I am currently struggling with my framebuffer in my 2D C++/OpenGL Game and failing to see my issues. It will not store some of my textures and can’t be updated properly and I can’t seem to find the reason.

To make texture picking easier, I portray all my textures in a framebuffer texture and store the ID and color values of each texture there. Therefore I created this framebuffer class:

void Framebuffer::Awake()
    {
        glm::vec2 windowSize = GlobalHelper::GetCurrentWindowSize();
        glm::vec4 viewportSize = GlobalHelper::GetViewportSize();
        glGenFramebuffers(1, &FBO);
        glBindFramebuffer(GL_FRAMEBUFFER, FBO);

        // color buffer
        glCreateTextures(GL_TEXTURE_2D, 1, &colorAttachment);
        glBindTexture(GL_TEXTURE_2D, colorAttachment);
        glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA8, viewportSize.z, viewportSize.w, 0, GL_RGBA, GL_UNSIGNED_BYTE, nullptr);
        glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
        glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
        glBindTexture(GL_TEXTURE_2D, 0);

        glFramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D, colorAttachment, 0);

        //ID buffer
        glCreateTextures(GL_TEXTURE_2D, 1, &IDAttachment);
        glBindTexture(GL_TEXTURE_2D, IDAttachment);
        glTexImage2D(GL_TEXTURE_2D, 0, GL_R32I, viewportSize.x, viewportSize.y, 0, GL_RED_INTEGER, GL_UNSIGNED_BYTE, nullptr);
        glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
        glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
        glBindTexture(GL_TEXTURE_2D, 0);

        glFramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT1, GL_TEXTURE_2D, IDAttachment, 0);
        GLenum drawBuffers[] = {GL_COLOR_ATTACHMENT0, GL_COLOR_ATTACHMENT1};
        glDrawBuffers(2, drawBuffers);

        glBindFramebuffer(GL_FRAMEBUFFER, 0);
    }

    void Framebuffer::Bind()
    {
        glBindFramebuffer(GL_FRAMEBUFFER, FBO);
        glClearTexImage(IDAttachment, 0, GL_RED_INTEGER, GL_INT, &defaultValue);
    }

    void Framebuffer::Unbind()
    {
        glBindFramebuffer(GL_FRAMEBUFFER, 0);
    }

I use these functions in my render loop to be able to move textures around, add and delete them and still have the actual values.

        colorBuffer = Framebuffer();
        colorBuffer.Awake();
while(!glfwWindowShouldClose(window)) {
            
            glClearColor(0.2f, 0.3f, 0.3f, 1.0f);
            glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
            colorBuffer.Bind();

            BatchRenderer::ResetStats();
            BatchRenderer::BeginBatch();

            GlobalHelper::GetCurrentScene()->OnlyGameUpdate();

            BatchRenderer::EndBatch();
            BatchRenderer::Flush();

            GetTexturePerMouseClick(&startMenuScene);
            colorBuffer.Unbind();

void Scene::OnlyGameUpdate()
    {
        for (const auto& x : sceneTextures)
        {
            BatchRenderer::DrawQuad({x.position.x, x.position.y, 0.0f}, 0.0f + x.rotation,
                                    {x.scale * (float)x.imageWidth, x.scale * (float)x.imageHeight}, x.ID, x.color, 0.0f, x.ID);
        }
    }

I am now having several issues with that.

1. issue: If I am trying to create another texture, such as a background texture, outside of the OnlyGameUpdate() function, the framebuffer will not store it and it can’t be seen in the framebuffer texture, but I actually need it to be able to store a background texture. If I load the image outside the function but then add it to the sceneTextures in the scene class, it works just fine.

2. issue: once I change the scene or the viewport and need to clear the framebuffer textures with:

glClearTexImage(IDAttachment, 0, GL_RED_INTEGER, GL_INT, &defaultValue);
        glClearTexImage(colorAttachment, 0, GL_RGBA, GL_FLOAT, &defaultColor);

it remains the same defaultValues forever and can’t be filled anew.

I have no idea what is happening, does anybody see a logical error or something obviously wrong here?