/*
 *                     OpenGL Maze Example
 *
 *              by  Stan Melax  melax@bioware.com
 *
 * In this little demo the player navigates through a simple maze
 * using the arrow keys.  The maze is defined by a 2D array where
 * each element in the array indicates solid or empty space.  This
 * program wraps polygon (quad) walls around the solid space and
 * disallows the player to navigate into solid space during the demo.
 * Note that all the walls are limited to being 90 degrees to each
 * other - there are no "angled" features.  The purpose of this
 * sample program is to show a beginning 3D game programmer some
 * things they can do.
 *
 * One other cool thing that this program does is that it constucts
 * a single quad strip to draw all the walls by doing a recursive
 * depth first search on the maze array data.
 *
 * Permission to execute this program, or look at the code is only
 * granted to those who do not like to sue other people :-)
 * Some of the window setup code was stolen from a simple Cosmo example.
 * OpenGL is a trademark of SGI.
 */


#include <stdio.h>
#include <stdlib.h>
#include <assert.h>
#include <windows.h>
#include <GL/gl.h>
#include <GL/glu.h>
#include <math.h>

#define IDM_APPLICATION_EXIT    (101)
#define IDM_APPLICATION_TEXTURE (102)
#define IDM_APPLICATION_BANK    (103)
HMENU hMENU;
HWND  hWND;
HDC   hDC;
HGLRC hGLRC;
int enablebank=0;
int enabletexture =0;


#define MAZE_HEIGHT (16)
#define MAZE_WIDTH  (16)

// unfortunately due to the way the polygon walls are generated there
// are restrictions on what the wall/maze data can look like.  See below.
char mazedata[MAZE_HEIGHT*16] = {
        "*****************       *      ** * *** * *    ** **  * ** * * **     *      * *********** *** **           *  ** ***** *** ***** *   *   *    **   *******    ** *   *   *  * ** ***** **** * **     *      * *** ** **** *** **   * *    *   ************** **"
};

int wall(int x,int y) {
        // true if the region at x,y is solid space that
        // should be surrounded by other solid space or polygon walls
        return (x>=0 && y>=0 && x<MAZE_WIDTH && y<MAZE_HEIGHT && ' ' != mazedata[y*16+x]);
}

 
/*
 * The next group of routines implements the depth-first search
 * that is used to wrap a quad strip around all the solid regions of the
 * maze.  Note this enforces certain topological restrictions on the
 * maze data itself.  There cant be any loops, clusters, or floating pieces
 * existing by themselves.  The solid nodes must be a tree (graph theory speak).
 *
 */
int onopen(int x,int y){
        //  returns whether node x,y is on the depth-first search open list
        assert(wall(x,y));
        return(mazedata[y*16+x]=='*');
}
void closeit(int x,int y) {
        //  puts node x,y on the closed list
        assert(wall(x,y));
printf("d1\n");
        assert(onopen(x,y));
printf("d2 %d %d %c\n",x,y,mazedata[y*16+x]);
        mazedata[y*16+x]= (char) 'X';
printf("d3\n");
}
int neighbor(int x,int y,int w,int *nx,int *ny){
        // if x,y has a neighbor in direction w then returns true
        switch(w) {
        case 0:
                *nx = x-1; *ny=y;   break;
        case 1:
                *nx = x;   *ny=y+1; break;
        case 2:
                *nx = x+1; *ny=y;   break;
        case 3:
                *nx = x;   *ny=y-1; break;
        default:
                assert(0);
        }
        return wall(*nx,*ny);
}
int diagnol(int x,int y,int w,int *nx,int *ny){
        switch(w) {
        case 0:
                *nx = x-1; *ny=y-1; break;
        case 1:
                *nx = x-1; *ny=y+1; break;
        case 2:
                *nx = x+1; *ny=y+1; break;
        case 3:
                *nx = x+1; *ny=y-1; break;
        default:
                assert(0);
        }
        return wall(*nx,*ny);
}
// normal vectors for each wall direction
float nrml[4][3] = {
        { -1.0f, 0.0f,0.0f},
        {  0.0f, 1.0f,0.0f},
        {  1.0f, 0.0f,0.0f},
        {  0.0f,-1.0f,0.0f},
};
// default color for each wall direction
float clr[4][3] = {
        {  1.0f, 0.0f,0.0f},
        {  0.0f, 1.0f,0.0f},
        {  0.0f, 0.0f,1.0f},
        {  1.0f, 1.0f,0.0f},
};
static float texcoordX=0.0f;
int dw(int x,int y,int p) {
        // the recursive draw wall routine that extends the quad strip
        int w=p;  // w is the current wall direction being considered
        closeit(x,y);
        do{
                int x2,y2;
                if(neighbor(x,y,w,&x2,&y2)) {
                        if(onopen(x2,y2)) {
                                dw(x2,y2,(w+3)%4);
                        }
                        else {
                                assert((w+1)%4 ==p); // or a loop or cluster exists
                                return 1;
                        }
                }
                else {
		    float fx;
		    float fy;
                        if(diagnol(x,y,w,&x2,&y2) && onopen(x2,y2)) {
                                dw(x2,y2,(w+2)%4);
                        }
                        glNormal3fv(nrml[w] );  // useful iff using lighting
                        glColor3fv(clr[w] );
                        texcoordX=(texcoordX<0.5)?1.0f:0.0f;
                        fx = (float)x+((w==1||w==2)?1.0f:0.0f);
                        fy = (float)y+((w==0||w==1)?1.0f:0.0f);
                        glTexCoord2f(texcoordX,0.0f);  // useful iff using textures
                        glVertex3f(fx,fy,0.0f);
                        glTexCoord2f(texcoordX,1.0f);
                        glVertex3f(fx,fy,1.0f);
                }
                        
                
                w++;w%=4;
        }while (w!=p);
        return 1;
}
int drawwalls() {
        int dl;
        glNewList(dl=glGenLists(1),GL_COMPILE);
        glBegin(GL_QUAD_STRIP);
        glVertex3f(0.0f, 0.0f, 0.0f);
        glVertex3f(0.0f, 0.0f, 1.0f);
        dw(0,0,0);
        glEnd();
        glEndList();
        return dl;
}
//-----------------------------------------------


int drawtop() {
        // draws the top and the bottom of the maze
        // which is useful for overhead views
        // The display list created here is only used for the intro
        // spinning bit.  No optimizations such as using quad strips
        // or combining adjacent polygons are done here.
        int x,y,dl;
        glNewList(dl=glGenLists(1),GL_COMPILE);
        glPushAttrib(GL_TEXTURE_BIT | GL_LIGHTING_BIT);
        glDisable(GL_LIGHTING);
        glDisable(GL_TEXTURE_2D);
    glColor3f(1.0f,1.0f,1.0f);
        glBegin(GL_QUADS);
    for(y=0;y<MAZE_HEIGHT;y++) {
     for(x=0;x<MAZE_WIDTH;x++) {
      if(wall(x,y)) {
                //bottomside:
        glVertex3f(x+0.0f ,y+0.0f ,0.0f );
        glVertex3f(x+0.0f ,y+1.0f ,0.0f );
        glVertex3f(x+1.0f ,y+1.0f ,0.0f );
        glVertex3f(x+1.0f ,y+0.0f ,0.0f );
                // topside:
        glVertex3f(x+0.0f ,y+0.0f ,1.0f );
        glVertex3f(x+1.0f ,y+0.0f ,1.0f );
        glVertex3f(x+1.0f ,y+1.0f ,1.0f );
        glVertex3f(x+0.0f ,y+1.0f ,1.0f );
          }
         }
        }
    glEnd();
        glPopAttrib();
    glEndList();
    return(dl);
}

#define STARTING_POINT_X (1.5f);
#define STARTING_POINT_Y (1.5f);
#define STARTING_HEADING (90.0f);
float player_x = STARTING_POINT_X ;
float player_y = STARTING_POINT_Y ;
float player_h = STARTING_HEADING ;  // player's heading
float player_s = 0.0f;  // forward speed of the player
float player_m = 1.0f;  // speed multiplier of the player
float player_t = 0.0f;  // player's turning (change in heading)
float player_b = 0.0f;  // viewpoint bank (roll)
int   walllist=0;
int       mazelist=0;
void  spinmaze(HDC hDC);
void  entermaze(HDC hDC);
void  navmaze(HDC hDC);
void  (*idlefunc)(HDC hDC)=NULL;

void spinmaze(HDC hDC) {
        // spin the maze around on 2 axis
        static float spin=720.0f;
        spin-=5.0f;  // change this line to be time dependant!
        glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
        glLoadIdentity();
        glPushMatrix();
        glTranslatef(0.0f,0.0f,-20.0f);
        glRotatef(spin, 0.0f, 1.0f, 1.0f);
        glTranslatef(-MAZE_WIDTH/2.0f,-MAZE_HEIGHT/2.0f,0.0f);
        glCallList(walllist);
        glCallList(mazelist);
        glPopMatrix();
        SwapBuffers(hDC);
        if(spin <=0.0f) {
                spin = 720.0f;
                idlefunc = entermaze;
                player_x = STARTING_POINT_X ;
                player_y = STARTING_POINT_Y ;
                player_h = STARTING_HEADING ;
  }
}

void entermaze(HDC hDC) {
        static float p=0.0f;
        p+=0.02f; // hmmm, should be time dependant
    glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
    glLoadIdentity();
    glPushMatrix();
    glRotatef(-90.0f*p,1.0f,0.0f,0.0f);
    glRotatef(player_h*p,0.0f,0.0f,1.0f);
    glTranslatef(-(player_x*p + MAZE_WIDTH /2.0f*(1-p)),
                     -(player_y*p + MAZE_HEIGHT/2.0f*(1-p)),
                     -(0.5f*p + 20.0f*(1-p)));
    glCallList(walllist);
        glCallList(mazelist);
    glPopMatrix();
    SwapBuffers(hDC);
        if(p>=1.0f) {
                p=0.0f;
                idlefunc = navmaze;
        }
}


int forward(float px,float py,float bf) {
    // this routine does wall collision detection
    // the inputs to this routine are:
    //         - the desired location
    //         - the minimum distance to wall allowed
        // changes:
    //         - the player's x and y coordinates
    // returns:
    //         - whether a wall caused change in target position
    // This is really easy with these walls that lie only on axes.
        // If the player collides into a wall at an angle he/she will
        // still slide along the wall - I hate programs where you stick
        // to the polygon and cant move until you back away from it.
        // This collision detection isn't perfect - if you're precise you
        // can jump through at a corner - but its tough.
        int x = ((int)player_x);
        int y = ((int)player_y);
    int h=0;            // number of walls hit
    if((px> x+1.0f - bf) && wall(x+1,y)) {
        px = (float)(x)+1.0f-bf;
        h++;
    }
    if(py> y+1.0f-bf && wall(x,y+1))  {
        py = (float)(y)+1.0f-bf;
        h++;
    }
    if(px< x+bf && wall(x-1,y)) {
        px = (float)(x)+bf;
        h++;
    }
    if(py< y+bf && wall(x,y-1)) {
        py = (float)(y)+bf;
        h++;
    }
        player_x=px;
        player_y=py;
        return h;
}


void navmaze(HDC hDC)
{
        // navigate through the maze and render it from the
        // players point of view.
        // Ideally updates to heading and position should be time dependant
    forward(player_x+player_m*player_s*(float)sin(player_h*3.14/180),
                player_y+player_m*player_s*(float)cos(player_h*3.14/180),
                0.2f);
        player_h+=player_t;
        player_b = 3*player_b/4 + player_t/4;
    glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
    glLoadIdentity();
    glPushMatrix();
    glRotatef(-90.0f,1.0f,0.0f,0.0f);
    if(enablebank) glRotatef(-player_b,0.0f,1.0f,0.0f); // add roll to viewpoint
    glRotatef(player_h,0.0f,0.0f,1.0f);
    glTranslatef(-player_x,-player_y,-0.5f);
    glCallList(walllist); // no need to draw the top since we're in the maze now
    glPopMatrix();
    SwapBuffers(hDC);
        if(player_x>MAZE_WIDTH || player_y>MAZE_HEIGHT) {
                // start over
                idlefunc = spinmaze;
        }
}

void readtexture(){
    unsigned char *image;
    int rc;
        // the bitmap must be a 24 bit bmp file thats 128x128
        // I think i mixed up red and blue componants - oh well :-)
        FILE *fp;
        fp = fopen("maze.bmp","rb");
        if(!fp) return;
        fseek(fp,54,SEEK_SET);
        image = (unsigned char *)malloc(128*128*3);
        assert(image);
        rc=fread(image,sizeof(unsigned char),128*128*3,fp);
        assert(rc == 128*128*3);
        glTexImage2D(GL_TEXTURE_2D,0,3,128,128,0,GL_RGB,
GL_UNSIGNED_BYTE,
                                 image);
                // let texture wrap-around
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT);
        // use point sampleing (fastest)
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
    glTexEnvi(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_DECAL);
        glEnable (GL_TEXTURE_2D);

        fclose(fp);
}

static void SetupDC(HDC hDC)
{
    PIXELFORMATDESCRIPTOR pfd = {
        sizeof(PIXELFORMATDESCRIPTOR),  /* size of this pfd */
        1,                              /* version num */
        PFD_DRAW_TO_WINDOW |            /* window types */
        PFD_SUPPORT_OPENGL |
        PFD_DOUBLEBUFFER,
        PFD_TYPE_RGBA,                  /* RGBA type */
        8,                              /* 8-bit color depth */
        0, 0, 0, 0, 0, 0,               /* color bits (ignored) */
        0,                              /* no alpha buffer */
        0,                              /* alpha bits (ignored) */
        0,                              /* no accumulation buffer */
        0, 0, 0, 0,                     /* accum bits (ignored) */
        16,                             /* 16-bit depth buffer */
        0,                              /* no stencil buffer */
        0,                              /* no auxiliary buffers */
        PFD_MAIN_PLANE,                 /* main layer */
        0,                              /* reserved */
        0, 0, 0,                        /* no layer, visible, damage */
                                        /* masks */
    };
    int SelectedPixelFormat;
    BOOL retVal;

    /* see if the pixel format exists */
    SelectedPixelFormat = ChoosePixelFormat(hDC, &pfd);
    if (SelectedPixelFormat == 0) {
        MessageBox(WindowFromDC(hDC),
                   "Failed to find acceptable pixel format.",
                   "OpenGL application error", MB_ICONERROR|MB_OK);
        exit(1);
    }

    /* use the pixel format */
    retVal = SetPixelFormat(hDC, SelectedPixelFormat, &pfd);
    if (retVal != TRUE) {
        MessageBox(WindowFromDC(hDC), "Failed to set pixel format.",
                   "OpenGL application error", MB_ICONERROR|MB_OK);
        exit(1);
    }
}

LRESULT APIENTRY WinProc(HWND hWND, UINT message, WPARAM wParam,
                         LPARAM lParam)
{

    switch (message) {
        case WM_CREATE:
            hDC = GetDC(hWND);
            SetupDC(hDC);
            hGLRC = wglCreateContext(hDC);
            wglMakeCurrent(hDC, hGLRC);
                        glEnable(GL_DEPTH_TEST);
                        glDisable(GL_LIGHTING);
                        glDisable(GL_TEXTURE);
                        glEnable(GL_CULL_FACE);
                        glShadeModel(GL_FLAT);
                        walllist = drawwalls();
                        mazelist = drawtop();
                        glMatrixMode(GL_PROJECTION);
                        glLoadIdentity();
                        gluPerspective(60.0, 1.0 , 0.1, 60.0);
                        glMatrixMode(GL_MODELVIEW);
                        glHint(GL_PERSPECTIVE_CORRECTION_HINT,GL_NICEST);
                        glLoadIdentity ();
                    glClearColor(0.0f, 0.0f, 0.0f, 0.0f);
                        idlefunc = spinmaze;
            return 0;
        case WM_DESTROY:
            if (hGLRC) {
                wglMakeCurrent(NULL, NULL);
                wglDeleteContext(hGLRC);
            }
            ReleaseDC(hWND, hDC);
            PostQuitMessage(0);
            return 0;
        case WM_PAINT:
            if (hGLRC) {
                                // not necessary to do anything here
                                // since we're constantly drawing to the window anyway
                //PAINTSTRUCT ps;
                //BeginPaint(hWND, &ps);
                //Redraw(hDC);
                //EndPaint(hWND, &ps);
                return 0;
            }
            break;
        case WM_CONTEXTMENU:
            TrackPopupMenu(hMENU, TPM_LEFTALIGN|TPM_RIGHTBUTTON,
                           LOWORD(lParam), HIWORD(lParam), 0, hWND,
                           NULL);
            break;
    case WM_SIZE:
	glViewport(0, 0, LOWORD(lParam), HIWORD(lParam));
	break;

        case WM_COMMAND:
            switch (LOWORD(wParam)) {
                case IDM_APPLICATION_EXIT:
                    PostQuitMessage(0);
                    break;
                case IDM_APPLICATION_TEXTURE:
                                        enabletexture ^= 1;
                                        ((enabletexture)?glEnable:glDisable)(GL_TEXTURE_2D);
                                        if(enabletexture)readtexture();
                    break;
                case IDM_APPLICATION_BANK:
                                        enablebank ^= 1;
                    break;
            }
            break;
                case WM_CHAR:
            switch (LOWORD((int)wParam)) {
                case VK_ESCAPE:
                    PostQuitMessage(0);
                    break;
                case 'b':
                                        enablebank ^= 1;
                case 't':
                                        enabletexture ^= 1;
                                        ((enabletexture)?glEnable:glDisable)(GL_TEXTURE_2D);
                                        if(enabletexture)readtexture();
                    break;
            }
                        break;
                case WM_KEYDOWN:
            switch (LOWORD((int)wParam)) {
                case VK_LEFT:
                    player_t = -5.0f;
                    break;
                case VK_RIGHT:
                    player_t = 5.0f;
                    break;
                case VK_UP:
                    player_s = 0.05f;
                    break;
                case VK_DOWN:
                                        player_s = -0.02f;
                    break;
                case VK_SHIFT:
                                        player_m = 3.0f;
                    break;
            }
                        break;
                case WM_KEYUP:
            switch (LOWORD((int)wParam)) {
                case VK_LEFT:
                                        // the reason for the "if(" is that sometimes
                                        // the player hits the right key down before the
                                        // left key is all the way up.
                    if(player_t<0.0f) player_t = 0.0f;
                    break;
                case VK_RIGHT:
                    if(player_t>0.0f) player_t = 0.0f;
                    break;
                case VK_UP:
                    player_s = 0.0f;
                    break;
                case VK_DOWN:
                                        player_s = 0.0f;
                    break;
                case VK_SHIFT:
                                        player_m = 1.0f;
                    break;
            }
                        break;

        default:
            break;
    }

    return DefWindowProc(hWND, message, wParam, lParam);
}

int APIENTRY WinMain(HINSTANCE hCurrentInst, HINSTANCE hPreviousInst,
                     LPSTR lpszCmdLine, int nCmdShow)
{
    char *className = "OpenGL";
    char *winName = "Maze Example";
    WNDCLASS winClass;
    MSG msg;

    /* Define and register the window class */
    winClass.style = CS_HREDRAW | CS_VREDRAW;
    winClass.lpfnWndProc = WinProc;
    winClass.cbClsExtra = 0;
    winClass.cbWndExtra = 0;
    winClass.hInstance = hCurrentInst;
    winClass.hIcon = LoadIcon(NULL, IDI_APPLICATION);
    winClass.hCursor = LoadCursor(NULL, IDC_ARROW);
    winClass.hbrBackground = GetStockObject(WHITE_BRUSH);
    winClass.lpszMenuName = NULL;
    winClass.lpszClassName = className;
    RegisterClass(&winClass);

    /* create window */
    hWND = CreateWindow(className,
                        winName,
                        WS_OVERLAPPEDWINDOW|WS_CLIPCHILDREN|WS_CLIPSIBLINGS,
                        0, 0,
                        600, 600,
                        NULL,              /* Parent window's handle */
                        NULL,              /* Menu handle */
                        hCurrentInst,      /* Instance handle */
                        NULL);             /* No additional data */

    /* add quit menu item */
    hMENU = CreatePopupMenu();
    AppendMenu(hMENU, MF_STRING, IDM_APPLICATION_EXIT, "Exit");
    AppendMenu(hMENU, MF_STRING, IDM_APPLICATION_TEXTURE, "Add/Remove Texture");
    AppendMenu(hMENU, MF_STRING, IDM_APPLICATION_BANK,    "Add/Remove Banking");

    ShowWindow(hWND, nCmdShow);

    UpdateWindow(hWND);

    /* process events */
    while (1) {
                // oops, busy wait when no messages or idlefunc - ohwell
                if(idlefunc)idlefunc(hDC);
                if(PeekMessage(&msg,NULL,0,0,PM_NOREMOVE)){
                if (GetMessage(&msg, NULL, 0, 0) != TRUE) {
                    return msg.wParam;
                }
                TranslateMessage(&msg);
                DispatchMessage(&msg);
            }

        }
}