Utils

The wgpu library provides a few utilities. Note that most functions below need to be explictly imported.

Logger

Errors, warnings, and info messages (including messages generated by wgpu-native) are logged using Python’s default logging mechanics. The wgpu logger instance is in wgpu.logger, but can also be obtained via:

import logging
logger = logging.getLogger("wgpu")

Diagnostics

To print a full diagnostic report:

wgpu.diagnostics.print_report()

To inspect (for example) the total buffer usage:

>>> counts = wgpu.diagnostics.object_counts.get_dict()
>>> print(counts["Buffer"])
{'count': 3, 'resource_mem': 784}
class wgpu._diagnostics.DiagnosticsRoot

Root object to access wgpu diagnostics (i.e. wgpu.diagnostics).

Per-topic diagnostics can be accessed as attributes on this object. These include system, wgpu_native_info, versions, object_counts, wgpu_natrive_counts.

get_dict()

Get a dict that represents the full diagnostics info.

The keys are the diagnostic topics, and the values are dicts of dicts. See e.g. wgpu.diagnostics.counts.get_dict() for a topic-specific dict.

get_report()

Get the full textual diagnostic report (as a str).

print_report()

Convenience method to print the full diagnostics report.

class wgpu._diagnostics.Diagnostics(name)

Object that represents diagnostics on a specific topic.

This is a base class that must be subclassed to provide diagnostics on a certain topic. Instantiating the class registers it with the root diagnostics object.

get_dict()

Get the diagnostics for this topic, in the form of a Python dict.

Subclasses must implement this method. The dict can be a simple map of keys to values (str, int, float):

foo: 1
bar: 2

If the values are dicts, the data has a table-like layout, with the keys representing the table header:

          count  mem

Adapter:      1  264
 Buffer:      4  704

Subdicts are also supported, which results in multi-row entries. In the report, the keys of the subdicts have colons behind them:

          count  mem  backend  o  v  e  el_size

Adapter:      1  264  vulkan:  1  0  0      264
                       d3d12:  1  0  0      220
 Buffer:      4  704  vulkan:  4  0  0      176
                       d3d12:  0  0  0      154
get_report()

Get the textual diagnostics report for this topic.

get_subscript()

Get informative text that helps interpret the report.

Subclasses can implement this method. The text will show below the table in the report.

print_report()

Print the diagnostics report for this topic.

Get default device

wgpu.utils.get_default_device()

Get a wgpu device object. If this succeeds, it’s likely that the WGPU lib is usable on this system. If not, this call will probably exit (Rust panic). When called multiple times, returns the same global device object (useful for e.g. unit tests).

Compute with buffers

from wgpu.utils.compute import compute_with_buffers
wgpu.utils.compute_with_buffers(*args, **kwargs)

Shadertoy

from wgpu.utils.shadertoy import Shadertoy
class wgpu.utils.shadertoy.Shadertoy(shader_code, resolution=(800, 450), offscreen=False)

Provides a “screen pixel shader programming interface” similar to shadertoy.

It helps you research and quickly build or test shaders using WGSL or GLSL via WGPU.

Parameters:

  • shader_code (str) – The shader code to use.

  • resolution (tuple) – The resolution of the shadertoy.

  • offscreen (bool) – Whether to render offscreen. Default is False.

The shader code must contain a entry point function:

WGSL: fn shader_main(frag_coord: vec2<f32>) -> vec4<f32>{} GLSL: void shader_main(out vec4 frag_color, in vec2 frag_coord){}

It has a parameter frag_coord which is the current pixel coordinate (in range 0..resolution, origin is bottom-left), and it must return a vec4<f32> color (for GLSL, it’s the out vec4 frag_color parameter), which is the color of the pixel at that coordinate.

some built-in variables are available in the shader:

  • i_time: the global time in seconds

  • i_time_delta: the time since last frame in seconds

  • i_frame: the frame number

  • i_resolution: the resolution of the shadertoy

  • i_mouse: the mouse position in pixels

  • i_date: the current date and time as a vec4 (year, month, day, seconds)

For GLSL, you can also use the aliases iTime, iTimeDelta, iFrame, iResolution, iMouse and iDate of these built-in variables, the entry point function also has an alias mainImage, so you can use the shader code copied from shadertoy website without making any changes.

property resolution

The resolution of the shadertoy as a tuple (width, height) in pixels.

property shader_code

The shader code to use.

property shader_type

The shader type, automatically detected from the shader code, can be “wgsl” or “glsl”.

snapshot(time_float: float = 0.0, mouse_pos: tuple = (0, 0, 0, 0))

Returns an image of the specified time. (Only available when offscreen=True)

Parameters:

  • time_float (float) – The time to snapshot. It essentially sets i_time to a specific number. (Default is 0.0)

  • mouse_pos (tuple) – The mouse position in pixels in the snapshot. It essentially sets i_mouse to a 4-tuple. (Default is (0,0,0,0))

Returns:

snapshot with transparancy. This object can be converted to a numpy array (without copying data)

Return type:

frame (memoryview)

using np.asarray(arr)