=bp;prev=last;return true;}
        last=bp;
    }
    return false;
}

static void updateChunks(int pcx,int pcz){
    for(int dx=-RENDER_DIST;dx<=RENDER_DIST;dx++)
    for(int dz=-RENDER_DIST;dz<=RENDER_DIST;dz++){
        ChunkKey k{pcx+dx,pcz+dz};
        if(CHUNKS.find(k)==CHUNKS.end()){
            auto c=std::make_unique<Chunk>(k.x,k.z);
            generateChunk(*c);
            CHUNKS[k]=std::move(c);
            for(auto& [nk,nc]:CHUNKS)
                if(abs(nk.x-k.x)+abs(nk.z-k.z)==1) nc->meshDirty=true;
        }
    }
    std::vector<ChunkKey> toRemove;
    for(auto& [k,c]:CHUNKS)
        if(abs(k.x-pcx)>RENDER_DIST+1||abs(k.z-pcz)>RENDER_DIST+1) toRemove.push_back(k);
    for(auto& k:toRemove) CHUNKS.erase(k);
}

int main(){
    SDL_Init(SDL_INIT_VIDEO);
    SDL_GL_SetAttribute(SDL_GL_CONTEXT_MAJOR_VERSION,3);
    SDL_GL_SetAttribute(SDL_GL_CONTEXT_MINOR_VERSION,3);
    SDL_GL_SetAttribute(SDL_GL_CONTEXT_PROFILE_MASK,SDL_GL_CONTEXT_PROFILE_CORE);
    SDL_GL_SetAttribute(SDL_GL_DOUBLEBUFFER,1);
    SDL_GL_SetAttribute(SDL_GL_DEPTH_SIZE,24);

    SDL_Window* win=SDL_CreateWindow("MiniCraft - Infinite World",
        SDL_WINDOWPOS_CENTERED,SDL_WINDOWPOS_CENTERED,SCREEN_W,SCREEN_H,SDL_WINDOW_OPENGL|SDL_WINDOW_SHOWN);
    SDL_GLContext ctx=SDL_GL_CreateContext(win);
    SDL_GL_SetSwapInterval(1);
    glewExperimental=GL_TRUE; glewInit();
    glEnable(GL_DEPTH_TEST); glEnable(GL_CULL_FACE); glCullFace(GL_BACK);
    glClearColor(0.53f,0.81f,0.98f,1.0f);

    GLuint prog=buildProgram();
    GLint mvpLoc=glGetUniformLocation(prog,"uMVP");
    GLint camLoc=glGetUniformLocation(prog,"uCamPos");

    initNoise(12345);
    std::cout<<"Generating spawn chunks...\n";
    updateChunks(0,0);
    // build all initial meshes immediately
    for(auto& [k,c]:CHUNKS) if(c->generated) buildChunkMesh(*c);

    Camera cam;
    for(int y=WORLD_H-1;y>=0;y--){
        uint8_t b=getBlock(0,y,0);
        if(b!=AIR&&b!=WATER){cam.pos.y=(float)y+1+PH+0.1f;break;}
    }
    cam.pos.x=0.5f; cam.pos.z=0.5f;

    glm::mat4 proj=glm::perspective(glm::radians(70.0f),(float)SCREEN_W/SCREEN_H,0.05f,500.0f);
    SDL_SetRelativeMouseMode(SDL_TRUE);

    uint8_t selectedBlock=GRASS;
    bool running=true;
    Uint64 last=SDL_GetPerformanceCounter();
    int lastPcx=INT_MAX,lastPcz=INT_MAX;

    std::cout<<"=== MiniCraft Infinite World ===\n"
             <<"WASD        Move\n"
             <<"Space       Jump\n"
             <<"Mouse       Look\n"
             <<"LMB         Destroy block\n"
             <<"RMB         Place block\n"
             <<"1-8         Grass/Dirt/Stone/Wood/Leaves/Sand/Snow/Water\n"
             <<"ESC         Quit\n";

    while(running){
        Uint64 now=SDL_GetPerformanceCounter();
        float dt=(float)(now-last)/SDL_GetPerformanceFrequency();
        if(dt>0.1f) dt=0.1f;
        last=now;

        SDL_Event e;
        while(SDL_PollEvent(&e)){
            if(e.type==SDL_QUIT) running=false;
            if(e.type==SDL_KEYDOWN){
                switch(e.key.keysym.sym){
                    case SDLK_ESCAPE:running=false;break;
                    case SDLK_1:selectedBlock=GRASS;break;
                    case SDLK_2:selectedBlock=DIRT;break;
                    case SDLK_3:selectedBlock=STONE;break;
                    case SDLK_4:selectedBlock=WOOD;break;
                    case SDLK_5:selectedBlock=LEAVES;break;
                    case SDLK_6:selectedBlock=SAND;break;
                    case SDLK_7:selectedBlock=SNOW;break;
                    case SDLK_8:selectedBlock=WATER;break;
                }
            }
            if(e.type==SDL_MOUSEMOTION){
                cam.yaw+=e.motion.xrel*MOUSE_SENS;
                cam.pitch-=e.motion.yrel*MOUSE_SENS;
                if(cam.pitch>89)cam.pitch=89; if(cam.pitch<-89)cam.pitch=-89;
            }
            if(e.type==SDL_MOUSEBUTTONDOWN){
                glm::ivec3 hit,prev;
                if(raycast(cam,hit,prev)){
                    if(e.button.button==SDL_BUTTON_LEFT) setBlock(hit.x,hit.y,hit.z,AIR);
                    else if(e.button.button==SDL_BUTTON_RIGHT) setBlock(prev.x,prev.y,prev.z,selectedBlock);
                }
            }
        }

        const Uint8* keys=SDL_GetKeyboardState(nullptr);
        glm::vec3 fwd=cam.forward(); fwd.y=0; if(glm::length(fwd)>0) fwd=glm::normalize(fwd);
        glm::vec3 rgt=cam.right();   rgt.y=0; if(glm::length(rgt)>0) rgt=glm::normalize(rgt);
        glm::vec3 move{0,0,0};
        if(keys[SDL_SCANCODE_W]) move+=fwd*MOVE_SPEED;
        if(keys[SDL_SCANCODE_S]) move-=fwd*MOVE_SPEED;
        if(keys[SDL_SCANCODE_D]) move+=rgt*MOVE_SPEED;
        if(keys[SDL_SCANCODE_A]) move-=rgt*MOVE_SPEED;
        if(keys[SDL_SCANCODE_SPACE]&&cam.onGround) cam.vel.y=JUMP_VEL;
        moveCamera(cam,move,dt);

        int pcx=(int)floorf(cam.pos.x/CHUNK_SIZE);
        int pcz=(int)floorf(cam.pos.z/CHUNK_SIZE);
        if(pcx!=lastPcx||pcz!=lastPcz){
            updateChunks(pcx,pcz); lastPcx=pcx; lastPcz=pcz;
        }

        int rebuilt=0;
        for(auto& [k,c]:CHUNKS)
            if(c->meshDirty&&c->generated){buildChunkMesh(*c);if(++rebuilt>=4)break;}

        glClear(GL_COLOR_BUFFER_BIT|GL_DEPTH_BUFFER_BIT);
        glUseProgram(prog);
        glm::mat4 mvp=proj*cam.view();
        glUniformMatrix4fv(mvpLoc,1,GL_FALSE,glm::value_ptr(mvp));
        glUniform3fv(camLoc,1,glm::value_ptr(cam.pos));
        for(auto& [k,c]:CHUNKS)
            if(c->indexCount>0){glBindVertexArray(c->VAO);glDrawElements(GL_TRIANGLES,c->indexCount,GL_UNSIGNED_INT,0);}

        SDL_GL_SwapWindow(win);
    }

    CHUNKS.clear();
    glDeleteProgram(prog);
    SDL_GL_DeleteContext(ctx);
    SDL_DestroyWindow(win);
    SDL_Quit();
    return 0;
}