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Temporal Anti-Aliasing

Reduces aliasing by accumulating jittered samples across frames.

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Quick Facts

Compact metadata for implementation and discovery.

Category: Rendering
Difficulty: Advanced
Family: Temporal Filtering
Tier: Specialized
Status: Verified
Review: Source Checked
Sources: 1
Formulas: 1
Relationships: 4
Code example: Ready
Visualization: Ready

Overview

Temporal Anti-Aliasing combines the current frame with reprojected history, using motion vectors and clamping to reduce ghosting.

Core Concepts

subpixel jitterhistory reprojectionmotion vectorneighborhood clamp

Quick facts

Complexity

Runtime and memory behavior at a glance.

Best

O(pixels)

Average

O(pixels)

Worst

O(pixels)

Space

O(pixels)

When to Use

Use when stable real-time images matter more than single-frame sharpness.
Use when real-time edge smoothing is a central requirement.

When Not to Use

Avoid when motion vectors are unavailable or ghosting is unacceptable.
Avoid when the renderer cannot provide the buffers, samples, or lighting data the technique needs.

What It Does

Jitters sample positions
Reprojects previous frame data
Blends current and historical color

Use Cases

Real-time edge smoothing
Shimmer reduction
Stable rendered images

Inputs

Current frame
History frame
Motion vectors
Jitter pattern

Outputs

Anti-aliased frame

Key Formulas (1)

Temporal blend

color = α · current + (1 − α) · history

color = alpha * current + (1 - alpha) * history

Combines current and reprojected historical color.

Pseudocode

1.Render with a subpixel jitter
2.Use motion vectors to find the previous sample position
3.Fetch history color
4.Clamp history against current neighborhood
5.Blend current and history colors

Canonical Example

Input: current color = 0.6, history color = 0.5
Output: output = blended color near 0.53
Explanation: The frame uses history to approximate more samples than one frame contains.

Implementation Notes

Visualize motion vectors and rejected history regions during debugging.
Debug with simple geometry, known lights, and visualized intermediate buffers.
Keep a tiny example with expected output beside the implementation.

Common Pitfalls

Blending invalid history creates trails behind moving objects.
Coordinate-space mismatches often cause artifacts that look like math errors.
Not defining boundary, empty, or degenerate inputs before implementation.

Interactive Mechanism Walkthrough

Spatial Primitive & Sweep-Line Canvas

Show jittered samples over multiple frames accumulating into a smoother edge.

Step 1 of 5: Render with a subpixel jitter

rendering-pipeline

Notes

TAA quality depends on motion vectors, history validation, and neighborhood clamping.

Sources (1)

What each reference supports for this entry.