Camera.cpp

/*-----------------------------------------------------------------------------

  Camera.cpp

  2009 Shamus Young

-------------------------------------------------------------------------------

  This tracks the position and oritentation of the camera. In screensaver 
  mode, it moves the camera around the world in order to create dramatic 
  views of the hot zone.  

-----------------------------------------------------------------------------*/

#define EYE_HEIGHT              2.0f
#define MAX_PITCH               85
#define FLYCAM_CIRCUT           60000
#define FLYCAM_CIRCUT_HALF      (FLYCAM_CIRCUT / 2)
#define FLYCAM_LEG              (FLYCAM_CIRCUT / 4)
#define ONE_SECOND              1000
#define CAMERA_CHANGE_INTERVAL  15
#define CAMERA_CYCLE_LENGTH     (CAMERA_MODES*CAMERA_CHANGE_INTERVAL)

#include <windows.h>
#include <math.h>
#include <time.h>

#include "glTypes.h"
#include "ini.h"
#include "macro.h"
#include "math.h"
#include "world.h"
#include "win.h"


enum
{
  CAMERA_FLYCAM1,
  CAMERA_ORBIT_INWARD,
  CAMERA_ORBIT_OUTWARD,
  CAMERA_ORBIT_ELLIPTICAL,
  CAMERA_FLYCAM2,
  CAMERA_SPEED,
  CAMERA_SPIN,
  CAMERA_FLYCAM3,
  CAMERA_MODES
};

static GLvector     angle;
static GLvector     position;
static GLvector     auto_angle;
static GLvector     auto_position;
static float        distance;
static GLvector     movement;
static bool         cam_auto;
static float        tracker;
static unsigned     last_update;
static int          camera_behavior;
static unsigned     last_move;

/*-----------------------------------------------------------------------------

-----------------------------------------------------------------------------*/

static GLvector flycam_position (unsigned t)
{

  unsigned    leg;
  float       delta;
  GLvector    start, end;
  GLbbox      hot_zone;

  hot_zone = WorldHotZone ();
  t %= FLYCAM_CIRCUT; 
  leg = t / FLYCAM_LEG;
  delta = (float)(t % FLYCAM_LEG) / FLYCAM_LEG;
  switch (leg) {
  case 0:
    start = glVector (hot_zone.min.x, 25.0f, hot_zone.min.z);
    end = glVector (hot_zone.min.x, 60.0f, hot_zone.max.z);
    break;
  case 1:
    start = glVector (hot_zone.min.x, 60.0f, hot_zone.max.z);
    end = glVector (hot_zone.max.x, 25.0f, hot_zone.max.z);
    break;
  case 2:
    start = glVector (hot_zone.max.x, 25.0f, hot_zone.max.z);
    end = glVector (hot_zone.max.x, 60.0f, hot_zone.min.z);
    break;
  case 3:
    start = glVector (hot_zone.max.x, 60.0f, hot_zone.min.z);
    end = glVector (hot_zone.min.x, 25.0f, hot_zone.min.z);
    break;
  }
  delta = MathScalarCurve (delta);
  return glVectorInterpolate (start, end, delta);


}

/*-----------------------------------------------------------------------------

-----------------------------------------------------------------------------*/

static void do_auto_cam ()
{

  float     dist;
  unsigned  t;
  unsigned  elapsed;
  unsigned  now;
  int       behavior; 
  GLvector  target;

  now = GetTickCount ();
  elapsed = now - last_update;
  elapsed = MIN (elapsed, 50); //limit to 1/20th second worth of time
  if (elapsed == 0)
    return;
  last_update = now;
  t = time (NULL) % CAMERA_CYCLE_LENGTH;
#if SCREENSAVER
  behavior = t / CAMERA_CHANGE_INTERVAL;
#else
  behavior = camera_behavior;
#endif
  tracker += (float)elapsed / 300.0f;
  //behavior = CAMERA_FLYCAM1; 
  switch (behavior) {
  case CAMERA_ORBIT_INWARD:
    auto_position.x = WORLD_HALF + sinf (tracker * DEGREES_TO_RADIANS) * 150.0f;
    auto_position.y = 60.0f;
    auto_position.z = WORLD_HALF + cosf (tracker * DEGREES_TO_RADIANS) * 150.0f;
    target = glVector (WORLD_HALF, 40.0f, WORLD_HALF);
    break;
  case CAMERA_ORBIT_OUTWARD:
    auto_position.x = WORLD_HALF + sinf (tracker * DEGREES_TO_RADIANS) * 250.0f;
    auto_position.y = 60.0f;
    auto_position.z = WORLD_HALF + cosf (tracker * DEGREES_TO_RADIANS) * 250.0f;
    target = glVector (WORLD_HALF, 30.0f, WORLD_HALF);
    break;
  case CAMERA_ORBIT_ELLIPTICAL:
    dist = 150.0f + sinf (tracker * DEGREES_TO_RADIANS / 1.1f) * 50;
    auto_position.x = WORLD_HALF + sinf (tracker * DEGREES_TO_RADIANS) * dist;
    auto_position.y = 60.0f;
    auto_position.z = WORLD_HALF + cosf (tracker * DEGREES_TO_RADIANS) * dist;
    target = glVector (WORLD_HALF, 50.0f, WORLD_HALF);
    break;
  case CAMERA_FLYCAM1:
  case CAMERA_FLYCAM2:
  case CAMERA_FLYCAM3:
    auto_position = (flycam_position (now) + flycam_position (now + 4000)) / 2.0f;
    target = flycam_position (now + FLYCAM_CIRCUT_HALF - ONE_SECOND * 3);
    break;
  case CAMERA_SPEED:
    auto_position = (flycam_position (now) + flycam_position (now + 500)) / 2.0f;
    target = flycam_position (now + ONE_SECOND * 5);
    auto_position.y /= 2;
    target.y /= 2;
    break;
  case CAMERA_SPIN:
  default:  
    target.x = WORLD_HALF + sinf (tracker * DEGREES_TO_RADIANS) * 300.0f;
    target.y = 30.0f;
    target.z = WORLD_HALF + cosf (tracker * DEGREES_TO_RADIANS) * 300.0f;
    auto_position.x = WORLD_HALF + sinf (tracker * DEGREES_TO_RADIANS) * 50.0f;
    auto_position.y = 60.0f;
    auto_position.z = WORLD_HALF + cosf (tracker * DEGREES_TO_RADIANS) * 50.0f;
  }
  dist = MathDistance (auto_position.x, auto_position.z, target.x, target.z);
  auto_angle.y = MathAngle (-MathAngle (auto_position.x, auto_position.z, target.x, target.z));
  auto_angle.x = 90.0f + MathAngle (0, auto_position.y, dist, target.y);

}


/*-----------------------------------------------------------------------------

-----------------------------------------------------------------------------*/

void CameraAutoToggle ()
{

  cam_auto = !cam_auto;

}

/*-----------------------------------------------------------------------------

-----------------------------------------------------------------------------*/

void CameraNextBehavior ()
{

  camera_behavior++;
  camera_behavior %= CAMERA_MODES;

}

/*-----------------------------------------------------------------------------

-----------------------------------------------------------------------------*/

void CameraYaw (float delta)
{

  angle.y -= delta;

}

/*-----------------------------------------------------------------------------

-----------------------------------------------------------------------------*/

void CameraPitch (float delta)
{

  angle.x -= delta;

}

/*-----------------------------------------------------------------------------

-----------------------------------------------------------------------------*/

void CameraPan (float delta)
{

  float           move_x, move_y;

  move_x = (float)sin (-angle.y * DEGREES_TO_RADIANS) / 10.0f;
  move_y = (float)cos (-angle.y * DEGREES_TO_RADIANS) / 10.0f;
  position.x -= move_y * delta;
  position.z -= -move_x * delta;

}

/*-----------------------------------------------------------------------------

-----------------------------------------------------------------------------*/

void CameraForward (float delta)
{

  float           move_x, move_y;

  move_y = (float)sin (-angle.y * DEGREES_TO_RADIANS) / 10.0f;
  move_x = (float)cos (-angle.y * DEGREES_TO_RADIANS) / 10.0f;
  position.x -= move_y * delta;
  position.z -= move_x * delta;

}

/*-----------------------------------------------------------------------------

-----------------------------------------------------------------------------*/

void CameraVertical (float val)
{

  movement.y += val;
  last_move = GetTickCount ();

}

/*-----------------------------------------------------------------------------

-----------------------------------------------------------------------------*/

void CameraLateral (float val)
{

  movement.x += val;
  last_move = GetTickCount ();

}

/*-----------------------------------------------------------------------------

-----------------------------------------------------------------------------*/

void CameraMedial (float val)
{

  movement.z += val;
  last_move = GetTickCount ();

}

/*-----------------------------------------------------------------------------

-----------------------------------------------------------------------------*/

GLvector CameraPosition (void)		
{
 
  if (cam_auto)
    return auto_position;
  return position;

}

/*-----------------------------------------------------------------------------

-----------------------------------------------------------------------------*/

void CameraReset ()		
{

  position.y = 50.0f;
  position.x = WORLD_HALF;
  position.z = WORLD_HALF;
  angle.x = 0.0f;
  angle.y = 0.0f;
  angle.z = 0.0f;

}

/*-----------------------------------------------------------------------------

-----------------------------------------------------------------------------*/

void CameraPositionSet (GLvector new_pos)		
{

  position = new_pos;

}

/*-----------------------------------------------------------------------------

-----------------------------------------------------------------------------*/

GLvector CameraAngle (void)		
{

  if (cam_auto)
    return auto_angle;
  return angle;

}

/*-----------------------------------------------------------------------------

-----------------------------------------------------------------------------*/

void CameraAngleSet (GLvector new_angle)		
{

  angle = new_angle;
  angle.x = CLAMP (angle.x, -80.0f, 80.0f);

}

/*-----------------------------------------------------------------------------

-----------------------------------------------------------------------------*/

void CameraInit (void)		
{

  angle = IniVector ("CameraAngle");
  position = IniVector ("CameraPosition");

}

/*-----------------------------------------------------------------------------

-----------------------------------------------------------------------------*/

void CameraUpdate (void)		
{

  CameraPan (movement.x);
  CameraForward (movement.z);
  position.y += movement.y / 10.0f;
  if (GetTickCount () - last_move > 1000)
    movement *= 0.9f;
  else
    movement *= 0.99f;
  if (SCREENSAVER)
    cam_auto = true;
  if (cam_auto) 
    do_auto_cam ();
  if (angle.y < 0.0f) 
    angle.y = 360.0f - (float)fmod (fabs (angle.y), 360.0f);
  angle.y = (float)fmod (angle.y, 360.0f);
  angle.x = CLAMP (angle.x, -MAX_PITCH, MAX_PITCH);
 
}

/*-----------------------------------------------------------------------------

-----------------------------------------------------------------------------*/

void CameraTerm (void)		
{

  //just store our most recent position in the ini
  IniVectorSet ("CameraAngle", angle);
  IniVectorSet ("CameraPosition", position);
 
}