java - OpenGL 中的立方体渲染怪癖

Question

我正在尝试使立方体能够正确渲染，但立方体的顶部和底部拒绝正常工作。

代码在这里:

package com.blazingkin.threeDee.thisguy;

import static org.lwjgl.opengl.GL11.glBegin;
import static org.lwjgl.opengl.GL11.glClear;
import static org.lwjgl.opengl.GL11.glEnd;
import static org.lwjgl.util.glu.GLU.gluPerspective;

import java.util.Random;

import org.lwjgl.LWJGLException;
import org.lwjgl.input.Keyboard;
import org.lwjgl.input.Mouse;
import org.lwjgl.opengl.Display;
import org.lwjgl.opengl.DisplayMode;
import org.lwjgl.opengl.GL11;


public class threeDMain {
    public static void main(String args[]){
        new threeDMain().start();
    }

    public void walkForward(float distance)
    {
        x -= distance * (float)Math.sin(Math.toRadians(pitch));
        z += distance * (float)Math.cos(Math.toRadians(pitch));
    }
    public void walkBackwards(float distance)
    {
        x += distance * (float)Math.sin(Math.toRadians(pitch));
        z -= distance * (float)Math.cos(Math.toRadians(pitch));
    }

    public void strafeLeft(float distance)
    {
        x -= distance * (float)Math.sin(Math.toRadians(pitch-90));
        z += distance * (float)Math.cos(Math.toRadians(pitch-90));
    }

    //strafes the camera right relitive to its current rotation (yaw)
    public void strafeRight(float distance)
    {
        x -= distance * (float)Math.sin(Math.toRadians(pitch+90));
        z += distance * (float)Math.cos(Math.toRadians(pitch+90));
    }

    public void lookThrough()
    {
        //roatate the pitch around the X axis
        GL11.glRotatef(yaw, 1.0f, 0.0f, 0.0f);
        //roatate the yaw around the Y axis
        GL11.glRotatef(pitch, 0.0f, 1.0f, 0.0f);
        //translate to the position vector's location
        GL11.glTranslatef(x, -y, z);
    }

    int screenX = 800;
    int screenY = 600;
    int displayType = 0;
    long timePassed = 0L;
    long lastTime;
    float x, y, z = 0;
    float pitch, yaw= 0;
    boolean mouseLocked = true;

    public void start(){
        try {
            DisplayMode d = new DisplayMode(screenX, screenY);
            Display.setDisplayMode(d);
            Display.setVSyncEnabled(true);
            if (displayType == 1){
                System.setProperty("org.lwjgl.opengl.Window.undecorated","true");
                Display.setFullscreen(true);
            }else{
                System.setProperty("org.lwjgl.opengl.Window.undecorated","false");
            }
            if (displayType == 2){
                Display.setFullscreen(true);
            }
            Display.create();
        } catch (LWJGLException e) {
            e.printStackTrace();
            System.exit(0);
        }
        lastTime = System.currentTimeMillis();


        // init OpenGL here
        GL11.glMatrixMode(GL11.GL_PROJECTION);
        GL11.glLoadIdentity();
        gluPerspective((float)90,(float)screenX/(float)screenY,0.001f,100);
        GL11.glMatrixMode(GL11.GL_MODELVIEW);
        Point[] points = new Point[100];
        Random r = new Random();
        for (int i = 0; i < points.length; i++){
            points[i] = new Point((r.nextFloat() - 0.5F) * 100,(r.nextFloat() - 0.5F) * 100, r.nextInt(200) - 200);
        }
        float speed = 0.2f;
        while (!Display.isCloseRequested()) {



            glClear(GL11.GL_COLOR_BUFFER_BIT | GL11.GL_DEPTH_BUFFER_BIT);   
            if (Keyboard.isKeyDown(Keyboard.KEY_D)){
                strafeRight(speed);
            }
            if (Keyboard.isKeyDown(Keyboard.KEY_A)){
                strafeLeft(speed);
            }
            if (Keyboard.isKeyDown(Keyboard.KEY_W)){
                walkForward(speed);
            }
            if (Keyboard.isKeyDown(Keyboard.KEY_S)){
                walkBackwards(speed);
            }
            if (Keyboard.isKeyDown(Keyboard.KEY_SPACE)){
                y+=speed;
            }
            if (Keyboard.isKeyDown(Keyboard.KEY_LSHIFT)){
                y-=speed;
            }
            while (Keyboard.next()){

                if (Keyboard.isKeyDown(Keyboard.KEY_ESCAPE)){
                    mouseLocked =! mouseLocked;
                }
            }
            if (Display.isActive()){
                if (mouseLocked){
                    Mouse.setCursorPosition(screenX/2, screenY/2);
                    yaw -= Mouse.getDY();
                    pitch += Mouse.getDX();
                }
            }
            yaw = yaw<-80?-80:yaw;
            yaw = yaw>80?80:yaw;
            pitch = pitch>360?pitch%360:pitch;
            pitch = pitch<-360?(pitch%360)*-1:pitch;

            GL11.glLoadIdentity();
            lookThrough();

            System.out.println(x+", "+y+", "+z);
                for (Point p: points){
                            GL11.glColor3f(1, 0, 1);
                            glBegin(GL11.GL_POLYGON);
                            //top face
                            GL11.glVertex3f(p.x, p.y+2, p.z);
                            GL11.glVertex3f(p.x, p.y+2, p.z+2);
                            GL11.glVertex3f(p.x+2, p.y+2, p.z+2);
                            GL11.glVertex3f(p.x+2, p.y+2, p.z);
                        glEnd();    
                            GL11.glColor3f(1,1,1);
                            glBegin(GL11.GL_POLYGON);
                            //bottom face

                                GL11.glVertex3f(p.x, p.y, p.z);
                                GL11.glVertex3f(p.x, p.y, p.z+2);
                                GL11.glVertex3f(p.x+2, p.y, p.z+2);
                                GL11.glVertex3f(p.x+2, p.y, p.z);
                            glEnd();



                    GL11.glColor3f(1, 0, 0);
                    glBegin(GL11.GL_POLYGON);
                        //back
                        GL11.glVertex3f(p.x, p.y, p.z);
                        GL11.glVertex3f(p.x+2, p.y, p.z);
                        GL11.glVertex3f(p.x+2, p.y+2, p.z);
                        GL11.glVertex3f(p.x, p.y+2, p.z);
                    glEnd();


                    GL11.glColor3f(0, 0, 1);
                    glBegin(GL11.GL_POLYGON);
                    //side 1 face (left)
                        GL11.glVertex3f(p.x, p.y, p.z);
                        GL11.glVertex3f(p.x, p.y, p.z+2);
                        GL11.glVertex3f(p.x, p.y+2, p.z+2);
                        GL11.glVertex3f(p.x, p.y+2, p.z);
                    glEnd();
                    GL11.glColor3f(1, 1, 0);
                    glBegin(GL11.GL_POLYGON);
                    //side 2 face (right)
                        GL11.glVertex3f(p.x+2, p.y, p.z);
                        GL11.glVertex3f(p.x+2, p.y, p.z+2);
                        GL11.glVertex3f(p.x+2, p.y+2, p.z+2);
                        GL11.glVertex3f(p.x+2, p.y+2, p.z);
                    glEnd();
                    GL11.glColor3f(0, 1, 1);
                    glBegin(GL11.GL_POLYGON);
                    //front
                        GL11.glVertex3f(p.x, p.y, p.z+2);
                        GL11.glVertex3f(p.x+2, p.y, p.z+2);
                        GL11.glVertex3f(p.x+2, p.y+2, p.z+2);
                        GL11.glVertex3f(p.x, p.y+2, p.z+2);
                    glEnd();


                }





            Display.update();
        }

        Display.destroy();
    }


    class Point{
        float x,y,z;
        public Point(float x, float y, float z){
            this.x = x;
            this.y = y;
            this.z = z;
        }

    }


}

基本上，它会渲染立方体的底部，也就是顶部应该在的位置，但只有当你在它下面以及当你在它里面时，它才会正确渲染

Answer 1

这可能是深度测试的问题。您无法在任何地方启用深度双重检查!试试这个:

GL11.glEnable(GL11.GL_DEPTH_TEST);

这对我有用。如果没有这个，事情看起来真的很奇怪，请告诉我这是否有帮助!