(* /*****************************************************************
  //                       Delphi-OpenCV Demo
  //               Copyright (C) 2013 Project Delphi-OpenCV
  // ****************************************************************
  // Contributor:
  // laentir Valetov
  // email:laex@bk.ru
  // ****************************************************************
  // You may retrieve the latest version of this file at the GitHub,
  // located at git://github.com/Laex/Delphi-OpenCV.git
  // ****************************************************************
  // The contents of this file are used with permission, subject to
  // the Mozilla Public License Version 1.1 (the "License"); you may
  // not use this file except in compliance with the License. You may
  // obtain a copy of the License at
  // http://www.mozilla.org/MPL/MPL-1_1Final.html
  //
  // Software distributed under the License is distributed on an
  // "AS IS" basis, WITHOUT WARRANTY OF ANY KIND, either express or
  // implied. See the License for the specific language governing
  // rights and limitations under the License.
  //  *************************************************************** *)

// JCL_DEBUG_EXPERT_GENERATEJDBG OFF
// JCL_DEBUG_EXPERT_INSERTJDBG OFF
// JCL_DEBUG_EXPERT_DELETEMAPFILE OFF
program cv_ExtractSURF;

{$APPTYPE CONSOLE}
{$POINTERMATH ON}
{$R *.res}

uses
  System.SysUtils,
  Windows,
  System.Generics.Collections,
  uLibName in '..\..\..\include\uLibName.pas',
  highgui_c in '..\..\..\include\highgui\highgui_c.pas',
  core_c in '..\..\..\include\Core\core_c.pas',
  Core.types_c in '..\..\..\include\Core\Core.types_c.pas',
  imgproc.types_c in '..\..\..\include\imgproc\imgproc.types_c.pas',
  imgproc_c in '..\..\..\include\imgproc\imgproc_c.pas',
  legacy in '..\..\..\include\legacy\legacy.pas',
  calib3d in '..\..\..\include\calib3d\calib3d.pas',
  imgproc in '..\..\..\include\imgproc\imgproc.pas',
  haar in '..\..\..\include\objdetect\haar.pas',
  objdetect in '..\..\..\include\objdetect\objdetect.pas',
  tracking in '..\..\..\include\video\tracking.pas',
  Core in '..\..\..\include\Core\core.pas',
  compat in '..\..\..\include\legacy\compat.pas',
  nonfree in '..\..\..\include\nonfree\nonfree.pas',
  Mat in '..\..\..\include\core\Mat.pas',
  core.types in '..\..\..\include\core\core.types.pas',
  cvUtils in '..\..\..\include\cvUtils.pas';

function compareSURFDescriptors(const d1: pSingle; const d2: pSingle; best: Double; length: Integer): Double;
var
  total_cost: Double;
  i: Integer;
  t0, t1, t2, t3: Double;
begin
  total_cost := 0;
  assert(length mod 4 = 0);
  i := 0;
  while i < length do
  begin
    t0 := d1[i] - d2[i];
    t1 := d1[i + 1] - d2[i + 1];
    t2 := d1[i + 2] - d2[i + 2];
    t3 := d1[i + 3] - d2[i + 3];
    total_cost := total_cost + t0 * t0 + t1 * t1 + t2 * t2 + t3 * t3;
    if (total_cost > best) then
      break;
    i := i + 4;
  end;
  Result := total_cost;
end;

function naiveNearestNeighbor(const vec: pSingle; laplacian: Integer; const model_keypoints: pCvSeq;
  const model_descriptors: pCvSeq): Integer;
Var
  length: Integer;
  i, neighbor: Integer;
  d, dist1, dist2: Double;
  reader, kreader: TCvSeqReader;
  kp: pCvSURFPoint;
  mvec: pSingle;
begin
  length := model_descriptors.elem_size div sizeof(single);
  neighbor := -1;
  dist1 := 1E6;
  dist2 := 1E6;
  cvStartReadSeq(model_keypoints, @kreader, 0);
  cvStartReadSeq(model_descriptors, @reader, 0);

  for i := 0 to model_descriptors.total-1 do
  begin
    kp := pCvSURFPoint(kreader.ptr);
    mvec := pSingle(reader.ptr);
    CV_NEXT_SEQ_ELEM(kreader.seq.elem_size, kreader);
    CV_NEXT_SEQ_ELEM(reader.seq.elem_size, reader);
    if (laplacian <> kp.laplacian) then
      continue;
    d := compareSURFDescriptors(vec, mvec, dist2, length);
    if (d < dist1) then
    begin
      dist2 := dist1;
      dist1 := d;
      neighbor := i;
    end
    else if (d < dist2) then
      dist2 := d;
  end;
  if (dist1 < 0.6 * dist2) then
    Exit(neighbor);
  Exit(-1);
end;

Type
  TCvPointArr = Array [0 .. 3] of TCvPoint;
  TIntegerDynArray = Array of Integer;
  pIntegerDynArray = ^TIntegerDynArray;

Procedure findPairs(objectKeypoints, objectDescriptors, imageKeypoints, imageDescriptors: pCvSeq;
  Var ptpairs: TIntegerDynArray);
Var
  i, nearest_neighbor, n: Integer;
  reader, kreader: TCvSeqReader;
  kp: pCvSURFPoint;
  descriptor: pSingle;
Begin
  cvStartReadSeq(objectKeypoints, @kreader);
  cvStartReadSeq(objectDescriptors, @reader);
  n := 0;
  SetLength(ptpairs, 0);
  initialize(ptpairs, 0);
  for i := 0 to objectDescriptors.total - 1 do
  begin
    kp := pCvSURFPoint(kreader.ptr);
    descriptor := pSingle(reader.ptr);
    CV_NEXT_SEQ_ELEM(kreader.seq.elem_size, kreader);
    CV_NEXT_SEQ_ELEM(reader.seq.elem_size, reader);
    nearest_neighbor := naiveNearestNeighbor(descriptor, kp.laplacian, imageKeypoints, imageDescriptors);
    if nearest_neighbor >= 0 Then
    begin
      n := n + 1;
      SetLength(ptpairs, n + 1);
      ptpairs[n] := nearest_neighbor;
    End;
  End;
End;

const
  object_filename = 'resource\box.png';
  scene_filename = 'resource\box_in_scene.png';

Var
  image, ObjImg, objectcolor, correspond: pIplImage;
  storage: pCvMemStorage;
  objectKeypoints, objectDescriptors, imageKeypoints, imageDescriptors: pCvSeq;
  params: TCvSURFParams;
  tt: Double;
  src_corners: TCvPointArr;
  i: Integer;
  ptpairs: TIntegerDynArray;
  p1, p2: pCvSURFPoint;

begin
  try
    initModule_nonfree;
    ObjImg := cvLoadImage(object_filename, CV_LOAD_IMAGE_GRAYSCALE);
    image := cvLoadImage(scene_filename, CV_LOAD_IMAGE_GRAYSCALE);
    storage := cvCreateMemStorage(0);

    objectcolor := cvCreateImage(cvSize(ObjImg.Width, ObjImg.Height), 8, 3);
    cvCvtColor(ObjImg, objectcolor, CV_GRAY2BGR);
    params := cvSURFParams(500, 1);
    tt := cvGetTickCount;
    cvExtractSURF(ObjImg, 0, @objectKeypoints, @objectDescriptors, storage, params);
    cvExtractSURF(image, 0, @imageKeypoints, @imageDescriptors, storage, params);
    tt := cvGetTickCount - tt;
    src_corners[0] := cvPoint(0, 0);
    src_corners[1] := cvPoint(ObjImg.Width, 0);
    src_corners[2] := cvPoint(ObjImg.Width, ObjImg.Height);
    src_corners[3] := cvPoint(0, ObjImg.Height);
    correspond := cvCreateImage(cvSize(image.Width, ObjImg.Height + image.Height), 8, 1);
    cvSetImageROI(correspond, cvRect(0, 0, ObjImg.Width, ObjImg.Height));
    cvCopy(ObjImg, correspond);
    cvSetImageROI(correspond, cvRect(0, ObjImg.Height, correspond.Width, correspond.Height));
    cvCopy(image, correspond);
    cvResetImageROI(correspond);

    findPairs(objectKeypoints, objectDescriptors, imageKeypoints, imageDescriptors, ptpairs);
    i := 0;
    While i < length(ptpairs) do
    begin
      p1 := pCvSURFPoint(cvGetSeqElem(objectKeypoints, ptpairs[i]));
      p2 := pCvSURFPoint(cvGetSeqElem(imageKeypoints, ptpairs[i]));
      cvLine(correspond, cvPointFrom32f(p1.pt), cvPoint(cvRound(p2.pt.x), cvRound(p2.pt.y + ObjImg.Height)),
        cvscalarAll(255));
      i := i + 1;
    End;

    cvShowImage('A', correspond);
    While True Do
      if cvWaitKey(50) = 27 Then
        break;

    cvReleaseImage(objectcolor);
    cvReleaseMemStorage(storage);
    cvReleaseImage(ObjImg);
    cvReleaseImage(image);
  except
    on E: Exception do
      WriteLn(E.ClassName, ': ', E.Message);
  end;

end.