Offset.h File Reference

The SVG offset filter primitive, expressed in the donner::gpu::shader IR. More...

#include "donner/gpu/shader/IrModule.h"
#include "donner/gpu/shader/programs/OffsetBindings.h"

Include dependency graph for Offset.h:

Namespaces
namespace	donner
	Top-level Donner namespace, which is split into different sub-namespaces such as donner::svg and donner::css.

Functions
ShaderResult< IrModule >	donner::gpu::shader::programs::BuildOffsetModule ()
	Builds the SVG offset filter program: one @compute @workgroup_size(8, 8, 1) entry point named cs_main that reads each destination texel from the source shifted by a whole number of pixels.

Detailed Description

The SVG offset filter primitive, expressed in the donner::gpu::shader IR.

Function Documentation

BuildOffsetModule()

ShaderResult< IrModule > donner::gpu::shader::programs::BuildOffsetModule

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Builds the SVG offset filter program: one @compute @workgroup_size(8, 8, 1) entry point named cs_main that reads each destination texel from the source shifted by a whole number of pixels.

The shift arrives in pixels and is rounded half away from zero, which is what the CPU filter path's std::round does and what WGSL's round does not: round is round-half-to-even and disagrees on every exact half, and a filter chain scaled so a shift lands on one would place the whole primitive a pixel away from the reference. The rounding is the shared recipe rather than a composition written here.

Callers provide finite pixel shifts in [-4096, 4096], matching the filter execution bounds.

Source texels outside the sampled texture produce transparent black. The specification defines no edge behaviour for this primitive, so there is no mode to select.

Invocations outside the destination extent return without writing, so a dispatch rounded up to whole workgroups is safe.