OpenGL ES 绘制圆环

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1、新建 MyRingRenderer.h

/* * 圆环 */public class MyRingRenderer extends MyAbstractRenderer {private float r_inner =0.2f; //内环 半径private float r_ring  =0.3f; //圆环 环半径   public void onSurfaceCreated(GL10 gl, EGLConfig arg1) {        //设置清屏色（背景）        gl.glClearColor(0, 0, 0, 1);        //启用顶点缓冲区        gl.glEnableClientState(GL10.GL_VERTEX_ARRAY);    }protected void drawBefore(GL10 gl) {gl.glClear(GL10.GL_COLOR_BUFFER_BIT);}protected void draw(GL10 gl) {int ringCount  =20;//把圆环 切成20块int blockCount =20;//把圆 切成20块float alpha =0;float beta  =0;float alphaStep =(float) ((2*Math.PI) /ringCount);float betaStep  =(float) ((2*Math.PI) /blockCount);List<Float> pos =new ArrayList<Float>();for(int i =0;i <ringCount;i++){//一次画两个相邻的圆alpha =i *alphaStep;for(int j =0; j <blockCount; j++){beta =j *betaStep;// z值为0的 以(0,0)点线段长度float lineD =(float) (r_inner +r_ring +r_ring *Math.cos(beta));// 投影到 x，y轴float x0 =(float) (Math.cos(alpha) *lineD);float y0 =(float) (Math.sin(alpha) *lineD);//由于 z轴靠近人的为正方向  +Math.PIfloat z0 =(float) (Math.sin(beta +Math.PI) *r_ring);float x1 =(float) (Math.cos(alpha +alphaStep) *lineD);float y1 =(float) (Math.sin(alpha +alphaStep) *lineD);float z1 =z0;pos.add(x0);pos.add(y0);pos.add(z0);pos.add(x1);pos.add(y1);pos.add(z1);}}ByteBuffer bb =BufferUtil.list2ByteBuffer(pos);gl.glVertexPointer(3, GL10.GL_FLOAT, 0, bb);gl.glDrawArrays(GL10.GL_LINE_STRIP, 0, pos.size()/3);}}

2、运行效果

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