透明度设置的问题

private void draw5Big(float z,float r,float g,float b,float a){
		MatrixState.pushMatrix();
		MatrixState.translate(0, 0, z);
		drawBallColorBig.drawSelf(r, g, b, a);
		MatrixState.popMatrix();
		
		MatrixState.pushMatrix();
		MatrixState.translate(-offset, offset, z);
		drawBallColorBig.drawSelf(r, g, b, a);
		MatrixState.popMatrix();
		
		MatrixState.pushMatrix();
		MatrixState.translate(-offset, -offset, z);
		drawBallColorBig.drawSelf(r, g, b, a);
		MatrixState.popMatrix();
		
		MatrixState.pushMatrix();
		MatrixState.translate(offset, offset, z);
		drawBallColorBig.drawSelf(r, g, b, a);
		MatrixState.popMatrix();
		
		MatrixState.pushMatrix();
		MatrixState.translate(offset, -offset, z);
		drawBallColorBig.drawSelf(r, g, b, a);
		MatrixState.popMatrix();
		
	}

要注意float a  设置成小数时应该有单位f，否则会出错！