started rewriting rendering and window handling

src/main/java/org/example/Game.java

@@ -1,11 +1,13 @@
 package org.example;
 
+import org.joml.*;
 import org.lwjgl.*;
 import org.lwjgl.Version;
 import org.lwjgl.glfw.*;
 import org.lwjgl.opengl.*;
 import org.lwjgl.system.*;
 
+import java.lang.Math;
 import java.nio.*;
 import java.io.*;
 import java.text.MessageFormat;
@@ -13,6 +15,9 @@ import java.text.MessageFormat;
 import static org.lwjgl.glfw.Callbacks.*;
 import static org.lwjgl.glfw.GLFW.*;
 import static org.lwjgl.opengl.GL11.*;
+import static org.lwjgl.opengl.GL15.*;
+import static org.lwjgl.opengl.GL20.*;
+import static org.lwjgl.opengl.GL30.*;
 import static org.lwjgl.system.MemoryStack.*;
 import static org.lwjgl.system.MemoryUtil.*;
 
@@ -21,7 +26,11 @@ import org.lwjgl.system.MemoryStack;
 
 public class Game
 {
+    public static final float Z_FAR = 1000.0f;
+    public static final float Z_NEAR = 0.1f;
+    public static final float FOV = (float) Math.toRadians(90.0f);
     private long window;
+    private Matrix4f projection_matrix;
 
     public void run()
     {
@@ -102,6 +111,12 @@ public class Game
         // Add stuff to world
         world.addEntity(new Entity("/objs/cube.obj", "/shaders/shader.frag", "/shaders/shader.vert"));
 
+        // Calculate Perspective Matrix
+        int w, h;
+        glfwGetWindowSize(window, w, h);
+        float aspect_ratio = (float) ;
+        this.projection_matrix = new Matrix4f().perspective(FOV, )
+
         // Main loop or something
         while ( !glfwWindowShouldClose(window) )
         {
@@ -109,10 +124,22 @@ public class Game
 
             glfwSwapBuffers(window);
 
+            for (Entity entity : world.entities)
+                render(entity);
+
             glfwPollEvents();
         }
     }
 
+    public void render(Entity entity) {
+        entity.shader.bind();
+
+        glBindVertexArray(entity.mesh.vao_id);
+        glEnableVertexAttribArray(0);
+        glEnableVertexAttribArray(1);
+        glDrawElements(GL_TRIANGLES, entity.mesh.vertex_count, GL_UNSIGNED_INT, 0);
+    }
+
     public static void main(String[] args)
     {
         new Game().run();