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：

 1 package com.fxb.newtest;

 2

 3 import com.badlogic.gdx.ApplicationAdapter;

 4 import com.badlogic.gdx.Gdx;

 5 import com.badlogic.gdx.graphics.Color;

 6 import com.badlogic.gdx.graphics.GL10;

 7 import com.badlogic.gdx.graphics.glutils.ShapeRenderer;

 8 import com.badlogic.gdx.graphics.glutils.ShapeRenderer.ShapeType;

 9

10 public class Lib011_CicleRect extends ApplicationAdapter{

11

12     ShapeRenderer rend;

13

14     @Override

15     public void create() {

16         // TODO Auto-generated method stub

17         rend = new ShapeRenderer();

18     }

19

20     public void DrawCircleRect( float x, float y, float width, float height, float radius, ShapeRenderer rend, Color color ){

21         rend.setColor( color );

22         rend.begin(ShapeType.Line);

23

24         //rend.rect( x, y, width, height );

25         rend.line( x+radius, y, x+width-radius, y );

26         rend.line( x+radius, y+height, x+width-radius, y+height );

27         rend.line( x, y+radius, x, y+height-radius );

28         rend.line( x+width, y+radius, x+width, y+height-radius );

29 /*

30         rend.arc( x+width-radius, y+height-radius, radius, 0, 90 );

31         rend.arc( x+radius, y+height-radius, radius, 90, 90 );

32         rend.arc( x+radius, y+radius, radius, 180, 90 );

33         rend.arc( x+width-radius, y+radius, radius, 270, 90 );

34         */

35

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

37

38         for( int i=0; i<segments; i++ ){

39             float x0 = x+width-radius;

40             float y0 = y+height-radius;

41             //float angle1 = (float)Math.PI*i*9f/180f;

42             //float angle2 = (float)Math.PI*(i+1)*9f/180f;

43             float angle1 = (float)Math.PI*i/(2*segments);

44             float angle2 = (float)Math.PI*(i+1)/(2*segments);

45             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) );

46         }

47

48         for( int i=0; i<segments; i++ ){

49             float x0 = x+radius;

50             float y0 = y+height-radius;

51             float angle1 = (float)Math.PI*(i+segments)/(2*segments);

52             float angle2 = (float)Math.PI*(i+segments+1)/(2*segments);

53             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) );

54         }

55

56         for( int i=0; i<segments; i++ ){

57             float x0 = x+radius;

58             float y0 = y+radius;

59             float angle1 = (float)Math.PI*(i+segments*2)/(2*segments);

60             float angle2 = (float)Math.PI*(i+segments*2+1)/(2*segments);

61             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) );

62         }

63         for( int i=0; i<segments; i++ ){

64             float x0 = x+width-radius;

65             float y0 = y+radius;

66             float angle1 = (float)Math.PI*(i+segments*3)/(2*segments);

67             float angle2 = (float)Math.PI*(i+segments*3+1)/(2*segments);

68             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) );

69         }

70

71         rend.end();

72     }

73

74     @Override

75     public void render() {

76         // TODO Auto-generated method stub

77         Gdx.gl.glClearColor( 0.5f, 0.5f, 0.5f, 1 );

78         Gdx.gl.glClear( GL10.GL_COLOR_BUFFER_BIT );

79

80         DrawCircleRect( 10, 10, 300, 200, 10, rend, Color.RED );

81         DrawCircleRect( 100, 60, 300, 200, 20, rend, Color.BLUE );

82         DrawCircleRect( 200, 110, 300, 200, 30, rend, Color.CYAN );

83         DrawCircleRect( 450, 160, 300, 200, 50, rend, Color.YELLOW );

84     }

85

86     @Override

87     public void dispose() {

88         // TODO Auto-generated method stub

89         rend.dispose();

90         super.dispose();

91     }

92

93 }

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。