import java.nio.ByteBuffer;
import org.lwjgl.BufferUtils;
import org.lwjgl.opengl.Display;
import org.lwjgl.opengl.DisplayMode;
import org.lwjgl.opengl.GL11;
import org.lwjgl.opengl.GL14;
import org.lwjgl.opengl.PixelFormat;

/**
 * This is not the beginners guide to rocket science...
 * It's all you ever need to know about 2D rendering for your silly game.
 * Please don't annoy people in #lwjgl with your incompetence.
 * This tutorial uses old-style immediate mode drawing which is enough for you.
 *
 * For any question you may have now, please refer to the fucking
 * OpenGL documentation, thats what it is for.
 *
 * Thank you.
 *
 * @author Evil[1]
 */
public class GraphicsForIdiots
{
    /**
     * Generate a texture image.
     * This is your "image loader" - there are lot's of image loading libraries.
     * Google is always your friend.
     * @return Texture identifier.
     */
    static int checkerboard()
    {
        // Checkerboard data.
        ByteBuffer buffer = BufferUtils.createByteBuffer(64 * 64 * 4);

        // Make a checkerboard.
        for(int i = 0; i < 64; i++)
        {
            for(int j = 0; j < 64; j++)
            {
                int color = ((i & 16) ^ (j & 16)) * 0xFF;

                buffer.put((byte)color);
                buffer.put((byte)color);
                buffer.put((byte)color);
                buffer.put((byte)color);
            }
        }

        // Flip the buffer.
        buffer.flip();

        // Create the texture identifier.
        int id = GL11.glGenTextures();

        // Bind the texture - so we can set the state of the texture object.
        GL11.glBindTexture(GL11.GL_TEXTURE_2D, id);

        // Wrap modes - we use repeat here.
        // For 2D sprites and non-repeating textures, GL13.GL_CLAMP_TO_EDGE is adviced as mode.
        // Homework: Try out different wrap modes.
        GL11.glTexParameteri(GL11.GL_TEXTURE_2D, GL11.GL_TEXTURE_WRAP_S, GL11.GL_REPEAT);
        GL11.glTexParameteri(GL11.GL_TEXTURE_2D, GL11.GL_TEXTURE_WRAP_T, GL11.GL_REPEAT);

        // Texture filter - we use mipmapping here as this gives the highest quality under minification.
        // For 2D games, often GL11.GL_LINEAR minification is sufficient. For "blocky" games, try GL11.GL_NEAREST.
        // Homework: Try out different filter modes.
        GL11.glTexParameteri(GL11.GL_TEXTURE_2D, GL11.GL_TEXTURE_MIN_FILTER, GL11.GL_LINEAR_MIPMAP_LINEAR);
        GL11.glTexParameteri(GL11.GL_TEXTURE_2D, GL11.GL_TEXTURE_MAG_FILTER, GL11.GL_LINEAR);

        // Old style automatic mipmap level creation.
        // This is a part of the texture object state, so set it before uploading.
        // Only needed if you use mipmapping.
        GL11.glTexParameteri(GL11.GL_TEXTURE_2D, GL14.GL_GENERATE_MIPMAP, GL11.GL_TRUE);

        // Upload the image.
        // This loads the base texture level, all other levels are generated by the driver if enabled.
        GL11.glTexImage2D(GL11.GL_TEXTURE_2D, 0, GL11.GL_RGBA8, 64, 64, 0, GL11.GL_RGBA, GL11.GL_UNSIGNED_BYTE, buffer);

        // Bind the default texture.
        // Because OpenGL is an annoying state machine... you sometimes wonder why a texture is bound.
        // So let's revert to some inital state.
        GL11.glBindTexture(GL11.GL_TEXTURE_2D, 0);

        // Done.
        return id;
    }

    /**
     * Your Game.
     * @param args Command line arguments.
     * @throws Exception If something goes boom because you are a bad programmer.
     */
    public static void main(String[] args)
    throws Exception
    {
        // Display properties.
        Display.setTitle("Tutorial 1: Rendering a quad!");
        Display.setDisplayMode(new DisplayMode(800, 600));

        // Let's create the display.
        Display.create(new PixelFormat(24, 0, 0, 0, 0));

        // Some hint to the driver.
        // It says: "If you (the driver) generate mipmaps, I wan't it nice!"
        GL11.glHint(GL14.GL_GENERATE_MIPMAP_HINT, GL11.GL_NICEST);

        // Set the clear color.
        GL11.glClearColor(0.6F, 0.8F, 1.0F, 1.0F);

        // Orthogonal projection, this is the 2D setup.
        GL11.glMatrixMode(GL11.GL_PROJECTION);
        GL11.glLoadIdentity();
        GL11.glOrtho(0.0F, 800.0F, 600.0F, 0.0F, -1.0F, 1.0F);

        // Identity modelview.
        GL11.glMatrixMode(GL11.GL_MODELVIEW);
        GL11.glLoadIdentity();

        // States.
        GL11.glDisable(GL11.GL_LIGHTING);
        GL11.glDisable(GL11.GL_CULL_FACE);

        // Create the texture.
        int id = checkerboard();

        // Main loop.
        while(!Display.isCloseRequested())
        {
            // Clear the screen.
            GL11.glClear(GL11.GL_COLOR_BUFFER_BIT);

            // Enable texturing.
            // As we want to draw textures, we need to enable it.
            GL11.glEnable(GL11.GL_TEXTURE_2D);

            // Bind our texture.
            GL11.glBindTexture(GL11.GL_TEXTURE_2D, id);

            // Begin quad rendering.
            GL11.glBegin(GL11.GL_QUADS);

            // Draw a quad with independend vertex colors.
            GL11.glColor3f(1.0F, 0.0F, 0.0F); GL11.glTexCoord2f(0.0F, 0.0F); GL11.glVertex2f( 10.0F,  10.0F);
            GL11.glColor3f(0.0F, 1.0F, 0.0F); GL11.glTexCoord2f(0.0F, 1.0F); GL11.glVertex2f( 10.0F, 150.0F);
            GL11.glColor3f(0.0F, 0.0F, 1.0F); GL11.glTexCoord2f(1.0F, 1.0F); GL11.glVertex2f(150.0F, 150.0F);
            GL11.glColor3f(1.0F, 1.0F, 0.0F); GL11.glTexCoord2f(1.0F, 0.0F); GL11.glVertex2f(150.0F,  10.0F);

            // Draw another quad using a single color.
            GL11.glColor3f(1.0F, 0.0F, 1.0F);
            GL11.glTexCoord2f(0.0F, 0.0F); GL11.glVertex2f(160.0F,  10.0F);
            GL11.glTexCoord2f(0.0F, 1.0F); GL11.glVertex2f(160.0F, 150.0F);
            GL11.glTexCoord2f(1.0F, 1.0F); GL11.glVertex2f(300.0F, 150.0F);
            GL11.glTexCoord2f(1.0F, 0.0F); GL11.glVertex2f(300.0F,  10.0F);

            // Draw another quad using a single color and repeating textures.
            // Se how mipmaps shine here...
            GL11.glColor3f(1.0F, 1.0F, 1.0F);
            GL11.glTexCoord2f(0.0F, 0.0F); GL11.glVertex2f(310.0F,  10.0F);
            GL11.glTexCoord2f(0.0F, 3.0F); GL11.glVertex2f(310.0F, 150.0F);
            GL11.glTexCoord2f(3.0F, 3.0F); GL11.glVertex2f(450.0F, 150.0F);
            GL11.glTexCoord2f(3.0F, 0.0F); GL11.glVertex2f(450.0F,  10.0F);

            // End quad rendering.
            GL11.glEnd();

            // 2D sprite rendering often uses alpha blending, so let's alpha blend.
            // Set the blend modes based on texture (source) alpha.
            GL11.glBlendFunc(GL11.GL_SRC_ALPHA, GL11.GL_ONE_MINUS_SRC_ALPHA);

            // Enable blending.
            GL11.glEnable(GL11.GL_BLEND);

            // Begin quad rendering.
            GL11.glBegin(GL11.GL_QUADS);

            // Draw a quad with independend vertex colors.
            GL11.glColor3f(1.0F, 0.0F, 0.0F); GL11.glTexCoord2f(0.0F, 0.0F); GL11.glVertex2f( 10.0F, 160.0F);
            GL11.glColor3f(0.0F, 1.0F, 0.0F); GL11.glTexCoord2f(0.0F, 1.0F); GL11.glVertex2f( 10.0F, 310.0F);
            GL11.glColor3f(0.0F, 0.0F, 1.0F); GL11.glTexCoord2f(1.0F, 1.0F); GL11.glVertex2f(150.0F, 310.0F);
            GL11.glColor3f(1.0F, 1.0F, 0.0F); GL11.glTexCoord2f(1.0F, 0.0F); GL11.glVertex2f(150.0F, 160.0F);

            // Draw another quad using a single color.
            GL11.glColor3f(1.0F, 0.0F, 1.0F);
            GL11.glTexCoord2f(0.0F, 0.0F); GL11.glVertex2f(160.0F, 160.0F);
            GL11.glTexCoord2f(0.0F, 1.0F); GL11.glVertex2f(160.0F, 310.0F);
            GL11.glTexCoord2f(1.0F, 1.0F); GL11.glVertex2f(300.0F, 310.0F);
            GL11.glTexCoord2f(1.0F, 0.0F); GL11.glVertex2f(300.0F, 160.0F);

            // Draw another quad using a single color and repeating textures.
            // Se how mipmaps shine here...
            GL11.glColor3f(1.0F, 1.0F, 1.0F);
            GL11.glTexCoord2f(0.0F, 0.0F); GL11.glVertex2f(310.0F, 160.0F);
            GL11.glTexCoord2f(0.0F, 3.0F); GL11.glVertex2f(310.0F, 310.0F);
            GL11.glTexCoord2f(3.0F, 3.0F); GL11.glVertex2f(450.0F, 310.0F);
            GL11.glTexCoord2f(3.0F, 0.0F); GL11.glVertex2f(450.0F, 160.0F);

            // End quad rendering.
            GL11.glEnd();

            // Disable alpha blending.
            GL11.glDisable(GL11.GL_BLEND);

            // Update.
            Display.update();
        }

        // Destroy.
        Display.destroy();
    }
}