Post-processing and compute effects

Bloom, TAA, GTAO, the sky LUTs and the debug views are not hard-wired stages. They are compute effects registered against a frame phase, and the twenty-line contract that carries them is the same one your own effect implements.

What ships in the box

Effects live in Rendering/Effects/. Each one registers into a compute phase, declares the textures it produces, and can be inspected as a 2D sprite by name — which is how the reference application's debug mode works.

Any of them can be put on screen with three lines, because effect outputs are addressable textures:

AddControl(new Sprite2D
{
    Name = Season.Rendering.Effects.GtaoEffect.TextureName,
    Color = Colors.White,
    PosX = 20, PosY = 580, Width = 240
});

Names follow one scheme: compute:// for 2D textures and compute3d:// for volumes. GTAO publishes compute://gtao/ao, the sky publishes compute://sky/skyview and compute3d://sky/aerial, and the plasma sample publishes compute://plasma. Nothing about consuming them is special — a Sprite2D or a material override takes the name and that is the whole interface.

The effect contract

ComputeEffect is an abstract class with five members. That is the entire extension surface.

public abstract class ComputeEffect
{
    public abstract string Name { get; }
    public abstract ComputePhase Phase { get; }

    // Create textures and pipelines. Return false and the effect is
    // dropped with nothing left behind.
    public abstract bool Initialize(IGraphics g);

    // Dispatch. Called once per frame, in phase order.
    public abstract void Record(IGraphics g);

    // Swapchain changed size. Recreate anything resolution-dependent.
    public virtual void OnResize(IGraphics g) { }
}

Writing a compute effect walks through PlasmaEffect line by line.

Bloom

A threshold-and-knee soft clip followed by a six-level downsample and upsample chain over HDR scene colour. Because scene colour is genuinely HDR, the threshold means something: it selects pixels brighter than white rather than pixels that happened to clip.

Anti-aliasing: four tiers, honestly labelled

AaMode has four values and they are not four qualities of the same thing — they operate in different colour spaces at different points in the frame.

TAA is implemented and stabilised on D3D12, Vulkan, Metal and WebGPU. The fallback to FXAA is automatic rather than an error, which means a scene requesting TAA still renders on a device that cannot deliver it — softer, but rendered.

TAA in detail

The camera jitters the projection matrix by a sub-pixel offset each frame, the resolve reprojects the previous result through motion vectors, and variance clipping decides how much of the history to trust. The interesting part is that both the jitter and the history live on Camera3D, where you can read them.

Known gaps

• Partial GTAO is a lite variant. Half-resolution horizon-based AO with depth-reconstructed normals, interleaved-gradient noise and a depth-aware blur. It is not full ground-truth AO, and the name is inherited from the technique family rather than claiming the reference implementation.
• Absent Depth of field, motion blur, chromatic aberration, colour grading LUTs. The post chain is tonemap, bloom and AA. Anything else is an effect you would write.
• Absent Upscalers. No FSR, DLSS or temporal upscaling. TAA resolves at native resolution.