{$INCLUDE "options.inc"}

unit uTouch;

interface

procedure initModule;

procedure onTouchDown(x,y: Longword; pointerId: SDL_FingerId);

procedure onTouchMotion(x,y: Longword; dx,dy: LongInt; pointerId: SDL_FingerId);

procedure onTouchUp(x,y: Longword; pointerId: SDL_FingerId);

function convertToCursor(scale: LongInt; xy: LongInt): LongInt;

procedure deleteFinger(id: SDL_FingerId);

procedure onTouchClick(x,y: Longword; pointerId: SDL_FingerId);

function calculateDelta(id1, id2: SDL_FingerId): hwFloat;

function getSecondPointer(id: SDL_FingerId): SDL_FingerId;

implementation

const

    clicktime = 200;

var

    pointerCount : Longword;

    xyCoord : array of LongInt;

    pointerIds : array of SDL_FingerId;

    timeSinceDown: array of Longword;

    //Pinch to zoom 

    pinchSize : hwFloat;

    baseZoomValue: GLFloat;

procedure onTouchDown(x,y: Longword; pointerId: SDL_FingerId);

begin

    WriteToConsole('down'); 

    xyCoord[pointerId*2] := convertToCursor(cScreenWidth,x);

    xyCoord[pointerId*2+1] := convertToCursor(cScreenHeight,y);

    case pointerCount of

        2:

        begin

            pinchSize := calculateDelta(pointerId, getSecondPointer(pointerId));

            baseZoomValue := ZoomValue

        end;

    end;//end case pointerCount of

end;

procedure onTouchMotion(x,y: Longword;dx,dy: LongInt; pointerId: SDL_FingerId);

var

    secondId : SDL_FingerId;

    currentPinchDelta, zoom : hwFloat;

begin

    xyCoord[pointerId*2] := convertToCursor(cScreenWidth, x);

    xyCoord[pointerId*2+1] := convertToCursor(cScreenHeight, y);

    case pointerCount of

       1:

           begin

           end;

       2:

           begin

               secondId := getSecondPointer(pointerId);

               currentPinchDelta := calculateDelta(pointerId, secondId) - pinchSize;

               zoom := currentPinchDelta/cScreenWidth;

               ZoomValue := baseZoomValue - ((hwFloat2Float(zoom) * cMinMaxZoomLevelDelta));

               //WriteToConsole(Format('Zoom in/out. ZoomValue = %f', [ZoomValue]));

//              if ZoomValue > cMaxZoomLevel then ZoomValue := cMaxZoomLevel;

//               if ZoomValue < cMinZoomLevel then ZoomValue := cMinZoomLevel;

            end;

    end; //end case pointerCount of

end;

procedure onTouchUp(x,y: Longword; pointerId: SDL_FingerId);

begin

    pointerCount := pointerCount-1;

    deleteFinger(pointerId);

end;

procedure onTouchClick(x,y: Longword; pointerId: SDL_FingerId);

begin

end;

function convertToCursor(scale: LongInt; xy: LongInt): LongInt;

begin

    convertToCursor := round(xy/32768*scale)

end;

var 

    index, tmp: Longword;

begin

    pointerCount := pointerCount + 1;

    //Check array sizes

    if length(pointerIds) < pointerCount then setLength(pointerIds, length(pointerIds)*2);

    if length(timeSinceDown) < id then setLength(timeSinceDown, id); 

    for index := 0 to pointerCount do //place the pointer ids as far back to the left as possible

    begin

        if pointerIds[index] = -1 then 

           begin

               pointerIds[index] := id;

               break;

           end;

    end;

    //set timestamp

end;

procedure deleteFinger(id: SDL_FingerId);

var

    index, i : Longint;

begin

    index := 0;

    for index := 0 to pointerCount do

    begin

         if pointerIds[index] = id then

         begin

             pointerIds[index] := -1;

             break;

         end;

    end;

    //put the last pointerId into the stop of the id to be removed, so that all pointerIds are to the far left

    for i := pointerCount downto index do

    begin

        if pointerIds[i] <> -1 then

        begin

            pointerIds[index] := pointerIds[i];

            break;

        end;

    end;

end;

function calculateDelta(id1, id2: SDL_FingerId): hwFloat;

begin

//    calculateDelta := Distance(xyCoord[id2*2] - xyCoord[id1*2], xyCoord[id2*2+1] - xyCoord[id1*2+1]);

    calculateDelta := int2hwFloat(trunc(sqrt(Power(xyCoord[id2*2]-xyCoord[id1*2],2) + Power(xyCoord[id2*2+1]-xyCoord[id1*2+1], 2))));

end;

// Under the premise that all pointer ids in pointerIds:SDL_FingerId are pack to the far left.

// If the pointer to be ignored is not pointerIds[0] the second must be there

function getSecondPointer(id: SDL_FingerId): SDL_FingerId;

begin

    if pointerIds[0] = id then getSecondPointer := pointerIds[1]

    else getSecondPointer := pointerIds[0];

end;

procedure initModule;

var

    index: Longword;

begin

    setLength(xyCoord, 10);

    setLength(pointerIds, 5);

    for index := Low(xyCoord) to High(xyCoord) do xyCoord[index] := -1;

    for index := Low(pointerIds) to High(pointerIds) do pointerIds[index] := -1;

end;

begin

end.