如何用纯Java代码实践基本的3D渲染技术？

实现基本的3D渲染技术通常需要对图形学有深入理解，并且使用Java通常会结合像Java3D这样的库。然而，Java3D已经较过时，现在更推荐使用JOGL（Java Binding for OpenGL）来实现。以下是一个简单的JOGL入门示例，展示如何在窗口中绘制一个红色的立方体：确保安装了JOGL库，可以在JOGL官方网站下载。创建一个新的Java项目，然后引入JOGL库。编写以下代码：

import javax.media.opengl.GL;
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 Basic3DRendering implements GLEventListener {
    public static void main(String[] args) {
        GLProfile profile = GLProfile.get(GLProfile.GL2);
        GLCapabilities capabilities = new GLCapabilities(profile);
        GLCanvas canvas = new GLCanvas(capabilities);
        canvas.addGLEventListener(new Basic3DRendering());

        JFrame frame = new JFrame("Basic 3D Rendering");
        frame.setSize(800, 600);
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.getContentPane().add(canvas);
        frame.setVisible(true);
    }

    @Override
    public void init(GLAutoDrawable drawable) {
        GL2 gl = drawable.getGL().getGL2();
        gl.glClearColor(0.0f, 0.0f, 0.0f, 0.0f);
    }

    @Override
    public void display(GLAutoDrawable drawable) {
        GL2 gl = drawable.getGL().getGL2();
        gl.glClear(GL.GL_COLOR_BUFFER_BIT | GL.GL_DEPTH_BUFFER_BIT);

        gl.glLoadIdentity();
        gl.glTranslatef(0.0f, 0.0f, -5.0f); // Translate into the screen

        // Draw a red cube
        gl.glColor3f(1.0f, 0.0f, 0.0f);
        gl.glBegin(GL.GL_QUADS);
        // Front face
        gl.glVertex3f(-1.0f, -1.0f, 1.0f);
        gl.glVertex3f(1.0f, -1.0f, 1.0f);
        gl.glVertex3f(1.0f, 1.0f, 1.0f);
        gl.glVertex3f(-1.0f, 1.0f, 1.0f);
        // Back face
        gl.glVertex3f(-1.0f, -1.0f, -1.0f);
        gl.glVertex3f(-1.0f, 1.0f, -1.0f);
        gl.glVertex3f(1.0f, 1.0f, -1.0f);
        gl.glVertex3f(1.0f, -1.0f, -1.0f);
        // Top face
        gl.glVertex3f(-1.0f, 1.0f, -1.0f);
        gl.glVertex3f(-1.0f, 1.0f, 1.0f);
        gl.glVertex3f(1.0f, 1.0f, 1.0f);
        gl.glVertex3f(1.0f, 1.0f, -1.0f);
        // Bottom face
        gl.glVertex3f(-1.0f, -1.0f, -1.0f);
        gl.glVertex3f(1.0f, -1.0f, -1.0f);
        gl.glVertex3f(1.0f, -1.0f, 1.0f);
        gl.glVertex3f(-1.0f, -1.0f, 1.0f);
        // Right face
        gl.glVertex3f(1.0f, -1.0f, -1.0f);
        gl.glVertex3f(1.0f, 1.0f, -1.0f);
        gl.glVertex3f(1.0f, 1.0f, 1.0f);
        gl.glVertex3f(1.0f, -1.0f, 1.0f);
        // Left face
        gl.glVertex3f(-1.0f, -1.0f, -1.0f);
        gl.glVertex3f(-1.0f, -1.0f, 1.0f);
        gl.glVertex3f(-1.0f, 1.0f, 1.0f);
        gl.glVertex3f(-1.0f, 1.0f, -1.0f);
        gl.glEnd();
    }

    @Override
    public void reshape(GLAutoDrawable drawable, int x, int y, int width, int height) {}

    @Override
    public void dispose(GLAutoDrawable drawable) {}
}

这个例子创建了一个窗口，并在其中渲染了一个红色的立方体。这仅是一个非常基础的示例，实际的3D渲染涉及到更多的复杂概念，如光照、纹理、摄像机控制等。可参考文档