zig-wgpu/README.md
2026-05-18 16:33:07 +02:00

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Here is the minimal README for the library, completely free of any citations or source references.
# Minimal Zig WebGPU Compute Library
This is a minimal, self-contained Zig library designed to simplify running compute shaders using WebGPU. It abstracts away much of the boilerplate required for GPU device initialization, memory management, and pipeline execution.
## Core Modules
The library exports five primary components:
* **`GpuDevice`**: Initializes the WebGPU instance, adapter, device, and queue. It is configured to prioritize high performance and automatically requests the `ShaderF16` feature if the adapter supports it. By default, it enforces a 2 GB VRAM limit.
* **`GpuArena` / `GpuAllocator`**: A memory management layer that tracks allocated VRAM bytes to prevent exceeding the device budget. The arena automatically destroys and releases all tracked WebGPU buffers when deinitialized.
* **`GpuBuffer`**: Wraps native WebGPU buffers. It automatically aligns buffer sizes forward to a multiple of 4 bytes. It provides a `.load()` method for CPU-to-GPU data transfers (handling both aligned and unaligned lengths smoothly) and a `.read()` method that utilizes a staging buffer to map GPU data back to the CPU.
* **`GpuProcess`**: Compiles WGSL source code into a compute pipeline. When running a process, it automatically splits the work into manageable chunks (up to 1 GB at a time) and dispatches workgroups of size 256.
## Quick Start Example
Below is a complete, self-contained example demonstrating how to initialize the GPU, load data, run a compute shader, and read the results back to the CPU:
```zig
const std = @import("std");
const GpuDevice = @import("GpuDevice.zig");
const GpuArena = @import("GpuArena.zig");
const GpuProcess = @import("GpuProcess.zig");
// Note: Assuming Vec is implemented via GpuBuffer as shown in example.zig
pub fn main(init: std.process.Init) !void {
const allocator = init.gpa;
// 1. Open GPU Device
const device = try GpuDevice.init(.{});
defer device.deinit();
// 2. Create a GPU Arena to hold GPU memory
var grena = GpuArena.init(allocator, device);
defer grena.deinit();
const gloc = grena.gpuAllocator();
// 3. Create a GPU process that loads the WGSL pipeline/shader
const add = try GpuProcess.init(device, @embedFile("shaders/add.wgsl"));
defer add.deinit();
// 4. Allocate and populate CPU memory
const data_a = try allocator.alloc(f16, 16);
defer allocator.free(data_a);
const data_b = try allocator.alloc(f16, 16);
defer allocator.free(data_b);
for (0..16) |i| {
data_a[i] = @floatFromInt(i);
data_b[i] = @floatFromInt(16 - 1 - i);
}
// 5. Allocate GPU memory (deinit handled automatically by grena)
const a = try Vec.initZero(gloc, 16);
const b = try Vec.initZero(gloc, 16);
// 6. Load CPU -> GPU
try a.load(data_a);
try b.load(data_b);
// 7. Run GPU Pipeline
const sum = try a.run(gloc, b, add);
// 8. Read GPU -> CPU
const out = try sum.read(allocator);
defer allocator.free(out);
std.debug.print("{any}\n", .{out});
}
```
## Dependencies
* **`wgpu.h`**: The library relies on the WebGPU C API headers to bind to the native system graphics.