Ios retina SDL_WINDOW_ALLOW_HIGHDPI and SDL_MOUSEBUTTONUP event coordinates

SDL Development
#1

SDL 2.0.7

I’m running my app on ios 5s iphone simulator which have [640, 1136] screen resolution.
I create window with SDL_WINDOW_RESIZABLE | SDL_WINDOW_ALLOW_HIGHDPI flags.

But when I trigger SDL_MOUSEBUTTONUP event is gives me wrong coordinates like my screen has 320 580 screen resolution.

    auto Window = SDL_CreateWindow("Hello world", SDL_WINDOWPOS_UNDEFINED, SDL_WINDOWPOS_UNDEFINED, 800, 600, SDL_WINDOW_RESIZABLE | SDL_WINDOW_ALLOW_HIGHDPI);
auto Renderer = SDL_CreateRenderer(Window, -1, SDL_RENDERER_ACCELERATED | SDL_RENDERER_PRESENTVSYNC);

SDL_Event event;
while (SDL_PollEvent(&event))
{
    switch (event.type)
    {
        case SDL_MOUSEBUTTONDOWN:
            if (App.onTouchDown(event.button.x, event.button.y)) NeedReDraw = true;
            break;

        case SDL_MOUSEBUTTONUP:
            if (App.onTouchUp(event.button.x, event.button.y)) NeedReDraw = true;
            break;
    }
}

What I’m doing wrong?

#2

I found changeset https://hg.libsdl.org/SDL/rev/0ef6b8b9ca6d.

Looking at the line

if (renderer->logical_w && window == renderer->window) {

It seems to be I shoud use SDL_RenderSetLogicalSize after render create and each time screen size and orientation changes?

#3

May be the best practise using SDL_FINGER events instead of MOUSE on mobile platforms?

#4

I was under the impression that this is the intended behaviour. Event
coordinates are always in points, they do not rescale if you use HIGHDPI. So
I added some logic to my code to handle it properly if the renderer’s size
(in pixels) is different from the screen size (in points).

---------- Původní e-mail ----------
Od: akk0rd87 noreply@discourse.libsdl.org
Komu: hardcoredaniel@seznam.cz
Předmět: [SDL] Ios retina SDL_WINDOW_ALLOW_HIGHDPI and SDL_MOUSEBUTTONUP
event coordinates
"

 akk0rd87(https://discourse.libsdl.org/u/akk0rd87)

February 4

SDL 2.0.7

I’m running my app on ios 5s iphone simulator which have [640, 1136] screen
resolution.
I create window with SDL_WINDOW_RESIZABLE | SDL_WINDOW_ALLOW_HIGHDPI flags.

But when I trigger SDL_MOUSEBUTTONUP event is gives me wrong coordinates
like my screen has 320 580 screen resolution.

auto Window = SDL_CreateWindow(“Hello world”, SDL_WINDOWPOS_UNDEFINED, SDL_WINDOWPOS_UNDEFINED, 800, 600, SDL_WINDOW_RESIZABLE | SDL_WINDOW_ALLOW_HIGHDPI);
auto Renderer = SDL_CreateRenderer(Window, -1, SDL_RENDERER_ACCELERATED | SDL_RENDERER_PRESENTVSYNC);

SDL_Event event;
while (SDL_PollEvent(&event))
{
switch (event.type)
{
case SDL_MOUSEBUTTONDOWN:
if (App.onTouchDown(event.button.x, event.button.y)) NeedReDraw = true;
break;

    case SDL_MOUSEBUTTONUP:
        if (App.onTouchUp(event.button.x, event.button.y)) NeedReDraw = true;
        break;
}

}

What I’m doing wrong?

#5

Thank you, hardcoredaniel. Now I handle FINGER events instead of Mouse events on ios and Android.

#6

hardcoredaniel, is your code open source and can be looked at?

#7

Yes, the code is open source. Nevertheless it’s spread all over the project, so I doubt you’ll find the interesting parts easily. This file contains most of the logic if you like to take a look:

https://bitbucket.org/hcdaniel/wmelite-rapaki-edition/src/8f873d69d2d8034e109ed439f5a64ba30d2d2dc3/src/BRenderSDL.cpp?at=default&fileviewer=file-view-default

The idea behind this are several “resolutions” or “coordinate systems”, and conversions between them:

  1. the game’s own native resolution (in my case: 1024 x 600)
  2. the systems “logical”/“point” resolution (for event coordinates)
  3. the systems “physical” rendering resolution (the actual pixels) - which can be equal to 2) if there is no high-resolution-display available

internally, event coordinates are transposed from 2) to 1) and rendering happens transposing from 1) to 3). Thus, a direct transformation between 3) and 2) and vice versa is not needed.

Regards,

Daniel