无法呈现简单顶点数组

我正在从传统的现代OpenGL迁移二维游戏。对我来说,这意味着使用着色和顶点数组而不是 glProjection , glOrtho 和 glBegin / glEnd .

我将相关代码简化为一个非常基本的示例。相机在(0,0,-1)处查看(0,0,0),我正在尝试绘制一个带点的三角形:

(0, 0, 0)
      X
      | '
      |   '
      |     '
      X-------X
(0, 1, 0)   (1, 1, 0)

即使使用一个非常简单的明暗器将所有片段渲染为白色,我也看不到这个三角形,只看到闪烁的背景色。

代码

package client.render.opengl;

import java.io.IOException;
import java.nio.ByteBuffer;
import java.nio.FloatBuffer;

import org.joml.Matrix4f;
import org.lwjgl.BufferUtils;
import org.lwjgl.glfw.GLFW;
import org.lwjgl.glfw.GLFWErrorCallback;
import org.lwjgl.opengl.GL;
import org.lwjgl.opengl.GL11;
import org.lwjgl.opengl.GL15;
import org.lwjgl.opengl.GL20;
import org.lwjgl.opengl.GL30;

import client.res.gfx.ScreenShader;

public class RenderingTest {

    private static final int NUM_VERTICES = 3;

    private static long window;
    private static int shaderProgram;
    private static int vao;
    private static int uniformLoc;
    private static Matrix4f viewProjMatrix = new Matrix4f();
    private static FloatBuffer fb16 = BufferUtils.createFloatBuffer(16);

    public static void main(String[] args) throws IOException {

        init();

        while (!GLFW.glfwWindowShouldClose(window)) {
            GLFW.glfwPollEvents();
            render();
            GLFW.glfwSwapBuffers(window);
        }
    }

    private static void init() throws IOException {

        // Setup an error callback
        GLFW.glfwSetErrorCallback(
                GLFWErrorCallback.createPrint(System.err)
        );

        // Initialise GLFW
        if (!GLFW.glfwInit()) {
            throw new IllegalStateException("Unable to initialize GLFW");
        }

        // Create window
        window = GLFW.glfwCreateWindow(800, 600, "test", 0, 0);
        GLFW.glfwMakeContextCurrent(window);
        GL.createCapabilities();
        GLFW.glfwShowWindow(window);

        // Load shader
        // Assume this code is good for now, it's too long to post here
        ScreenShader.initialise();
        shaderProgram = ScreenShader.shader.getProgram();
        uniformLoc = ScreenShader.shader.getUniformLoc(ScreenShader.UNIFORM_VIEW_PROJ_MATRIX);

        // Define our vertices
        ByteBuffer vertexBuffer = ByteBuffer.allocateDirect(NUM_VERTICES * 2 * Float.BYTES);
        vertexBuffer.putFloat(0).putFloat(0); // Vertex 1
        vertexBuffer.putFloat(0).putFloat(1); // Vertex 2
        vertexBuffer.putFloat(1).putFloat(1); // Vertex 3
        vertexBuffer.flip();

        // Create VAO
        vao = GL30.glGenVertexArrays();
        GL30.glBindVertexArray(vao);

        // Create VBO and fill it with vertex positions
        int vboIdPositions = GL15.glGenBuffers();
        GL15.glBindBuffer(GL15.GL_ARRAY_BUFFER, vboIdPositions);
        GL15.glBufferData(GL15.GL_ARRAY_BUFFER, vertexBuffer, GL15.GL_STATIC_DRAW);
        GL20.glVertexAttribPointer(0, 2, GL11.GL_FLOAT, false, 0, 0);
        GL15.glBindBuffer(GL15.GL_ARRAY_BUFFER, 0); // Deselect

        // Unbind the VAO
        GL30.glBindVertexArray(0);
    }

    public static void render() {

        // Render a random background to prove the loop is working
        GL11.glClearColor(
                (float) (Math.random() * 0.2f),
                (float) (Math.random() * 0.2f),
                (float) (Math.random() * 0.2f),
                1.0f);
        GL11.glClear(GL11.GL_COLOR_BUFFER_BIT);

        // Use shader
        GL20.glUseProgram(shaderProgram);

        // Get camera position
        float cameraX = 0;
        float cameraY = 0;

        // Set view and projection
        viewProjMatrix
                .setOrtho(
                        0,
                        800,
                        600,
                        0,
                        0.01f,
                        10
                ).lookAt(
                        cameraX, cameraY, -1,    // Camera position
                        cameraX, cameraY, 0,     // Camera "look" vector
                        0, 1, 0                  // Camera "up" vector
                );

        // Pass this matrix to our shader
        GL20.glUniformMatrix4fv(uniformLoc, false, viewProjMatrix.get(fb16));

        // Bind our vertex array
        GL30.glBindVertexArray(vao);

        // Enable vertex attributes
        GL20.glEnableVertexAttribArray(0);

        // Draw the vertices
        GL11.glDrawArrays(GL11.GL_TRIANGLES, 0, NUM_VERTICES);

        // Disable vertex attributes
        GL20.glDisableVertexAttribArray(0);

        // Unbind vertex array
        GL30.glBindVertexArray(0);

        // Release shader
        GL20.glUseProgram(0);
    }

}

顶点着色器

#version 330

uniform mat4 view_proj_matrix;

layout(location = 0) in vec2 in_vertex;

void main(void) {
    gl_Position = view_proj_matrix * vec4(in_vertex, 0, 1);
}

片段着色器

#version 330

out vec4 frag_colour;

void main(void) {
    frag_colour = vec4(1, 1, 1, 1);
}

我不知道如何进步,因为我甚至不能让这个玩具例子发挥作用。有人能看到我做错了什么,或者给我指出一个使用joml和lwjgl2和shaders的工作示例吗?