www.pudn.com > OpenCV-Intel.zip > cvconvhull.cpp
/*M///////////////////////////////////////////////////////////////////////////////////////
//
// IMPORTANT: READ BEFORE DOWNLOADING, COPYING, INSTALLING OR USING.
//
// By downloading, copying, installing or using the software you agree to this license.
// If you do not agree to this license, do not download, install,
// copy or use the software.
//
//
// Intel License Agreement
// For Open Source Computer Vision Library
//
// Copyright (C) 2000, Intel Corporation, all rights reserved.
// Third party copyrights are property of their respective owners.
//
// Redistribution and use in source and binary forms, with or without modification,
// are permitted provided that the following conditions are met:
//
// * Redistribution's of source code must retain the above copyright notice,
// this list of conditions and the following disclaimer.
//
// * Redistribution's in binary form must reproduce the above copyright notice,
// this list of conditions and the following disclaimer in the documentation
// and/or other materials provided with the distribution.
//
// * The name of Intel Corporation may not be used to endorse or promote products
// derived from this software without specific prior written permission.
//
// This software is provided by the copyright holders and contributors "as is" and
// any express or implied warranties, including, but not limited to, the implied
// warranties of merchantability and fitness for a particular purpose are disclaimed.
// In no event shall the Intel Corporation or contributors be liable for any direct,
// indirect, incidental, special, exemplary, or consequential damages
// (including, but not limited to, procurement of substitute goods or services;
// loss of use, data, or profits; or business interruption) however caused
// and on any theory of liability, whether in contract, strict liability,
// or tort (including negligence or otherwise) arising in any way out of
// the use of this software, even if advised of the possibility of such damage.
//
//M*/
#include "_cv.h"
static int
icvSklansky_32s( CvPoint** array, int start, int end, int* stack, int nsign, int sign2 )
{
int incr = end > start ? 1 : -1;
/* prepare first triangle */
int pprev = start, pcur = pprev + incr, pnext = pcur + incr;
int stacksize = 3;
if( start == end ||
(array[start]->x == array[end]->x &&
array[start]->y == array[end]->y) )
{
stack[0] = start;
return 1;
}
stack[0] = pprev;
stack[1] = pcur;
stack[2] = pnext;
end += incr; /* make end = afterend */
while( pnext != end )
{
/* check the angle p1,p2,p3 */
int cury = array[pcur]->y;
int nexty = array[pnext]->y;
int by = nexty - cury;
if( CV_SIGN(by) != nsign )
{
int ax = array[pcur]->x - array[pprev]->x;
int bx = array[pnext]->x - array[pcur]->x;
int ay = cury - array[pprev]->y;
int convexity = ay*bx - ax*by;/* if >0 then convex angle */
if( CV_SIGN(convexity) == sign2 && (ax != 0 || ay != 0) )
{
pprev = pcur;
pcur = pnext;
pnext += incr;
stack[stacksize] = pnext;
stacksize++;
}
else
{
if( pprev == start )
{
pcur = pnext;
stack[1] = pcur;
pnext += incr;
stack[2] = pnext;
}
else
{
stack[stacksize-2] = pnext;
pcur = pprev;
pprev = stack[stacksize-4];
stacksize--;
}
}
}
else
{
pnext += incr;
stack[stacksize-1] = pnext;
}
}
return --stacksize;
}
static int
icvSklansky_32f( CvPoint2D32f** array, int start, int end, int* stack, int nsign, int sign2 )
{
int incr = end > start ? 1 : -1;
/* prepare first triangle */
int pprev = start, pcur = pprev + incr, pnext = pcur + incr;
int stacksize = 3;
if( start == end ||
(array[start]->x == array[end]->x &&
array[start]->y == array[end]->y) )
{
stack[0] = start;
return 1;
}
stack[0] = pprev;
stack[1] = pcur;
stack[2] = pnext;
end += incr; /* make end = afterend */
while( pnext != end )
{
/* check the angle p1,p2,p3 */
float cury = array[pcur]->y;
float nexty = array[pnext]->y;
float by = nexty - cury;
if( CV_SIGN( by ) != nsign )
{
float ax = array[pcur]->x - array[pprev]->x;
float bx = array[pnext]->x - array[pcur]->x;
float ay = cury - array[pprev]->y;
float convexity = ay*bx - ax*by;/* if >0 then convex angle */
if( CV_SIGN( convexity ) == sign2 && (ax != 0 || ay != 0) )
{
pprev = pcur;
pcur = pnext;
pnext += incr;
stack[stacksize] = pnext;
stacksize++;
}
else
{
if( pprev == start )
{
pcur = pnext;
stack[1] = pcur;
pnext += incr;
stack[2] = pnext;
}
else
{
stack[stacksize-2] = pnext;
pcur = pprev;
pprev = stack[stacksize-4];
stacksize--;
}
}
}
else
{
pnext += incr;
stack[stacksize-1] = pnext;
}
}
return --stacksize;
}
typedef int (*sklansky_func)( CvPoint** points, int start, int end,
int* stack, int sign, int sign2 );
#define cmp_pts( pt1, pt2 ) \
((pt1)->x < (pt2)->x || (pt1)->x <= (pt2)->x && (pt1)->y < (pt2)->y)
static CV_IMPLEMENT_QSORT( icvSortPointsByPointers_32s, CvPoint*, cmp_pts )
static CV_IMPLEMENT_QSORT( icvSortPointsByPointers_32f, CvPoint2D32f*, cmp_pts )
static void
icvCalcAndWritePtIndices( CvPoint** pointer, int* stack, int start, int end,
CvSeq* ptseq, CvSeqWriter* writer )
{
CV_FUNCNAME( "icvCalcAndWritePtIndices" );
__BEGIN__;
int i, incr = start < end ? 1 : -1;
int idx, first_idx = ptseq->first->start_index;
for( i = start; i != end; i += incr )
{
CvPoint* ptr = (CvPoint*)pointer[stack[i]];
CvSeqBlock* block = ptseq->first;
while( (unsigned)(idx = (int)(ptr - (CvPoint*)block->data)) >= (unsigned)block->count )
{
block = block->next;
if( block == ptseq->first )
CV_ERROR( CV_StsError, "Internal error" );
}
idx += block->start_index - first_idx;
CV_WRITE_SEQ_ELEM( idx, *writer );
}
__END__;
}
CV_IMPL CvSeq*
cvConvexHull2( const CvArr* array, void* hull_storage,
int orientation, int return_points )
{
CvSeq* hull = 0;
CvPoint** pointer = 0;
CvPoint2D32f** pointerf = 0;
int* stack = 0;
CV_FUNCNAME( "cvConvexHull2" );
__BEGIN__;
CvMat* mat = 0;
CvSeqReader reader;
CvSeqWriter writer;
CvContour contour_header, hull_header;
CvSeqBlock block, hullblock;
CvSeq* ptseq = 0;
CvSeq* hullseq = 0;
int is_float;
int* t_stack;
int t_count;
int i, miny_ind = 0, maxy_ind = 0, total;
int hulltype;
int stop_idx;
sklansky_func sklansky;
if( CV_IS_SEQ( array ))
{
ptseq = (CvSeq*)array;
if( !CV_IS_SEQ_POINT_SET( ptseq ))
CV_ERROR( CV_StsBadArg, "Unsupported sequence type" );
if( hull_storage == 0 )
hull_storage = ptseq->storage;
}
else
{
CV_CALL( ptseq = cvPointSeqFromMat(
CV_SEQ_KIND_GENERIC, array, &contour_header, &block ));
}
if( CV_IS_STORAGE( hull_storage ))
{
if( return_points )
{
CV_CALL( hullseq = cvCreateSeq(
CV_SEQ_KIND_CURVE|CV_SEQ_ELTYPE(ptseq)|
CV_SEQ_FLAG_CLOSED|CV_SEQ_FLAG_CONVEX,
sizeof(CvContour), sizeof(CvPoint),(CvMemStorage*)hull_storage ));
}
else
{
CV_CALL( hullseq = cvCreateSeq(
CV_SEQ_KIND_CURVE|CV_SEQ_ELTYPE_PPOINT|
CV_SEQ_FLAG_CLOSED|CV_SEQ_FLAG_CONVEX,
sizeof(CvContour), sizeof(CvPoint*), (CvMemStorage*)hull_storage ));
}
}
else
{
if( !CV_IS_MAT( hull_storage ))
CV_ERROR(CV_StsBadArg, "Destination must be valid memory storage or matrix");
mat = (CvMat*)hull_storage;
if( mat->cols != 1 && mat->rows != 1 || !CV_IS_MAT_CONT(mat->type))
CV_ERROR( CV_StsBadArg,
"The hull matrix should be continuous and have a single row or a single column" );
if( mat->cols + mat->rows - 1 < ptseq->total )
CV_ERROR( CV_StsBadSize, "The hull matrix size might be not enough to fit the hull" );
if( CV_MAT_TYPE(mat->type) != CV_SEQ_ELTYPE(ptseq) &&
CV_MAT_TYPE(mat->type) != CV_32SC1 )
CV_ERROR( CV_StsUnsupportedFormat,
"The hull matrix must have the same type as input or 32sC1 (integers)" );
CV_CALL( hullseq = cvMakeSeqHeaderForArray(
CV_SEQ_KIND_CURVE|CV_MAT_TYPE(mat->type)|CV_SEQ_FLAG_CLOSED,
sizeof(contour_header), CV_ELEM_SIZE(mat->type), mat->data.ptr,
mat->cols + mat->rows - 1, (CvSeq*)&hull_header, &hullblock ));
cvClearSeq( hullseq );
}
total = ptseq->total;
if( total == 0 )
{
if( mat )
CV_ERROR( CV_StsBadSize,
"Point sequence can not be empty if the output is matrix" );
EXIT;
}
cvStartAppendToSeq( hullseq, &writer );
is_float = CV_SEQ_ELTYPE(ptseq) == CV_32FC2;
hulltype = CV_SEQ_ELTYPE(hullseq);
sklansky = !is_float ? (sklansky_func)icvSklansky_32s :
(sklansky_func)icvSklansky_32f;
CV_CALL( pointer = (CvPoint**)cvAlloc( ptseq->total*sizeof(pointer[0]) ));
CV_CALL( stack = (int*)cvAlloc( (ptseq->total + 2)*sizeof(stack[0]) ));
pointerf = (CvPoint2D32f**)pointer;
cvStartReadSeq( ptseq, &reader );
for( i = 0; i < total; i++ )
{
pointer[i] = (CvPoint*)reader.ptr;
CV_NEXT_SEQ_ELEM( ptseq->elem_size, reader );
}
// sort the point set by x-coordinate, find min and max y
if( !is_float )
{
icvSortPointsByPointers_32s( pointer, total, 0 );
for( i = 1; i < total; i++ )
{
int y = pointer[i]->y;
if( pointer[miny_ind]->y > y )
miny_ind = i;
if( pointer[maxy_ind]->y < y )
maxy_ind = i;
}
}
else
{
icvSortPointsByPointers_32f( pointerf, total, 0 );
for( i = 1; i < total; i++ )
{
float y = pointerf[i]->y;
if( pointerf[miny_ind]->y > y )
miny_ind = i;
if( pointerf[maxy_ind]->y < y )
maxy_ind = i;
}
}
if( pointer[0]->x == pointer[total-1]->x &&
pointer[0]->y == pointer[total-1]->y )
{
if( hulltype == CV_SEQ_ELTYPE_PPOINT )
{
CV_WRITE_SEQ_ELEM( pointer[0], writer );
}
else if( hulltype == CV_SEQ_ELTYPE_INDEX )
{
int index = 0;
CV_WRITE_SEQ_ELEM( index, writer );
}
else
{
CvPoint pt = pointer[0][0];
CV_WRITE_SEQ_ELEM( pt, writer );
}
goto finish_hull;
}
/*upper half */
{
int *tl_stack = stack;
int tl_count = sklansky( pointer, 0, maxy_ind, tl_stack, -1, 1 );
int *tr_stack = tl_stack + tl_count;
int tr_count = sklansky( pointer, ptseq->total - 1, maxy_ind, tr_stack, -1, -1 );
/* gather upper part of convex hull to output */
if( orientation == CV_COUNTER_CLOCKWISE )
{
CV_SWAP( tl_stack, tr_stack, t_stack );
CV_SWAP( tl_count, tr_count, t_count );
}
if( hulltype == CV_SEQ_ELTYPE_PPOINT )
{
for( i = 0; i < tl_count - 1; i++ )
CV_WRITE_SEQ_ELEM( pointer[tl_stack[i]], writer );
for( i = tr_count - 1; i > 0; i-- )
CV_WRITE_SEQ_ELEM( pointer[tr_stack[i]], writer );
}
else if( hulltype == CV_SEQ_ELTYPE_INDEX )
{
CV_CALL( icvCalcAndWritePtIndices( pointer, tl_stack,
0, tl_count-1, ptseq, &writer ));
CV_CALL( icvCalcAndWritePtIndices( pointer, tr_stack,
tr_count-1, 0, ptseq, &writer ));
}
else
{
for( i = 0; i < tl_count - 1; i++ )
CV_WRITE_SEQ_ELEM( pointer[tl_stack[i]][0], writer );
for( i = tr_count - 1; i > 0; i-- )
CV_WRITE_SEQ_ELEM( pointer[tr_stack[i]][0], writer );
}
stop_idx = tr_count > 2 ? tr_stack[1] : tl_count > 2 ? tl_stack[tl_count - 2] : -1;
}
/* lower half */
{
int *bl_stack = stack;
int bl_count = sklansky( pointer, 0, miny_ind, bl_stack, 1, -1 );
int *br_stack = stack + bl_count;
int br_count = sklansky( pointer, ptseq->total - 1, miny_ind, br_stack, 1, 1 );
if( orientation != CV_COUNTER_CLOCKWISE )
{
CV_SWAP( bl_stack, br_stack, t_stack );
CV_SWAP( bl_count, br_count, t_count );
}
if( stop_idx >= 0 )
{
int check_idx = bl_count > 2 ? bl_stack[1] :
bl_count + br_count > 2 ? br_stack[2-bl_count] : -1;
if( check_idx == stop_idx || check_idx >= 0 &&
pointer[check_idx]->x == pointer[stop_idx]->x &&
pointer[check_idx]->y == pointer[stop_idx]->y )
{
/* if all the points lie on the same line, then
the bottom part of the convex hull is the mirrored top part
(except the exteme points).*/
bl_count = MIN( bl_count, 2 );
br_count = MIN( br_count, 2 );
}
}
if( hulltype == CV_SEQ_ELTYPE_PPOINT )
{
for( i = 0; i < bl_count - 1; i++ )
CV_WRITE_SEQ_ELEM( pointer[bl_stack[i]], writer );
for( i = br_count - 1; i > 0; i-- )
CV_WRITE_SEQ_ELEM( pointer[br_stack[i]], writer );
}
else if( hulltype == CV_SEQ_ELTYPE_INDEX )
{
CV_CALL( icvCalcAndWritePtIndices( pointer, bl_stack,
0, bl_count-1, ptseq, &writer ));
CV_CALL( icvCalcAndWritePtIndices( pointer, br_stack,
br_count-1, 0, ptseq, &writer ));
}
else
{
for( i = 0; i < bl_count - 1; i++ )
CV_WRITE_SEQ_ELEM( pointer[bl_stack[i]][0], writer );
for( i = br_count - 1; i > 0; i-- )
CV_WRITE_SEQ_ELEM( pointer[br_stack[i]][0], writer );
}
}
finish_hull:
CV_CALL( cvEndWriteSeq( &writer ));
if( mat )
{
if( mat->rows > mat->cols )
mat->rows = hullseq->total;
else
mat->cols = hullseq->total;
}
else
{
hull = hullseq;
((CvContour*)hull)->rect = cvBoundingRect( ptseq, ptseq == (CvSeq*)&contour_header );
/*if( ptseq != (CvSeq*)&contour_header )
hullseq->v_prev = ptseq;*/
}
__END__;
cvFree( (void**)&pointer );
cvFree( (void**)&stack );
return hull;
}
/* contour must be a simple polygon */
/* it must have more than 3 points */
CV_IMPL CvSeq*
cvConvexityDefects( const CvArr* array,
const CvArr* hullarray,
CvMemStorage* storage )
{
CvSeq* defects = 0;
CV_FUNCNAME( "cvConvexityDefects" );
__BEGIN__;
int i, index;
CvPoint* hull_cur;
/* is orientation of hull different from contour one */
int rev_orientation;
CvContour contour_header;
CvContour hull_header;
CvSeqBlock block, hullblock;
CvSeq *ptseq = (CvSeq*)array, *hull = (CvSeq*)hullarray;
CvSeqReader hull_reader;
CvSeqReader ptseq_reader;
CvSeqWriter writer;
int is_index;
if( CV_IS_SEQ( ptseq ))
{
if( !CV_IS_SEQ_POINT_SET( ptseq ))
CV_ERROR( CV_StsUnsupportedFormat,
"Input sequence is not a sequence of points" );
if( !storage )
storage = ptseq->storage;
}
else
{
CV_CALL( ptseq = cvPointSeqFromMat(
CV_SEQ_KIND_GENERIC, array, &contour_header, &block ));
}
if( CV_SEQ_ELTYPE( ptseq ) != CV_32SC2 )
CV_ERROR( CV_StsUnsupportedFormat,
"Floating-point coordinates are not supported here" );
if( CV_IS_SEQ( hull ))
{
int hulltype = CV_SEQ_ELTYPE( hull );
if( hulltype != CV_SEQ_ELTYPE_PPOINT && hulltype != CV_SEQ_ELTYPE_INDEX )
CV_ERROR( CV_StsUnsupportedFormat,
"Convex hull must represented as a sequence "
"of indices or sequence of pointers" );
if( !storage )
storage = hull->storage;
}
else
{
CvMat* mat = (CvMat*)hull;
if( !CV_IS_MAT( hull ))
CV_ERROR(CV_StsBadArg, "Convex hull is neither sequence nor matrix");
if( mat->cols != 1 && mat->rows != 1 ||
!CV_IS_MAT_CONT(mat->type) || CV_MAT_TYPE(mat->type) != CV_32SC1 )
CV_ERROR( CV_StsBadArg,
"The matrix should be 1-dimensional and continuous array of int's" );
if( mat->cols + mat->rows - 1 > ptseq->total )
CV_ERROR( CV_StsBadSize, "Convex hull is larger than the point sequence" );
CV_CALL( hull = cvMakeSeqHeaderForArray(
CV_SEQ_KIND_CURVE|CV_MAT_TYPE(mat->type)|CV_SEQ_FLAG_CLOSED,
sizeof(hull_header), CV_ELEM_SIZE(mat->type), mat->data.ptr,
mat->cols + mat->rows - 1, (CvSeq*)&hull_header, &hullblock ));
}
is_index = CV_SEQ_ELTYPE(hull) == CV_SEQ_ELTYPE_INDEX;
if( !storage )
CV_ERROR( CV_StsNullPtr, "NULL storage pointer" );
CV_CALL( defects = cvCreateSeq( CV_SEQ_KIND_GENERIC, sizeof(CvSeq),
sizeof(CvConvexityDefect), storage ));
if( ptseq->total < 4 || hull->total < 3)
{
//CV_ERROR( CV_StsBadSize,
// "point seq size must be >= 4, convex hull size must be >= 3" );
EXIT;
}
/* recognize co-orientation of ptseq and its hull */
{
int sign = 0;
int index1, index2, index3;
if( !is_index )
{
CvPoint* pos = *CV_SEQ_ELEM( hull, CvPoint*, 0 );
CV_CALL( index1 = cvSeqElemIdx( ptseq, pos ));
pos = *CV_SEQ_ELEM( hull, CvPoint*, 1 );
CV_CALL( index2 = cvSeqElemIdx( ptseq, pos ));
pos = *CV_SEQ_ELEM( hull, CvPoint*, 2 );
CV_CALL( index3 = cvSeqElemIdx( ptseq, pos ));
}
else
{
index1 = *CV_SEQ_ELEM( hull, int, 0 );
index2 = *CV_SEQ_ELEM( hull, int, 1 );
index3 = *CV_SEQ_ELEM( hull, int, 2 );
}
sign += (index2 > index1) ? 1 : 0;
sign += (index3 > index2) ? 1 : 0;
sign += (index1 > index3) ? 1 : 0;
rev_orientation = (sign == 2) ? 0 : 1;
}
cvStartReadSeq( ptseq, &ptseq_reader, 0 );
cvStartReadSeq( hull, &hull_reader, rev_orientation );
if( !is_index )
{
hull_cur = *(CvPoint**)hull_reader.prev_elem;
index = cvSeqElemIdx( ptseq, (char*)hull_cur, 0 );
}
else
{
index = *(int*)hull_reader.prev_elem;
hull_cur = CV_GET_SEQ_ELEM( CvPoint, ptseq, index );
}
cvSetSeqReaderPos( &ptseq_reader, index );
cvStartAppendToSeq( defects, &writer );
/* cycle through ptseq and hull with computing defects */
for( i = 0; i < hull->total; i++ )
{
CvConvexityDefect defect;
int is_defect = 0;
double dx0, dy0;
double depth = 0, scale;
CvPoint* hull_next;
if( !is_index )
hull_next = *(CvPoint**)hull_reader.ptr;
else
{
int t = *(int*)hull_reader.ptr;
hull_next = CV_GET_SEQ_ELEM( CvPoint, ptseq, t );
}
dx0 = (double)hull_next->x - (double)hull_cur->x;
dy0 = (double)hull_next->y - (double)hull_cur->y;
assert( dx0 != 0 || dy0 != 0 );
scale = 1./sqrt(dx0*dx0 + dy0*dy0);
defect.start = hull_cur;
defect.end = hull_next;
for(;;)
{
/* go through ptseq to achieve next hull point */
CV_NEXT_SEQ_ELEM( sizeof(CvPoint), ptseq_reader );
if( ptseq_reader.ptr == (char*)hull_next )
break;
else
{
CvPoint* cur = (CvPoint*)ptseq_reader.ptr;
/* compute distance from current point to hull edge */
double dx = (double)cur->x - (double)hull_cur->x;
double dy = (double)cur->y - (double)hull_cur->y;
/* compute depth */
double dist = fabs(-dy0*dx + dx0*dy) * scale;
if( dist > depth )
{
depth = dist;
defect.depth_point = cur;
defect.depth = (float)depth;
is_defect = 1;
}
}
}
if( is_defect )
{
CV_WRITE_SEQ_ELEM( defect, writer );
}
hull_cur = hull_next;
if( rev_orientation )
{
CV_PREV_SEQ_ELEM( hull->elem_size, hull_reader );
}
else
{
CV_NEXT_SEQ_ELEM( hull->elem_size, hull_reader );
}
}
defects = cvEndWriteSeq( &writer );
__END__;
return defects;
}
CV_IMPL int
cvCheckContourConvexity( const CvArr* array )
{
int flag = -1;
CV_FUNCNAME( "cvCheckContourConvexity" );
__BEGIN__;
int i;
int orientation = 0;
CvSeqReader reader;
CvContour contour_header;
CvSeqBlock block;
CvSeq* contour = (CvSeq*)array;
if( CV_IS_SEQ(contour) )
{
if( !CV_IS_SEQ_POLYGON(contour))
CV_ERROR( CV_StsUnsupportedFormat,
"Input sequence must be polygon (closed 2d curve)" );
}
else
{
CV_CALL( contour = cvPointSeqFromMat(
CV_SEQ_KIND_CURVE|CV_SEQ_FLAG_CLOSED, array, &contour_header, &block ));
}
if( contour->total == 0 )
EXIT;
cvStartReadSeq( contour, &reader, 0 );
flag = 1;
if( CV_SEQ_ELTYPE( contour ) == CV_32SC2 )
{
CvPoint *prev_pt = (CvPoint*)reader.prev_elem;
CvPoint *cur_pt = (CvPoint*)reader.ptr;
int dx0 = cur_pt->x - prev_pt->x;
int dy0 = cur_pt->y - prev_pt->y;
for( i = 0; i < contour->total; i++ )
{
int dxdy0, dydx0;
int dx, dy;
/*int orient; */
CV_NEXT_SEQ_ELEM( sizeof(CvPoint), reader );
prev_pt = cur_pt;
cur_pt = (CvPoint *) reader.ptr;
dx = cur_pt->x - prev_pt->x;
dy = cur_pt->y - prev_pt->y;
dxdy0 = dx * dy0;
dydx0 = dy * dx0;
/* find orientation */
/*orient = -dy0 * dx + dx0 * dy;
orientation |= (orient > 0) ? 1 : 2;
*/
orientation |= (dydx0 > dxdy0) ? 1 : ((dydx0 < dxdy0) ? 2 : 3);
if( orientation == 3 )
{
flag = 0;
break;
}
dx0 = dx;
dy0 = dy;
}
}
else
{
assert( CV_SEQ_ELTYPE(contour) == CV_32FC2 );
CvPoint2D32f *prev_pt = (CvPoint2D32f*)reader.prev_elem;
CvPoint2D32f *cur_pt = (CvPoint2D32f*)reader.ptr;
float dx0 = cur_pt->x - prev_pt->x;
float dy0 = cur_pt->y - prev_pt->y;
for( i = 0; i < contour->total; i++ )
{
float dxdy0, dydx0;
float dx, dy;
/*int orient; */
CV_NEXT_SEQ_ELEM( sizeof(CvPoint2D32f), reader );
prev_pt = cur_pt;
cur_pt = (CvPoint2D32f*) reader.ptr;
dx = cur_pt->x - prev_pt->x;
dy = cur_pt->y - prev_pt->y;
dxdy0 = dx * dy0;
dydx0 = dy * dx0;
/* find orientation */
/*orient = -dy0 * dx + dx0 * dy;
orientation |= (orient > 0) ? 1 : 2;
*/
orientation |= (dydx0 > dxdy0) ? 1 : ((dydx0 < dxdy0) ? 2 : 3);
if( orientation == 3 )
{
flag = 0;
break;
}
dx0 = dx;
dy0 = dy;
}
}
__END__;
return flag;
}
/* End of file. */