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Problem with rendering a quad using VBOs and VAOs

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Problem with rendering a quad using VBOs and VAOs
« on: August 15, 2020, 18:29:47 »
So, I just started learning LWJGL 3 and I used a mixture of a couple of tutorials and example code to make something that should render a rectangle to a magenta screen using VAOs and VBOs. There are no errors but the rectangle doesn't appear on screen (all I can see is a magenta screen). I tried using the old LWJGL pipeline (glBegin() and glEnd()) and it does work so I tried changing random things in the rendering code and the loading to VAOs and VBOs. I also tried to bind the VBO too but it didn't change anything. I also tried debugging and it seems like there is a VAO and a VBO that is created.

Can someone take a look at my code and see if something looks wrong? Here it is (sorry if its a bit messy. Like I said, I don't think the problem is in the Main or Window class but I have no idea about LWJGL so I wanted to put it here anyways. If you have time, please also look at them. Otherwise I would really appreciate it if you could look at the Loader and Renderer classes):
The Raw Model class:
Code: [Select]
    package engine.io;

    public class RawModel {
private int vaoID;
private int vertexCount;

public RawModel(int vaoID, int vertexCount) {
this.vaoID = vaoID;
this.vertexCount = vertexCount;

public int getVaoID() {
return vaoID;

public int getVertexCount() {
return vertexCount;

The loader class:
Code: [Select]
    package engine.io;

    import java.nio.FloatBuffer;
    import java.util.ArrayList;
    import java.util.List;
    import org.lwjgl.BufferUtils;
    import org.lwjgl.opengl.GL11;
    import org.lwjgl.opengl.GL15;
    import org.lwjgl.opengl.GL20;
    import org.lwjgl.opengl.GL30;
    import org.lwjgl.system.MemoryUtil;
    public class Loader {
private List<Integer> vaos = new ArrayList<Integer>();
private List<Integer> vbos = new ArrayList<Integer>();

public RawModel loadToVAO(float[] positions) {
int vaoID = createVAO();
storeDataInAttributeList(0, positions);
return new RawModel(vaoID, positions.length/3);

private int createVAO() {
int vaoID = GL30.glGenVertexArrays();
return vaoID;

private void storeDataInAttributeList(int attributeNumber, float[] data) {
int vboID = GL15.glGenBuffers();
GL15.glBindBuffer(GL15.GL_ARRAY_BUFFER, vboID);
FloatBuffer buffer = storeDataInFloatBuffer(data);
GL15.glBufferData(GL15.GL_ARRAY_BUFFER, buffer, GL15.GL_STATIC_DRAW);
GL20.glVertexAttribPointer(attributeNumber, 3, GL11.GL_FLOAT, false, 0, 0);
GL15.glBindBuffer(GL15.GL_ARRAY_BUFFER, 0);

private void unbindVAO() {

private FloatBuffer storeDataInFloatBuffer(float[] data) {
FloatBuffer buffer = MemoryUtil.memAllocFloat(data.length);
return buffer;

public void cleanUp() {
for (int vao : vaos) {
for (int vbo : vbos) {

The renderer class:
Code: [Select]
        package engine.io;
    import org.lwjgl.opengl.GL11;
    import org.lwjgl.opengl.GL15;
    import org.lwjgl.opengl.GL20;
    import org.lwjgl.opengl.GL30;
    public class Renderer {

public void prepare() {
GL11.glClearColor(1f, 0f, 1f, 1f);

public void render(RawModel model) {
GL11.glDrawArrays(GL11.GL_TRIANGLES, 0, model.getVertexCount());

Here is the Main class:

Code: [Select]
    import org.lwjgl.*;
    import org.lwjgl.glfw.*;
    import org.lwjgl.opengl.*;
    import org.lwjgl.system.*;

    import engine.io.Loader;
    import engine.io.RawModel;
    import engine.io.Renderer;
    import engine.io.Window;

    import java.nio.*;

    import static org.lwjgl.glfw.Callbacks.*;
    import static org.lwjgl.glfw.GLFW.*;
    import static org.lwjgl.opengl.GL11.*;
    import static org.lwjgl.system.MemoryStack.*;
    import static org.lwjgl.system.MemoryUtil.*;

    public class Main {

private Window window;

Loader loader = new Loader();
Renderer renderer = new Renderer();

float[] vertices = {
            // Left bottom triangle
            -0.5f, 0.5f, 0f,
            -0.5f, -0.5f, 0f,
            0.5f, -0.5f, 0f,
            // Right top triangle
            0.5f, -0.5f, 0f,
            0.5f, 0.5f, 0f,
            -0.5f, 0.5f, 0f

RawModel model;

public void run() {




private void loop() {
while ( !glfwWindowShouldClose(window.getWindowNum()) ) {
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT); // clear the framebuffer


glfwSwapBuffers(window.getWindowNum()); // swap the color buffers


public void setup() {
window = new Window(900, 300, "Flappy Bird");


model = loader.loadToVAO(vertices);

GL11.glViewport(0, 0, 900, 300);

public static void main(String[] args) {
new Main().run();

Here is the window class:

    package engine.io;

    import static org.lwjgl.glfw.GLFW.*;
    import static org.lwjgl.opengl.GL11.*;
    import static org.lwjgl.system.MemoryStack.stackPush;
    import static org.lwjgl.system.MemoryUtil.*;
    import java.nio.IntBuffer;
    //import static org.lwjgl.glfw.GLFW.*;
    import org.lwjgl.glfw.GLFW;
    import org.lwjgl.glfw.GLFWErrorCallback;
    import org.lwjgl.glfw.GLFWVidMode;
    import org.lwjgl.system.MemoryStack;

    public class Window {
private int width, height;
private String title;
private long window;

public Window(int width, int height, String title) {
this.width = width;
this.height = height;
this.title = title;

public void create() {

if (!glfwInit())
throw new IllegalStateException("Unable to initialize GLFW");

// Configure GLFW
glfwDefaultWindowHints(); // optional, the current window hints are already the default
glfwWindowHint(GLFW_VISIBLE, GLFW_FALSE); // the window will stay hidden after creation
glfwWindowHint(GLFW_RESIZABLE, GLFW_TRUE); // the window will be resizable

// Create the window
window = glfwCreateWindow(width, height, "Flappy Bird", NULL, NULL);
if (window == NULL)
throw new RuntimeException("Failed to create the GLFW window");

// Get the thread stack and push a new frame
try (MemoryStack stack = stackPush()) {
IntBuffer pWidth = stack.mallocInt(1); // int*
IntBuffer pHeight = stack.mallocInt(1); // int*

// Get the window size passed to glfwCreateWindow
glfwGetWindowSize(window, pWidth, pHeight);

// Get the resolution of the primary monitor
GLFWVidMode vidmode = glfwGetVideoMode(glfwGetPrimaryMonitor());

// Center the window
glfwSetWindowPos(window, (vidmode.width() - pWidth.get(0)) / 2, (vidmode.height() - pHeight.get(0)) / 2);
} // the stack frame is popped automatically
// Setup a key callback. It will be called every time a key is pressed, repeated
// or released.
glfwSetKeyCallback(window, (window, key, scancode, action, mods) -> {
if (key == GLFW_KEY_ESCAPE && action == GLFW_RELEASE)
glfwSetWindowShouldClose(window, true); // We will detect this in the rendering loop

// Make the OpenGL context current
// Enable v-sync

// Make the window visible


public long getWindowNum() {
return window;

Re: Problem with rendering a quad using VBOs and VAOs
« Reply #1 on: September 14, 2020, 01:40:21 »

    I ran your code, and the rectangle appeared.