[SOLVED] Problem with OpenGL via LWJGL

OpenGL Development
#1

hi guys… first and foremost… this is my first post, idk if this is the right section… but here it goes…

i’m working on a project… it’s a game programming library, focusing on portability in the java environment… i am currently working on the display function… as a system dependency, J2SE can use OpenGL for its graphics functionalities such as display or for rendering, etc…

i’m not doing things from scratch, my adviser (now on temporary leave) told me to look for some open source libraries in the Internet to lighten my load… I found LWJGL which provides classes and interface for OpenGL… so i use it for the J2SE OpenGL module of my library…

the program i’ve written so far works perfectly for basic polygon rendering in both OpenGL and native hardware accelerated graphics… however, when I proceed to image rendering there seems to be some problem…

the image above shows the output after i run the OpenGL rendering program…

here is the code for initializing LWJGL

private void initGL() {
		GL11.glEnable(GL11.GL_TEXTURE_2D);
		GL11.glDisable(GL11.GL_DEPTH_TEST);
 
		GL11.glMatrixMode(GL11.GL_PROJECTION);
		GL11.glLoadIdentity();
 
		GL11.glOrtho(0, this.size.width, this.size.height, 0, -1, 1);
 
		GL11.glEnable(GL11.GL_BLEND);
		GL11.glClearColor(0, 0, 0, 0);
 
		GL11.glBlendFunc(GL11.GL_SRC_ALPHA, GL11.GL_ONE_MINUS_SRC_ALPHA);
	}
 
	private void initGraphics() {
		try {
			DisplayMode best = (this.isFullscreen) ? 
					this.getBestDisplayMode(size) : new DisplayMode(
							this.size.width, this.size.height);
 
			if(best == null) {
				throw new Exception();
			}
 
			org.lwjgl.opengl.Display.setDisplayMode(best);
		} catch(Exception e) {
 
		}
 
		try {
			org.lwjgl.opengl.Display.setTitle(this.title);
			org.lwjgl.opengl.Display.setFullscreen(this.isFullscreen);
			org.lwjgl.opengl.Display.setVSyncEnabled(this.usingVsync);
			org.lwjgl.opengl.Display.create();
		} catch(Exception e) {
 
		}
	}

and here is the code for rendering the image:

public boolean drawImage(Image img,
							 int x, int y, int width, int height,
							 ImageObserver observer) {
		startPainting();
 
 
		GL11.glPushMatrix();
 
	    Texture texture = textureLoader.getTexture((BufferedImage) img);
		texture.bind();
 
		GL11.glTranslatef(x, y, 0);
 
		GL11.glBegin(GL11.GL_QUADS);
			GL11.glTexCoord2f(0, 0);
			GL11.glVertex2f(0, 0);
 
			GL11.glTexCoord2f(0, texture.getHeight());
			GL11.glVertex2f(0, height);
 
			GL11.glTexCoord2f(texture.getWidth(), texture.getHeight());
			GL11.glVertex2f(width, height);
 
			GL11.glTexCoord2f(texture.getWidth(), 0);
			GL11.glVertex2f(width, 0);
		GL11.glEnd();
 
		GL11.glPopMatrix();
 
 
		endPainting();
 
	    return true;
    }

oh btw here is how i called the rendering routine:

public void render(Graphics g) {
		g.setColor(Color.RED);
		g.fillRect(0, 0, 640, 480);
		image.render(g, 0, 0);
	}

any help to make the OpenGL rendered image look exactly like the image below? thanks in advance :slight_smile:

#2

You’re drawing a red quad for the background before calling drawImage, right? Your call to glColor is still in effect. Add this in your drawImage() function (just after GL11.glTranslatef(x, y, 0); is fine):

GL11.glColor3f(1, 1, 1);

When with drawing textures, the texture sample is multiplied by the OpenGL color you’ve specified.

#3

it’s just as you said, i was thinking of the same about the color but idk what to do, i thought i need GL.glFlush(), silly me ::slight_smile: … but anyway, it works now ;D thanks alot :slight_smile: