SDL/test/testgesture.c

/*
  Copyright (C) 1997-2013 Sam Lantinga <slouken@libsdl.org>

  This software is provided 'as-is', without any express or implied
  warranty.  In no event will the authors be held liable for any damages
  arising from the use of this software.

  Permission is granted to anyone to use this software for any purpose,
  including commercial applications, and to alter it and redistribute it
  freely.
*/
/*  Usage:
 *  Spacebar to begin recording a gesture on all touches.
 *  s to save all touches into "./gestureSave"
 *  l to load all touches from "./gestureSave"
 */

#include <stdio.h>
#include <math.h>

#include "SDL.h"
#include "SDL_touch.h"
#include "SDL_gesture.h"

/* Make sure we have good macros for printing 32 and 64 bit values */
#ifndef PRIs32
#define PRIs32 "d"
#endif
#ifndef PRIu32
#define PRIu32 "u"
#endif
#ifndef PRIs64
#ifdef __WIN32__
#define PRIs64 "I64"
#else
#define PRIs64 "lld"
#endif
#endif
#ifndef PRIu64
#ifdef __WIN32__
#define PRIu64 "I64u"
#else
#define PRIu64 "llu"
#endif
#endif

#define WIDTH 640
#define HEIGHT 480
#define BPP 4
#define DEPTH 32

//MUST BE A POWER OF 2!
#define EVENT_BUF_SIZE 256


#define VERBOSE 0

static SDL_Window *window;
static SDL_Event events[EVENT_BUF_SIZE];
static int eventWrite;


static int colors[7] = {0xFF,0xFF00,0xFF0000,0xFFFF00,0x00FFFF,0xFF00FF,0xFFFFFF};

typedef struct {
  float x,y;
} Point;

typedef struct {
  float ang,r;
  Point p;
} Knob;

static Knob knob;

void handler (int sig)
{
  SDL_Log ("exiting...(%d)", sig);
  exit (0);
}

void perror_exit (char *error)
{
  perror (error);
  handler (9);
}

void setpix(SDL_Surface *screen, float _x, float _y, unsigned int col)
{
  Uint32 *pixmem32;
  Uint32 colour;
  Uint8 r,g,b;
  int x = (int)_x;
  int y = (int)_y;
  float a;

  if(x < 0 || x >= screen->w) return;
  if(y < 0 || y >= screen->h) return;

  pixmem32 = (Uint32*) screen->pixels  + y*screen->pitch/BPP + x;

  SDL_memcpy(&colour,pixmem32,screen->format->BytesPerPixel);

  SDL_GetRGB(colour,screen->format,&r,&g,&b);
  //r = 0;g = 0; b = 0;
  a = (float)((col>>24)&0xFF);
  if(a == 0) a = 0xFF; //Hack, to make things easier.
  a /= 0xFF;
  r = (Uint8)(r*(1-a) + ((col>>16)&0xFF)*(a));
  g = (Uint8)(g*(1-a) + ((col>> 8)&0xFF)*(a));
  b = (Uint8)(b*(1-a) + ((col>> 0)&0xFF)*(a));
  colour = SDL_MapRGB( screen->format,r, g, b);


  *pixmem32 = colour;
}

void drawLine(SDL_Surface *screen,float x0,float y0,float x1,float y1,unsigned int col) {
  float t;
  for(t=0;t<1;t+=(float)(1.f/SDL_max(SDL_fabs(x0-x1),SDL_fabs(y0-y1))))
    setpix(screen,x1+t*(x0-x1),y1+t*(y0-y1),col);
}

void drawCircle(SDL_Surface* screen,float x,float y,float r,unsigned int c)
{
  float tx,ty;
  float xr;
  for(ty = (float)-SDL_fabs(r);ty <= (float)SDL_fabs((int)r);ty++) {
    xr = (float)sqrt(r*r - ty*ty);
    if(r > 0) { //r > 0 ==> filled circle
      for(tx=-xr+.5f;tx<=xr-.5;tx++) {
    setpix(screen,x+tx,y+ty,c);
      }
    }
    else {
      setpix(screen,x-xr+.5f,y+ty,c);
      setpix(screen,x+xr-.5f,y+ty,c);
    }
  }
}

void drawKnob(SDL_Surface* screen,Knob k) {
  drawCircle(screen,k.p.x*screen->w,k.p.y*screen->h,k.r*screen->w,0xFFFFFF);
  drawCircle(screen,(k.p.x+k.r/2*SDL_cosf(k.ang))*screen->w,
                (k.p.y+k.r/2*SDL_sinf(k.ang))*screen->h,k.r/4*screen->w,0);
}

void DrawScreen(SDL_Surface* screen)
{
  int i;
#if 1
  SDL_FillRect(screen, NULL, 0);
#else
  int x, y;
  for(y = 0;y < screen->h;y++)
    for(x = 0;x < screen->w;x++)
    setpix(screen,(float)x,(float)y,((x%255)<<16) + ((y%255)<<8) + (x+y)%255);
#endif

  //draw Touch History
  for(i = eventWrite; i < eventWrite+EVENT_BUF_SIZE; ++i) {
    const SDL_Event *event = &events[i&(EVENT_BUF_SIZE-1)];
    float age = (float)(i - eventWrite) / EVENT_BUF_SIZE;
    float x, y;
    unsigned int c, col;

    if(event->type == SDL_FINGERMOTION ||
       event->type == SDL_FINGERDOWN ||
       event->type == SDL_FINGERUP) {
      x = event->tfinger.x;
      y = event->tfinger.y;

      //draw the touch:
      c = colors[event->tfinger.fingerId%7];
      col = ((unsigned int)(c*(.1+.85))) | (unsigned int)(0xFF*age)<<24;

      if(event->type == SDL_FINGERMOTION)
    drawCircle(screen,x*screen->w,y*screen->h,5,col);
      else if(event->type == SDL_FINGERDOWN)
    drawCircle(screen,x*screen->w,y*screen->h,-10,col);
    }
  }

  if(knob.p.x > 0)
    drawKnob(screen,knob);

  SDL_UpdateWindowSurface(window);
}

SDL_Surface* initScreen(int width,int height)
{
  if (!window) {
    window = SDL_CreateWindow("Gesture Test",
                              SDL_WINDOWPOS_CENTERED, SDL_WINDOWPOS_CENTERED,
                              width, height, SDL_WINDOW_RESIZABLE);
  }
  if (!window) {
    return NULL;
  }
  return SDL_GetWindowSurface(window);
}

int main(int argc, char* argv[])
{
  SDL_Surface *screen;
  SDL_Event event;
  SDL_bool quitting = SDL_FALSE;
  SDL_RWops *src;

  //gesture variables
  knob.r = .1f;
  knob.ang = 0;

  if (SDL_Init(SDL_INIT_VIDEO) < 0 ) return 1;

  if (!(screen = initScreen(WIDTH,HEIGHT)))
    {
      SDL_Quit();
      return 1;
    }

  while(!quitting) {
    while(SDL_PollEvent(&event))
      {
    //Record _all_ events
    events[eventWrite & (EVENT_BUF_SIZE-1)] = event;
    eventWrite++;

    switch (event.type)
      {
      case SDL_QUIT:
        quitting = SDL_TRUE;
        break;
      case SDL_KEYDOWN:
        switch (event.key.keysym.sym)
          {
          case SDLK_SPACE:
        SDL_RecordGesture(-1);
        break;
          case SDLK_s:
        src = SDL_RWFromFile("gestureSave","w");
        SDL_Log("Wrote %i templates",SDL_SaveAllDollarTemplates(src));
        SDL_RWclose(src);
        break;
          case SDLK_l:
        src = SDL_RWFromFile("gestureSave","r");
        SDL_Log("Loaded: %i",SDL_LoadDollarTemplates(-1,src));
        SDL_RWclose(src);
        break;
          case SDLK_ESCAPE:
        quitting = SDL_TRUE;
        break;
        }
        break;
      case SDL_WINDOWEVENT:
            if (event.window.event == SDL_WINDOWEVENT_RESIZED) {
          if (!(screen = initScreen(event.window.data1, event.window.data2)))
          {
        SDL_Quit();
        return 1;
          }
            }
        break;
      case SDL_FINGERMOTION:
#if VERBOSE
        SDL_Log("Finger: %i,x: %i, y: %i",event.tfinger.fingerId,
               event.tfinger.x,event.tfinger.y);
#endif
        break;
      case SDL_FINGERDOWN:
#if VERBOSE
        SDL_Log("Finger: %"PRIs64" down - x: %i, y: %i",
           event.tfinger.fingerId,event.tfinger.x,event.tfinger.y);
#endif
        break;
      case SDL_FINGERUP:
#if VERBOSE
        SDL_Log("Finger: %"PRIs64" up - x: %i, y: %i",
               event.tfinger.fingerId,event.tfinger.x,event.tfinger.y);
#endif
        break;
      case SDL_MULTIGESTURE:
#if VERBOSE
        SDL_Log("Multi Gesture: x = %f, y = %f, dAng = %f, dR = %f",
           event.mgesture.x,
           event.mgesture.y,
           event.mgesture.dTheta,
           event.mgesture.dDist);
        SDL_Log("MG: numDownTouch = %i",event.mgesture.numFingers);
#endif
        knob.p.x = event.mgesture.x;
        knob.p.y = event.mgesture.y;
        knob.ang += event.mgesture.dTheta;
        knob.r += event.mgesture.dDist;
        break;
      case SDL_DOLLARGESTURE:
        SDL_Log("Gesture %"PRIs64" performed, error: %f",
           event.dgesture.gestureId,
           event.dgesture.error);
        break;
      case SDL_DOLLARRECORD:
        SDL_Log("Recorded gesture: %"PRIs64"",event.dgesture.gestureId);
        break;
      }
      }
    DrawScreen(screen);
  }
  SDL_Quit();
  return 0;
}