Touch vs Mouse

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A Touch Event and a Mouse Event are not same event.

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What is the difference?

This is one of the hardest things to grasp when moving from a desktop development to mobile, is the understanding that there is no such thing as a "mouse" in the mobile development world. There are only touch events and unlike mouse events, touch events do not maintain state.

And that's it in a nutshell...

Take note:

• There is no concept of a Left button events (i.e. Click, Down, Up etc)
• There is no concept of a Right button events (i.e. Click, Down, Up etc)
• There is no concept of Mouse Location Events (Hover etc)

So how do we use Touch Events?

The good news is, a single touch event, olc::GetTouch() , can be likened to a olc::GetMouse(0) which means your simple fire and forget code will work the very same.

For example:

• olc::GetTouch().bPressed can be executed the same as olc::GetMouse(0).bPressed
• olc::GetTouch().bHeld can be executed the same as olc::GetMouse(0).bHeld
• olc::GetTouch().bReleased can be executed the same as olc::GetMouse(0).bReleased

However that is where the likeness ends.

To use Touch Events in the OLOC PGE 2.0 Mobile simple execute olc::GetTouch() or olc::GetTouchPos() commands. You can also select which touch by passing the index of that touch, i.e. olc::GetTouch(1) or olc::GetTouchPos(1) .

Always keep in mind that touch events do not maintain state.

For Example

• If a user places 1 finger on the screen:
  • The OS (Android/iOS) will intrepid this as Touch Event 0 or olc::GetTouch() / olc::GetTouch(0)
• If the user then places a second finger on the screen
  • The OS (Android/iOS) will intrepid this as Touch Event 1 or olc::GetTouch(1)
• If the user then places a third finger on the screen
  • The OS (Android/iOS) will intrepid this as Touch Event 2 or olc::GetTouch(2)
• And all is happy with the world until the user raises any finger
• The OS will then re-intrepid the touch events, and work out what is the most likely the new Touch Event 0 and Touch Event 1
• This means you can never rely on the state of your touch events and must code them without state
• i.e. Touch Event 0, could now become Touch Event 1 or Touch Event 2 becomes 1, there is no state