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 static final float PI = (float)Math.PI;

  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)

    {

    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 x1,float y1, float x2, float y2, float alpha)

    {

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

    mOX = 0.5f*(x1+x2) - ctg*0.5f*(y1-y2);

    mOY = 0.5f*(y1+y2) + ctg*0.5f*(x1-x2);

    float dx = mOX-x1;

    float dy = mOY-y1;

    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 drawCurrSide(Canvas canvas, Paint paint, int left, int top, float stroke,

                            float pX, float pY, float cX, float cY, float pAngle)

    {

    pX = (0.5f+pX)*TEXTURE_HEIGHT;

    pY = (0.5f-pY)*TEXTURE_HEIGHT;

    cX = (0.5f+cX)*TEXTURE_HEIGHT;

    cY = (0.5f-cY)*TEXTURE_HEIGHT;

    if( pAngle==0 )

      {

      float aX = pX-cX;

      float aY = pY-cY;

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

      aX /= aLen;

      aY /= aLen;

      // 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);

      }

    else

      {

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

      float ox = mOX;

      float oy = mOY;

      float r  = mR;

      float dx = ox-pX;

      float dy = oy-pY;

      float startA = computeAngle(dy,dx);

      float sweepA = -2*pAngle;

      startA *= 180/PI;

      sweepA *= 180/PI;

      canvas.drawArc( left+ox-r, top+oy-r, left+ox+r, top+oy+r, startA, sweepA, false, paint);

      }

    }

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

  private float computeSideAngle(float vX, float vY, float curvature)

    {

    float ret = computeAngle(vX,vY)+curvature;

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

    if( ret<0     ) ret += 2*PI;

    return ret;

    }

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

  private float angleMidpoint(float angle1, float angle2)

    {

    float diff = angle2-angle1;

    if( diff<0 ) diff = -diff;

    float avg = (angle1+angle2)/2;

    if( diff>PI )

      {

      avg -= PI;

      if( avg<0 ) avg += 2*PI;

      }

    return avg;

    }

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

  private void drawRoundCorner(Canvas canvas, Paint paint,int color, int left, int top, float stroke,

                              float radius, float currX, float currY, float pA, float cA)

    {

    currX = (0.5f+currX)*TEXTURE_HEIGHT;

    currY = (0.5f-currY)*TEXTURE_HEIGHT;

    float R = radius*TEXTURE_HEIGHT + stroke/2;

    boolean isConvex = (!(pA<cA && cA<pA+PI) && !(pA<cA+2*PI && cA+2*PI<pA+PI));

    float startA, stopA, centerA, alpha, D;

    if( isConvex )

      {

      startA = cA + PI;

      stopA  = pA + PI;

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

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

      centerA= angleMidpoint(pA,cA) - PI/2;

      if( centerA<0 ) centerA += 2*PI;

      float diff = cA-centerA;

      if( diff<0 ) diff += 2*PI;

      alpha = diff> PI/2 ? PI-diff : diff;

      D = (float)(R/Math.sin(alpha));

      }

    else

      {

      startA = pA;

      stopA  = cA;

      centerA= angleMidpoint(pA,cA) + PI/2;

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

      float diff = centerA-cA;

      if( diff<0 ) diff += 2*PI;

      alpha = diff> PI/2 ? PI-diff : diff;

      D = (float)((R-stroke)/Math.sin(alpha));

      }

    float sweepA = stopA-startA;

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

    float sinA = (float)(Math.sin(centerA));

    float cosA = (float)(Math.cos(centerA));

    float oX= currX - D*sinA;

    float oY= currY + D*cosA;

    startA *= 180/PI;

    sweepA *= 180/PI;

    if( !isConvex ) paint.setColor(color);

    canvas.drawArc( left+oX-R, top+oY-R, left+oX+R, top+oY+R, startA, sweepA, false, paint);

    if( !isConvex ) 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++)

      {

      drawCurrSide(canvas,paint,left,top,stroke,prevX,prevY,currX,currY,prevA);

      float prevAngle = computeSideAngle(currX-prevX,currY-prevY,-prevA);

      float currAngle = computeSideAngle(nextX-currX,nextY-currY,+currA);

      drawRoundCorner(canvas,paint,color,left,top,stroke,radii[vert],currX,currY,prevAngle,currAngle);

      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();

    }

  }