3D environnement + 2D HUD help plz

[Wicpar]

Hello!

I am quite a newb in lwjgl even if I use it for some time now, and I wonder what I should do to render a 3D environnement with a 2D HUD containing slick text.

I know it should do something like that:

init 3D rendering
render all 3D
unload the 3D stuff
init the hud rendering
render the hud
clear the screen

In this I would like to know if it affects performance too much(if yes an alternative is welcome) and what is the code I have to write so it loads the 3D environnement with shaders and then the HUD containing textures and text.

Thanks for your help

[quew8]

Essentially the difference between rendering 3D stuff and 2D stuff, is the projection matrix and the depth test. For 3D you are either going to have a perspective (frustum) projection or a 3D orthographic one and you are going to have the depth test enabled. For 2D you are going to have a flat (near and far depth set to 0) orthographic and have the depth test disabled.

So that is all there is to it:

Enable Depth Test
Setup 3D Projection Matrix
Draw 3D Stuff
Disable Depth Test
Setup 2D Projection Matrix
Draw 2D Stuff

[Wicpar]

ok thanks, so I only have to do that. but do I have to disable the 3D projection matrix or does it do it when you load the 2D one?
here is the code I have:

private static float	fov	= 45, znear3D = 0.01f, zfar3D = 1000, znear2D = 1, zfar2D = -1;

	public static void init2D() {
		glDisable(GL_DEPTH_TEST);
		glDisable(GL_LIGHTING);

		glClearColor(0.0f, 0.0f, 0.0f, 0.0f);
		glClearDepth(1);
		glEnable(GL_BLEND);
		glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
		glMatrixMode(GL_PROJECTION);
		glLoadIdentity();
		glViewport(0, 0, Display.getWidth(), Display.getHeight());
		glOrtho(0, Display.getWidth(), Display.getHeight(), 0, znear2D, zfar2D);
		glMatrixMode(GL_MODELVIEW);
	}

	public static void init3D() {
		glMatrixMode(GL_PROJECTION);
		glLoadIdentity();

		gluPerspective(fov, ((float) Display.getDisplayMode().getWidth()) / ((float) Display.getDisplayMode().getHeight()), znear3D, zfar3D);
		glMatrixMode(GL_MODELVIEW);
		glLoadIdentity();

		glEnable(GL_TEXTURE_2D);
		glShadeModel(GL_SMOOTH);
		glClearColor(0.0f, 0.0f, 0.0f, 0.0f);
		glClearDepth(1.0f);
		glEnable(GL_DEPTH_TEST);
		glDepthFunc(GL_LEQUAL);
		glHint(GL_PERSPECTIVE_CORRECTION_HINT, GL_NICEST);
	}

Is it right or does it need some optimisation?

[Mickelukas]

Mine looks like this:

    public static void make2D() {
        //Remove the Z axis
        GL11.glDisable(GL11.GL_LIGHTING);
        GL11.glDisable(GL11.GL_DEPTH_TEST);
        GL11.glMatrixMode(GL11.GL_PROJECTION);
        GL11.glPushMatrix();
        GL11.glLoadIdentity();
        GL11.glOrtho(0, Main.getAppletSize().getWidth(), 0, Main.getAppletSize().getHeight(), -1, 1);
        GL11.glMatrixMode(GL11.GL_MODELVIEW);
        GL11.glPushMatrix();
        GL11.glLoadIdentity();
    }

    public static void make3D() {
        //Restore the Z axis
        GL11.glMatrixMode(GL11.GL_PROJECTION);
        GL11.glPopMatrix();
        GL11.glMatrixMode(GL11.GL_MODELVIEW);
        GL11.glPopMatrix();
        GL11.glEnable(GL11.GL_DEPTH_TEST);
        GL11.glEnable(GL11.GL_LIGHTING);
    }

[Wicpar]

ok thanks, but how should I do from your code to init the other stuff? and make the window resizable?

[Mickelukas]

The code I sent was purely the overlay conversion, it doesn't have anything to do with resizing the window...?

Mike

[Wicpar]

ok, was just wondering how to make the window resizable from that code, but nevermind, i'm following the thinatrix tutorials