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_STROKE;

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;

      }

    }

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

// TODO: support concave vertices

  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 color, 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;

    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;

    boolean isConvex = sweepAngle<=Math.PI;  // the corner is convex

    // draw a little more - stroke*(aX,aY) more - so

    // that we draw over the rounded corners (Kilominx!)

    canvas.drawLine(left+pX,top+pY,left+cX-stroke*aX,top+cY-stroke*aY,paint);

    float R = r*TEXTURE_HEIGHT+stroke/2;

    if( isConvex )

      {

      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);

      }

    else

      {

      startAngle= computeAngle(aX,aY);

      endAngle  = computeAngle(-bX,-bY);

      sweepAngle= endAngle-startAngle;

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

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

      float A = (R-stroke)/C;

      left += (cX+A*sX);

      top  += (cY+A*sY);

      startAngle *= 180/(Math.PI);

      sweepAngle *= 180/(Math.PI);

      paint.setColor(color);

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

      paint.setColor(COLOR_STROKE);

      }

    }

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

// 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.save();

    canvas.clipRect(left,top,left+TEXTURE_HEIGHT,top+TEXTURE_HEIGHT);

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

    paint.setColor(COLOR_STROKE);

    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, color, 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];

        }

      }

    canvas.restore();

    }

  }