A 2D isometric tile based game ?

[Mindless]

Hello everyone.

I'm new user of LWJGL and OpenGL, and despite of the lack of documentation, I'm loving lwjgl for combining java and opengl. So I wanted to make my "first" project with lwjgl.

It is a 2D isometric tile based game. I have few knowledges but I'm lost with opengl.

I saw NeHe tutorial and I try to sort the source code to "port" it to Java. But one problem is source code for LWJGL is obsolete, for example DeviL is not supported anymore.

So, can you advice me about remplacing DeviL ?

And, to finish my post, I would like to know if you have some ideas/tutorials about making a tile map in opengl ? I thought about drawing a grid of quad and placing a texture on each.

Thanks for helping me,

ML

[bobjob]

yeah, The Nehe tuts are a bit out of date now.

Updates for the Nehe tutorials:
Texture Loading:
-use the slick texture loader.
Code Changes:
-The GLU api import statement need to be changed to something like import org.lwjgl.util.glu.GLU; instead of org.lwjgl.glu.GLU; or whatever the old one was.
-There was also one other thing that had a a little change in it, you just had to remove an int out of the function call, cant remeber which one. If you use a good IDE like eclipse or netbeans it should highlight the problem for you.

As for a good Tile Map editor, I would recommend juddmans tilemap editor http://juddman.googlepages.com/ It saves tile maps in text format.
In the text file, each line is a layer of the map, and each character in the line is the tile number that should be displayed.

After going through a few of the Nehe tutorials, you should learn there are two main views. One is perspective the other is Orthoganal (i hope i spelt it right).
For rendering isometric you will NOT need perspective view, just orthoganal view. Rotate the camera on the x axis 45 degrees, and yAxis 45 degrees. then everything you render should be displayed in isometric view.

[Mindless]

Thanks !

If you or other buddies have some other tips, I would enjoy its ! :p

And, how can I move arround an object to have a 3D impression ? I mean, when you are in front of a tree you see the tree behind you, but when you are on the tile behind it, how do you change its drawing ?

[bobjob]

that will all become clear with the Nehe Tutorials. If I start sperting out technical terms, its only going to confuse you. the main thing to know is that openGL can record depth.

[Mindless]

Hello,

Finally I cannot remplace DeviL by Slick, I don't understand what is necessary, can you help me or do the conversion ?

I put the original source.

/*
 *      This Code Was Created By Jeff Molofee 2000
 *      A HUGE Thanks To Fredric Echols For Cleaning Up
 *      And Optimizing The Base Code, Making It More Flexible!
 *      If You've Found This Code Useful, Please Let Me Know.
 *      Visit My Site At nehe.gamedev.net
 */

import java.nio.ByteBuffer;
import java.nio.ByteOrder;
import java.nio.IntBuffer;

import org.lwjgl.opengl.Display;
import org.lwjgl.opengl.DisplayMode;
import org.lwjgl.opengl.GL11;
import org.lwjgl.opengl.glu.GLU;
import org.lwjgl.devil.IL;
import org.lwjgl.input.Keyboard;

/**
 * @author Mark Bernard
 * date:    16-Nov-2003
 *
 * Port of NeHe's Lesson 6 to LWJGL
 * Title: Texture Mapping
 * Uses version 0.8alpha of LWJGL http://www.lwjgl.org/
 *
 * Be sure that the LWJGL libraries are in your classpath
 *
 * Ported directly from the C++ version
 *
 * 2004-05-08: Updated to version 0.9alpha of LWJGL.
 *             Changed from all static to all instance objects.
 * 2004-09-21: Updated to version 0.92alpha of LWJGL.
 * 2004-12-17: Updated to version 0.94alpha of LWJGL and to use
 *             DevIL for image loading.
 */
public class Lesson06 {
    private boolean done = false;
    private boolean fullscreen = false;
    private final String windowTitle = "NeHe's OpenGL Lesson 6 for LWJGL (Texture Mapping)";
    private boolean f1 = false;
    private DisplayMode displayMode;

    private float xrot;            // X Rotation ( NEW )
    private float yrot;            // Y Rotation ( NEW )
    private float zrot;            // Z Rotation ( NEW )
    private int texture;           // Storage For One Texture ( NEW )

    public static void main(String args[]) {
        boolean fullscreen = false;
        if(args.length>0) {
            if(args[0].equalsIgnoreCase("fullscreen")) {
                fullscreen = true;
            }
        }

        Lesson06 l6 = new Lesson06();
        l6.run(fullscreen);
    }
    public void run(boolean fullscreen) {
        this.fullscreen = fullscreen;
        try {
            init();
            while (!done) {
                mainloop();
                render();
                Display.update();
            }
            cleanup();
        }
        catch (Exception e) {
            e.printStackTrace();
            System.exit(0);
        }
    }
    private void mainloop() {
        if(Keyboard.isKeyDown(Keyboard.KEY_ESCAPE)) {       // Exit if Escape is pressed
            done = true;
        }
        if(Display.isCloseRequested()) {                     // Exit if window is closed
            done = true;
        }
        if(Keyboard.isKeyDown(Keyboard.KEY_F1) && !f1) {    // Is F1 Being Pressed?
            f1 = true;                                      // Tell Program F1 Is Being Held
            switchMode();                                   // Toggle Fullscreen / Windowed Mode
        }
        if(!Keyboard.isKeyDown(Keyboard.KEY_F1)) {          // Is F1 Being Pressed?
            f1 = false;
        }
    }

    private void switchMode() {
        fullscreen = !fullscreen;
        try {
            Display.setFullscreen(fullscreen);
        }
        catch(Exception e) {
            e.printStackTrace();
        }
    }

    private boolean render() {
        GL11.glClear(GL11.GL_COLOR_BUFFER_BIT | GL11.GL_DEPTH_BUFFER_BIT); // Clear The Screen And The Depth Buffer

        GL11.glLoadIdentity(); // Reset The Current Modelview Matrix

        GL11.glTranslatef(0.0f, 0.0f, -5.0f); // Move Into The Screen 5 Units
        GL11.glRotatef(xrot, 1.0f, 0.0f, 0.0f); // Rotate On The X Axis
        GL11.glRotatef(yrot, 0.0f, 1.0f, 0.0f); // Rotate On The Y Axis
        GL11.glRotatef(zrot, 0.0f, 0.0f, 1.0f); // Rotate On The Z Axis
        GL11.glBindTexture(GL11.GL_TEXTURE_2D, texture); // Select Our Texture
        GL11.glBegin(GL11.GL_QUADS);
        // Front Face
        GL11.glTexCoord2f(0.0f, 0.0f);
        GL11.glVertex3f(-1.0f, -1.0f, 1.0f); // Bottom Left Of The Texture and Quad
        GL11.glTexCoord2f(1.0f, 0.0f);
        GL11.glVertex3f(1.0f, -1.0f, 1.0f); // Bottom Right Of The Texture and Quad
        GL11.glTexCoord2f(1.0f, 1.0f);
        GL11.glVertex3f(1.0f, 1.0f, 1.0f); // Top Right Of The Texture and Quad
        GL11.glTexCoord2f(0.0f, 1.0f);
        GL11.glVertex3f(-1.0f, 1.0f, 1.0f); // Top Left Of The Texture and Quad
        // Back Face
        GL11.glTexCoord2f(1.0f, 0.0f);
        GL11.glVertex3f(-1.0f, -1.0f, -1.0f); // Bottom Right Of The Texture and Quad
        GL11.glTexCoord2f(1.0f, 1.0f);
        GL11.glVertex3f(-1.0f, 1.0f, -1.0f); // Top Right Of The Texture and Quad
        GL11.glTexCoord2f(0.0f, 1.0f);
        GL11.glVertex3f(1.0f, 1.0f, -1.0f); // Top Left Of The Texture and Quad
        GL11.glTexCoord2f(0.0f, 0.0f);
        GL11.glVertex3f(1.0f, -1.0f, -1.0f); // Bottom Left Of The Texture and Quad
        // Top Face
        GL11.glTexCoord2f(0.0f, 1.0f);
        GL11.glVertex3f(-1.0f, 1.0f, -1.0f); // Top Left Of The Texture and Quad
        GL11.glTexCoord2f(0.0f, 0.0f);
        GL11.glVertex3f(-1.0f, 1.0f, 1.0f); // Bottom Left Of The Texture and Quad
        GL11.glTexCoord2f(1.0f, 0.0f);
        GL11.glVertex3f(1.0f, 1.0f, 1.0f); // Bottom Right Of The Texture and Quad
        GL11.glTexCoord2f(1.0f, 1.0f);
        GL11.glVertex3f(1.0f, 1.0f, -1.0f); // Top Right Of The Texture and Quad
        // Bottom Face
        GL11.glTexCoord2f(1.0f, 1.0f);
        GL11.glVertex3f(-1.0f, -1.0f, -1.0f); // Top Right Of The Texture and Quad
        GL11.glTexCoord2f(0.0f, 1.0f);
        GL11.glVertex3f(1.0f, -1.0f, -1.0f); // Top Left Of The Texture and Quad
        GL11.glTexCoord2f(0.0f, 0.0f);
        GL11.glVertex3f(1.0f, -1.0f, 1.0f); // Bottom Left Of The Texture and Quad
        GL11.glTexCoord2f(1.0f, 0.0f);
        GL11.glVertex3f(-1.0f, -1.0f, 1.0f); // Bottom Right Of The Texture and Quad
        // Right face
        GL11.glTexCoord2f(1.0f, 0.0f);
        GL11.glVertex3f(1.0f, -1.0f, -1.0f); // Bottom Right Of The Texture and Quad
        GL11.glTexCoord2f(1.0f, 1.0f);
        GL11.glVertex3f(1.0f, 1.0f, -1.0f); // Top Right Of The Texture and Quad
        GL11.glTexCoord2f(0.0f, 1.0f);
        GL11.glVertex3f(1.0f, 1.0f, 1.0f); // Top Left Of The Texture and Quad
        GL11.glTexCoord2f(0.0f, 0.0f);
        GL11.glVertex3f(1.0f, -1.0f, 1.0f); // Bottom Left Of The Texture and Quad
        // Left Face
        GL11.glTexCoord2f(0.0f, 0.0f);
        GL11.glVertex3f(-1.0f, -1.0f, -1.0f); // Bottom Left Of The Texture and Quad
        GL11.glTexCoord2f(1.0f, 0.0f);
        GL11.glVertex3f(-1.0f, -1.0f, 1.0f); // Bottom Right Of The Texture and Quad
        GL11.glTexCoord2f(1.0f, 1.0f);
        GL11.glVertex3f(-1.0f, 1.0f, 1.0f); // Top Right Of The Texture and Quad
        GL11.glTexCoord2f(0.0f, 1.0f);
        GL11.glVertex3f(-1.0f, 1.0f, -1.0f); // Top Left Of The Texture and Quad
        GL11.glEnd();

        xrot += 0.3f; // X Axis Rotation
        yrot += 0.2f; // Y Axis Rotation
        zrot += 0.4f; // Z Axis Rotation

        return true;
    }
    private void createWindow() throws Exception {
        Display.setFullscreen(fullscreen);
        DisplayMode d[] = Display.getAvailableDisplayModes();
        for (int i = 0; i < d.length; i++) {
            if (d[i].getWidth() == 640
                && d[i].getHeight() == 480
                && d[i].getBitsPerPixel() == 32) {
                displayMode = d[i];
                break;
            }
        }
        Display.setDisplayMode(displayMode);
        Display.setTitle(windowTitle);
        Display.create();
    }

    private void init() throws Exception {
        createWindow();
        IL.create();

        loadTextures();
        initGL();
    }

    private void loadTextures() {
        texture = loadTexture("Data/NeHe.bmp");
    }

    private void initGL() {
        GL11.glEnable(GL11.GL_TEXTURE_2D); // Enable Texture Mapping
        GL11.glShadeModel(GL11.GL_SMOOTH); // Enable Smooth Shading
        GL11.glClearColor(0.0f, 0.0f, 0.0f, 0.0f); // Black Background
        GL11.glClearDepth(1.0f); // Depth Buffer Setup
        GL11.glEnable(GL11.GL_DEPTH_TEST); // Enables Depth Testing
        GL11.glDepthFunc(GL11.GL_LEQUAL); // The Type Of Depth Testing To Do

        GL11.glMatrixMode(GL11.GL_PROJECTION); // Select The Projection Matrix
        GL11.glLoadIdentity(); // Reset The Projection Matrix

        // Calculate The Aspect Ratio Of The Window
        GLU.gluPerspective(45.0f, (float) displayMode.getWidth() / (float) displayMode.getHeight(), 0.1f, 100.0f);
        GL11.glMatrixMode(GL11.GL_MODELVIEW); // Select The Modelview Matrix

        // Really Nice Perspective Calculations
        GL11.glHint(GL11.GL_PERSPECTIVE_CORRECTION_HINT, GL11.GL_NICEST);
    }
    private void cleanup() {
        Display.destroy();
    }
    /**
     * Texture loading using DevIL
     * Example created by Mark Bernard
     */
    private int loadTexture(String path) {
        IntBuffer image = ByteBuffer.allocateDirect(4).order(ByteOrder.nativeOrder()).asIntBuffer();
        IL.ilGenImages(1, image);
        IL.ilBindImage(image.get(0));
        IL.ilLoadImage(path);
        IL.ilConvertImage(IL.IL_RGB, IL.IL_BYTE);
        ByteBuffer scratch = ByteBuffer.allocateDirect(IL.ilGetInteger(IL.IL_IMAGE_WIDTH) * IL.ilGetInteger(IL.IL_IMAGE_HEIGHT) * 3);
        IL.ilCopyPixels(0, 0, 0, IL.ilGetInteger(IL.IL_IMAGE_WIDTH), IL.ilGetInteger(IL.IL_IMAGE_HEIGHT), 1, IL.IL_RGB, IL.IL_BYTE, scratch);
        
        // Create A IntBuffer For Image Address In Memory
        IntBuffer buf = ByteBuffer.allocateDirect(4).order(ByteOrder.nativeOrder()).asIntBuffer();
        GL11.glGenTextures(buf); // Create Texture In OpenGL

        GL11.glBindTexture(GL11.GL_TEXTURE_2D, buf.get(0));
        // Typical Texture Generation Using Data From The Image

        // Linear Filtering
        GL11.glTexParameteri(GL11.GL_TEXTURE_2D, GL11.GL_TEXTURE_MIN_FILTER, GL11.GL_LINEAR);
        // Linear Filtering
        GL11.glTexParameteri(GL11.GL_TEXTURE_2D, GL11.GL_TEXTURE_MAG_FILTER, GL11.GL_LINEAR);
        // Generate The Texture
        GL11.glTexImage2D(GL11.GL_TEXTURE_2D, 0, GL11.GL_RGB, IL.ilGetInteger(IL.IL_IMAGE_WIDTH), 
                IL.ilGetInteger(IL.IL_IMAGE_HEIGHT), 0, GL11.GL_RGB, GL11.GL_UNSIGNED_BYTE, scratch);

        return buf.get(0); // Return Image Address In Memory
    }
}

[bobjob]

Sorry I dont use the Slick texture loader myself.

Maybe you should download the LWGJL version 1.4.?? also make sure to download the 1.4 util library. It should make all the Nehe Lessons alot easyer to convert.

then when you feel more confident, upgrade to LWJGL 2.

[Mindless]

Sorry I dont use the Slick texture loader myself.

Maybe you should download the LWGJL version 1.4.?? also make sure to download the 1.4 util library. It should make all the Nehe Lessons alot easyer to convert.

then when you feel more confident, upgrade to LWJGL 2.

I don't understand the aim to take an old version to just launch a source ? When you told me slick is good for texture loading, I thought you used it lol. What do you use so ?

[bobjob]

My own texture loader, that takes a java bufferedImage and converts it into a byteBuffer before passing it to openGL.

Using an older version of LWJGL, means alot letss tweeking for the NeHe code. Its not hard to upgrade, but it seems your having trouble with taking out Devil so it might be a better oiption.

[Evil-Devil]

What kind of textures you like to load, TGA, DDS?
If so i could provide samples.

[Mindless]

Euhm, I don't know these formats.

When I say "texture", I mean a picture that I can use to fill a square.

[Evil-Devil]

And i mean the fileformat which is used as Texture. for example JPG, PNG, GIF or any other mainstream format
Don't know if you will need any advance formats like DDS, tho they support mipmaps by default

[bobjob]

Here is a thread that should point you in the right direction.
http://lwjgl.org/forum/index.php/topic,2162.0.html