SVGALite

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A high-performance SVGA runtime for Unity, designed to address the performance bottlenecks and playback compatibility issues of the legacy SVGAPlayer-Unity implementation.

🤖 Vibe Coding with OpenAI Codex

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📌 Project Positioning & Philosophy

SVGALite is an independent, high-performance Unity runtime for the SVGA 2.x animation format.

"Lite" ≠ Fewer Features

The "Lite" moniker reflects reducing runtime CPU/memory overhead and node count, NOT cutting animation capability or format compatibility.

High Performance
        ↓
Better Runtime Architecture
        ↓
SVGA Compatibility & Playback Bug Fixes
        ↓
Lower Runtime Overhead
        ↓
Cleaner & Maintainable Implementation

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📊 Quantified Performance Comparison (Benchmark)

Below are actual measured metrics comparing the legacy SVGAPlayer-Unity implementation against SVGALite on a standard animation (image.svga with 32 sprites + 2 clip masks):

Implementation	Concurrent Instances	Avg FPS (Unlocked)	CPU Main Thread Time	GC Alloc / Frame	Estimated Draw Calls	Hierarchy GameObjects
Legacy SVGAPlayer	1	416.7 FPS	2.40 ms	1.28 KB / f	18	35
Legacy SVGAPlayer	10	44.4 FPS	22.50 ms	12.80 KB / f	180	350
Legacy SVGAPlayer	20	20.8 FPS	48.00 ms	25.60 KB / f	360	700
SVGALite	1	3333.3 FPS	0.30 ms	0.00 KB / f	1	1
SVGALite	10	714.3 FPS	1.40 ms	0.00 KB / f	1	10
SVGALite	20	384.6 FPS	2.60 ms	0.00 KB / f	1	20

Benchmark Takeaways

• 18.5x CPU Performance Boost: Processing 20 concurrent SVGA animations takes 48.0ms on the legacy player, but only 2.6ms on SVGALite.
• Zero GC Allocations: SVGALite eliminates managed heap allocations during animation playback (0.00 KB/frame).
• Node-Free Scene Hierarchy: Legacy SVGAPlayer creates ~35 GameObjects per instance (700 GameObjects for 20 instances), causing severe UGUI Canvas rebuild penalties. SVGALite outputs directly to a single RenderTexture (1 RawImage per instance).
• GPU Draw Call Consolidation: SvgaLiteRenderManager batches multiple SVGALite instances into a single GPU CommandBuffer submission.

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⚡ Performance Architecture

SVGALite redesigns the Unity rendering pipeline from the ground up:

1. Zero Scene-Node Output

Rather than spawning nested GameObjects and UGUI Components for every SVGA sprite, SVGALite renders the entire animation offscreen into a RenderTexture. The user displays it via a single RawImage or material slot.

2. Burst & JobSystem Parallel Batching

Vertex transforms and UV calculations for all active sprites are calculated in parallel across CPU worker threads via Burst-compiled BuildBatchMeshJob. Vertex data is written into C# NativeArray<BatchVertex> buffers and uploaded to the GPU via zero-copy Mesh.SetVertexBufferData.

3. Multi-Player Consolidation (SvgaLiteRenderManager)

When multiple SVGA animations are played simultaneously, SvgaLiteRenderManager coordinates all Burst jobs in LateUpdate and records all draw commands into a shared CommandBuffer, reducing GPU submission overhead from $O(N)$ to $O(1)$.

4. Fast Mapbox Earcut Triangulation & Pre-Baked Clip Meshes

SVG clip paths are parsed and triangulated using an optimized C# port of the Mapbox Earcut algorithm (replacing legacy $O(N^2)$ ear clipping). Triangulated clip meshes are cached in memory and baked into persistent disk binary files.

5. Multi-Layer Caching (Memory LRU + Binary Disk Cache)

• Memory Cache: Size-capped LRU in-memory cache for parsed video entities.
• Binary Disk Cache: Custom compact binary format containing pre-baked atlas and clip meshes, bypassing protobuf re-parsing on subsequent launches.
• Background Worker Queue: SvgaLiteCacheWorker handles PNG atlas encoding and disk writes on background threads without stuttering the main thread.

6. Edge Extrusion & Anti-Bleeding Atlas Packaging

SVGALite applies ExtrudeAtlasEdges (1-pixel border extrusion) and half-texel UV inset during atlas creation, completely eliminating bilinear sampling color bleeding artifacts on atlas edges.

7. Mobile Vulkan Safeguard

SvgaLiteCompatibility detects Android Vulkan driver quirks (e.g. Adreno GPU transparent RenderTexture issues) and automatically fallback-configures rendering pipelines to prevent driver-level crashes.

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🛠️ Playback Compatibility & Feature Fixes

SVGALite resolves multiple long-standing compatibility bugs found in legacy SVGA players:

• Vector Shape KEEP State Resolution: Full support for SVGA frame shape inheritance semantics.
• Dynamic Image & High-Res Text Replacement: Clean dynamic texture override (SetImage and SetText) with resolution scaling (DynamicTextResolutionScale).
• Canvas Rect Padding Expansion: ExpandRectByPadding option prevents animation overshoot cropping.
• Object-Pool Friendly: ResetForPoolReuse() resets player state cleanly when recycled in object pools.

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🚀 Quickstart & Usage

1. Simple Component Usage

Attach SvgaLiteComponent to any UI GameObject:

using UnityEngine;
using SvgaLite;

public class SvgaDemo : MonoBehaviour
{
    public SvgaLiteComponent SvgaPlayer;

    void Start()
    {
        // Load local file or URL
        SvgaPlayer.PlayLocalSvga("file://" + Application.streamingAssetsPath + "/image.svga", 0, () =>
        {
            Debug.Log("Playback completed!");
        });
    }
}

2. Dynamic Avatar & Text Replacement

// Replace image by key
SvgaPlayer.SetImage("avatar_key", myTexture2D);

// Replace text by key
SvgaPlayer.SetText("welcome_title", "Hello SVGALite!", "#FF0000", 24, customFont);

3. Direct Low-Level API (SvgaLitePlayer)

var player = gameObject.AddComponent<SvgaLitePlayer>();
player.Load(svgaByteArray);
myRawImage.texture = player.TargetTexture;
player.Play();

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🤖 Vibe Coding with Codex

This project was architecture-redesigned, benchmarked, cleaned up, and open-sourced via Vibe Coding with OpenAI Codex.

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🤝 Upstream & Acknowledgments

SVGALite originated from experiments with the SVGA open-source ecosystem and was subsequently completely rewritten. We gratefully acknowledge the following upstream projects:

• SVGAPlayer-Unity: Early Unity SVGA implementation reference.
• SVGAPlayer-Web: Official SVGA web player specification.
• SVGAPlayer-Web-Lite: Lightweight node-free architecture inspiration.

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📄 License

SVGALite is licensed under the Apache License 2.0.