An on-screen joystick is based on multi-touch handling. Two structures contain descriptions of a single joystick button and an axis. The button is given an index and is specified by its color in the FColour field of the sBitmapButton structure. When a user taps the screen where the underlying pixel in the joystick mask has the color matching with one of the buttons, the clScreenJoystick class sets the pressed flag for the button:
struct sBitmapButton
{
ivec4 FColour;
int FIndex;
};The sBitmapAxis structure represents a single stick of a joystick and contains two axes corresponding to vertical and horizontal directions. On the joystick mask bitmap, it is represented as a circular element centered at FPosition with the radius FRadius. The FAxis1 and FAxis2 indices specify which logical joystick axes are affected by this onscreen stick.
The FColour field is used to determine whether the user is touching this axis:
struct sBitmapAxis
{
float FRadius;
vec2...