/*
 * This program is under the GNU GPL.
 * Use at your own risk.
 *
 * written by David Bucciarelli (tech.hmw@plus.it)
 *            Humanware s.r.l.
 */

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <math.h>
#include <time.h>

#ifdef _WIN32
#include <windows.h>
#endif

#include <GL/glut.h>

#if defined(GL_VERSION_1_1)
/* Routines called directly. */
#elif defined(GL_EXT_texture_object) && defined(GL_EXT_copy_texture) && defined(GL_EXT_subtexture)
#define glBindTexture(A,B)     glBindTextureEXT(A,B)
#define glGenTextures(A,B)     glGenTexturesEXT(A,B)
#define glDeleteTextures(A,B)  glDeleteTexturesEXT(A,B)
#else
#define glBindTexture(A,B)
#define glGenTextures(A,B)
#define glDeleteTextures(A,B)
#endif

#include "image.h"

static int WIDTH=640;
static int HEIGHT=480;

#define FRAME 50

#define NUMBLOC 5

/* Some <math.h> files do not define M_PI... */
#ifndef M_PI
#define M_PI 3.14159265358979323846
#endif

extern int striplength_skin_13[];
extern float stripdata_skin_13[];

extern int striplength_skin_12[];
extern float stripdata_skin_12[];

extern int striplength_skin_11[];
extern float stripdata_skin_11[];

extern int striplength_skin_9[];
extern float stripdata_skin_9[];

static float obs[3]={1000.0,0.0,2.0};
static float dir[3];
static float v=0.0;
static float alpha=90.0;
static float beta=90.0;

static int fog=1;
static int bfcull=1;
static int usetex=1;
static int cstrip=0;
static int help=1;
static int joyavailable=0;
static int joyactive=0;

static GLuint t1id,t2id;

static void inittextures(void)
{
  IMAGE *img;
  GLenum gluerr;
  
  glGenTextures(1,&t1id);
  glBindTexture(GL_TEXTURE_2D,t1id);

  if(!(img=ImageLoad("tile.rgb"))) {
    fprintf(stderr,"Error reading a texture.\n");
    exit(-1);
  }

  glPixelStorei(GL_UNPACK_ALIGNMENT,4);
  if((gluerr=gluBuild2DMipmaps(GL_TEXTURE_2D, 3, img->sizeX, img->sizeY, GL_RGB,
			       GL_UNSIGNED_BYTE, (GLvoid *)(img->data)))) {
    fprintf(stderr,"GLULib%s\n",gluErrorString(gluerr));
    exit(-1);
  }

  glTexParameterf(GL_TEXTURE_2D,GL_TEXTURE_WRAP_S,GL_REPEAT);
  glTexParameterf(GL_TEXTURE_2D,GL_TEXTURE_WRAP_T,GL_REPEAT);
  
  glTexParameterf(GL_TEXTURE_2D,GL_TEXTURE_MIN_FILTER,GL_NEAREST_MIPMAP_LINEAR);
  glTexParameterf(GL_TEXTURE_2D,GL_TEXTURE_MAG_FILTER,GL_LINEAR);

  glTexEnvf(GL_TEXTURE_ENV,GL_TEXTURE_ENV_MODE,GL_MODULATE);

  glGenTextures(1,&t2id);
  glBindTexture(GL_TEXTURE_2D,t2id);

  if(!(img=ImageLoad("bw.rgb"))) {
    fprintf(stderr,"Error reading a texture.\n");
    exit(-1);
  }

  glPixelStorei(GL_UNPACK_ALIGNMENT,4);
  if((gluerr=gluBuild2DMipmaps(GL_TEXTURE_2D, 3, img->sizeX, img->sizeY, GL_RGB,
			       GL_UNSIGNED_BYTE, (GLvoid *)(img->data)))) {
    fprintf(stderr,"GLULib%s\n",gluErrorString(gluerr));
    exit(-1);
  }

  glTexParameterf(GL_TEXTURE_2D,GL_TEXTURE_WRAP_S,GL_REPEAT);
  glTexParameterf(GL_TEXTURE_2D,GL_TEXTURE_WRAP_T,GL_REPEAT);
  
  glTexParameterf(GL_TEXTURE_2D,GL_TEXTURE_MIN_FILTER,GL_NEAREST_MIPMAP_LINEAR);
  glTexParameterf(GL_TEXTURE_2D,GL_TEXTURE_MAG_FILTER,GL_LINEAR);

  glTexEnvf(GL_TEXTURE_ENV,GL_TEXTURE_ENV_MODE,GL_MODULATE);
}

static void drawobjs(int *l, float *f)
{
  int mend,j;

  if(cstrip) {
    float r=0.33,g=0.33,b=0.33;

    for(;(*l)!=0;) {
      mend=*l++;

      r+=0.33;
      if(r>1.0) {
	r=0.33;
	g+=0.33;
	if(g>1.0) {
	  g=0.33;
	  b+=0.33;
	  if(b>1.0)
	    b=0.33;
	}
      }

      glColor3f(r,g,b);
      glBegin(GL_TRIANGLE_STRIP);
      for(j=0;j<mend;j++) {
	f+=4;
	glTexCoord2fv(f); f+=2;
	glVertex3fv(f); f+=3;
      }
      glEnd();
    }
  } else
    for(;(*l)!=0;) {
      mend=*l++;

      glBegin(GL_TRIANGLE_STRIP);
      for(j=0;j<mend;j++) {
	glColor4fv(f); f+=4;
	glTexCoord2fv(f); f+=2;
	glVertex3fv(f); f+=3;
      }
      glEnd();
    }
}

static float gettime(void)
{
  static clock_t told=0;
  clock_t tnew,ris;

  tnew=clock();

  ris=tnew-told;

  told=tnew;

  return(ris/(float)CLOCKS_PER_SEC);
}

static void calcposobs(void)
{
  dir[0]=sin(alpha*M_PI/180.0);
  dir[1]=cos(alpha*M_PI/180.0)*sin(beta*M_PI/180.0);
  dir[2]=cos(beta*M_PI/180.0);

  obs[0]+=v*dir[0];
  obs[1]+=v*dir[1];
  obs[2]+=v*dir[2];
}

/* ARGSUSED1 */
static void special(int k, int x, int y)
{
  switch(k) {
  case GLUT_KEY_LEFT:
    alpha-=2.0;
    break;
  case GLUT_KEY_RIGHT:
    alpha+=2.0;
    break;
  case GLUT_KEY_DOWN:
    beta-=2.0;
    break;
  case GLUT_KEY_UP:
    beta+=2.0;
    break;
  }
}

/* ARGSUSED1 */
static void key(unsigned char k, int x, int y)
{
  switch(k) {
  case 27:
    exit(0);
    break;
    
  case 'a':
    v+=0.01;
    break;
  case 'z':
    v-=0.01;
    break;

  case 'j':
    joyactive=(!joyactive);
    break;
  case 'h':
    help=(!help);
    break;
  case 'f':
    fog=(!fog);
    break;
  case 't':
    usetex=(!usetex);
    break;
  case 'b':
    if(bfcull) {
      glDisable(GL_CULL_FACE);
      bfcull=0;
    } else {
      glEnable(GL_CULL_FACE);
      bfcull=1;
    }
    break;
  case 'm':
    cstrip=(!cstrip);
    break;

  case 'd':
    fprintf(stderr,"Deleting textures...\n");
    glDeleteTextures(1,&t1id);
    glDeleteTextures(1,&t2id);
    fprintf(stderr,"Loading textures...\n");
    inittextures();
    fprintf(stderr,"Done.\n");
    break;
  }
}

static void reshape(int w, int h) 
{
  WIDTH=w;
  HEIGHT=h;
  glMatrixMode(GL_PROJECTION);
  glLoadIdentity();
  gluPerspective(80.0,w/(float)h,1.0,50.0);
  glMatrixMode(GL_MODELVIEW);
  glLoadIdentity();
  glViewport(0,0,w,h);
}

static void printstring(void *font, char *string)
{
  int len,i;

  len=(int)strlen(string);
  for(i=0;i<len;i++)
    glutBitmapCharacter(font,string[i]);
}

static void printhelp(void)
{
  glEnable(GL_BLEND);
  glBlendFunc(GL_SRC_ALPHA,GL_ONE_MINUS_SRC_ALPHA);
  glColor4f(0.0,0.0,0.0,0.5);
  glRecti(40,40,600,440);
  glDisable(GL_BLEND);

  glColor3f(1.0,0.0,0.0);
  glRasterPos2i(300,420);
  printstring(GLUT_BITMAP_TIMES_ROMAN_24,"Help");

  glRasterPos2i(60,390);
  printstring(GLUT_BITMAP_TIMES_ROMAN_24,"h - Togle Help");
  glRasterPos2i(60,360);
  printstring(GLUT_BITMAP_TIMES_ROMAN_24,"t - Togle Textures");
  glRasterPos2i(60,330);
  printstring(GLUT_BITMAP_TIMES_ROMAN_24,"f - Togle Fog");
  glRasterPos2i(60,300);
  printstring(GLUT_BITMAP_TIMES_ROMAN_24,"m - Togle strips");
  glRasterPos2i(60,270);
  printstring(GLUT_BITMAP_TIMES_ROMAN_24,"b - Togle Back face culling");
  glRasterPos2i(60,240);
  printstring(GLUT_BITMAP_TIMES_ROMAN_24,"Arrow Keys - Rotate");
  glRasterPos2i(60,210);
  printstring(GLUT_BITMAP_TIMES_ROMAN_24,"a - Increase velocity");
  glRasterPos2i(60,180);
  printstring(GLUT_BITMAP_TIMES_ROMAN_24,"z - Decrease velocity");

  glRasterPos2i(60,150);
  if(joyavailable)
    printstring(GLUT_BITMAP_TIMES_ROMAN_24,"j - Togle jostick control (Joystick control available)");
  else
    printstring(GLUT_BITMAP_TIMES_ROMAN_24,"(No Joystick control available)");
}

static void dojoy(void)
{
#ifdef _WIN32
  static UINT max[2]={0,0};
  static UINT min[2]={0xffffffff,0xffffffff},center[2];
  MMRESULT res;
  JOYINFO joy;

  res=joyGetPos(JOYSTICKID1,&joy);

  if(res==JOYERR_NOERROR) {
    joyavailable=1;

    if(max[0]<joy.wXpos)
      max[0]=joy.wXpos;
    if(min[0]>joy.wXpos)
      min[0]=joy.wXpos;
    center[0]=(max[0]+min[0])/2;

    if(max[1]<joy.wYpos)
      max[1]=joy.wYpos;
    if(min[1]>joy.wYpos)
      min[1]=joy.wYpos;
    center[1]=(max[1]+min[1])/2;

    if(joyactive) {
      if(fabs(center[0]-(float)joy.wXpos)>0.1*(max[0]-min[0]))
	alpha-=2.0*(center[0]-(float)joy.wXpos)/(max[0]-min[0]);
      if(fabs(center[1]-(float)joy.wYpos)>0.1*(max[1]-min[1]))
	beta+=2.0*(center[1]-(float)joy.wYpos)/(max[1]-min[1]);

      if(joy.wButtons & JOY_BUTTON1)
	v+=0.01;
      if(joy.wButtons & JOY_BUTTON2)
	v-=0.01;
    }
  } else
    joyavailable=0;
#endif
}

static void draw(void)
{
  static int count=0;
  static char frbuf[80];
  int i;
  float fr,base,offset;

  dojoy();

  glEnable(GL_DEPTH_TEST);

  /*
    if(count & 1) {
    glDepthRange(1.0,0.5);
    glDepthFunc(GL_GREATER);
    } else {
    glDepthRange(0.0,0.5);
    glDepthFunc(GL_LESS);
    }
    */

  /*glClear(GL_COLOR_BUFFER_BIT);*/

  glClear(GL_COLOR_BUFFER_BIT|GL_DEPTH_BUFFER_BIT);
  
  if(usetex)
    glEnable(GL_TEXTURE_2D);
  else
    glDisable(GL_TEXTURE_2D);
  
  if(fog)
    glEnable(GL_FOG);
  else
    glDisable(GL_FOG);
  
  glShadeModel(GL_SMOOTH);

  glPushMatrix();
  calcposobs();
  gluLookAt(obs[0],obs[1],obs[2],
	    obs[0]+dir[0],obs[1]+dir[1],obs[2]+dir[2],
	    0.0,0.0,1.0);

  if(dir[0]>0) {
    offset=8.0;
    base=obs[0]-fmod(obs[0],8.0);
  } else {
    offset=-8.0;
    base=obs[0]+(8.0-fmod(obs[0],8.0));
  }

  glPushMatrix();
  glTranslatef(base-offset/2.0,0.0,0.0);
  for(i=0;i<NUMBLOC;i++) {
    glTranslatef(offset,0.0,0.0);
    glBindTexture(GL_TEXTURE_2D,t1id);
    drawobjs(striplength_skin_11,stripdata_skin_11);
    glBindTexture(GL_TEXTURE_2D,t2id);
    drawobjs(striplength_skin_12,stripdata_skin_12);
    drawobjs(striplength_skin_9,stripdata_skin_9);
    drawobjs(striplength_skin_13,stripdata_skin_13);
  }
  glPopMatrix();
  glPopMatrix();

  if((count % FRAME)==0) {
    fr=gettime();
    sprintf(frbuf,"Frame rate: %f",FRAME/fr);
  }

  glDisable(GL_TEXTURE_2D);
  glDisable(GL_DEPTH_TEST);
  glDisable(GL_FOG);
  glShadeModel(GL_FLAT);

  glMatrixMode(GL_PROJECTION);
  glLoadIdentity();
  glOrtho(-0.5,639.5,-0.5,479.5,-1.0,1.0);
  glMatrixMode(GL_MODELVIEW);
  glLoadIdentity();

  glColor3f(1.0,0.0,0.0);
  glRasterPos2i(10,10);
  printstring(GLUT_BITMAP_HELVETICA_18,frbuf);
  glRasterPos2i(350,470);
  printstring(GLUT_BITMAP_HELVETICA_10,"Tunnel V1.3 Written by David Bucciarelli (tech.hmw@plus.it)");

  if(help)
    printhelp();

  reshape(WIDTH,HEIGHT);

  glutSwapBuffers();
 
  count++;
}

int main(int ac, char **av)
{
  float fogcolor[4]={0.7,0.7,0.7,1.0};

  fprintf(stderr,"Tunnel V1.3\nWritten by David Bucciarelli (tech.hmw@plus.it)\n");

  /*
    #ifdef _WIN32
    if(!SetPriorityClass(GetCurrentProcess(),REALTIME_PRIORITY_CLASS)) {
    fprintf(stderr,"Error setting the process class.\n");
    return 0;
    }

    if(!SetThreadPriority(GetCurrentThread(),THREAD_PRIORITY_TIME_CRITICAL)) {
    fprintf(stderr,"Error setting the process priority.\n");
    return 0;
    }
    #endif
    */

  glutInitWindowPosition(0,0);
  glutInitWindowSize(WIDTH,HEIGHT);
  glutInit(&ac,av);

  glutInitDisplayMode(GLUT_RGB|GLUT_DEPTH|GLUT_DOUBLE);

  glutCreateWindow("Tunnel");

  glMatrixMode(GL_PROJECTION);
  glLoadIdentity();
  gluPerspective(80.0,WIDTH/(float)HEIGHT,1.0,50.0);

  glMatrixMode(GL_MODELVIEW);

  glShadeModel(GL_SMOOTH);
  glEnable(GL_DEPTH_TEST);
  glEnable(GL_CULL_FACE);
  glEnable(GL_TEXTURE_2D);

  glEnable(GL_FOG);
  glFogi(GL_FOG_MODE,GL_EXP2);
  glFogfv(GL_FOG_COLOR,fogcolor);

  glFogf(GL_FOG_DENSITY,0.06);
#ifdef FX
  glHint(GL_FOG_HINT,GL_NICEST);

  /*fxMesaTextureUsePalette(1); */
#endif

  inittextures();

#ifndef FX
  glDisable(GL_TEXTURE_2D);
  usetex=0;
#endif

  glClearColor(fogcolor[0],fogcolor[1],fogcolor[2],fogcolor[3]);
  glClear(GL_COLOR_BUFFER_BIT|GL_DEPTH_BUFFER_BIT);

  calcposobs();

  glutReshapeFunc(reshape);
  glutDisplayFunc(draw);
  glutKeyboardFunc(key);
  glutSpecialFunc(special);
  glutIdleFunc(draw);

  glutMainLoop();

  return 0;             /* ANSI C requires main to return int. */
}