Rendering Pipeline

NeoFlux uses a command-based rendering pipeline. The application layer generates RenderCommand objects, and the render layer consumes and executes them.

RenderCommand

RenderCommand is a tagged union that represents a single drawing operation:

Type	Description
kBeginFrame	Start a new frame (clear, DPI scale)
kEndFrame	End frame (submit + present through the tgfx Window)
kDrawRect	Draw a filled rectangle
kDrawRoundedRect	Draw a filled rounded rectangle
kDrawText	Draw text glyphs
kTranslate	Push a translate transform
kClipRect	Set a clip rectangle
kRestore	Pop transform/clip state

Commands are created via factory functions:

RenderCommand cmd = RenderCommand::MakeDrawRect(rect, color);
RenderCommand text_cmd = RenderCommand::MakeDrawText(x, y, text, font, color);

SPSC Ring Queue

Commands are passed from the application layer to the render layer via a lock-free SPSC ring queue:

// Application layer (producer):
render_layer_->Submit(cmd);

// Render layer (consumer):
while (running_) {
  RenderCommand cmd;
  while (queue_.TryPop(cmd)) {
    Execute(cmd);
  }
  WaitForNextFrame();
}

The queue capacity is configurable via --render_queue_capacity (default 2048).

Desktop Rendering (tgfx)

Desktop and mobile share one rendering shape: a tgfx Window owns the GPU context and the swapchain, Surface::MakeFrom(context, window) acquires a per-frame surface, and context->submit() presents. Only window creation is platform-specific:

Backend	tgfx Window	Native handle source
TGFX_USE_OPENGL (Linux)	tgfx::EGLWindow::MakeFrom(XID)	glfwGetX11Window()
TGFX_USE_OPENGL (Windows)	tgfx::WGLWindow::MakeFrom(HWND)	glfwGetWin32Window()
TGFX_USE_METAL (Apple)	tgfx::MetalWindow::MakeFrom(CAMetalLayer*)	GLFW NSWindow content view
TGFX_USE_VULKAN (Windows)	tgfx::VulkanWindow::MakeFrom(HWND)	glfwGetWin32Window()
TGFX_USE_D3D12 (Windows)	tgfx::D3D12Window::MakeForHwnd(HWND)	glfwGetWin32Window()
Android	tgfx::EGLWindow::MakeFrom(ANativeWindow*)	app shell

GLFW windows are created with GLFW_NO_API; NeoFlux never manages a GL/EGL/WGL context itself. There is no built-in rasterizer behind tgfx — tgfx is the only rendering implementation.

Text Rendering (tgfx)

Text is drawn by TgfxRenderer::Execute with canvas->drawSimpleText using typefaces loaded by FontManager (FreeType-backed inside tgfx):

1. FontManager scans assets/fonts/ and picks a default typeface.
2. TgfxRenderer::Init loads it via tgfx::Typeface::MakeFromPath.
3. Text commands create a sized tgfx::Font and draw directly on the canvas; tgfx handles glyph rasterization, caching, and subpixel positioning.

Frame Synchronization

The render thread waits for commands using a condition variable:

// Application layer signals new frame:
frame_cv_.notify_one();

// Render thread waits:
std::unique_lock lock(frame_mutex_);
frame_cv_.wait(lock, [this] { return has_commands_ || !running_; });

This minimizes idle CPU usage when no rendering is needed.

Frame Synchronization

The render thread waits for commands using a condition variable:

// Application layer signals new frame:
frame_cv_.notify_one();

// Render thread waits:
std::unique_lock lock(frame_mutex_);
frame_cv_.wait(lock, [this] { return has_commands_ || !running_; });

This minimizes idle CPU usage when no rendering is needed.