src/events/SDL_gesture.c
changeset 4657 eed063a0bf5b
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4656:b5007b7995c6 4657:eed063a0bf5b
       
     1 /*
       
     2     SDL - Simple DirectMedia Layer
       
     3     Copyright (C) 1997-2010 Sam Lantinga
       
     4 
       
     5     This library is free software; you can redistribute it and/or
       
     6     modify it under the terms of the GNU Lesser General Public
       
     7     License as published by the Free Software Foundation; either
       
     8     version 2.1 of the License, or (at your option) any later version.
       
     9 
       
    10     This library is distributed in the hope that it will be useful,
       
    11     but WITHOUT ANY WARRANTY; without even the implied warranty of
       
    12     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
       
    13     Lesser General Public License for more details.
       
    14 
       
    15     You should have received a copy of the GNU Lesser General Public
       
    16     License along with this library; if not, write to the Free Software
       
    17     Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
       
    18 
       
    19     Sam Lantinga
       
    20     slouken@libsdl.org
       
    21 */
       
    22 #include "SDL_config.h"
       
    23 
       
    24 /* General mouse handling code for SDL */
       
    25 
       
    26 #include "SDL_events.h"
       
    27 #include "SDL_events_c.h"
       
    28 #include "SDL_gesture_c.h"
       
    29 
       
    30 //TODO: Replace with malloc
       
    31 #define MAXFINGERS 3
       
    32 #define MAXTOUCHES 2
       
    33 
       
    34 typedef struct {
       
    35   float x,y;
       
    36 } Point;
       
    37 
       
    38 
       
    39 typedef struct {
       
    40   Point p;
       
    41   float pressure;
       
    42   int id;
       
    43 } Finger;
       
    44 
       
    45 typedef struct {
       
    46   Finger f;
       
    47   Point cv;
       
    48   float dtheta,dDist;
       
    49 } TouchPoint;
       
    50 
       
    51 
       
    52 typedef struct {
       
    53   int id;
       
    54   Point res;
       
    55   Point centroid;
       
    56   TouchPoint gestureLast[MAXFINGERS];
       
    57   int numDownFingers;
       
    58 } GestureTouch;
       
    59 
       
    60 GestureTouch gestureTouch[MAXTOUCHES];
       
    61 int numGestureTouches = 0;
       
    62 int SDL_GestureAddTouch(SDL_Touch* touch) { 
       
    63   if(numGestureTouches >= MAXTOUCHES) return -1;
       
    64   
       
    65   gestureTouch[numGestureTouches].res.x = touch->xres;
       
    66   gestureTouch[numGestureTouches].res.y = touch->yres;
       
    67   gestureTouch[numGestureTouches].numDownFingers = 0;
       
    68 
       
    69   gestureTouch[numGestureTouches].res.x = touch->xres;
       
    70   gestureTouch[numGestureTouches].id = touch->id;
       
    71 
       
    72   numGestureTouches++;
       
    73   return 0;
       
    74 }
       
    75 
       
    76 GestureTouch * SDL_GetGestureTouch(int id) {
       
    77   int i;
       
    78   for(i = 0;i < numGestureTouches; i++) {
       
    79     //printf("%i ?= %i\n",gestureTouch[i].id,id);
       
    80     if(gestureTouch[i].id == id) return &gestureTouch[i];
       
    81   }
       
    82   return NULL;
       
    83 }
       
    84 
       
    85 int SDL_SendGestureMulti(GestureTouch* touch,float dTheta,float dDist) {
       
    86   SDL_Event event;
       
    87   event.mgesture.type = SDL_MULTIGESTURE;
       
    88   event.mgesture.touchId = touch->id;
       
    89   event.mgesture.x = touch->centroid.x;
       
    90   event.mgesture.y = touch->centroid.y;
       
    91   event.mgesture.dTheta = dTheta;
       
    92   event.mgesture.dDist = dDist;  
       
    93   return SDL_PushEvent(&event) > 0;
       
    94 }
       
    95 
       
    96 void SDL_GestureProcessEvent(SDL_Event* event)
       
    97 {
       
    98   if(event->type == SDL_FINGERMOTION || 
       
    99      event->type == SDL_FINGERDOWN ||
       
   100      event->type == SDL_FINGERUP) {
       
   101     GestureTouch* inTouch = SDL_GetGestureTouch(event->tfinger.touchId);
       
   102 
       
   103 
       
   104     //Shouldn't be possible
       
   105     if(inTouch == NULL) return;
       
   106     
       
   107     
       
   108     float x = ((float)event->tfinger.x)/inTouch->res.x;
       
   109     float y = ((float)event->tfinger.y)/inTouch->res.y;
       
   110     int j,empty = -1;
       
   111     
       
   112     for(j = 0;j<inTouch->numDownFingers;j++) {
       
   113       if(inTouch->gestureLast[j].f.id != event->tfinger.fingerId) continue;
       
   114 
       
   115       if(event->type == SDL_FINGERUP) {
       
   116 	inTouch->numDownFingers--;
       
   117 	inTouch->gestureLast[j] = inTouch->gestureLast[inTouch->numDownFingers];
       
   118 	break;
       
   119       }
       
   120       else {
       
   121 	float dx = x - inTouch->gestureLast[j].f.p.x;
       
   122 	float dy = y - inTouch->gestureLast[j].f.p.y;
       
   123 	inTouch->centroid.x += dx/inTouch->numDownFingers;
       
   124 	inTouch->centroid.y += dy/inTouch->numDownFingers;    
       
   125 	if(inTouch->numDownFingers > 1) {
       
   126 	  Point lv; //Vector from centroid to last x,y position
       
   127 	  Point v; //Vector from centroid to current x,y position
       
   128 	  lv = inTouch->gestureLast[j].cv;
       
   129 	  float lDist = sqrt(lv.x*lv.x + lv.y*lv.y);
       
   130 	  //printf("lDist = %f\n",lDist);
       
   131 	  v.x = x - inTouch->centroid.x;
       
   132 	  v.y = y - inTouch->centroid.y;
       
   133 	  inTouch->gestureLast[j].cv = v;
       
   134 	  float Dist = sqrt(v.x*v.x+v.y*v.y);
       
   135 	  // cos(dTheta) = (v . lv)/(|v| * |lv|)
       
   136 	  
       
   137 	  //Normalize Vectors to simplify angle calculation
       
   138 	  lv.x/=lDist;
       
   139 	  lv.y/=lDist;
       
   140 	  v.x/=Dist;
       
   141 	  v.y/=Dist;
       
   142 	  float dtheta = atan2(lv.x*v.y - lv.y*v.x,lv.x*v.x + lv.y*v.y);
       
   143 	  
       
   144 	  float dDist = (Dist - lDist);
       
   145 	  if(lDist == 0) {dDist = 0;dtheta = 0;} //To avoid impossible values
       
   146 	  inTouch->gestureLast[j].dDist = dDist;
       
   147 	  inTouch->gestureLast[j].dtheta = dtheta;
       
   148 	  
       
   149 	  //printf("dDist = %f, dTheta = %f\n",dDist,dtheta);
       
   150 	  //gdtheta = gdtheta*.9 + dtheta*.1;
       
   151 	  //gdDist  =  gdDist*.9 +  dDist*.1
       
   152 	  //knob.r += dDist/numDownFingers;
       
   153 	  //knob.ang += dtheta;
       
   154 	  //printf("thetaSum = %f, distSum = %f\n",gdtheta,gdDist);
       
   155 	  //printf("id: %i dTheta = %f, dDist = %f\n",j,dtheta,dDist);
       
   156 	  SDL_SendGestureMulti(inTouch,dtheta,dDist);
       
   157 	}
       
   158 	else {
       
   159 	  inTouch->gestureLast[j].dDist = 0;
       
   160 	  inTouch->gestureLast[j].dtheta = 0;
       
   161 	  inTouch->gestureLast[j].cv.x = 0;
       
   162 	  inTouch->gestureLast[j].cv.y = 0;
       
   163 	}
       
   164 	inTouch->gestureLast[j].f.p.x = x;
       
   165 	inTouch->gestureLast[j].f.p.y = y;
       
   166 	break;
       
   167 	//pressure?
       
   168       }      
       
   169     }
       
   170     
       
   171     if(j == inTouch->numDownFingers) {
       
   172       //printf("Finger Down!!!\n");
       
   173       inTouch->numDownFingers++;
       
   174       inTouch->centroid.x = (inTouch->centroid.x*(inTouch->numDownFingers - 1)+ 
       
   175 			     x)/inTouch->numDownFingers;
       
   176       inTouch->centroid.y = (inTouch->centroid.y*(inTouch->numDownFingers - 1)+
       
   177 			     y)/inTouch->numDownFingers;
       
   178       
       
   179       inTouch->gestureLast[j].f.id = event->tfinger.fingerId;
       
   180       inTouch->gestureLast[j].f.p.x  = x;
       
   181       inTouch->gestureLast[j].f.p.y  = y;	
       
   182       inTouch->gestureLast[j].cv.x = 0;
       
   183       inTouch->gestureLast[j].cv.y = 0;
       
   184     }
       
   185   }
       
   186 }  
       
   187   
       
   188   /* vi: set ts=4 sw=4 expandtab: */
       
   189