/* bzflag
 * Copyright (c) 1993-2017 Tim Riker
 *
 * This package is free software;  you can redistribute it and/or
 * modify it under the terms of the license found in the file
 * named COPYING that should have accompanied this file.
 *
 * THIS PACKAGE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
 */


// interface header
#include "RoofTops.h"

// local interface headers
#include "Obstacle.h"
#include "Ray.h"
#include "CollisionManager.h"
#include "Teleporter.h"


/****************************************************************************/

// NOTE - this could also be used with a 'rain on windshield' effect

// FIXME - this should use a pregenerated list of 3D polygons
//       - use something like a split quadtree  (16 divs top layer, etc...)
//       - splitting polygons is only helpful if they break into diff cells
//	 - return the isFlatTop() state?  (for making puddles)
//	 - return the plane normal?  (also for making puddles)
//       - check the hit position for under-the-wall leaks?

void RoofTops::load()
{
  return;
}


void RoofTops::clear()
{
  return;
}


float RoofTops::getTopHeight(float x, float y, float maxHeight)
{
  const float zSpeed = -1.0f;

  // setup the test ray
  const float dir[3] = { 0.0f, 0.0f, zSpeed };
  const float org[3] = { x, y, maxHeight };
  Ray ray(org, dir);

  // get the obstacle list
  const ObsList* olist = COLLISIONMGR.rayTest (&ray, MAXFLOAT);

  float minTime = MAXFLOAT;

  for (int i = 0; i < olist->count; i++) {
    const Obstacle* obs = olist->list[i];
    const float t = obs->intersect(ray);
    if (obs->getType() == Teleporter::getClassName()) {
      // the physics for teles is whacked, imho
      continue;
    }
    else if ((t > 0.0f) && (t < minTime)) {
      minTime = t;
    }
  }

  float height = maxHeight + (minTime * zSpeed);

  if (height < 0.0f) {
    height = 0.0f;
  }

  return height;
}


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