void queue_pop (struct queue *q) {
if (q->count == 0) {
return;
}
q->count--;
q->out = fast_mod ( (q->out + 1), q->size );
}
void queue_push (struct queue *q, void *e) {
unsigned int loc;
if (q->count == q->size) {
/* queue is full! */
return;
}
loc = fast_mod ( (q->out + q->count), q->size );
memcpy (queue_addr(q, loc), e, q->elem_size);
q->count++;
}
void Path::addArc(const FloatPoint& p, float r, float sa, float ea,
bool clockwise) {
SkScalar cx = SkFloatToScalar(p.x());
SkScalar cy = SkFloatToScalar(p.y());
SkScalar radius = SkFloatToScalar(r);
SkRect oval;
oval.set(cx - radius, cy - radius, cx + radius, cy + radius);
float sweep = ea - sa;
bool prependOval = false;
/* Note if clockwise and the sign of the sweep disagree. This particular
logic was deduced from http://canvex.lazyilluminati.com/misc/arc.html
*/
if (clockwise && (sweep > 0 || sweep < -g2PI)) {
sweep = fmodf(sweep, g2PI) - g2PI;
} else if (!clockwise && (sweep < 0 || sweep > g2PI)) {
sweep = fmodf(sweep, g2PI) + g2PI;
}
// If the abs(sweep) >= 2PI, then we need to add a circle before we call
// arcTo, since it treats the sweep mod 2PI. We don't have a prepend call,
// so we just remember this, and at the end create a new path with an oval
// and our current path, and then swap then.
//
if (sweep >= g2PI || sweep <= -g2PI) {
prependOval = true;
// SkDebugf("addArc sa=%g ea=%g cw=%d sweep %g treat as circle\n", sa, ea, clockwise, sweep);
// now reduce sweep to just the amount we need, so that the current
// point is left where the caller expects it.
sweep = fmodf(sweep, g2PI);
}
sa = fast_mod(sa, g2PI);
SkScalar startDegrees = SkFloatToScalar(sa * g180OverPI);
SkScalar sweepDegrees = SkFloatToScalar(sweep * g180OverPI);
// SkDebugf("addArc sa=%g ea=%g cw=%d sweep=%g ssweep=%g\n", sa, ea, clockwise, sweep, SkScalarToFloat(sweepDegrees));
m_path->arcTo(oval, startDegrees, sweepDegrees, false);
if (prependOval) {
SkPath tmp;
tmp.addOval(oval);
tmp.addPath(*m_path);
m_path->swap(tmp);
}
}
/** @brief MATLAB Driver.
**/
void
mexFunction(int nout, mxArray *out[],
int nin, const mxArray *in[])
{
int M,N,S=0,smin=0,K,num_levels=0 ;
const int* dimensions ;
const double* P_pt ;
const double* G_pt ;
float* descr_pt ;
float* buffer_pt ;
float sigma0 ;
float magnif = 3.0f ; /* Spatial bin extension factor. */
int NBP = 4 ; /* Number of bins for one spatial direction (even). */
int NBO = 8 ; /* Number of bins for the ortientation. */
int mode = NOSCALESPACE ;
int buffer_size=0;
enum {IN_G=0,IN_P,IN_SIGMA0,IN_S,IN_SMIN} ;
enum {OUT_L=0} ;
/* ------------------------------------------------------------------
** Check the arguments
** --------------------------------------------------------------- */
if (nin < 3) {
mexErrMsgTxt("At least three arguments are required") ;
} else if (nout > 1) {
mexErrMsgTxt("Too many output arguments.");
}
if( !uIsRealScalar(in[IN_SIGMA0]) ) {
mexErrMsgTxt("SIGMA0 should be a real scalar") ;
}
if(!mxIsDouble(in[IN_G]) ||
mxGetNumberOfDimensions(in[IN_G]) > 3) {
mexErrMsgTxt("G should be a real matrix or 3-D array") ;
}
sigma0 = (float) *mxGetPr(in[IN_SIGMA0]) ;
dimensions = mxGetDimensions(in[IN_G]) ;
M = dimensions[0] ;
N = dimensions[1] ;
G_pt = mxGetPr(in[IN_G]) ;
P_pt = mxGetPr(in[IN_P]) ;
K = mxGetN(in[IN_P]) ;
if( !uIsRealMatrix(in[IN_P],-1,-1)) {
mexErrMsgTxt("P should be a real matrix") ;
}
if ( mxGetM(in[IN_P]) == 4) {
/* Standard (scale space) mode */
mode = SCALESPACE ;
num_levels = dimensions[2] ;
if(nin < 5) {
mexErrMsgTxt("Five arguments are required in standard mode") ;
}
if( !uIsRealScalar(in[IN_S]) ) {
mexErrMsgTxt("S should be a real scalar") ;
}
if( !uIsRealScalar(in[IN_SMIN]) ) {
mexErrMsgTxt("SMIN should be a real scalar") ;
}
if( !uIsRealMatrix(in[IN_P],4,-1)) {
mexErrMsgTxt("When the e mode P should be a 4xK matrix.") ;
}
S = (int)(*mxGetPr(in[IN_S])) ;
smin = (int)(*mxGetPr(in[IN_SMIN])) ;
} else if ( mxGetM(in[IN_P]) == 3 ) {
mode = NOSCALESPACE ;
num_levels = 1 ;
S = 1 ;
smin = 0 ;
} else {
mexErrMsgTxt("P should be either a 3xK or a 4xK matrix.") ;
}
/* Parse the property-value pairs */
{
char str [80] ;
int arg = (mode == SCALESPACE) ? IN_SMIN + 1 : IN_SIGMA0 + 1 ;
while(arg < nin) {
int k ;
if( !uIsString(in[arg],-1) ) {
mexErrMsgTxt("The first argument in a property-value pair"
" should be a string") ;
}
mxGetString(in[arg], str, 80) ;
#ifdef WINDOWS
for(k = 0 ; properties[k] && strcmpi(str, properties[k]) ; ++k) ;
#else
for(k = 0 ; properties[k] && strcasecmp(str, properties[k]) ; ++k) ;
#endif
switch (k) {
case PROP_NBP:
if( !uIsRealScalar(in[arg+1]) ) {
mexErrMsgTxt("'NumSpatialBins' should be real scalar") ;
}
NBP = (int) *mxGetPr(in[arg+1]) ;
if( NBP <= 0 || (NBP & 0x1) ) {
mexErrMsgTxt("'NumSpatialBins' must be positive and even") ;
}
break ;
case PROP_NBO:
if( !uIsRealScalar(in[arg+1]) ) {
mexErrMsgTxt("'NumOrientBins' should be a real scalar") ;
}
NBO = (int) *mxGetPr(in[arg+1]) ;
if( NBO <= 0 ) {
mexErrMsgTxt("'NumOrientlBins' must be positive") ;
}
break ;
case PROP_MAGNIF:
if( !uIsRealScalar(in[arg+1]) ) {
mexErrMsgTxt("'Magnif' should be a real scalar") ;
}
magnif = (float) *mxGetPr(in[arg+1]) ;
if( magnif <= 0 ) {
mexErrMsgTxt("'Magnif' must be positive") ;
}
break ;
case PROP_UNKNOWN:
mexErrMsgTxt("Property unknown.") ;
break ;
}
arg += 2 ;
}
}
/* -----------------------------------------------------------------
* Pre-compute gradient and angles
* -------------------------------------------------------------- */
/* Alloc two buffers and make sure their size is multiple of 128 for
* better alignment (used also by the Altivec code below.)
*/
buffer_size = (M*N*num_levels + 0x7f) & (~ 0x7f) ;
buffer_pt = (float*) mxMalloc( sizeof(float) * 2 * buffer_size ) ;
descr_pt = (float*) mxCalloc( NBP*NBP*NBO*K, sizeof(float) ) ;
{
/* Offsets to move in the scale space. */
const int yo = 1 ;
const int xo = M ;
const int so = M*N ;
int x,y,s ;
#define at(x,y) (*(pt + (x)*xo + (y)*yo))
/* Compute the gradient */
for(s = 0 ; s < num_levels ; ++s) {
const double* pt = G_pt + s*so ;
for(x = 1 ; x < N-1 ; ++x) {
for(y = 1 ; y < M-1 ; ++y) {
float Dx = 0.5 * ( at(x+1,y) - at(x-1,y) ) ;
float Dy = 0.5 * ( at(x,y+1) - at(x,y-1) ) ;
buffer_pt[(x*xo+y*yo+s*so) + 0 ] = Dx ;
buffer_pt[(x*xo+y*yo+s*so) + buffer_size] = Dy ;
}
}
}
/* Compute angles and modules */
{
float* pt = buffer_pt ;
int j = 0 ;
while (j < N*M*num_levels) {
#if defined( MACOSX ) && defined( __ALTIVEC__ )
if( ((unsigned int)pt & 0x7) == 0 && j+3 < N*M*num_levels ) {
/* If aligned to 128 bit and there are at least 4 pixels left */
float4 a, b, c, d ;
a.vec = vec_ld(0,(vector float*)(pt )) ;
b.vec = vec_ld(0,(vector float*)(pt + buffer_size)) ;
c.vec = vatan2f(b.vec,a.vec) ;
a.x[0] = a.x[0]*a.x[0]+b.x[0]*b.x[0] ;
a.x[1] = a.x[1]*a.x[1]+b.x[1]*b.x[1] ;
a.x[2] = a.x[2]*a.x[2]+b.x[2]*b.x[2] ;
a.x[3] = a.x[3]*a.x[3]+b.x[3]*b.x[3] ;
d.vec = vsqrtf(a.vec) ;
vec_st(c.vec,0,(vector float*)(pt + buffer_size)) ;
vec_st(d.vec,0,(vector float*)(pt )) ;
j += 4 ;
pt += 4 ;
} else {
#endif
float Dx = *(pt ) ;
float Dy = *(pt + buffer_size) ;
*(pt ) = sqrtf(Dx*Dx + Dy*Dy) ;
if (*pt > 0)
*(pt + buffer_size) = atan2f(Dy, Dx) ;
else
*(pt + buffer_size) = 0 ;
j += 1 ;
pt += 1 ;
#if defined( MACOSX ) && defined( __ALTIVEC__ )
}
#endif
}
}
}
/* -----------------------------------------------------------------
* Do the job
* -------------------------------------------------------------- */
if(K > 0) {
int p ;
/* Offsets to move in the buffer */
const int yo = 1 ;
const int xo = M ;
const int so = M*N ;
/* Offsets to move in the descriptor. */
/* Use Lowe's convention. */
const int binto = 1 ;
const int binyo = NBO * NBP ;
const int binxo = NBO ;
const int bino = NBO * NBP * NBP ;
for(p = 0 ; p < K ; ++p, descr_pt += bino) {
/* The SIFT descriptor is a three dimensional histogram of the position
* and orientation of the gradient. There are NBP bins for each spatial
* dimesions and NBO bins for the orientation dimesion, for a total of
* NBP x NBP x NBO bins.
*
* The support of each spatial bin has an extension of SBP = 3sigma
* pixels, where sigma is the scale of the keypoint. Thus all the bins
* together have a support SBP x NBP pixels wide . Since weighting and
* interpolation of pixel is used, another half bin is needed at both
* ends of the extension. Therefore, we need a square window of SBP x
* (NBP + 1) pixels. Finally, since the patch can be arbitrarly rotated,
* we need to consider a window 2W += sqrt(2) x SBP x (NBP + 1) pixels
* wide.
*/
const float x = (float) *P_pt++ ;
const float y = (float) *P_pt++ ;
const float s = (float) (mode == SCALESPACE) ? (*P_pt++) : 0.0 ;
const float theta0 = (float) *P_pt++ ;
const float st0 = sinf(theta0) ;
const float ct0 = cosf(theta0) ;
const int xi = (int) floor(x+0.5) ; /* Round-off */
const int yi = (int) floor(y+0.5) ;
const int si = (int) floor(s+0.5) - smin ;
const float sigma = sigma0 * powf(2, s / S) ;
const float SBP = magnif * sigma ;
const int W = (int) floor( sqrt(2.0) * SBP * (NBP + 1) / 2.0 + 0.5) ;
int bin ;
int dxi ;
int dyi ;
const float* pt ;
float* dpt ;
/* Check that keypoints are within bounds . */
if(xi < 0 ||
xi > N-1 ||
yi < 0 ||
yi > M-1 ||
((mode==SCALESPACE) &&
(si < 0 ||
si > dimensions[2]-1) ) )
continue ;
/* Center the scale space and the descriptor on the current keypoint.
* Note that dpt is pointing to the bin of center (SBP/2,SBP/2,0).
*/
pt = buffer_pt + xi*xo + yi*yo + si*so ;
dpt = descr_pt + (NBP/2) * binyo + (NBP/2) * binxo ;
#define atd(dbinx,dbiny,dbint) (*(dpt + (dbint)*binto + (dbiny)*binyo + (dbinx)*binxo))
/*
* Process each pixel in the window and in the (1,1)-(M-1,N-1)
* rectangle.
*/
for(dxi = max(-W, 1-xi) ; dxi <= min(+W, N-2-xi) ; ++dxi) {
for(dyi = max(-W, 1-yi) ; dyi <= min(+W, M-2-yi) ; ++dyi) {
/* Compute the gradient. */
float mod = *(pt + dxi*xo + dyi*yo + 0 ) ;
float angle = *(pt + dxi*xo + dyi*yo + buffer_size ) ;
#ifdef LOWE_COMPATIBLE
float theta = fast_mod(-angle + theta0) ;
#else
float theta = fast_mod(angle - theta0) ;
#endif
/* Get the fractional displacement. */
float dx = ((float)(xi+dxi)) - x;
float dy = ((float)(yi+dyi)) - y;
/* Get the displacement normalized w.r.t. the keypoint orientation
* and extension. */
float nx = ( ct0 * dx + st0 * dy) / SBP ;
float ny = (-st0 * dx + ct0 * dy) / SBP ;
float nt = NBO * theta / (2*M_PI) ;
/* Get the gaussian weight of the sample. The gaussian window
* has a standard deviation of NBP/2. Note that dx and dy are in
* the normalized frame, so that -NBP/2 <= dx <= NBP/2. */
const float wsigma = NBP/2 ;
float win = expf(-(nx*nx + ny*ny)/(2.0 * wsigma * wsigma)) ;
/* The sample will be distributed in 8 adijacient bins.
* Now we get the ``lower-left'' bin. */
int binx = fast_floor( nx - 0.5 ) ;
int biny = fast_floor( ny - 0.5 ) ;
int bint = fast_floor( nt ) ;
float rbinx = nx - (binx+0.5) ;
float rbiny = ny - (biny+0.5) ;
float rbint = nt - bint ;
int dbinx ;
int dbiny ;
int dbint ;
/* Distribute the current sample into the 8 adijacient bins. */
for(dbinx = 0 ; dbinx < 2 ; ++dbinx) {
for(dbiny = 0 ; dbiny < 2 ; ++dbiny) {
for(dbint = 0 ; dbint < 2 ; ++dbint) {
if( binx+dbinx >= -(NBP/2) &&
binx+dbinx < (NBP/2) &&
biny+dbiny >= -(NBP/2) &&
biny+dbiny < (NBP/2) ) {
float weight = win
* mod
* fabsf(1 - dbinx - rbinx)
* fabsf(1 - dbiny - rbiny)
* fabsf(1 - dbint - rbint) ;
atd(binx+dbinx, biny+dbiny, (bint+dbint) % NBO) += weight ;
}
}
}
}
}
}
{
/* Normalize the histogram to L2 unit length. */
normalize_histogram(descr_pt, descr_pt + NBO*NBP*NBP) ;
/* Truncate at 0.2. */
for(bin = 0; bin < NBO*NBP*NBP ; ++bin) {
if (descr_pt[bin] > 0.2) descr_pt[bin] = 0.2;
}
/* Normalize again. */
normalize_histogram(descr_pt, descr_pt + NBO*NBP*NBP) ;
}
}
}
/* Restore pointer to the beginning of the descriptors. */
descr_pt -= NBO*NBP*NBP*K ;
{
int k ;
double* L_pt ;
out[OUT_L] = mxCreateDoubleMatrix(NBP*NBP*NBO, K, mxREAL) ;
L_pt = mxGetPr(out[OUT_L]) ;
for(k = 0 ; k < NBP*NBP*NBO*K ; ++k) {
L_pt[k] = descr_pt[k] ;
}
}
mxFree(descr_pt) ;
mxFree(buffer_pt) ;
}
void *queue_back (struct queue *q) {
if (q->count == 0) {
return NULL;
}
return queue_addr (q, fast_mod( (q->out + q->count - 1), q->size ) );
}
static inline int
wave_guide_get_pos (WaveGuide *wave, int x)
{
return fast_mod (wave->pos + x, wave->wavelen);
}
