boundbox.h

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/* SPDX-FileCopyrightText: 2011-2022 Blender Foundation
 *
 * SPDX-License-Identifier: Apache-2.0 */
 
#pragma once
 
#include <cfloat>
#include <cmath>
 
#include "util/math.h"
#include "util/transform.h"
#include "util/types.h"
 
CCL_NAMESPACE_BEGIN
 
/* 3D BoundBox */
 
class BoundBox {
 public:
  float3 min, max;
 
  __forceinline BoundBox() = default;
 
  __forceinline BoundBox(const float3 &pt) : min(pt), max(pt) {}
 
  __forceinline BoundBox(const float3 &min_, const float3 &max_) : min(min_), max(max_) {}
 
  enum empty_t { empty = 0 };
 
  __forceinline BoundBox(empty_t /*unused*/)
      : min(make_float3(FLT_MAX, FLT_MAX, FLT_MAX)), max(make_float3(-FLT_MAX, -FLT_MAX, -FLT_MAX))
  {
  }
 
  __forceinline void grow(const float3 &pt)
  {
    /* the order of arguments to min is such that if pt is nan, it will not
     * influence the resulting bounding box */
    min = ccl::min(pt, min);
    max = ccl::max(pt, max);
  }
 
  __forceinline void grow(const float3 &pt, const float border)
  {
    const float3 shift = make_float3(border, border, border);
    min = ccl::min(pt - shift, min);
    max = ccl::max(pt + shift, max);
  }
 
  __forceinline void grow(const BoundBox &bbox)
  {
    min = ccl::min(bbox.min, min);
    max = ccl::max(bbox.max, max);
  }
 
  __forceinline void grow_safe(const float3 &pt)
  {
    /* the order of arguments to min is such that if pt is nan, it will not
     * influence the resulting bounding box */
    if (isfinite(pt.x) && isfinite(pt.y) && isfinite(pt.z)) {
      min = ccl::min(pt, min);
      max = ccl::max(pt, max);
    }
  }
 
  __forceinline void grow_safe(const float3 &pt, const float border)
  {
    if (isfinite(pt.x) && isfinite(pt.y) && isfinite(pt.z) && isfinite(border)) {
      const float3 shift = make_float3(border, border, border);
      min = ccl::min(pt - shift, min);
      max = ccl::max(pt + shift, max);
    }
  }
 
  __forceinline void grow_safe(const BoundBox &bbox)
  {
    if (isfinite_safe(bbox.min)) {
      min = ccl::min(bbox.min, min);
    }
    if (isfinite_safe(bbox.max)) {
      max = ccl::max(bbox.max, max);
    }
  }
 
  __forceinline void intersect(const BoundBox &bbox)
  {
    min = ccl::max(min, bbox.min);
    max = ccl::min(max, bbox.max);
  }
 
  /* todo: avoid using this */
  __forceinline float safe_area() const
  {
    if (!((min.x <= max.x) && (min.y <= max.y) && (min.z <= max.z))) {
      return 0.0f;
    }
 
    return area();
  }
 
  __forceinline float area() const
  {
    return half_area() * 2.0f;
  }
 
  __forceinline float half_area() const
  {
    const float3 d = max - min;
    return (d.x * d.z + d.y * d.z + d.x * d.y);
  }
 
  __forceinline float3 center() const
  {
    return 0.5f * (min + max);
  }
 
  __forceinline float3 center2() const
  {
    return min + max;
  }
 
  __forceinline float3 size() const
  {
    return max - min;
  }
 
  __forceinline bool valid() const
  {
    return (min.x <= max.x) && (min.y <= max.y) && (min.z <= max.z) &&
           (isfinite(min.x) && isfinite(min.y) && isfinite(min.z)) &&
           (isfinite(max.x) && isfinite(max.y) && isfinite(max.z));
  }
 
  BoundBox transformed(const Transform *tfm) const
  {
    BoundBox result = BoundBox::empty;
 
    /* Avoid transforming empty bounding box since the code below performs per-corner transform
     * which will convert non-valid bounds to valid. */
    if (!valid()) {
      return result;
    }
 
    for (int i = 0; i < 8; i++) {
      float3 p;
 
      p.x = (i & 1) ? min.x : max.x;
      p.y = (i & 2) ? min.y : max.y;
      p.z = (i & 4) ? min.z : max.z;
 
      result.grow(transform_point(tfm, p));
    }
 
    return result;
  }
 
  __forceinline bool intersects(const BoundBox &other)
  {
    const float3 center_diff = center() - other.center();
    const float3 total_size = (size() + other.size()) * 0.5f;
    return fabsf(center_diff.x) <= total_size.x && fabsf(center_diff.y) <= total_size.y &&
           fabsf(center_diff.z) <= total_size.z;
  }
};
 
__forceinline BoundBox merge(const BoundBox &bbox, const float3 &pt)
{
  return BoundBox(min(bbox.min, pt), max(bbox.max, pt));
}
 
__forceinline BoundBox merge(const BoundBox &a, const BoundBox &b)
{
  return BoundBox(min(a.min, b.min), max(a.max, b.max));
}
 
__forceinline BoundBox merge(const BoundBox &a,
                             const BoundBox &b,
                             const BoundBox &c,
                             const BoundBox &d)
{
  return merge(merge(a, b), merge(c, d));
}
 
__forceinline BoundBox intersect(const BoundBox &a, const BoundBox &b)
{
  return BoundBox(max(a.min, b.min), min(a.max, b.max));
}
 
__forceinline BoundBox intersect(const BoundBox &a, const BoundBox &b, const BoundBox &c)
{
  return intersect(a, intersect(b, c));
}
 
/* 2D BoundBox */
 
class BoundBox2D {
 public:
  float left = 0.0f;
  float right = 1.0f;
  float bottom = 0.0f;
  float top = 1.0f;
 
  BoundBox2D() = default;
 
  BoundBox2D(const float2 radius)
      : left(-radius.x), right(radius.x), bottom(-radius.y), top(radius.y)
  {
  }
 
  bool operator==(const BoundBox2D &other) const
  {
    return (left == other.left && right == other.right && bottom == other.bottom &&
            top == other.top);
  }
 
  float width()
  {
    return right - left;
  }
 
  float height()
  {
    return top - bottom;
  }
 
  BoundBox2D operator*(float f) const
  {
    BoundBox2D result;
 
    result.left = left * f;
    result.right = right * f;
    result.bottom = bottom * f;
    result.top = top * f;
 
    return result;
  }
 
  BoundBox2D subset(const BoundBox2D &other) const
  {
    BoundBox2D subset;
 
    subset.left = left + other.left * (right - left);
    subset.right = left + other.right * (right - left);
    subset.bottom = bottom + other.bottom * (top - bottom);
    subset.top = bottom + other.top * (top - bottom);
 
    return subset;
  }
 
  BoundBox2D make_relative_to(const BoundBox2D &other) const
  {
    BoundBox2D result;
 
    result.left = ((left - other.left) / (other.right - other.left));
    result.right = ((right - other.left) / (other.right - other.left));
    result.bottom = ((bottom - other.bottom) / (other.top - other.bottom));
    result.top = ((top - other.bottom) / (other.top - other.bottom));
 
    return result;
  }
 
  BoundBox2D clamp(const float mn = 0.0f, const float mx = 1.0f)
  {
    BoundBox2D result;
 
    result.left = ccl::clamp(left, mn, mx);
    result.right = ccl::clamp(right, mn, mx);
    result.bottom = ccl::clamp(bottom, mn, mx);
    result.top = ccl::clamp(top, mn, mx);
 
    return result;
  }
 
  BoundBox2D offset(const float2 offset) const
  {
    BoundBox2D result;
 
    result.left = left + offset.x;
    result.right = right + offset.x;
    result.bottom = bottom + offset.y;
    result.top = top + offset.y;
 
    return result;
  }
};
 
CCL_NAMESPACE_END