本章教你如何缩放对象,即使用JOGL增大或减小对象的大小.
使用 glScalef(缩放对象)完成对象的缩放接口的float x,float y,float z)方法.此方法接受三个浮点参数,使用它们分别沿x,y和z轴指定比例因子.
例如,在以下程序中,三角形减小为50%.这里,值50作为参数沿所有轴传递.
让我们通过程序来缩放三角形 :
import javax.media.opengl.GL2; import javax.media.opengl.GLAutoDrawable; import javax.media.opengl.GLCapabilities; import javax.media.opengl.GLEventListener; import javax.media.opengl.GLProfile; import javax.media.opengl.awt.GLCanvas; import javax.swing.JFrame; public class Scaling implements GLEventListener { @Override public void display( GLAutoDrawable drawable ) { final GL2 gl = drawable.getGL().getGL2(); gl.glScalef( 0.50f,0.25f,0.50f ); gl.glBegin( GL2.GL_TRIANGLES ); // Drawing Using Triangles gl.glColor3f( 1.0f, 0.0f, 0.0f ); // Red gl.glVertex3f( 0.5f,0.7f,0.0f ); // Top gl.glColor3f( 0.0f,1.0f,0.0f ); // blue gl.glVertex3f( -0.2f,-0.50f,0.0f ); // Bottom Left gl.glColor3f( 0.0f,0.0f,1.0f ); // green gl.glVertex3f( 0.5f,-0.5f,0.0f ); // Bottom Right gl.glEnd(); } @Override public void dispose( GLAutoDrawable arg0 ) { //method body } @Override public void init( GLAutoDrawable arg0 ) { // method body } @Override public void reshape( GLAutoDrawable arg0, int arg1, int arg2, int arg3, int arg4 ) { // method body } public static void main( String[] args ) { //getting the capabilities object of GL2 profile final GLProfile profile = GLProfile.get( GLProfile.GL2 ); GLCapabilities capabilities = new GLCapabilities(profile); // The canvas final GLCanvas glcanvas = new GLCanvas( capabilities ); Scaling scaling = new Scaling(); glcanvas.addGLEventListener( scaling ); glcanvas.setSize( 400, 400 ); //creating frame final JFrame frame = new JFrame (" Dimnished Triangle (Scaling )"); //adding canvas to it frame.getContentPane().add(glcanvas); frame.setSize(frame.getContentPane().getPreferredSize()); frame.setVisible(true); } //end of main } //end of classimport javax.media.opengl.GL2;
在编译和执行上述程序时,我们得到以下输出.在这里,你可以观察到一个减小的三角形与TriangleColor.java生成的原始三角形相比;<