TwistyPuzzleLib

///////////////////////////////////////////////////////////////////////////////////////////////////

// Copyright 2020 Leszek Koltunski                                                               //

//                                                                                               //

// This file is part of Magic Cube.                                                              //

//                                                                                               //

// Magic Cube is free software: you can redistribute it and/or modify                            //

// it under the terms of the GNU General Public License as published by                          //

// the Free Software Foundation, either version 2 of the License, or                             //

// (at your option) any later version.                                                           //

//                                                                                               //

// Magic Cube is distributed in the hope that it will be useful,                                 //

// but WITHOUT ANY WARRANTY; without even the implied warranty of                                //

// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the                                 //

// GNU General Public License for more details.                                                  //

//                                                                                               //

// You should have received a copy of the GNU General Public License                             //

// along with Magic Cube.  If not, see <http://www.gnu.org/licenses/>.                           //

///////////////////////////////////////////////////////////////////////////////////////////////////

package org.distorted.objectlib.helpers;

import static org.distorted.objectlib.main.TwistyObject.COLOR_BLACK;

import static org.distorted.objectlib.main.TwistyObject.TEXTURE_HEIGHT;

import android.graphics.Canvas;

import android.graphics.Paint;

///////////////////////////////////////////////////////////////////////////////////////////////////

public class FactorySticker

  {

  private static FactorySticker mThis;

  private float mOX, mOY, mR;

///////////////////////////////////////////////////////////////////////////////////////////////////

  private FactorySticker()

    {

    }

///////////////////////////////////////////////////////////////////////////////////////////////////

  public static FactorySticker getInstance()

    {

    if( mThis==null ) mThis = new FactorySticker();

    return mThis;

    }

///////////////////////////////////////////////////////////////////////////////////////////////////

  private float computeAngle(float dx, float dy)

    {

    float PI = (float)Math.PI;

    double angle = Math.atan2(dy,dx);

    float ret = (float)(3*PI/2-angle);

    if( ret>2*PI ) ret-= 2*PI;

    return ret;

    }

///////////////////////////////////////////////////////////////////////////////////////////////////

  private float getAngle(float[] angles, int index)

    {

    return angles==null ? 0 : angles[index];

    }

///////////////////////////////////////////////////////////////////////////////////////////////////

  private void computeCircleCoords(float lX,float lY, float rX, float rY, float alpha)

    {

    float ctg= 1.0f/((float)Math.tan(alpha));

    mOX = 0.5f*(lX+rX) + ctg*0.5f*(lY-rY);

    mOY = 0.5f*(lY+rY) - ctg*0.5f*(lX-rX);

    float dx = mOX-lX;

    float dy = mOY-lY;

    mR = (float)Math.sqrt(dx*dx+dy*dy);

    }

///////////////////////////////////////////////////////////////////////////////////////////////////

// circle1: center (x1,y1) radius r1; circle2: center (x2,y2) radius r2.

// Guaranteed to intersect in two points. Find the intersection. Which one? the one that's closer

// to (nearx,neary).

  private void findCircleIntersection(float x1,float y1, float r1, float x2, float y2, float r2, float nearx, float neary )

    {

    float dx = x2-x1;

    float dy = y2-y1;

    float d = (float)Math.sqrt(dx*dx+dy*dy);

    if( d>0 )

      {

      float Dx = dx/d;

      float Dy = dy/d;

      float cos = (r1*r1+d*d-r2*r2)/(2*r1*d);

      float sin = (float)Math.sqrt(1-cos*cos);

      float ox1 = x1 + r1*cos*Dx + r1*sin*Dy;

      float oy1 = y1 + r1*cos*Dy - r1*sin*Dx;

      float ox2 = x1 + r1*cos*Dx - r1*sin*Dy;

      float oy2 = y1 + r1*cos*Dy + r1*sin*Dx;

      dx = nearx-ox1;

      dy = neary-oy1;

      float d1 = dx*dx+dy*dy;

      dx = nearx-ox2;

      dy = neary-oy2;

      float d2 = dx*dx+dy*dy;

      if( d1<d2 )

        {

        mOX = ox1;

        mOY = oy1;

        }

      else

        {

        mOX = ox2;

        mOY = oy2;

        }

      }

    else

      {

      mOX = x1;

      mOY = y1;

      }

    }

///////////////////////////////////////////////////////////////////////////////////////////////////

  private void drawCurrCurveV(Canvas canvas, Paint paint, int left, int top, float r, float stroke, float pX, float pY, float cX, float cY, float nX, float nY, float pA, float cA)

    {

    pX = (0.5f+pX)*TEXTURE_HEIGHT;

    pY = (0.5f-pY)*TEXTURE_HEIGHT;

    cX = (0.5f+cX)*TEXTURE_HEIGHT;

    cY = (0.5f-cY)*TEXTURE_HEIGHT;

    nX = (0.5f+nX)*TEXTURE_HEIGHT;

    nY = (0.5f-nY)*TEXTURE_HEIGHT;

    computeCircleCoords(pX,pY,cX,cY,pA);

    float o1x = mOX;

    float o1y = mOY;

    float r1  = mR;

    computeCircleCoords(cX,cY,nX,nY,cA);

    float o2x = mOX;

    float o2y = mOY;

    float r2  = mR;

    float dx = o1x-pX;

    float dy = o1y-pY;

    float startA = computeAngle(dy,dx);

    float sweepA = 2*pA;

    startA *= 180/(Math.PI);

    sweepA *= 180/(Math.PI);

    canvas.drawArc( left+o1x-r1, top+o1y-r1, left+o1x+r1, top+o1y+r1, startA, sweepA, false, paint);

    float r3 = r*TEXTURE_HEIGHT + stroke/2;

    float R1 = r1 + (pA < 0 ? r3:-r3);

    float R2 = r2 + (cA < 0 ? r3:-r3);

    findCircleIntersection(o1x,o1y,R1,o2x,o2y,R2,cX,cY);

    float o3x = mOX;

    float o3y = mOY;

    dx = pA<0 ? o3x-o1x : o1x-o3x;

    dy = pA<0 ? o3y-o1y : o1y-o3y;

    startA = computeAngle(dy,dx);

    dx = cA<0 ? o3x-o2x : o2x-o3x;

    dy = cA<0 ? o3y-o2y : o2y-o3y;

    float endA = computeAngle(dy,dx);

    sweepA = endA-startA;

    if( sweepA<0 ) sweepA += 2*Math.PI;

    startA *= 180/(Math.PI);

    sweepA *= 180/(Math.PI);

    canvas.drawArc( left+o3x-r3, top+o3y-r3, left+o3x+r3, top+o3y+r3, startA, sweepA, false, paint);

    }

///////////////////////////////////////////////////////////////////////////////////////////////////

  private void drawCurrVertex(Canvas canvas, Paint paint, int left, int top, float r, float stroke, float pX, float pY, float cX, float cY, float nX, float nY)

    {

    pX = (0.5f+pX)*TEXTURE_HEIGHT;

    pY = (0.5f-pY)*TEXTURE_HEIGHT;

    cX = (0.5f+cX)*TEXTURE_HEIGHT;

    cY = (0.5f-cY)*TEXTURE_HEIGHT;

    nX = (0.5f+nX)*TEXTURE_HEIGHT;

    nY = (0.5f-nY)*TEXTURE_HEIGHT;

    canvas.drawLine(left+pX,top+pY,left+cX,top+cY,paint);

    float aX = pX-cX;

    float aY = pY-cY;

    float bX = cX-nX;

    float bY = cY-nY;

    float aLen = (float)Math.sqrt(aX*aX+aY*aY);

    float bLen = (float)Math.sqrt(bX*bX+bY*bY);

    aX /= aLen;

    aY /= aLen;

    bX /= bLen;

    bY /= bLen;

    float sX = (aX-bX)/2;

    float sY = (aY-bY)/2;

    float sLen = (float)Math.sqrt(sX*sX+sY*sY);

    sX /= sLen;

    sY /= sLen;

    float startAngle = computeAngle(bX,-bY);

    float endAngle   = computeAngle(aX,-aY);

    float sweepAngle = endAngle-startAngle;

    if( sweepAngle<0 ) sweepAngle += 2*Math.PI;

    float R = r*TEXTURE_HEIGHT+stroke/2;

    float C = (float)Math.cos(sweepAngle/2);

    float A = R/C;

    left += (cX+A*sX);

    top  += (cY+A*sY);

    if( C< (2*R-stroke)/(2*R+stroke) )

      {

      float alpha = startAngle + sweepAngle/2;

      float B  = (R-stroke/2)/C;

      float sx = (float)Math.cos(alpha);

      float sy = (float)Math.sin(alpha);

      float startX = left + R*sx;

      float startY = top  + R*sy;

      float stopX  = left + B*sx;

      float stopY  = top  + B*sy;

      canvas.drawLine(startX,startY,stopX,stopY,paint);

      }

    startAngle *= 180/(Math.PI);

    sweepAngle *= 180/(Math.PI);

    canvas.drawArc( left-R, top-R, left+R, top+R, startAngle, sweepAngle, false, paint);

    }

///////////////////////////////////////////////////////////////////////////////////////////////////

// PUBLIC

  public void drawRoundedPolygon(Canvas canvas, Paint paint, int left, int top, int color, ObjectSticker sticker)

    {

    float stroke = sticker.getStroke();

    float[] vertices = sticker.getCoords();

    float[] angles = sticker.getCurvature();

    float[] radii = sticker.getRadii();

    stroke *= TEXTURE_HEIGHT;

    paint.setAntiAlias(true);

    paint.setStrokeWidth(stroke);

    paint.setColor(color);

    paint.setStyle(Paint.Style.FILL);

    canvas.drawRect(left,top,left+TEXTURE_HEIGHT,top+TEXTURE_HEIGHT,paint);

    paint.setColor(COLOR_BLACK);

    paint.setStyle(Paint.Style.STROKE);

    int length = vertices.length;

    int numVertices = length/2;

    float prevX = vertices[length-2];

    float prevY = vertices[length-1];

    float currX = vertices[0];

    float currY = vertices[1];

    float nextX = vertices[2];

    float nextY = vertices[3];

    float prevA = getAngle(angles,numVertices-1);

    float currA = getAngle(angles,0);

    for(int vert=0; vert<numVertices; vert++)

      {

      if( prevA==0 )

        {

        drawCurrVertex(canvas, paint, left, top, radii[vert], stroke, prevX,prevY,currX,currY,nextX,nextY);

        }

      else

        {

        drawCurrCurveV(canvas, paint, left, top, radii[vert], stroke, prevX,prevY,currX,currY,nextX,nextY,prevA,currA);

        }

      prevX = currX;

      prevY = currY;

      currX = nextX;

      currY = nextY;

      prevA = currA;

      currA = getAngle(angles, vert==numVertices-1 ? 0 : vert+1);

      if( 2*(vert+2)+1 < length )

        {

        nextX = vertices[2*(vert+2)  ];

        nextY = vertices[2*(vert+2)+1];

        }

      else

        {

        nextX = vertices[0];

        nextY = vertices[1];

        }

      }

    }

  }