Module final_blend 

Final blend pipeline: composites primary + secondary chain outputs into the renderer’s display texture.

When no transition is active (secondary == None), the pass behaves as a passthrough of primary.final_texture. When a transition is in flight, it samples both chains’ final_texture and lerps them by progress:

display.rgb = mix(secondary.rgb, primary.rgb, progress)

progress is the Transition::progress eased value in [0, 1]. At progress = 0 the display shows the old preset (the secondary chain, fading out); at progress = 1 the new one (primary, fading in). The eased curve is fed straight from [onedrop_engine::transition].

Cost when no transition is in flight: one fullscreen triangle on a single sampled texture (~0.1 ms at 1080p on a modern GPU). The fallback 1×1 secondary view keeps the bind group layout uniform across both states so we never rebuild the pipeline mid-frame.

Structs

BlendUniforms

Per-pass uniforms: progress is the eased transition value in [0, 1]; has_secondary is 1 when a secondary chain is active, 0 otherwise — keeps the shader from sampling the fallback texture for nothing.

FinalBlendPipeline

Owns the blend pipeline, its bind group, the per-frame uniform buffer, and the display target it writes into. Created once at renderer init and never reallocated; only the bind group is rebuilt when a secondary chain is added or removed.

Constants

SHADER 🔒

Functions

make_bind_group 🔒