not sure how you even came up with this t.tfinger.x it should be your event instance e.tfinger.x
from testgesture.c
x = ((float)event->tfinger.x)/inTouch->xres;
y = ((float)event->tfinger.y)/inTouch->yres;
what you should have
x = ((float)e.tfinger.x)/t->xres;
y = ((float)e.tfinger.y)/t->yres;
then if you keep looking where it calls the draw from testgesture.c
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);
you notice how it multiply’s the x and y by the screen width and height giving the final x and y coordinate
or you could do
x = ((float)e.tfinger.x)/t->xres * screen_width;
y = ((float)e.tfinger.y)/t->yres * screen_height;
the reason for 0 is because it equals a small decimal number below 1 so an int will be either 1 or 0 so you need to multiply for the final int value or use floats.
Also note on iOS for me to get the right coordinates I seem to have needed to use the latest screen size width and height even though my width was actually 480.
x = ((float)e.tfinger.x)/t->xres * 568;
y = ((float)e.tfinger.y)/t->yres * 320;
Gabriele Greco wrote:> Can someone point me to a working example?
I’m trying to follow testgesture.c but it seems that there is something strange going on.
I get xres / yres at 32768 when I call SDL_GetTouch() on my FINGERDOWN event, and this cause my coords to always be 0,0:
case SDL_FINGERDOWN:
?{ ?
? ?SDL_Touch *t = SDL_GetTouch(e.tfinger.touchId);
? ?int x = t.tfinger.x / t->xres,
? ? ? ?y ?= t.tfinger.y / t->yres;
// -> x and y are always 0
[…]
Maybe this has something to do with the fact I’m using a logical size for the window different from the physical one?
Tests done on iOS6, both on real device (iphone5) and simulator.
–
Bye,
?Gabry
