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SDL_gesture.c
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SDL_gesture.c
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/*
SDL - Simple DirectMedia Layer
Copyright (C) 1997-2010 Sam Lantinga
This library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
This library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with this library; if not, write to the Free Software Founation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
Sam Lantinga
slouken@libsdl.org
*/
#include "SDL_config.h"
/* General mouse handling code for SDL */
#include "SDL_events.h"
#include "SDL_events_c.h"
#include "SDL_gesture_c.h"
//TODO: Replace with malloc
#define MAXFINGERS 3
#define MAXTOUCHES 2
#define MAXTEMPLATES 4
#define MAXPATHSIZE 1024
#define DOLLARNPOINTS 64
#define DOLLARSIZE 256
//PHI = ((sqrt(5)-1)/2)
#define PHI 0.618033989
typedef struct {
float x,y;
} Point;
typedef struct {
Point p;
float pressure;
int id;
} Finger;
typedef struct {
float length;
int numPoints;
Point p[MAXPATHSIZE];
} DollarPath;
typedef struct {
Finger f;
Point cv;
float dtheta,dDist;
DollarPath dollarPath;
} TouchPoint;
typedef struct {
Point path[DOLLARNPOINTS];
unsigned long hash;
} DollarTemplate;
typedef struct {
int id;
Point res;
Point centroid;
TouchPoint gestureLast[MAXFINGERS];
int numDownFingers;
int numDollarTemplates;
DollarTemplate dollarTemplate[MAXTEMPLATES];
SDL_bool recording;
} GestureTouch;
GestureTouch gestureTouch[MAXTOUCHES];
int numGestureTouches = 0;
SDL_bool recordAll;
int SDL_RecordGesture(int touchId) {
int i;
if(touchId < 0) recordAll = SDL_TRUE;
for(i = 0;i < numGestureTouches; i++) {
if((touchId < 0) || (gestureTouch[i].id == touchId)) {
gestureTouch[i].recording = SDL_TRUE;
if(touchId >= 0)
return 1;
}
}
return (touchId < 0);
}
unsigned long SDL_HashDollar(Point* points) {
unsigned long hash = 5381;
int i;
for(i = 0;i < DOLLARNPOINTS; i++) {
hash = ((hash<<5) + hash) + points[i].x;
hash = ((hash<<5) + hash) + points[i].y;
}
return hash;
}
int SaveTemplate(DollarTemplate *templ, FILE *fp) {
int i;
fprintf(fp,"%lu ",templ->hash);
for(i = 0;i < DOLLARNPOINTS;i++) {
fprintf(fp,"%i %i ",(int)templ->path[i].x,(int)templ->path[i].y);
}
fprintf(fp,"\n");
}
int SDL_SaveAllDollarTemplates(FILE *fp) {
int i,j,rtrn = 0;
for(i = 0; i < numGestureTouches; i++) {
GestureTouch* touch = &gestureTouch[i];
for(j = 0;j < touch->numDollarTemplates; j++) {
rtrn += SaveTemplate(&touch->dollarTemplate[i],fp);
}
}
return rtrn;
}
int SDL_SaveDollarTemplate(unsigned long gestureId, FILE *fp) {
int i,j;
for(i = 0; i < numGestureTouches; i++) {
GestureTouch* touch = &gestureTouch[i];
for(j = 0;j < touch->numDollarTemplates; j++) {
if(touch->dollarTemplate[i].hash == gestureId) {
return SaveTemplate(&touch->dollarTemplate[i],fp);
}
}
}
}
int SDL_LoadDollarTemplates(int touchId, FILE *fp) {
int i,loaded = 0;
GestureTouch *touch = NULL;
if(touchId >= 0) {
for(i = 0;i < numGestureTouches; i++)
if(gestureTouch[i].id == touchId)
touch = &gestureTouch[i];
if(touch == NULL) return -1;
}
while(!feof(fp)) {
DollarTemplate templ;
fscanf(fp,"%lu ",&templ.hash);
for(i = 0;i < DOLLARNPOINTS; i++) {
int x,y;
if(fscanf(fp,"%i %i ",&x,&y) != 2) break;
templ.path[i].x = x;
templ.path[i].y = y;
}
fscanf(fp,"\n");
if(touchId >= 0) {
if(SDL_AddDollarGesture(touch,templ)) loaded++;
}
else {
for(i = 0;i < numGestureTouches; i++) {
if(gestureTouch[i].id == touchId) {
touch = &gestureTouch[i];
SDL_AddDollarGesture(touch,templ);
}
}
loaded++;
}
}
return 1;
}
//path is an already sampled set of points
//Returns the index of the gesture on success, or -1
int SDL_AddDollarGesture(GestureTouch* inTouch,Point* path) {
if(inTouch == NULL) {
if(numGestureTouches == 0) return -1;
int i = 0;
for(i = 0;i < numGestureTouches; i++) {
inTouch = &gestureTouch[i];
if(inTouch->numDollarTemplates < MAXTEMPLATES) {
DollarTemplate *templ =
&inTouch->dollarTemplate[inTouch->numDollarTemplates];
memcpy(templ->path,path,DOLLARNPOINTS*sizeof(Point));
templ->hash = SDL_HashDollar(templ->path);
inTouch->numDollarTemplates++;
}
}
return inTouch->numDollarTemplates - 1;
}else if(inTouch->numDollarTemplates < MAXTEMPLATES) {
DollarTemplate *templ =
&inTouch->dollarTemplate[inTouch->numDollarTemplates];
memcpy(templ->path,path,DOLLARNPOINTS*sizeof(Point));
templ->hash = SDL_HashDollar(templ->path);
inTouch->numDollarTemplates++;
return inTouch->numDollarTemplates - 1;
}
return -1;
}
float dollarDifference(Point* points,Point* templ,float ang) {
// Point p[DOLLARNPOINTS];
float dist = 0;
Point p;
int i;
for(i = 0; i < DOLLARNPOINTS; i++) {
p.x = points[i].x * cos(ang) - points[i].y * sin(ang);
p.y = points[i].x * sin(ang) + points[i].y * cos(ang);
dist += sqrt((p.x-templ[i].x)*(p.x-templ[i].x)+
(p.y-templ[i].y)*(p.y-templ[i].y));
}
return dist/DOLLARNPOINTS;
}
float bestDollarDifference(Point* points,Point* templ) {
//------------BEGIN DOLLAR BLACKBOX----------------//
//-TRANSLATED DIRECTLY FROM PSUDEO-CODE AVAILABLE AT-//
//-"http://depts.washington.edu/aimgroup/proj/dollar/"-//
float ta = -M_PI/4;
float tb = M_PI/4;
float dt = M_PI/90;
float x1 = PHI*ta + (1-PHI)*tb;
float f1 = dollarDifference(points,templ,x1);
float x2 = (1-PHI)*ta + PHI*tb;
float f2 = dollarDifference(points,templ,x2);
while(abs(ta-tb) > dt) {
if(f1 < f2) {
tb = x2;
x2 = x1;
f2 = f1;
x1 = PHI*ta + (1-PHI)*tb;
f1 = dollarDifference(points,templ,x1);
}
else {
ta = x1;
x1 = x2;
f1 = f2;
x2 = (1-PHI)*ta + PHI*tb;
f2 = dollarDifference(points,templ,x2);
}
}
/*
if(f1 <= f2)
printf("Min angle (x1): %f\n",x1);
else if(f1 > f2)
printf("Min angle (x2): %f\n",x2);
*/
return SDL_min(f1,f2);
}
float dollarRecognize(DollarPath path,int *bestTempl,GestureTouch* touch) {
Point points[DOLLARNPOINTS];
int numPoints = dollarNormalize(path,points);
int i;
int bestDiff = 10000;
*bestTempl = -1;
for(i = 0;i < touch->numDollarTemplates;i++) {
int diff = bestDollarDifference(points,touch->dollarTemplate[i].path);
if(diff < bestDiff) {bestDiff = diff; *bestTempl = i;}
}
return bestDiff;
}
//DollarPath contains raw points, plus (possibly) the calculated length
int dollarNormalize(DollarPath path,Point *points) {
int i;
//Calculate length if it hasn't already been done
if(path.length <= 0) {
for(i=1;i<path.numPoints;i++) {
float dx = path.p[i ].x -
path.p[i-1].x;
float dy = path.p[i ].y -
path.p[i-1].y;
path.length += sqrt(dx*dx+dy*dy);
}
}
//Resample
float interval = path.length/(DOLLARNPOINTS - 1);
float dist = 0;
int numPoints = 0;
Point centroid; centroid.x = 0;centroid.y = 0;
//printf("(%f,%f)\n",path.p[path.numPoints-1].x,path.p[path.numPoints-1].y);
for(i = 1;i < path.numPoints;i++) {
float d = sqrt((path.p[i-1].x-path.p[i].x)*(path.p[i-1].x-path.p[i].x)+
(path.p[i-1].y-path.p[i].y)*(path.p[i-1].y-path.p[i].y));
//printf("d = %f dist = %f/%f\n",d,dist,interval);
while(dist + d > interval) {
points[numPoints].x = path.p[i-1].x +
((interval-dist)/d)*(path.p[i].x-path.p[i-1].x);
points[numPoints].y = path.p[i-1].y +
((interval-dist)/d)*(path.p[i].y-path.p[i-1].y);
centroid.x += points[numPoints].x;
centroid.y += points[numPoints].y;
numPoints++;
dist -= interval;
}
dist += d;
}
if(numPoints < 1) return 0;
centroid.x /= numPoints;
centroid.y /= numPoints;
//printf("Centroid (%f,%f)",centroid.x,centroid.y);
//Rotate Points so point 0 is left of centroid and solve for the bounding box
float xmin,xmax,ymin,ymax;
xmin = centroid.x;
xmax = centroid.x;
ymin = centroid.y;
ymax = centroid.y;
float ang = atan2(centroid.y - points[0].y,
centroid.x - points[0].x);
for(i = 0;i<numPoints;i++) {
float px = points[i].x;
float py = points[i].y;
points[i].x = (px - centroid.x)*cos(ang) -
(py - centroid.y)*sin(ang) + centroid.x;
points[i].y = (px - centroid.x)*sin(ang) +
(py - centroid.y)*cos(ang) + centroid.y;
if(points[i].x < xmin) xmin = points[i].x;
if(points[i].x > xmax) xmax = points[i].x;
if(points[i].y < ymin) ymin = points[i].y;
if(points[i].y > ymax) ymax = points[i].y;
}
//Scale points to DOLLARSIZE, and translate to the origin
float w = xmax-xmin;
float h = ymax-ymin;
for(i=0;i<numPoints;i++) {
points[i].x = (points[i].x - centroid.x)*DOLLARSIZE/w;
points[i].y = (points[i].y - centroid.y)*DOLLARSIZE/h;
}
return numPoints;
}
int SDL_GestureAddTouch(SDL_Touch* touch) {
if(numGestureTouches >= MAXTOUCHES) return -1;
gestureTouch[numGestureTouches].res.x = touch->xres;
gestureTouch[numGestureTouches].res.y = touch->yres;
gestureTouch[numGestureTouches].numDownFingers = 0;
gestureTouch[numGestureTouches].res.x = touch->xres;
gestureTouch[numGestureTouches].id = touch->id;
gestureTouch[numGestureTouches].numDollarTemplates = 0;
gestureTouch[numGestureTouches].recording = SDL_FALSE;
numGestureTouches++;
return 0;
}
GestureTouch * SDL_GetGestureTouch(int id) {
int i;
for(i = 0;i < numGestureTouches; i++) {
//printf("%i ?= %i\n",gestureTouch[i].id,id);
if(gestureTouch[i].id == id) return &gestureTouch[i];
}
return NULL;
}
int SDL_SendGestureMulti(GestureTouch* touch,float dTheta,float dDist) {
SDL_Event event;
event.mgesture.type = SDL_MULTIGESTURE;
event.mgesture.touchId = touch->id;
event.mgesture.x = touch->centroid.x;
event.mgesture.y = touch->centroid.y;
event.mgesture.dTheta = dTheta;
event.mgesture.dDist = dDist;
return SDL_PushEvent(&event) > 0;
}
int SDL_SendGestureDollar(GestureTouch* touch,int gestureId,float error) {
SDL_Event event;
event.dgesture.type = SDL_DOLLARGESTURE;
event.dgesture.touchId = touch->id;
/*
//TODO: Add this to give location of gesture?
event.mgesture.x = touch->centroid.x;
event.mgesture.y = touch->centroid.y;
*/
event.dgesture.gestureId = gestureId;
event.dgesture.error = error;
return SDL_PushEvent(&event) > 0;
}
int SDL_SendDollarRecord(GestureTouch* touch,int gestureId) {
SDL_Event event;
event.dgesture.type = SDL_DOLLARRECORD;
event.dgesture.touchId = touch->id;
event.dgesture.gestureId = gestureId;
return SDL_PushEvent(&event) > 0;
}
void SDL_GestureProcessEvent(SDL_Event* event)
{
if(event->type == SDL_FINGERMOTION ||
event->type == SDL_FINGERDOWN ||
event->type == SDL_FINGERUP) {
GestureTouch* inTouch = SDL_GetGestureTouch(event->tfinger.touchId);
//Shouldn't be possible
if(inTouch == NULL) return;
float x = ((float)event->tfinger.x)/inTouch->res.x;
float y = ((float)event->tfinger.y)/inTouch->res.y;
int j,empty = -1;
for(j = 0;j<inTouch->numDownFingers;j++) {
if(inTouch->gestureLast[j].f.id != event->tfinger.fingerId) continue;
//Finger Up
if(event->type == SDL_FINGERUP) {
inTouch->numDownFingers--;
if(inTouch->recording) {
inTouch->recording = SDL_FALSE;
Point path[DOLLARNPOINTS];
dollarNormalize(inTouch->gestureLast[j].dollarPath,path);
int index;
if(recordAll) {
index = SDL_AddDollarGesture(NULL,path);
int i;
for(i = 0;i < numGestureTouches; i++)
gestureTouch[i].recording = SDL_FALSE;
}
else {
index = SDL_AddDollarGesture(inTouch,path);
}
if(index >= 0) {
SDL_SendDollarRecord(inTouch,inTouch->dollarTemplate[index].hash);
}
else {
SDL_SendDollarRecord(inTouch,-1);
}
}
else {
int bestTempl;
float error;
error = dollarRecognize(inTouch->gestureLast[j].dollarPath,
&bestTempl,inTouch);
if(bestTempl >= 0){
//Send Event
int gestureId = inTouch->dollarTemplate[bestTempl].hash;
SDL_SendGestureDollar(inTouch,gestureId,error);
printf("Dollar error: %f\n",error);
}
}
inTouch->gestureLast[j] = inTouch->gestureLast[inTouch->numDownFingers];
break;
}
else {
float dx = x - inTouch->gestureLast[j].f.p.x;
float dy = y - inTouch->gestureLast[j].f.p.y;
DollarPath* path = &inTouch->gestureLast[j].dollarPath;
if(path->numPoints < MAXPATHSIZE) {
path->p[path->numPoints].x = x;
path->p[path->numPoints].y = y;
path->length += sqrt(dx*dx + dy*dy);
path->numPoints++;
}
inTouch->centroid.x += dx/inTouch->numDownFingers;
inTouch->centroid.y += dy/inTouch->numDownFingers;
if(inTouch->numDownFingers > 1) {
Point lv; //Vector from centroid to last x,y position
Point v; //Vector from centroid to current x,y position
lv = inTouch->gestureLast[j].cv;
float lDist = sqrt(lv.x*lv.x + lv.y*lv.y);
//printf("lDist = %f\n",lDist);
v.x = x - inTouch->centroid.x;
v.y = y - inTouch->centroid.y;
inTouch->gestureLast[j].cv = v;
float Dist = sqrt(v.x*v.x+v.y*v.y);
// cos(dTheta) = (v . lv)/(|v| * |lv|)
//Normalize Vectors to simplify angle calculation
lv.x/=lDist;
lv.y/=lDist;
v.x/=Dist;
v.y/=Dist;
float dtheta = atan2(lv.x*v.y - lv.y*v.x,lv.x*v.x + lv.y*v.y);
float dDist = (Dist - lDist);
if(lDist == 0) {dDist = 0;dtheta = 0;} //To avoid impossible values
inTouch->gestureLast[j].dDist = dDist;
inTouch->gestureLast[j].dtheta = dtheta;
//printf("dDist = %f, dTheta = %f\n",dDist,dtheta);
//gdtheta = gdtheta*.9 + dtheta*.1;
//gdDist = gdDist*.9 + dDist*.1
//knob.r += dDist/numDownFingers;
//knob.ang += dtheta;
//printf("thetaSum = %f, distSum = %f\n",gdtheta,gdDist);
//printf("id: %i dTheta = %f, dDist = %f\n",j,dtheta,dDist);
SDL_SendGestureMulti(inTouch,dtheta,dDist);
}
else {
inTouch->gestureLast[j].dDist = 0;
inTouch->gestureLast[j].dtheta = 0;
inTouch->gestureLast[j].cv.x = 0;
inTouch->gestureLast[j].cv.y = 0;
}
inTouch->gestureLast[j].f.p.x = x;
inTouch->gestureLast[j].f.p.y = y;
break;
//pressure?
}
}
if(j == inTouch->numDownFingers) {
//printf("Finger Down!!!\n");
inTouch->numDownFingers++;
inTouch->centroid.x = (inTouch->centroid.x*(inTouch->numDownFingers - 1)+
x)/inTouch->numDownFingers;
inTouch->centroid.y = (inTouch->centroid.y*(inTouch->numDownFingers - 1)+
y)/inTouch->numDownFingers;
inTouch->gestureLast[j].f.id = event->tfinger.fingerId;
inTouch->gestureLast[j].f.p.x = x;
inTouch->gestureLast[j].f.p.y = y;
inTouch->gestureLast[j].cv.x = 0;
inTouch->gestureLast[j].cv.y = 0;
inTouch->gestureLast[j].dollarPath.length = 0;
inTouch->gestureLast[j].dollarPath.p[0].x = x;
inTouch->gestureLast[j].dollarPath.p[0].y = y;
inTouch->gestureLast[j].dollarPath.numPoints = 1;
}
}
}
/* vi: set ts=4 sw=4 expandtab: */