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The following code produces the image that follows. The image I am using for the background is 640 x 480, as is the displayMode. The texture background is a .bmp and is loaded with the Slick texture loader. I am confuse to why it is not filling the Quad and why it is reflected. EDIT: The background of my OpenGL scene is pink, the black you see is from the Quad created. The background image is the green block with a 2px light blue border with "test" plastered on it.

private void renderBackground(){
    float w = displayMode.getHeight()/2;
    float h = displayMode.getWidth()/2;

    GL11.glMatrixMode(GL11.GL_PROJECTION);
    GL11.glPushMatrix();

    GL11.glLoadIdentity();
    GLU.gluOrtho2D(-w, w, -h, h);

    GL11.glMatrixMode(GL11.GL_MODELVIEW);
    GL11.glPushMatrix();

    GL11.glLoadIdentity();      
    GL11.glDisable(GL11.GL_DEPTH_TEST);

    if(useTextures)background.bind();
    GL11.glBegin(GL11.GL_QUADS);

    GL11.glTexCoord2f(0.0f, 0.0f);
    GL11.glVertex2f(-w,-h);

    GL11.glTexCoord2f(1.0f, 0.0f);
    GL11.glVertex2f(w,-h);

    GL11.glTexCoord2f(1.0f, 1.0f);
    GL11.glVertex2f(w, h);

    GL11.glTexCoord2f(0.0f, 1.0f);
    GL11.glVertex2f(-w, h);

    GL11.glEnd();

    GL11.glEnable(GL11.GL_DEPTH_TEST);
    GL11.glMatrixMode(GL11.GL_PROJECTION);
    GL11.glPopMatrix();
    GL11.glMatrixMode(GL11.GL_MODELVIEW);
    GL11.glPopMatrix();
}

OpenGL Texture mismapping

Now when I add GL11.glTranslatef(20.0f, 20.0f, 0.0f); you will notice that the pink appears, which is the colour created int my "initGL" method: GL11.glClearColor(1.0f, 0.75f, 0.796f, 0.0f);enter image description here

My GL_PROJECTION contains the following before pushing it, my GL_MODELVIEW is unmodified when renderBackground() is called.

    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, 25.0f);
    //position camera
    GLU.gluLookAt(5.0f, 3.0f, -5.0f, 0.0f, 0.0f, -10.0f, 0.0f, 1.0f, 0.0f);
    GL11.glMatrixMode(GL11.GL_MODELVIEW); // Select The Modelview Matrix
share|improve this question
    
"it is displaying so incorrectly": And the correct display would be...what? –  genpfault May 10 '11 at 2:56
    
I'm sorry, my mistake. I was expecting the entire polygon to be filled with my texture. –  kieve May 10 '11 at 2:58
    
It looks like it is filled. Do you want the polygon to fill the entire viewport? If so, what are the contents of your GL_PROJECTION and GL_MODELVIEW matrices before you push them? –  genpfault May 10 '11 at 2:59
    
I thank you for trying to assist me, I edited my question to show my reasoning that the black is part of the polygon. –  kieve May 10 '11 at 3:08
    
gluLookAt belongs in the modelview matrix, not the projection matrix. The projection matrix is kind of the "lens" of the OpenGL camera, but only the lens. The viewpoint is set, by opposite movement of the world. –  datenwolf May 10 '11 at 6:31
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2 Answers 2

up vote 3 down vote accepted

I need more information to determine the problem, but here is a list with some possibilities.

1) You are using an older video card, which does not support texture non-power of 2, since you are using a library to load the texture, maybe it is detecting it, creating a power of two image, and filling it with black.

2) You (or some library you are using) changed the matrix of the texture matrix stack, and it is changing the texture coordinates.

3) You are doing something wrong when you load the texture (or call the library to do so).

The first thing I would check is if your video card supports texture non-power of 2 extension. You can check it at runtime, see how to detect if openGL/card supports non power of 2?

share|improve this answer
    
Thanks, as it turns out, textures that are not powers of 2 are not supported. –  kieve May 10 '11 at 3:29
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up vote 0 down vote

What I see first, is that you compute

float w = displayMode.getHeight()/2;
float h = displayMode.getWidth()/2;

switched?

Second, the texture could be flipped because the loader flipped it (when I remember right this happened to me, too especially with BMPs).

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