C#•6d ago

Flickering (/blink) bug effect on opentk

    public class FrameBuffer2D
{
   
    public FrameBuffer2D(IntPtr renderer, int width, int height)
    {
        sdlRenderer = renderer;
        Resize(width, height);
    }

    public void Bind() => GL.BindFramebuffer(FramebufferTarget.Framebuffer, FBO);
    public void Unbind() => GL.BindFramebuffer(FramebufferTarget.Framebuffer, 0);

        public void ReadToSDLTexture()
        {
            byte[] pixels = new byte[Width * Height * 4];

            // copia os pixels do OpenGL
            
            GL.BindTexture(TextureTarget.Texture2D, ColorTex);
            GL.GetTexImage(TextureTarget.Texture2D, 0, PixelFormat.Rgba, PixelType.UnsignedByte, pixels);
            GL.BindTexture(TextureTarget.Texture2D, 0);

            // atualiza a SDL texture
            unsafe
            {
                fixed (byte* p = pixels)
                {
                    SDL.SDL_UpdateTexture(SDLTexture, IntPtr.Zero, (IntPtr)p, Width * 4);
                }
            }
        }


    public void DrawSDL(int x, int y, int w, int h)
    {
        SDL.SDL_Rect dst = new SDL.SDL_Rect { x = x, y = y, w = w, h = h };
        SDL.SDL_RenderCopy(sdlRenderer, SDLTexture, IntPtr.Zero, ref dst);
    }
}

}

    public class FrameBuffer2D
{
   
    public FrameBuffer2D(IntPtr renderer, int width, int height)
    {
        sdlRenderer = renderer;
        Resize(width, height);
    }

    public void Bind() => GL.BindFramebuffer(FramebufferTarget.Framebuffer, FBO);
    public void Unbind() => GL.BindFramebuffer(FramebufferTarget.Framebuffer, 0);

        public void ReadToSDLTexture()
        {
            byte[] pixels = new byte[Width * Height * 4];

            // copia os pixels do OpenGL
            
            GL.BindTexture(TextureTarget.Texture2D, ColorTex);
            GL.GetTexImage(TextureTarget.Texture2D, 0, PixelFormat.Rgba, PixelType.UnsignedByte, pixels);
            GL.BindTexture(TextureTarget.Texture2D, 0);

            // atualiza a SDL texture
            unsafe
            {
                fixed (byte* p = pixels)
                {
                    SDL.SDL_UpdateTexture(SDLTexture, IntPtr.Zero, (IntPtr)p, Width * 4);
                }
            }
        }


    public void DrawSDL(int x, int y, int w, int h)
    {
        SDL.SDL_Rect dst = new SDL.SDL_Rect { x = x, y = y, w = w, h = h };
        SDL.SDL_RenderCopy(sdlRenderer, SDLTexture, IntPtr.Zero, ref dst);
    }
}

}

Hello, I have this framebuffer class to render the game engine's scene and consequently copy it to an SDL texture (to be able to implement it within the UI that is made in SDL2), but I am experiencing flickering effects when adding a game object to the scene

58 Replies

IarleyOP•6d ago

Consequently, I also have the SpriteBatch2D class, which is responsible for rendering sprites.

message.txt

IarleyOP•6d ago

public void Run()
    {
        while (IsRunning)
        {
            ProcessEvents();

            // Atualiza delta/time no início do frame
            Time.Update();

            // Render Game World -> OpenGL FBO
            framebuffer.Bind();
            GL.Viewport(0, 0, framebuffer.Width, framebuffer.Height);

            GL.ClearColor(0.0f, 0.0f, 0.0f, 1f);
            GL.Clear(ClearBufferMask.ColorBufferBit);

            if (!SceneManager.CurrentScene.Paused)
            {
                SceneManager.CurrentScene.Update(Time.DeltaTime, framebuffer.Width, framebuffer.Height);
                Logger.Log("Scene is Running - [" + (int)Time.FPS + "] FPS", Logger.LogLevel.Info);
            }

            framebuffer.Unbind();
            GL.Finish();
            framebuffer.ReadToSDLTexture();

            // Render UI + Framebuffer (SDL)
            SDL.SDL_SetRenderDrawColor(_renderer, 25, 25, 25, 255);
            SDL.SDL_RenderClear(_renderer);

            // primeiro update de UI (lógica), depois desenho
            UIManager.Update();
            UIManager.Draw(_renderer);

            SDL.SDL_RenderPresent(_renderer);
            SDL.SDL_RenderClear(_renderer);

        }

        Quit();
    }

public void Run()
    {
        while (IsRunning)
        {
            ProcessEvents();

            // Atualiza delta/time no início do frame
            Time.Update();

            // Render Game World -> OpenGL FBO
            framebuffer.Bind();
            GL.Viewport(0, 0, framebuffer.Width, framebuffer.Height);

            GL.ClearColor(0.0f, 0.0f, 0.0f, 1f);
            GL.Clear(ClearBufferMask.ColorBufferBit);

            if (!SceneManager.CurrentScene.Paused)
            {
                SceneManager.CurrentScene.Update(Time.DeltaTime, framebuffer.Width, framebuffer.Height);
                Logger.Log("Scene is Running - [" + (int)Time.FPS + "] FPS", Logger.LogLevel.Info);
            }

            framebuffer.Unbind();
            GL.Finish();
            framebuffer.ReadToSDLTexture();

            // Render UI + Framebuffer (SDL)
            SDL.SDL_SetRenderDrawColor(_renderer, 25, 25, 25, 255);
            SDL.SDL_RenderClear(_renderer);

            // primeiro update de UI (lógica), depois desenho
            UIManager.Update();
            UIManager.Draw(_renderer);

            SDL.SDL_RenderPresent(_renderer);
            SDL.SDL_RenderClear(_renderer);

        }

        Quit();
    }

my run method If someone can identify the error and help me fix the bug, I would be grateful. @CityPop

hugeman•6d ago

You unbind the framebuffer before reading the texture, not sure if that causes issues but maybe rearrange it? Is the flickering every other frame or is it random?

IarleyOP•6d ago

every other frame lemme try it

hugeman•6d ago

Every other frame sounds something to do with with swap buffers function but i could be wrong

Cattywampus•6d ago

most flickers in sdl mostly just the wrong ordering

IarleyOP•6d ago

It didn’t work, I’ve already tried several things, I’ve tried refactoring the rendering system, I’ve literally tried everything, I asked the AI for help and it didn’t work

Cattywampus•6d ago

the order should be : Clear Render Render present //Your timestep condition and repeat

IarleyOP•6d ago

// Atualiza delta/time no início do frame
            Time.Update();

            // Render Game World -> OpenGL FBO
            framebuffer.Bind();
            GL.Viewport(0, 0, framebuffer.Width, framebuffer.Height);

            GL.ClearColor(0.0f, 0.0f, 0.0f, 1f);
            GL.Clear(ClearBufferMask.ColorBufferBit);

            if (!SceneManager.CurrentScene.Paused)
            {
                SceneManager.CurrentScene.Update(Time.DeltaTime, framebuffer.Width, framebuffer.Height);
                Logger.Log("Scene is Running - [" + (int)Time.FPS + "] FPS", Logger.LogLevel.Info);
            }

            framebuffer.Unbind();
            GL.Finish();
            framebuffer.ReadToSDLTexture();

            // Render UI + Framebuffer (SDL)
            SDL.SDL_SetRenderDrawColor(_renderer, 25, 25, 25, 255);
            SDL.SDL_RenderClear(_renderer);

            // primeiro update de UI (lógica), depois desenho
            UIManager.Update();
            UIManager.Draw(_renderer);

            SDL.SDL_RenderPresent(_renderer);
            SDL.SDL_RenderClear(_renderer);

// Atualiza delta/time no início do frame
            Time.Update();

            // Render Game World -> OpenGL FBO
            framebuffer.Bind();
            GL.Viewport(0, 0, framebuffer.Width, framebuffer.Height);

            GL.ClearColor(0.0f, 0.0f, 0.0f, 1f);
            GL.Clear(ClearBufferMask.ColorBufferBit);

            if (!SceneManager.CurrentScene.Paused)
            {
                SceneManager.CurrentScene.Update(Time.DeltaTime, framebuffer.Width, framebuffer.Height);
                Logger.Log("Scene is Running - [" + (int)Time.FPS + "] FPS", Logger.LogLevel.Info);
            }

            framebuffer.Unbind();
            GL.Finish();
            framebuffer.ReadToSDLTexture();

            // Render UI + Framebuffer (SDL)
            SDL.SDL_SetRenderDrawColor(_renderer, 25, 25, 25, 255);
            SDL.SDL_RenderClear(_renderer);

            // primeiro update de UI (lógica), depois desenho
            UIManager.Update();
            UIManager.Draw(_renderer);

            SDL.SDL_RenderPresent(_renderer);
            SDL.SDL_RenderClear(_renderer);

IarleyOP•6d ago

Gaming

Programming

Flickering (/blink) bug effect on opentk

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