Question

I’ve started to learn lwjgl and got a problem!
What I am doing:

1. load a texture

2. start rendering cycle

3. draw rectangle and apply texture

4. check for keyboard and mouse events and rotate/move camera

   public static void main(String[] args) {
   try {
       Display.setDisplayMode(new DisplayMode(320, 200));
       Display.create();
   } catch (Exception e) {
       System.out.println(e);
   }
   
   Texture texture = null;
   try {
       texture = TextureLoader.getTexture("JPG", ResourceLoader.getResourceAsStream("basic.jpg"), true);
   } catch (Exception e) {
       System.out.println(e);
       return;
   }
   
   GL11.glMatrixMode(GL11.GL_PROJECTION);
   GL11.glLoadIdentity();
   GL11.glOrtho(0, 320, 0, 200, 1, -1);
   GL11.glMatrixMode(GL11.GL_MODELVIEW);
   
   while (!Display.isCloseRequested()) {
       GL11.glClear(GL11.GL_COLOR_BUFFER_BIT | GL11.GL_DEPTH_BUFFER_BIT);
       Color.white.bind();
       texture.bind();
       GL11.glBegin(GL11.GL_QUAD_STRIP);
           GL11.glTexCoord2f(0, 0);
           GL11.glVertex3f(100, 100, 0);
           GL11.glTexCoord2f(0, 1);
           GL11.glVertex3f(100, 140, 0);
           GL11.glTexCoord2f(1, 1);
           GL11.glVertex3f(140, 140, 0);
           GL11.glTexCoord2f(1, 0);
           GL11.glVertex3f(140, 100, 0);
       GL11.glEnd();
   
       Display.update();
       processInput();
       try {
           //Thread.sleep(20);
       } catch (Exception e) {
           System.out.println(e);
       }
   }
   
   Display.destroy();
   
   }
   
   public static void processInput() {
   long delta = getDelta();
   long divider = 10000000;
   float camx = 0, camy = 0, camz = 0;
   float roll = 0;
   if (Keyboard.isKeyDown(Keyboard.KEY_W)) {
       camz += 1.0f * delta / divider;
   }
   if (Keyboard.isKeyDown(Keyboard.KEY_S)) {
       camz -= 1.0f * delta / divider;
   }
   if (Keyboard.isKeyDown(Keyboard.KEY_D)) {
       camx -= 1.0f * delta / divider;
   }
   if (Keyboard.isKeyDown(Keyboard.KEY_A)) {
       camx += 1.0f * delta / divider;
   }
   if (Keyboard.isKeyDown(Keyboard.KEY_SPACE)) {
       camy -= 1.0f * delta / divider;
   }
   if (Keyboard.isKeyDown(Keyboard.KEY_C)) {
       camy += 1.0f * delta / divider;
   }
   if (Mouse.isButtonDown(0)) {
       roll += 1.0f * delta / divider;
   }
   if (Mouse.isButtonDown(1)) {
       roll -= 1.0f * delta / divider;
   }
   GL11.glTranslatef(camx, camy, camz);
   GL11.glTranslatef(160, 100, 0);
   GL11.glRotatef(roll, 0, 0, 1);
   GL11.glTranslatef(-160, -100, 0);
   }
   

When I rotate and move everything in the XY plane it works perfectly. But when I try moving along Z axis the whole rectangle disappears. What I am doing wrong?

Answer 1

Ok, I got a solution by myself after looking at initial parameters. The

GL11.glOrtho(0, 320, 0, 200, 1, -1);

function defines rendering are and everything out of this box won’t be rendered. Thus, after moving along z axis the item disappears. I changed render box to

GL11.glOrtho(0, 320, 0, 200, 100, -100);

and that works.