JOGL (Java OpenGL) - Textures

Textures the Classic Way

You need the following tools at your disposal:

• An int in an int[] (array) to store the texture id.
• A PNG image containing the texture.
• A GL object to operate on.

With that, go to the init stage:

1. have an int[] array for texture identifiers (1 int per texture)
2. load image data into a byteArray, but do not do anything with it yet
3. announce to OpenGL (GL) how many textures you want ever in this app:
   glGenTextures(<textureCount>, <fittinglySizedIntArray>);
4. per tex, announce to OpenGL what type it is:
   glBindTexture(GL_TEXTURE_2D, textureArray[<position>]);
5. per tex, load the image byteArray into graphics card (where texId == textureArray[<position>]):
   gl.glTexImage2D(<texId>, <always-0>,
                <dataToUse: RGB, wid, hei, border>,
                <dataSrc: RGB, UNSIGNED_BYTE, byteArray);
6. globally tell OpenGL what to do when zoom in (MAG) or zoom out (MIN):
   glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
7. globally tell OpenGL to enable 2D textures:
   glEnable(GL_TEXTURE_2D);

And in the display stage:

1. announce (before glBegin()) which texture you want to use:
   glBindTexture(GL_TEXTURE_2D, textureArray[<position>]);
2. draw only quads:
   glBegin(GL_QUADS);
3. for each quad, announce texture corner position before quad corner position:
   glTexCoord2f(0.0f, 0.0f);
glVertex3f(-1.0f, -1.0f,  1.0f);

The above is certainly not a complete, tutorial-like description of how to use textures the native way. For details, may I refer you to the NeHe tutorial, which explains it much better. I hope this small excerpt persuaded you to use the JOGL TextureRenderer, as described in my JOGL tutorial. And with this, have a good time!