libgdx学习记录12——圆角矩形CircleRect

libgdx提供了ShapeRenderer这个工具，用它可以画点、画线、画圆、画矩形、画椭圆、画扇形，但是没有提供画圆角矩形的方法。

刚开始自己尝试分成8端，4端画直线，4端画扇形，发现多了半径几部分，于是又改成全部画线。

4端弧采用逐个描点实现。

具体代码：

 package com.fxb.newtest;

 import com.badlogic.gdx.ApplicationAdapter;
 import com.badlogic.gdx.Gdx;
 import com.badlogic.gdx.graphics.Color;
 import com.badlogic.gdx.graphics.GL10;
 import com.badlogic.gdx.graphics.glutils.ShapeRenderer;
 import com.badlogic.gdx.graphics.glutils.ShapeRenderer.ShapeType;

 public class Lib011_CicleRect extends ApplicationAdapter{

     ShapeRenderer rend;

     @Override
     public void create() {
         // TODO Auto-generated method stub
         rend = new ShapeRenderer();
     }

     public void DrawCircleRect( float x, float y, float width, float height, float radius, ShapeRenderer rend, Color color ){
         rend.setColor( color );
         rend.begin(ShapeType.Line);

         //rend.rect( x, y, width, height );
         rend.line( x+radius, y, x+width-radius, y );
         rend.line( x+radius, y+height, x+width-radius, y+height );
         rend.line( x, y+radius, x, y+height-radius );
         rend.line( x+width, y+radius, x+width, y+height-radius );
 /*
         rend.arc( x+width-radius, y+height-radius, radius, 0, 90 );
         rend.arc( x+radius, y+height-radius, radius, 90, 90 );
         rend.arc( x+radius, y+radius, radius, 180, 90 );
         rend.arc( x+width-radius, y+radius, radius, 270, 90 );
         */

         int segments = (int)( *(float)Math.cbrt( radius ) );

         for( int i=; i<segments; i++ ){
             float x0 = x+width-radius;
             float y0 = y+height-radius;
             //float angle1 = (float)Math.PI*i*9f/180f;
             //float angle2 = (float)Math.PI*(i+1)*9f/180f;
             float angle1 = (float)Math.PI*i/(*segments);
             float angle2 = (float)Math.PI*(i+)/(*segments);
             rend.line( x0+radius*(float)Math.cos(angle1), y0+radius*(float)Math.sin(angle1), x0+radius*(float)Math.cos(angle2), y0+radius*(float)Math.sin(angle2) );
         }

         for( int i=; i<segments; i++ ){
             float x0 = x+radius;
             float y0 = y+height-radius;
             float angle1 = (float)Math.PI*(i+segments)/(*segments);
             float angle2 = (float)Math.PI*(i+segments+)/(*segments);
             rend.line( x0+radius*(float)Math.cos(angle1), y0+radius*(float)Math.sin(angle1), x0+radius*(float)Math.cos(angle2), y0+radius*(float)Math.sin(angle2) );
         }

         for( int i=; i<segments; i++ ){
             float x0 = x+radius;
             float y0 = y+radius;
             float angle1 = (float)Math.PI*(i+segments*)/(*segments);
             float angle2 = (float)Math.PI*(i+segments*+)/(*segments);
             rend.line( x0+radius*(float)Math.cos(angle1), y0+radius*(float)Math.sin(angle1), x0+radius*(float)Math.cos(angle2), y0+radius*(float)Math.sin(angle2) );
         }
         for( int i=; i<segments; i++ ){
             float x0 = x+width-radius;
             float y0 = y+radius;
             float angle1 = (float)Math.PI*(i+segments*)/(*segments);
             float angle2 = (float)Math.PI*(i+segments*+)/(*segments);
             rend.line( x0+radius*(float)Math.cos(angle1), y0+radius*(float)Math.sin(angle1), x0+radius*(float)Math.cos(angle2), y0+radius*(float)Math.sin(angle2) );
         }    

         rend.end();
     }

     @Override
     public void render() {
         // TODO Auto-generated method stub
         Gdx.gl.glClearColor( 0.5f, 0.5f, 0.5f,  );
         Gdx.gl.glClear( GL10.GL_COLOR_BUFFER_BIT );

         DrawCircleRect( , , , , , rend, Color.RED );
         DrawCircleRect( , , , , , rend, Color.BLUE );
         DrawCircleRect( , , , , , rend, Color.CYAN );
         DrawCircleRect( , , , , , rend, Color.YELLOW );
     }

     @Override
     public void dispose() {
         // TODO Auto-generated method stub
         rend.dispose();
         super.dispose();
     }

 }

运行结果：

4个矩形的圆角半径分别为10,20,30,50像素。

分段数采用源码中的构造方式，

int segments = (int)( 6*(float)Math.cbrt( radius ) );

当然还可以做优化的，以后可以尝试。