BasicTextureTest.java

import java.awt.Color;
import java.awt.Graphics2D;
import java.awt.image.BufferedImage;
import java.awt.Font;
import java.nio.ByteBuffer;

import org.lwjgl.BufferUtils;
import org.lwjgl.LWJGLException;
import org.lwjgl.opengl.Display;
import org.lwjgl.opengl.DisplayMode;
import org.lwjgl.opengl.GL12;

import static org.lwjgl.opengl.GL11.*;

public class BasicTextureTest {

   private static final int WIDTH = 800, HEIGHT = 600;

   public static void main(String[] args){

      try{
         Display.setDisplayMode(new DisplayMode(800, 600));
         Display.create();
      }catch(LWJGLException e){
         e.printStackTrace();
      }

      glMatrixMode(GL_PROJECTION);
      glOrtho(0, WIDTH, HEIGHT, 0, -1, 1); //2D projection matrix
      glMatrixMode(GL_MODELVIEW);

      glClearColor(0, 1, 0, 0); //Green clear color


      //Generate a small test image by drawing to a BufferedImage
      //It's of course also possible to just load an image using ImageIO.load()
      BufferedImage test = new BufferedImage(512, 512, BufferedImage.TYPE_INT_ARGB);
      Graphics2D g2d = test.createGraphics();
      g2d.setFont(new Font("Arial", Font.PLAIN, 50));
      g2d.setColor(Color.blue);
      g2d.drawString("Test image", 20, 20); //Some blue text
      //g2d.drawRect(10, 10, 10, 10);

      int textureID = loadTexture(test);

      glEnable(GL_TEXTURE_2D); //Enable texturing


      while(!Display.isCloseRequested()){
         glClear(GL_COLOR_BUFFER_BIT);

         //Enable blending so the green background can be seen through the texture
         glEnable(GL_BLEND);
         glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);

         glPushMatrix();
         glTranslatef(100, 100, 0);
         glBindTexture(GL_TEXTURE_2D, textureID);
         glBegin(GL_QUADS);
         {
            glTexCoord2f(0, 0);
            glVertex2f(0, 0);

            glTexCoord2f(1, 0);
            glVertex2f(128, 0);

            glTexCoord2f(1, 1);
            glVertex2f(128, 128);

            glTexCoord2f(0, 1);
            glVertex2f(0, 128);
         }
         glEnd();
         glPopMatrix();

         Display.update();
      }
   }

   private static final int BYTES_PER_PIXEL = 4;
   public static int loadTexture(BufferedImage image){

      int[] pixels = new int[image.getWidth() * image.getHeight()];
        image.getRGB(0, 0, image.getWidth(), image.getHeight(), pixels, 0, image.getWidth());

        ByteBuffer buffer = BufferUtils.createByteBuffer(image.getWidth() * image.getHeight() * BYTES_PER_PIXEL); //4 for RGBA, 3 for RGB

        for(int y = 0; y < image.getHeight(); y++){
            for(int x = 0; x < image.getWidth(); x++){
                int pixel = pixels[y * image.getWidth() + x];
                buffer.put((byte) ((pixel >> 16) & 0xFF));     // Red component
                buffer.put((byte) ((pixel >> 8) & 0xFF));      // Green component
                buffer.put((byte) (pixel & 0xFF));               // Blue component
                buffer.put((byte) ((pixel >> 24) & 0xFF));    // Alpha component. Only for RGBA
            }
        }

        buffer.flip(); //FOR THE LOVE OF GOD DO NOT FORGET THIS

        // You now have a ByteBuffer filled with the color data of each pixel.
        // Now just create a texture ID and bind it. Then you can load it using
        // whatever OpenGL method you want, for example:

      int textureID = glGenTextures(); //Generate texture ID
        glBindTexture(GL_TEXTURE_2D, textureID); //Bind texture ID

        //Setup wrap mode
        glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL12.GL_CLAMP_TO_EDGE);
        glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL12.GL_CLAMP_TO_EDGE);

        //Setup texture scaling filtering
        glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
        glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
        glTexCoord2f(20, 20);
        //Send texel data to OpenGL
        glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA8, image.getWidth(), image.getHeight(), 0, GL_RGBA, GL_UNSIGNED_BYTE, buffer);

        //Return the texture ID so we can bind it later again
      return textureID;
   }
}