Starting Point - Mobile Games
Whilst many of the modules in the SpecialEffect DevKit might be applicable to your game, we’ve compiled a selection of input and gameplay modules which may be considered particularly relevant for games developed for, or ported to, mobile platforms where a touch screen is the default input device.
The modules listed below can be expanded to reveal information on how they might be applied to various interactions on mobile devices. This can be used as a starting point when interacting with the DevKit, if suitable for your game.
1.2 Supporting Multiple Input Devices
“Give players a choice of different input devices to play your game.”
The input devices a game supports can determine whether or not someone is able to play that game. Players may find different input devices more accessible or more comfortable to use than others.
In addition to featuring a touch screen, both iOS and Android mobile devices support a wide range of additional input devices, such as gamepads, mice, keyboards, microphones, and even switch interfaces.
Players may find different input devices more accessible or more comfortable to use than others, and those different devices may offer additional input methods that players may prefer to use, from analog sticks and buttons, to touch or motion. Having the choice to access a game using various compatible devices available on a particular platform, as well as options for how those devices are handled by the game, can be helpful and necessary for some players. This is especially true in instances where the player is using a particular device to access the user interface of the operating system outside of the game itself.
More information on supporting assistive input devices, such as switch interfaces, can be found in Apple and Google’s developer resources.
1.3 Simultaneous Input
“Let players use more than one input device at the same time.”
The more input devices your game supports, the greater the chance the player will be able to use the input device they prefer. However, some players may find certain parts of different devices more accessible than others, so might benefit from being able to play with more than one of the same or different devices at the same time, using inputs from each device for different actions.
This method of play can be supported by allowing multiple devices to be used concurrently, acting as if only one device were being used. One use-case for this might be a player positioning a gamepad to allow controlling an analog stick with one part of their body, such as their chin, for an analog action like character movement, and then using switches positioned near their hands for digital actions like jump or shoot. By supporting simultaneous input in this way, a setup like this becomes possible for players.
1.5 Input Methods
“Choose input devices that offer various input methods, or provide alternatives.”
When thinking about which input devices to support in your game, consider the input methods available to each device, such as buttons and analog sticks, keys, a pointing device like a mouse, motion, touch, speech recognition, or even eye tracking.
Some players may have input methods they prefer to use over others, so the more input devices you’re able to support that feature these input methods, the greater the chance that someone will be able to play your game.
Touch is an input method that is almost always supported by games on mobile devices, however some players may find this input method partially or even fully inaccessible to them. By supporting other input devices such as gamepads, switch interfaces, or even microphones to support speech recognition, players can use the input methods that they find most accessible.
2.2 Remapping
“Ideally, let players remap any action to any input, at any point in the game.”
Some players may struggle to physically reach or have accurate control over certain inputs and so may prefer to use other inputs instead. By allowing players to change which inputs control which actions, you allow them to create a layout that suits them.
You can present remapping as changing the input that performs an action. For example, by letting the player decide which input to use for attack. Players may want to map the actions they consider most important to the inputs they find most easily accessible, so prioritise making the most critical actions in your game remappable.
For instance, when using a touch screen some players may find certain parts of the screen difficult or impossible to reach, so for actions that are mapped to these areas you could allow players to remap them to a different part of the screen that they have better access over. Or if your game supports additional input devices you could let players map actions to an input on these devices instead, like the buttons on a gamepad, which might also be an input method they find preferable.
3.2 Configuring Interactions
“Let players decide which input event performs an action, and the timing of that event.”
Every input interaction in a game contains one or more input events. In the case of a digital input this could either be a press, or a release of that input.
You could allow players to adjust which events perform each action. So, you might let players choose to have an action be performed when an input is released, or perhaps on the second press down of an input in a sequence.
While it is useful to let players customise input interactions in this way generally, it is also important to ensure players can choose to perform an action on the first press of an input where possible.
Input interactions often also contain timing elements alongside these input events, which you might also let the player configure. If an input needs to be released before or after being held for a specific amount of time for an action to be performed, you might allow players to adjust this time to customise the interaction further.
Whilst these input interactions can take any form, there are some in particular that mobile games often feature, and which can be difficult for some players. Allowing players to adjust the input interaction that performs each action means that they might be able to avoid interactions they find particularly challenging, such as swipe interactions and repeated presses.
3.3 Continuous Holds
“Provide alternative options for actions that require an input to be continuously held.”
Some games will require you to hold an input down to continuously perform an action. An alternative to this interaction might be to press the input once to initiate the action, and then again to complete it.
For instance, perhaps an interaction in your game requires an object to be moved by pressing on the touch screen at its location and then dragged across the screen to a new position where the object is then placed by releasing the press. Some players may find swipe interactions like this particularly difficult so you could provide an option that allows the player to just tap the screen once to pick up an object, and then again to place it, rather than the default swipe interaction. Simplifying touch interactions in this way could also help players to avoid dragging when using analog sticks, mice, and assistive mice which emulate touch input on mobile devices.
3.5 Repeated Presses
“Let players avoid repeated button presses in quick succession.”
If players are required to press an input repeatedly and in quick succession for a certain amount of time, an option to avoid this can be worthwhile.
For instance, in your game you might require the player to tap the touch screen repeatedly and at a certain rate in order to carry out an action like opening a chest. An alternative to this might be to let the player hold down on the screen to open the chest instead, as some players may struggle to tap the screen at the required rate.
As holding down on the touch screen can still be difficult for some, providing other options can also be useful, such as reducing the number and rate of presses needed, or you might even consider reducing the interaction down to a single tap of the screen if possible.
3.6 Input Methods
“Allow players to modify input interactions for all input methods.”
The ability to modify input interactions should also apply to all of the input methods that your game supports, such as buttons, triggers, analog sticks, switches, and motion.
If you’ve provided an alternative for a continuous hold or swipe interaction in your game, consider if the same could be offered to players using a switch interface for example, so that they are able to press the switch once to toggle the action on or off. Similarly for repeated press interactions, allow players using a gamepad to hold a button down or simply press it once to complete an action, and provide similar alternatives for the other input methods that your game supports.
4.2 Inner Deadzone
“Let players adjust the inner deadzones of each input to suit their movement.”
The inner deadzone is an area between two distinct values of an analog input, in which the bound action will not activate. By allowing players to adjust this area, players can choose the amount of input required to initiate an action.
Having the ability to increase the inner deadzone can be useful for players with involuntary movement trying to avoid unintentionally performing an action, whereas decreasing the inner deadzone can be useful for players who would prefer to initiate an action with less input from the device, and therefore less physical movement overall.
Depending on the style of your game you may have opted to have character movement be controlled with a touch screen interaction that emulates typical analog stick movement, often visualised with a UI element to provide feedback to the player. So the player presses down on the screen to activate the interaction, and then while still pressing down moves in the desired direction to move the character, until releasing the input. Letting players adjust the distance they need to drag before the action activates, allows them to decide how much physical movement is required.
4.3 Outer Threshold
“Adjusting the outer threshold can help players to perform an action fully.”
The outer threshold is the opposite of the inner deadzone, in that it’s an area between two values of an analog input where an action will activate at its maximum value. The point at which a character will move at their maximum speed for instance.
Letting players adjust this area can allow some players to reach the maximum value of the action with less physical movement.
Similarly to inner deadzones and touch screen interactions that emulate analog sticks, letting players adjust the distance they need to drag before the action activates at its maximum value allows them to configure analog settings to match the amount of physical movement that is preferable for them.
5.2 Action Information
“Give players information about available actions and required inputs during gameplay."
Providing players with information on the various parts of your game, before starting and throughout, will allow them to make an informed decision on whether or not a game is suitable for them, and subsequently make the most of the input setup that they use. If your game requires particularly complex touch interactions without alternatives, a player may decide that they are unlikely to be able to play successfully, so making this information clear before purchase can be important.
If a player does decide to play your game, informing them on the actions they can perform, both generally and for specific contexts, can be useful for the player if they want to know which inputs are required while playing.
While a controls screen that shows which action each input corresponds to can be useful, they can be less flexible when trying to show controls for different contexts and for different input interactions. Input prompts and reminders that show the required inputs and interactions needed to perform actions while actively playing, can be a more understandable way to present controls.
If you do use input prompts in your game, you should try to account for as many of the devices your game supports as you can. So, on mobile you might have touch control prompts, as well gamepad input prompts or switch interface prompts, depending on the device the player is using, either by detection, or by letting the player manually decide.
5.6 Testing Configurations
“Give players options to test their setups while becoming familiar with your game.”
In order for players to get familiar with your game, with the various actions they can perform, and to test how adjusting the various settings will affect their experience, consider adding a consequence-free area or mode for the player to practice in.
How you implement this will depend greatly on the nature of your game, and for some games it might not be suitable, but for those that it would be, it can be a very useful tool for players to get familiar with your game before they make potentially irreversible actions.
You might have a contained sandbox area that features simplified elements of what the player will encounter in the main experience, showing them how each action behaves and what effect it will have. By allowing players to configure settings while in these areas, they could test which inputs and input interactions should be bound to which specific actions. This is especially important in games with many permanent decisions and where misplaced actions can be costly.
6.4 Timing Elements
“Let players reduce or remove the need for quick or precisely timed movements.”
At certain points in your game, you may require the player to respond quickly to something, or to precisely time when an input is used. Some players may struggle to do this, so it can be useful to provide options that affect the level of precision, or speed of response needed to access those parts of your game.
One way of reducing the need for both quick responses and precise timing simultaneously, would be to allow changing the speed of multiple elements or possibly the entire game. Letting players slow things down will give them more time to respond to events and could also increase the window players might have to precisely time an input interaction.
Many games designed for mobile devices often feature mechanics that require increasingly quick responses from the player, often as a way to increase difficulty. Some players may find their response time is limited by their input setup, so allowing them to adjust the speed of the required responses can be very beneficial. You may need to consider how this will affect the balance of your game, especially in competitive environments, and perhaps you might decide to offer other methods of difficulty progression as an alternative.
6.5 Analog Action Assists
“Give players options to assist their control of analog actions.”
For actions in your game that are controlled by analog inputs, consider providing options that make it easier for the player to have a good level of control over those actions.
There may be players who don’t quite have the required dexterity with an analog input to optimally perform an action, and so would benefit from options to have these actions assisted in some way.
Allowing the player to increase the size of elements within an interface or menu might reduce the level of dexterity needed with touch screen interfaces that require the player to press or swipe across them to select or interact. Equally, letting players also adjust the position and spacing of these interactable elements can make it easier for the player to create a setup that’s suitable for their range of movements.
Another way of assisting players with swipe interactions or interactions that require the player to press down on a touch screen and drag an object in the game along a path, is to provide an option that assists the path of the object, keeping it closer to the players intended and more optimal route.
7.2 Alternative Actions
“Offer players alternative ways to perform actions.”
There may be actions in your game that require the use of certain inputs or input interactions that some players may find challenging. Providing alternative ways to perform these actions might simplify your game and allow more people to access it.
Perhaps your game contains an action that requires a particularly complex swipe interaction, like having to rotate a wheel by pressing and dragging in a circular motion. Some players might struggle with this interaction, so consider if you might be able to offer an alternative option that adds a UI element to the screen which can be pressed to perform that action in the same way.
7.3 Automatic Digital Actions
“Allow players to automate certain digital actions.”
Even when alternative ways to perform certain actions are available, some players may find there are still too many actions overall for them to play successfully. In these cases, it might be possible to reduce the number of actions the player needs to perform by partially or fully automating them. Which could in turn reduce the total number of inputs required to play your game.
There are a number of ways you might automate digital actions, and how this is implemented will depend on the nature of each action and each game. One way of having a digital action be performed automatically is to let the player set it to happen only when in certain contexts within the game.
For instance, perhaps your game requires the player to either jump over or duck under and obstacle to progress. You could provide an option that automates one or both actions, so that the player automatically jumps or ducks when approaching the obstacle, allowing them to progress without needing to manually jump or duck, if performing both of these actions is challenging for the player.
We hope this has been useful for getting started when considering the motor accessibility of your own game. If you are interested in additional areas of motor accessibility that may also be related to your game, you might want to use our Checklist. This can be used to assess which motor accessibility options your game currently supports, and to determine what could be supported in the future.