#include <stdio.h>
#include <stdlib.h>
#include <cmath>
#include <vector>
#include <GL/gl.h>
#include <GL/glu.h>
#include <SDL/SDL.h>

#define SCREEN_WIDTH  600
#define SCREEN_HEIGHT 600
#define SCREEN_BPP     32
#define PI 3.14159265358979
#define GRAVITY 0.000005

namespace move { float rotax, rotay, rotaz, zoom; }
struct map {
    int w, h;
    int data[300][300];
};
struct partikkeli {
    float x, y, xplus, yplus, a, v;
    char r, g, b;
};

int     videoFlags;
int     running = true;
const   SDL_VideoInfo *videoInfo;
SDL_Surface *heightmap, *surface;
SDL_Event event;
map     world;
Uint8   *napit;
int     palette[255][3];


float sina(float a) { return sin(a*PI/180); }
float cosa(float a) { return cos(a*PI/180); }


std::vector<partikkeli> partikkelit;


void handleEvent() {
    napit = SDL_GetKeyState(NULL);
    if (napit[SDLK_a]){
        move::rotay-=(0.5+napit[SDLK_LSHIFT]);
    } else if (napit[SDLK_d]) {
        move::rotay+=(0.5+napit[SDLK_LSHIFT]);
    }
    if (napit[SDLK_UP]){
        move::rotax+=(0.5+napit[SDLK_LSHIFT]);
    } else if (napit[SDLK_DOWN]) {
        move::rotax-=(0.5+napit[SDLK_LSHIFT]);
    }
    if (napit[SDLK_LEFT]){
        move::rotaz-=(0.5+napit[SDLK_LSHIFT]);
    } else if (napit[SDLK_RIGHT]) {
        move::rotaz+=(0.5+napit[SDLK_LSHIFT]);
    }
    if (napit[SDLK_w]){
        move::zoom+=(0.03+napit[SDLK_LSHIFT]/2);
    } else if (napit[SDLK_s]) {
        move::zoom-=(0.03+napit[SDLK_LSHIFT]/2);
    }

    while ( SDL_PollEvent( &event ) ) {
        switch( event.type ) {
        case SDL_KEYDOWN:
            switch ( event.key.keysym.sym ) {
            case SDLK_ESCAPE:
                exit(0);
                break;
            default:
                break;
            }
            break;
        case SDL_QUIT:
            running = false;
            break;
        default:
            break;
        }
    }
}

int initGL() {
    glShadeModel( GL_SMOOTH );
    glClearColor( 0.0f, 0.0f, 0.0f, 0.0f );
    glClearDepth( 1.0f );
    glEnable( GL_LINE_SMOOTH );
    glEnable( GL_DEPTH_TEST );
    glDepthFunc( GL_LEQUAL );
    glHint( GL_PERSPECTIVE_CORRECTION_HINT, GL_NICEST );
    return 1;
}

int runAndDraw( int frm ) {

    move::rotax = (move::rotax<-90?-90:(move::rotax>90?90:move::rotax));

    glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
    glLoadIdentity();
    glTranslatef(0.0,0.0f,move::zoom);

    glRotatef(move::rotax, 1, 0, 0);
    glRotatef(move::rotay, 0, 1, 0);
    glRotatef(move::rotaz, 0, 0, 1);



    for (int y = 0; y < world.h-1; y++)
    for (int x = 0; x < world.w-1; x++) {
        glBegin( GL_TRIANGLES );
            glColor3f(palette[world.data[x][y]][0]/255.0, palette[world.data[x][y]][1]/255.0, palette[world.data[x][y]][2]/255.0);

            glVertex3f((-(world.w/2)+x)/400.0,      world.data[x][y]/2550.0,    (-(world.h/2)+y)/400.0);
            glVertex3f((-(world.w/2)+x+1)/400.0,    world.data[x+1][y]/2550.0,  (-(world.h/2)+y)/400.0);
            glVertex3f((-(world.w/2)+x)/400.0,      world.data[x][y+1]/2550.0,  (-(world.h/2)+y+1)/400.0);

            glVertex3f((-(world.w/2)+x+1)/400.0,    world.data[x+1][y+1]/2550.0,(-(world.h/2)+y+1)/400.0);
            glVertex3f((-(world.w/2)+x+1)/400.0,    world.data[x+1][y]/2550.0,  (-(world.h/2)+y)/400.0);
            glVertex3f((-(world.w/2)+x)/400.0,      world.data[x][y+1]/2550.0,  (-(world.h/2)+y+1)/400.0);
        glEnd();
    }


    SDL_GL_SwapBuffers( );


    static GLint T0     = 0;
    static GLint Frames = 0;
    Frames++;
    {
    GLint t = SDL_GetTicks();
    if (t - T0 >= 5000) {
        GLfloat seconds = (t - T0) / 1000.0;
        GLfloat fps = Frames / seconds;
        printf("%d frame per %g second = %g FPS\n", Frames, seconds, fps);
        T0 = t;
        Frames = 0;
    }
    }

    return 1;
}

int main( int argc, char **argv ) {
    atexit(SDL_Quit);

    if ( SDL_Init( SDL_INIT_VIDEO ) < 0 ) exit(-1);
    videoInfo = SDL_GetVideoInfo();
    if ( !videoInfo ) exit(-2);

    videoFlags  = SDL_OPENGL | SDL_GL_DOUBLEBUFFER | SDL_HWPALETTE | SDL_RESIZABLE | SDL_HWSURFACE;
    SDL_GL_SetAttribute( SDL_GL_DOUBLEBUFFER, 1 );
    surface = SDL_SetVideoMode( SCREEN_WIDTH, SCREEN_HEIGHT, SCREEN_BPP, videoFlags );
    if ( !surface ) exit(-3);

    initGL();

    GLfloat ratio = ( GLfloat )SCREEN_WIDTH / ( GLfloat )SCREEN_HEIGHT;
    glViewport( 0, 0, ( GLsizei )SCREEN_WIDTH, ( GLsizei )SCREEN_HEIGHT );

    glMatrixMode( GL_PROJECTION );
    glLoadIdentity();
    gluPerspective( 45.0f, ratio, 0.1f, 100.0f );
    glMatrixMode( GL_MODELVIEW );
    glLoadIdentity();

    srand(SDL_GetTicks());

    SDL_Surface *palettetmp= SDL_LoadBMP("palette.bmp");
    if (palettetmp == NULL) exit (-10);
    palettetmp = SDL_DisplayFormat(palettetmp);
    SDL_LockSurface(palettetmp);
    for (int y = 0; y < 255; y++) {
        Uint32 a =   ((unsigned int*)palettetmp->pixels)[y];
        palette[y] = {(a >> 16) % 256, (a >> 8) % 256, a%256};
    }
    SDL_UnlockSurface(palettetmp);


    /* 3047538.bmp */
    // PITÄÄ OLLA KOOLTAAN PIENEMPÄÄ KUIN 300px*300px
    heightmap = SDL_LoadBMP("Heightmap.bmp");
    if (heightmap == NULL) exit (-11);
    heightmap = SDL_DisplayFormat(heightmap);

    SDL_LockSurface(heightmap);
    for (int y = 0; y < heightmap->h; y++)
    for (int x = 0; x < heightmap->w; x++) {
        Uint32 a =   ((unsigned int*)heightmap->pixels)[y*(heightmap->pitch/sizeof(unsigned int)) + x];
        world.data[x][y] =
        (.3*((a >> 16) % 256))+
        (.59*((a >> 8) % 256))+
        (.11*(a%256));
    }


    world.w = heightmap->w;
    world.h = heightmap->h;
    SDL_UnlockSurface(heightmap);

    move::rotax = 45;
    move::rotay = 20;
    move::zoom = -.7;

    for (int i = 0; i < 1000; i++) {
        partikkeli tmp;
        tmp.x = SCREEN_WIDTH/2;
        tmp.y = SCREEN_HEIGHT/2;
        tmp.a = rand()%360;
        tmp.v = (rand()/RAND_MAX);
        tmp.xplus = cosa(tmp.a)/(tmp.v);
        tmp.xplus = sina(tmp.a)/(tmp.v);
        tmp.r = 255;
        tmp.g = 255;
        tmp.b = 255;
        partikkelit.push_back(tmp);
    }

    for (int frm = 0; running; frm++) {
        handleEvent();
        runAndDraw(frm);
    }
    exit(0);
    return( 0 );
}