package test;
import java.nio.FloatBuffer;

import org.lwjgl.opengl.GL15;

import static org.lwjgl.glfw.GLFW.*;
import static org.lwjgl.opengl.GL.*;
import static org.lwjgl.opengl.GL11.*;
import static org.lwjgl.opengl.GL15.*;
import static org.lwjgl.opengl.GL20.glEnableVertexAttribArray;
import static org.lwjgl.opengl.GL20.glVertexAttribPointer;
import static org.lwjgl.opengl.GL30.glBindVertexArray;
import static org.lwjgl.opengl.GL30.glGenVertexArrays;
import static org.lwjgl.system.MemoryUtil.*;
import static org.lwjgl.system.MemoryStack.*;

public class TestGLFWCore {
    public static void main(String[] args) {
        // Initialize GLFW
        glfwInit();

        // Create window
        glfwWindowHint(GLFW_RESIZABLE, GLFW_FALSE);
        glfwWindowHint(GLFW_OPENGL_PROFILE, GLFW_OPENGL_CORE_PROFILE);
        glfwWindowHint(GLFW_OPENGL_FORWARD_COMPAT, GL_TRUE);
        glfwWindowHint(GLFW_CONTEXT_VERSION_MAJOR, 3);
        glfwWindowHint(GLFW_CONTEXT_VERSION_MINOR, 2);
        long window = glfwCreateWindow(800, 600, "OpenGL 3.2 Core Window", NULL, NULL);
        glfwMakeContextCurrent(window);
        createCapabilities();

        // Setup geometry
        int size = 2;
        int verts = 3;
        int bytes = 4;
        int vbo;
        int vao;
        stackPush();
        {
            // Initial vertex data
            FloatBuffer buffer = stackMallocFloat(verts * size);
            buffer.put(-0.5f).put(-0.5f); // Vert 1
            buffer.put(+0.5f).put(-0.5f); // Vert 2
            buffer.put(+0.0f).put(+0.5f); // Vert 3
            buffer.flip();

            // Generate buffers
            vbo = glGenBuffers();
            vao = glGenVertexArrays();

            // Upload Vertex Buffer
            glBindBuffer(GL_ARRAY_BUFFER, vbo);
            glBufferData(GL_ARRAY_BUFFER, buffer, GL_STATIC_DRAW);
            glBindVertexArray(vao);

            // Set attributes
            glEnableVertexAttribArray(0);
            glVertexAttribPointer( 0, size, GL_FLOAT, false, size*bytes, 0 );

            // Unbind
            glBindBuffer(GL15.GL_ARRAY_BUFFER, 0);
            glBindVertexArray(0);
        }
        stackPop();

        // Game loop
        while (!glfwWindowShouldClose(window)) {
            // Poll
            glfwPollEvents();

            // Bind
            glBindVertexArray(vao);

            // Draw
            glDrawArrays(GL_TRIANGLES, 0, verts);

            // Blit
            glfwSwapBuffers(window);
        }

        // Terminate
        glfwTerminate();
    }
}