cvkg-render-gpu

GPU Shader Pipeline

cvkg-render-gpu is the "Surtr" pipeline: a high-performance, wgpu-powered GPU renderer designed for "Berserker" aesthetics and complex visual effects.

Boundaries and Responsibilities

This crate is the authoritative drawing backend for CVKG. It does NOT handle windowing or higher-level layout. Its responsibilities include:

Managing the Muspelheim multi-pass pipeline (Bloom, Blur, Composite).
Tessellating 2D primitives and SVG strokes into GPU-ready meshes using lyon.
Managing a Mega-Atlas for high-efficiency text and image batching.
Executing real-time parsing and evaluation of Animated SVGs via roxmltree and usvg.
Propagating full 3x3 affine transformation matrices for complex nested scaling, skew, and rotation.
Implementing advanced shader effects: Bifrost (frost), Gungnir (glow), and Mjolnir (geometric clipping/shattering).
Optimizing VRAM usage via LRU-based cache eviction and atlas recycling.

Public API Overview

Core Types

SurtrRenderer: The central GPU controller managing device state, pipelines, and buffers.
Vertex: The unified vertex format supporting position, color, radius, and effect-specific metadata.
DrawCall: Represents a batched GPU operation organized by texture and transparency layer.

Systems

Muspelheim Passes: Specialized pipelines for Gaussian blur and bloom extraction.
ShelfPacker: A high-speed atlas packing algorithm for real-time UI textures.
RunicTextEngine: Integration with cvkg-runic-text for GPU-accelerated glyph rendering.

Key Methods

SurtrRenderer::forge(): Initializes the GPU device and pipelines for a target window.
SurtrRenderer::begin_frame() / SurtrRenderer::end_frame(): Manages the command encoder lifecycle.

Known Limitations

Requires a GPU supporting SAMPLED_TEXTURE_AND_STORAGE_BUFFER_ARRAY_NON_UNIFORM_INDEXING.
Texture atlas size is currently fixed at 4096x4096px.
Culling is hierarchical but relies on the cvkg-scene crate for complex queries.